feat: Add automatic price reduction on reposts (#691)

README.md

@@ -384,8 +384,16 @@ description_suffix: # optional suffix to be added to the description overriding
 # or category ID (e.g. 161/278)
 category: # e.g. "Elektronik > Notebooks"
 
-price: # without decimals, e.g. 75
+price: # price in euros; decimals allowed but will be rounded to nearest whole euro on processing (prefer whole euros for predictability)
 price_type: # one of: FIXED, NEGOTIABLE, GIVE_AWAY (default: NEGOTIABLE)
+auto_price_reduction:
+  enabled: # true or false to enable automatic price reduction on reposts (default: false)
+  strategy: # "PERCENTAGE" or "FIXED" (required when enabled is true)
+  amount: # reduction amount; interpreted as percent for PERCENTAGE or currency units for FIXED (prefer whole euros for predictability)
+  min_price: # required when enabled is true; minimum price floor (use 0 for no lower bound, prefer whole euros for predictability)
+  delay_reposts: # number of reposts to wait before first reduction (default: 0)
+  delay_days: # number of days to wait after publication before reductions (default: 0)
+  # NOTE: All prices are rounded to whole euros after each reduction step.
 
 special_attributes:
   # haus_mieten.zimmer_d: value # Zimmer
@@ -428,8 +436,61 @@ id: # the ID assigned by kleinanzeigen.de
 created_on: # ISO timestamp when the ad was first published
 updated_on: # ISO timestamp when the ad was last published
 content_hash: # hash of the ad content, used to detect changes
+repost_count: # how often the ad has been (re)published; used for automatic price reductions
 ```
 
+#### Automatic price reduction on reposts
+
+When `auto_price_reduction.enabled` is set to `true`, the bot lowers the configured `price` every time the ad is reposted. The starting point for the calculation is always the base price from your ad file (the value of `price`), ensuring the first publication uses the unchanged amount. For each repost the bot subtracts either a percentage of the previously published price (strategy: PERCENTAGE) or a fixed amount (strategy: FIXED) and clamps the result to `min_price`.
+
+**Important:** Price reductions only apply when using the `publish` command (which deletes the old ad and creates a new one). Using the `update` command to modify ad content does NOT trigger price reductions or increment `repost_count`.
+
+`repost_count` is tracked for every ad (and persisted inside the corresponding `ad_*.yaml`) so reductions continue across runs.
+
+`min_price` is required whenever `enabled` is `true` and must be less than or equal to `price`; this makes an explicit floor (including `0`) mandatory. If `min_price` equals the current price, the bot will log a warning and perform no reduction.
+
+**Note:** `repost_count` and price reduction counters are only incremented and persisted after a successful publish. Failed publish attempts do not advance the counters.
+
+**PERCENTAGE strategy example:**
+
+```yaml
+price: 150
+price_type: FIXED
+auto_price_reduction:
+  enabled: true
+  strategy: PERCENTAGE
+  amount: 10
+  min_price: 90
+  delay_reposts: 0
+  delay_days: 0
+```
+
+This posts the ad at 150 € the first time, then 135 € (−10%), 122 € (−10%), 110 € (−10%), 99 € (−10%), and stops decreasing at 90 €.
+
+**Note:** The bot applies commercial rounding (ROUND_HALF_UP) to full euros after each reduction step. For example, 121.5 rounds to 122, and 109.8 rounds to 110. This step-wise rounding affects the final price progression, especially for percentage-based reductions.
+
+**FIXED strategy example:**
+
+```yaml
+price: 150
+price_type: FIXED
+auto_price_reduction:
+  enabled: true
+  strategy: FIXED
+  amount: 15
+  min_price: 90
+  delay_reposts: 0
+  delay_days: 0
+```
+
+This posts the ad at 150 € the first time, then 135 € (−15 €), 120 € (−15 €), 105 € (−15 €), and stops decreasing at 90 €.
+
+**Note on `delay_days` behavior:** The `delay_days` parameter counts complete 24-hour periods (whole days) since the ad was published. For example, if `delay_days: 7` and the ad was published 6 days and 23 hours ago, the reduction will not yet apply. This ensures predictable behavior and avoids partial-day ambiguity.
+
+Set `auto_price_reduction.enabled: false` (or omit the entire `auto_price_reduction` section) to keep the existing behaviour—prices stay fixed and `repost_count` only acts as tracked metadata for future changes.
+
+You can configure `auto_price_reduction` once under `ad_defaults` in `config.yaml`. The `min_price` can be set there or overridden per ad file as needed.
+
 ### <a name="description-prefix-suffix"></a>3) Description Prefix and Suffix
 
 You can add prefix and suffix text to your ad descriptions in two ways:

pyproject.toml

@@ -353,7 +353,8 @@ markers = [
   "slow: marks a test as long running",
   "smoke: marks a test as a high-level smoke test (critical path, no mocks)",
   "itest: marks a test as an integration test (i.e. a test with external dependencies)",
-  "asyncio: mark test as async"
+  "asyncio: mark test as async",
+  "unit: marks a test as a unit test"
 ]
 asyncio_mode = "auto"
 asyncio_default_fixture_loop_scope = "function"

schemas/ad.schema.json

@@ -1,5 +1,76 @@
 {
   "$defs": {
+    "AutoPriceReductionConfig": {
+      "properties": {
+        "enabled": {
+          "default": false,
+          "description": "automatically lower the price of reposted ads",
+          "title": "Enabled",
+          "type": "boolean"
+        },
+        "strategy": {
+          "anyOf": [
+            {
+              "enum": [
+                "FIXED",
+                "PERCENTAGE"
+              ],
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "PERCENTAGE reduces by a percentage of the previous price, FIXED reduces by a fixed amount",
+          "title": "Strategy"
+        },
+        "amount": {
+          "anyOf": [
+            {
+              "exclusiveMinimum": 0,
+              "type": "number"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "magnitude of the reduction; interpreted as percent for PERCENTAGE or currency units for FIXED",
+          "title": "Amount"
+        },
+        "min_price": {
+          "anyOf": [
+            {
+              "minimum": 0,
+              "type": "number"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "required when enabled is true; minimum price floor (use 0 for no lower bound)",
+          "title": "Min Price"
+        },
+        "delay_reposts": {
+          "default": 0,
+          "description": "number of reposts to wait before applying the first automatic price reduction",
+          "minimum": 0,
+          "title": "Delay Reposts",
+          "type": "integer"
+        },
+        "delay_days": {
+          "default": 0,
+          "description": "number of days to wait after publication before applying automatic price reductions",
+          "minimum": 0,
+          "title": "Delay Days",
+          "type": "integer"
+        }
+      },
+      "title": "AutoPriceReductionConfig",
+      "type": "object"
+    },
     "ContactPartial": {
       "properties": {
         "name": {
@@ -181,6 +252,32 @@
       "default": null,
       "title": "Price Type"
     },
+    "auto_price_reduction": {
+      "anyOf": [
+        {
+          "$ref": "#/$defs/AutoPriceReductionConfig"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null,
+      "description": "automatic price reduction configuration"
+    },
+    "repost_count": {
+      "default": 0,
+      "description": "number of successful publications for this ad (persisted between runs)",
+      "minimum": 0,
+      "title": "Repost Count",
+      "type": "integer"
+    },
+    "price_reduction_count": {
+      "default": 0,
+      "description": "internal counter: number of automatic price reductions already applied",
+      "minimum": 0,
+      "title": "Price Reduction Count",
+      "type": "integer"
+    },
     "shipping_type": {
       "anyOf": [
         {

schemas/config.schema.json

@@ -64,6 +64,10 @@
           "title": "Price Type",
           "type": "string"
         },
+        "auto_price_reduction": {
+          "$ref": "#/$defs/AutoPriceReductionConfig",
+          "description": "automatic price reduction configuration"
+        },
         "shipping_type": {
           "default": "SHIPPING",
           "enum": [
@@ -107,6 +111,77 @@
       "title": "AdDefaults",
       "type": "object"
     },
+    "AutoPriceReductionConfig": {
+      "properties": {
+        "enabled": {
+          "default": false,
+          "description": "automatically lower the price of reposted ads",
+          "title": "Enabled",
+          "type": "boolean"
+        },
+        "strategy": {
+          "anyOf": [
+            {
+              "enum": [
+                "FIXED",
+                "PERCENTAGE"
+              ],
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "PERCENTAGE reduces by a percentage of the previous price, FIXED reduces by a fixed amount",
+          "title": "Strategy"
+        },
+        "amount": {
+          "anyOf": [
+            {
+              "exclusiveMinimum": 0,
+              "type": "number"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "magnitude of the reduction; interpreted as percent for PERCENTAGE or currency units for FIXED",
+          "title": "Amount"
+        },
+        "min_price": {
+          "anyOf": [
+            {
+              "minimum": 0,
+              "type": "number"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "required when enabled is true; minimum price floor (use 0 for no lower bound)",
+          "title": "Min Price"
+        },
+        "delay_reposts": {
+          "default": 0,
+          "description": "number of reposts to wait before applying the first automatic price reduction",
+          "minimum": 0,
+          "title": "Delay Reposts",
+          "type": "integer"
+        },
+        "delay_days": {
+          "default": 0,
+          "description": "number of days to wait after publication before applying automatic price reductions",
+          "minimum": 0,
+          "title": "Delay Days",
+          "type": "integer"
+        }
+      },
+      "title": "AutoPriceReductionConfig",
+      "type": "object"
+    },
     "BrowserConfig": {
       "properties": {
         "arguments": {

src/kleinanzeigen_bot/__init__.py

@@ -5,6 +5,7 @@ import atexit, enum, json, os, re, signal, sys, textwrap  # isort: skip
 import getopt  # pylint: disable=deprecated-module
 import urllib.parse as urllib_parse
 from gettext import gettext as _
+from pathlib import Path
 from typing import Any, Final
 
 import certifi, colorama, nodriver  # isort: skip
@@ -13,7 +14,7 @@ from wcmatch import glob
 
 from . import extract, resources
 from ._version import __version__
-from .model.ad_model import MAX_DESCRIPTION_LENGTH, Ad, AdPartial
+from .model.ad_model import MAX_DESCRIPTION_LENGTH, Ad, AdPartial, calculate_auto_price
 from .model.config_model import Config
 from .update_checker import UpdateChecker
 from .utils import dicts, error_handlers, loggers, misc
@@ -36,6 +37,145 @@ class AdUpdateStrategy(enum.Enum):
     MODIFY = enum.auto()
 
 
+def _repost_cycle_ready(ad_cfg:Ad, ad_file_relative:str) -> bool:
+    """
+    Check if the repost cycle delay has been satisfied.
+
+    :param ad_cfg: The ad configuration
+    :param ad_file_relative: Relative path to the ad file for logging
+    :return: True if ready to apply price reduction, False otherwise
+    """
+    total_reposts = ad_cfg.repost_count or 0
+    delay_reposts = ad_cfg.auto_price_reduction.delay_reposts
+    applied_cycles = ad_cfg.price_reduction_count or 0
+    eligible_cycles = max(total_reposts - delay_reposts, 0)
+
+    if total_reposts <= delay_reposts:
+        remaining = (delay_reposts + 1) - total_reposts
+        LOG.info(
+            _("Auto price reduction delayed for [%s]: waiting %s more reposts (completed %s, applied %s reductions)"),
+            ad_file_relative,
+            max(remaining, 1),  # Clamp to 1 to avoid showing "0 more reposts" when at threshold
+            total_reposts,
+            applied_cycles
+        )
+        return False
+
+    if eligible_cycles <= applied_cycles:
+        LOG.debug(
+            _("Auto price reduction already applied for [%s]: %s reductions match %s eligible reposts"),
+            ad_file_relative,
+            applied_cycles,
+            eligible_cycles
+        )
+        return False
+
+    return True
+
+
+def _day_delay_elapsed(ad_cfg:Ad, ad_file_relative:str) -> bool:
+    """
+    Check if the day delay has elapsed since the ad was last published.
+
+    :param ad_cfg: The ad configuration
+    :param ad_file_relative: Relative path to the ad file for logging
+    :return: True if the delay has elapsed, False otherwise
+    """
+    delay_days = ad_cfg.auto_price_reduction.delay_days
+    if delay_days == 0:
+        return True
+
+    reference = ad_cfg.updated_on or ad_cfg.created_on
+    if not reference:
+        LOG.info(
+            _("Auto price reduction delayed for [%s]: waiting %s days but publish timestamp missing"),
+            ad_file_relative,
+            delay_days
+        )
+        return False
+
+    # Note: .days truncates to whole days (e.g., 1.9 days -> 1 day)
+    # This is intentional: delays count complete 24-hour periods since publish
+    # Both misc.now() and stored timestamps use UTC (via misc.now()), ensuring consistent calculations
+    elapsed_days = (misc.now() - reference).days
+    if elapsed_days < delay_days:
+        LOG.info(
+            _("Auto price reduction delayed for [%s]: waiting %s days (elapsed %s)"),
+            ad_file_relative,
+            delay_days,
+            elapsed_days
+        )
+        return False
+
+    return True
+
+
+def apply_auto_price_reduction(ad_cfg:Ad, _ad_cfg_orig:dict[str, Any], ad_file_relative:str) -> None:
+    """
+    Apply automatic price reduction to an ad based on repost count and configuration.
+
+    This function modifies ad_cfg in-place, updating the price and price_reduction_count
+    fields when a reduction is applicable.
+
+    :param ad_cfg: The ad configuration to potentially modify
+    :param _ad_cfg_orig: The original ad configuration (unused, kept for compatibility)
+    :param ad_file_relative: Relative path to the ad file for logging
+    """
+    if not ad_cfg.auto_price_reduction.enabled:
+        return
+
+    base_price = ad_cfg.price
+    if base_price is None:
+        LOG.warning(_("Auto price reduction is enabled for [%s] but no price is configured."), ad_file_relative)
+        return
+
+    if ad_cfg.auto_price_reduction.min_price is not None and ad_cfg.auto_price_reduction.min_price == base_price:
+        LOG.warning(
+            _("Auto price reduction is enabled for [%s] but min_price equals price (%s) - no reductions will occur."),
+            ad_file_relative,
+            base_price
+        )
+        return
+
+    if not _repost_cycle_ready(ad_cfg, ad_file_relative):
+        return
+
+    if not _day_delay_elapsed(ad_cfg, ad_file_relative):
+        return
+
+    applied_cycles = ad_cfg.price_reduction_count or 0
+    next_cycle = applied_cycles + 1
+
+    effective_price = calculate_auto_price(
+        base_price = base_price,
+        auto_price_reduction = ad_cfg.auto_price_reduction,
+        target_reduction_cycle = next_cycle
+    )
+
+    if effective_price is None:
+        return
+
+    if effective_price == base_price:
+        # Still increment counter so small fractional reductions can accumulate over multiple cycles
+        ad_cfg.price_reduction_count = next_cycle
+        LOG.info(
+            _("Auto price reduction kept price %s after attempting %s reduction cycles"),
+            effective_price,
+            next_cycle
+        )
+        return
+
+    LOG.info(
+        _("Auto price reduction applied: %s -> %s after %s reduction cycles"),
+        base_price,
+        effective_price,
+        next_cycle
+    )
+    ad_cfg.price = effective_price
+    ad_cfg.price_reduction_count = next_cycle
+    # Note: price_reduction_count is persisted to ad_cfg_orig only after successful publish
+
+
 class KleinanzeigenBot(WebScrapingMixin):
 
     def __init__(self) -> None:
@@ -364,7 +504,11 @@ class KleinanzeigenBot(WebScrapingMixin):
         dicts.save_dict(
             self.config_file_path,
             default_config.model_dump(exclude_none = True, exclude = {"ad_defaults": {"description"}}),
-            header = "# yaml-language-server: $schema=https://raw.githubusercontent.com/Second-Hand-Friends/kleinanzeigen-bot/refs/heads/main/schemas/config.schema.json"
+            header = (
+                "# yaml-language-server: $schema="
+                "https://raw.githubusercontent.com/Second-Hand-Friends/kleinanzeigen-bot"
+                "/refs/heads/main/schemas/config.schema.json"
+            )
         )
 
     def load_config(self) -> None:
@@ -571,6 +715,18 @@ class KleinanzeigenBot(WebScrapingMixin):
     def load_ad(self, ad_cfg_orig:dict[str, Any]) -> Ad:
         return AdPartial.model_validate(ad_cfg_orig).to_ad(self.config.ad_defaults)
 
+    def __apply_auto_price_reduction(self, ad_cfg:Ad, _ad_cfg_orig:dict[str, Any], ad_file_relative:str) -> None:
+        """Delegate to the module-level function."""
+        apply_auto_price_reduction(ad_cfg, _ad_cfg_orig, ad_file_relative)
+
+    def __repost_cycle_ready(self, ad_cfg:Ad, ad_file_relative:str) -> bool:
+        """Delegate to the module-level function."""
+        return _repost_cycle_ready(ad_cfg, ad_file_relative)
+
+    def __day_delay_elapsed(self, ad_cfg:Ad, ad_file_relative:str) -> bool:
+        """Delegate to the module-level function."""
+        return _day_delay_elapsed(ad_cfg, ad_file_relative)
+
     async def check_and_wait_for_captcha(self, *, is_login_page:bool = True) -> None:
         try:
             captcha_timeout = self._timeout("captcha_detection")
@@ -775,6 +931,15 @@ class KleinanzeigenBot(WebScrapingMixin):
             if self.config.publishing.delete_old_ads == "BEFORE_PUBLISH" and not self.keep_old_ads:
                 await self.delete_ad(ad_cfg, published_ads, delete_old_ads_by_title = self.config.publishing.delete_old_ads_by_title)
 
+            # Apply auto price reduction only for REPLACE operations (actual reposts)
+            # This ensures price reductions only happen on republish, not on UPDATE
+            try:
+                ad_file_relative = str(Path(ad_file).relative_to(Path(self.config_file_path).parent))
+            except ValueError:
+                # On Windows, relative_to fails when paths are on different drives
+                ad_file_relative = ad_file
+            self.__apply_auto_price_reduction(ad_cfg, ad_cfg_orig, ad_file_relative)
+
             LOG.info("Publishing ad '%s'...", ad_cfg.title)
             await self.web_open(f"{self.root_url}/p-anzeige-aufgeben-schritt2.html")
         else:
@@ -979,6 +1144,22 @@ class KleinanzeigenBot(WebScrapingMixin):
         if not ad_cfg.created_on and not ad_cfg.id:
             ad_cfg_orig["created_on"] = ad_cfg_orig["updated_on"]
 
+        # Increment repost_count and persist price_reduction_count only for REPLACE operations (actual reposts)
+        # This ensures counters only advance on republish, not on UPDATE
+        if mode == AdUpdateStrategy.REPLACE:
+            # Increment repost_count after successful publish
+            # Note: This happens AFTER publish, so price reduction logic (which runs before publish)
+            # sees the count from the PREVIOUS run. This is intentional: the first publish uses
+            # repost_count=0 (no reduction), the second publish uses repost_count=1 (first reduction), etc.
+            current_reposts = int(ad_cfg_orig.get("repost_count", ad_cfg.repost_count or 0))
+            ad_cfg_orig["repost_count"] = current_reposts + 1
+            ad_cfg.repost_count = ad_cfg_orig["repost_count"]
+
+            # Persist price_reduction_count after successful publish
+            # This ensures failed publishes don't incorrectly increment the reduction counter
+            if ad_cfg.price_reduction_count is not None and ad_cfg.price_reduction_count > 0:
+                ad_cfg_orig["price_reduction_count"] = ad_cfg.price_reduction_count
+
         if mode == AdUpdateStrategy.REPLACE:
             LOG.info(" -> SUCCESS: ad published with ID %s", ad_id)
         else:

src/kleinanzeigen_bot/model/ad_model.py

@@ -4,18 +4,22 @@
 from __future__ import annotations
 
 import hashlib, json  # isort: skip
+from collections.abc import Mapping, Sequence
 from datetime import datetime  # noqa: TC003 Move import into a type-checking block
-from typing import Annotated, Any, Dict, Final, List, Literal, Mapping, Sequence
+from decimal import ROUND_CEILING, ROUND_HALF_UP, Decimal
+from gettext import gettext as _
+from typing import Annotated, Any, Final, Literal
 
 from pydantic import AfterValidator, Field, field_validator, model_validator
 from typing_extensions import Self
 
-from kleinanzeigen_bot.model.config_model import AdDefaults  # noqa: TC001 Move application import into a type-checking block
+from kleinanzeigen_bot.model.config_model import AdDefaults, AutoPriceReductionConfig  # noqa: TC001 Move application import into a type-checking block
 from kleinanzeigen_bot.utils import dicts
 from kleinanzeigen_bot.utils.misc import parse_datetime, parse_decimal
 from kleinanzeigen_bot.utils.pydantics import ContextualModel
 
 MAX_DESCRIPTION_LENGTH:Final[int] = 4000
+EURO_PRECISION:Final[Decimal] = Decimal("1")
 
 
 def _OPTIONAL() -> Any:
@@ -61,6 +65,45 @@ def _validate_shipping_option_item(v:str) -> str:
 ShippingOption = Annotated[str, AfterValidator(_validate_shipping_option_item)]
 
 
+def _validate_auto_price_reduction_constraints(
+    price:int | None,
+    auto_price_reduction:AutoPriceReductionConfig | dict[str, Any] | None
+) -> None:
+    """
+    Validate auto_price_reduction configuration constraints.
+
+    Raises ValueError if:
+    - auto_price_reduction is enabled but price is None
+    - min_price exceeds price
+    """
+    if not auto_price_reduction:
+        return
+
+    # Handle both dict (from before validation) and AutoPriceReductionConfig (after validation)
+    if isinstance(auto_price_reduction, dict):
+        enabled = auto_price_reduction.get("enabled", False)
+        min_price = auto_price_reduction.get("min_price")
+    else:
+        enabled = auto_price_reduction.enabled
+        min_price = auto_price_reduction.min_price
+
+    if not enabled:
+        return
+
+    if price is None:
+        raise ValueError(_("price must be specified when auto_price_reduction is enabled"))
+
+    if min_price is not None:
+        try:
+            min_price_dec = Decimal(str(min_price))
+            price_dec = Decimal(str(price))
+        except Exception:
+            # Let Pydantic's type validation surface the underlying issue
+            return
+        if min_price_dec > price_dec:
+            raise ValueError(_("min_price must not exceed price"))
+
+
 class AdPartial(ContextualModel):
     active:bool | None = _OPTIONAL()
     type:Literal["OFFER", "WANTED"] | None = _OPTIONAL()
@@ -69,14 +112,28 @@ class AdPartial(ContextualModel):
     description_prefix:str | None = _OPTIONAL()
     description_suffix:str | None = _OPTIONAL()
     category:str
-    special_attributes:Dict[str, str] | None = _OPTIONAL()
+    special_attributes:dict[str, str] | None = _OPTIONAL()
     price:int | None = _OPTIONAL()
     price_type:Literal["FIXED", "NEGOTIABLE", "GIVE_AWAY", "NOT_APPLICABLE"] | None = _OPTIONAL()
+    auto_price_reduction:AutoPriceReductionConfig | None = Field(
+        default = None,
+        description = "automatic price reduction configuration"
+    )
+    repost_count:int = Field(
+        default = 0,
+        ge = 0,
+        description = "number of successful publications for this ad (persisted between runs)"
+    )
+    price_reduction_count:int = Field(
+        default = 0,
+        ge = 0,
+        description = "internal counter: number of automatic price reductions already applied"
+    )
     shipping_type:Literal["PICKUP", "SHIPPING", "NOT_APPLICABLE"] | None = _OPTIONAL()
     shipping_costs:float | None = _OPTIONAL()
-    shipping_options:List[ShippingOption] | None = _OPTIONAL()
+    shipping_options:list[ShippingOption] | None = _OPTIONAL()
     sell_directly:bool | None = _OPTIONAL()
-    images:List[str] | None = _OPTIONAL()
+    images:list[str] | None = _OPTIONAL()
     contact:ContactPartial | None = _OPTIONAL()
     republication_interval:int | None = _OPTIONAL()
 
@@ -106,13 +163,19 @@ class AdPartial(ContextualModel):
 
     @model_validator(mode = "before")
     @classmethod
-    def _validate_price_and_price_type(cls, values:Dict[str, Any]) -> Dict[str, Any]:
+    def _validate_price_and_price_type(cls, values:dict[str, Any]) -> dict[str, Any]:
         price_type = values.get("price_type")
         price = values.get("price")
+        auto_price_reduction = values.get("auto_price_reduction")
+
         if price_type == "GIVE_AWAY" and price is not None:
             raise ValueError("price must not be specified when price_type is GIVE_AWAY")
         if price_type == "FIXED" and price is None:
             raise ValueError("price is required when price_type is FIXED")
+
+        # Validate auto_price_reduction configuration
+        _validate_auto_price_reduction_constraints(price, auto_price_reduction)
+
         return values
 
     def update_content_hash(self) -> Self:
@@ -120,7 +183,14 @@ class AdPartial(ContextualModel):
 
         # 1) Dump to a plain dict, excluding the metadata fields:
         raw = self.model_dump(
-            exclude = {"id", "created_on", "updated_on", "content_hash"},
+            exclude = {
+                "id",
+                "created_on",
+                "updated_on",
+                "content_hash",
+                "repost_count",
+                "price_reduction_count",
+            },
             exclude_none = True,
             exclude_unset = True,
         )
@@ -162,11 +232,70 @@ class AdPartial(ContextualModel):
             target = ad_cfg,
             defaults = ad_defaults.model_dump(),
             ignore = lambda k, _: k == "description",  # ignore legacy global description config
-            override = lambda _, v: not isinstance(v, list) and v in {None, ""}  # noqa: PLC1901 can be simplified
+            override = lambda _, v: (
+                not isinstance(v, list) and (v is None or (isinstance(v, str) and v == ""))  # noqa: PLC1901
+            )
         )
+        # Ensure internal counters are integers (not user-configurable)
+        if not isinstance(ad_cfg.get("price_reduction_count"), int):
+            ad_cfg["price_reduction_count"] = 0
+        if not isinstance(ad_cfg.get("repost_count"), int):
+            ad_cfg["repost_count"] = 0
         return Ad.model_validate(ad_cfg)
 
 
+def calculate_auto_price(
+    *,
+    base_price:int | float | None,
+    auto_price_reduction:AutoPriceReductionConfig | None,
+    target_reduction_cycle:int
+) -> int | None:
+    """
+    Calculate the effective price for the current run using commercial rounding.
+
+    Args:
+        base_price: original configured price used as the starting point.
+        auto_price_reduction: reduction configuration (enabled, strategy, amount, min_price, delays).
+        target_reduction_cycle: which reduction cycle to calculate the price for (0 = no reduction, 1 = first reduction, etc.).
+
+    Percentage reductions apply to the current price each cycle (compounded). Each reduction step is rounded
+    to full euros (commercial rounding with ROUND_HALF_UP) before the next reduction is applied.
+    Returns an int representing whole euros, or None when base_price is None.
+    """
+    if base_price is None:
+        return None
+
+    price = Decimal(str(base_price))
+
+    if not auto_price_reduction or not auto_price_reduction.enabled or target_reduction_cycle <= 0:
+        return int(price.quantize(EURO_PRECISION, rounding = ROUND_HALF_UP))
+
+    if auto_price_reduction.strategy is None or auto_price_reduction.amount is None:
+        return int(price.quantize(EURO_PRECISION, rounding = ROUND_HALF_UP))
+
+    if auto_price_reduction.min_price is None:
+        raise ValueError(_("min_price must be specified when auto_price_reduction is enabled"))
+
+    # Prices are published as whole euros; ensure the configured floor cannot be undercut by int() conversion.
+    price_floor = Decimal(str(auto_price_reduction.min_price)).quantize(EURO_PRECISION, rounding = ROUND_CEILING)
+    repost_cycles = target_reduction_cycle
+
+    for _cycle in range(repost_cycles):
+        reduction_value = (
+            price * Decimal(str(auto_price_reduction.amount)) / Decimal("100")
+            if auto_price_reduction.strategy == "PERCENTAGE"
+            else Decimal(str(auto_price_reduction.amount))
+        )
+        price -= reduction_value
+        # Commercial rounding: round to full euros after each reduction step
+        price = price.quantize(EURO_PRECISION, rounding = ROUND_HALF_UP)
+        if price <= price_floor:
+            price = price_floor
+            break
+
+    return int(price)
+
+
 # pyright: reportGeneralTypeIssues=false, reportIncompatibleVariableOverride=false
 class Contact(ContactPartial):
     name:str
@@ -183,3 +312,12 @@ class Ad(AdPartial):
     sell_directly:bool
     contact:Contact
     republication_interval:int
+    auto_price_reduction:AutoPriceReductionConfig = Field(default_factory = AutoPriceReductionConfig)
+    price_reduction_count:int = 0
+
+    @model_validator(mode = "after")
+    def _validate_auto_price_config(self) -> "Ad":
+        # Validate the final Ad object after merging with defaults
+        # This ensures the merged configuration is valid even if raw YAML had None values
+        _validate_auto_price_reduction_constraints(self.price, self.auto_price_reduction)
+        return self

src/kleinanzeigen_bot/model/config_model.py

@@ -4,7 +4,8 @@
 from __future__ import annotations
 
 import copy
-from typing import Annotated, Any, List, Literal
+from gettext import gettext as _
+from typing import Annotated, Any, Final, Literal
 
 from pydantic import AfterValidator, Field, model_validator
 from typing_extensions import deprecated
@@ -14,6 +15,52 @@ from kleinanzeigen_bot.utils import dicts
 from kleinanzeigen_bot.utils.misc import get_attr
 from kleinanzeigen_bot.utils.pydantics import ContextualModel
 
+_MAX_PERCENTAGE:Final[int] = 100
+
+
+class AutoPriceReductionConfig(ContextualModel):
+    enabled:bool = Field(
+        default = False,
+        description = "automatically lower the price of reposted ads"
+    )
+    strategy:Literal["FIXED", "PERCENTAGE"] | None = Field(
+        default = None,
+        description = "PERCENTAGE reduces by a percentage of the previous price, FIXED reduces by a fixed amount"
+    )
+    amount:float | None = Field(
+        default = None,
+        gt = 0,
+        description = "magnitude of the reduction; interpreted as percent for PERCENTAGE or currency units for FIXED"
+    )
+    min_price:float | None = Field(
+        default = None,
+        ge = 0,
+        description = "required when enabled is true; minimum price floor (use 0 for no lower bound)"
+    )
+    delay_reposts:int = Field(
+        default = 0,
+        ge = 0,
+        description = "number of reposts to wait before applying the first automatic price reduction"
+    )
+    delay_days:int = Field(
+        default = 0,
+        ge = 0,
+        description = "number of days to wait after publication before applying automatic price reductions"
+    )
+
+    @model_validator(mode = "after")
+    def _validate_config(self) -> "AutoPriceReductionConfig":
+        if self.enabled:
+            if self.strategy is None:
+                raise ValueError(_("strategy must be specified when auto_price_reduction is enabled"))
+            if self.amount is None:
+                raise ValueError(_("amount must be specified when auto_price_reduction is enabled"))
+            if self.min_price is None:
+                raise ValueError(_("min_price must be specified when auto_price_reduction is enabled"))
+            if self.strategy == "PERCENTAGE" and self.amount > _MAX_PERCENTAGE:
+                raise ValueError(_("Percentage reduction amount must not exceed %s") % _MAX_PERCENTAGE)
+        return self
+
 
 class ContactDefaults(ContextualModel):
     name:str | None = None
@@ -35,9 +82,13 @@ class AdDefaults(ContextualModel):
     description_prefix:str | None = Field(default = None, description = "prefix for the ad description")
     description_suffix:str | None = Field(default = None, description = " suffix for the ad description")
     price_type:Literal["FIXED", "NEGOTIABLE", "GIVE_AWAY", "NOT_APPLICABLE"] = "NEGOTIABLE"
+    auto_price_reduction:AutoPriceReductionConfig = Field(
+        default_factory = AutoPriceReductionConfig,
+        description = "automatic price reduction configuration"
+    )
     shipping_type:Literal["PICKUP", "SHIPPING", "NOT_APPLICABLE"] = "SHIPPING"
     sell_directly:bool = Field(default = False, description = "requires shipping_type SHIPPING to take effect")
-    images:List[str] | None = Field(default = None)
+    images:list[str] | None = Field(default = None)
     contact:ContactDefaults = Field(default_factory = ContactDefaults)
     republication_interval:int = 7
 
@@ -62,7 +113,7 @@ class DownloadConfig(ContextualModel):
         default = False,
         description = "if true, all shipping options matching the package size will be included"
     )
-    excluded_shipping_options:List[str] = Field(
+    excluded_shipping_options:list[str] = Field(
         default_factory = list,
         description = "list of shipping options to exclude, e.g. ['DHL_2', 'DHL_5']"
     )
@@ -79,7 +130,7 @@ class DownloadConfig(ContextualModel):
 
 
 class BrowserConfig(ContextualModel):
-    arguments:List[str] = Field(
+    arguments:list[str] = Field(
         default_factory = lambda: ["--user-data-dir=.temp/browser-profile"],
         description = "See https://peter.sh/experiments/chromium-command-line-switches/"
     )
@@ -87,7 +138,7 @@ class BrowserConfig(ContextualModel):
         default = None,
         description = "path to custom browser executable, if not specified will be looked up on PATH"
     )
-    extensions:List[str] = Field(
+    extensions:list[str] = Field(
         default_factory = list,
         description = "a list of .crx extension files to be loaded"
     )
@@ -175,7 +226,7 @@ GlobPattern = Annotated[str, AfterValidator(_validate_glob_pattern)]
 
 
 class Config(ContextualModel):
-    ad_files:List[GlobPattern] = Field(
+    ad_files:list[GlobPattern] = Field(
         default_factory = lambda: ["./**/ad_*.{json,yml,yaml}"],
         min_items = 1,
         description = """

src/kleinanzeigen_bot/resources/translations.de.yaml

@@ -96,6 +96,17 @@ kleinanzeigen_bot/__init__.py:
     "Skipping because ad is reserved": "Überspringen, da Anzeige reserviert ist"
     "DONE: (Re-)published %s": "FERTIG: %s (erneut) veröffentlicht"
     "ad": "Anzeige"
+  apply_auto_price_reduction:
+    "Auto price reduction is enabled for [%s] but no price is configured.": "Automatische Preisreduzierung ist für [%s] aktiviert, aber es wurde kein Preis konfiguriert."
+    "Auto price reduction is enabled for [%s] but min_price equals price (%s) - no reductions will occur.": "Automatische Preisreduzierung ist für [%s] aktiviert, aber min_price entspricht dem Preis (%s) - es werden keine Reduktionen auftreten."
+    "Auto price reduction applied: %s -> %s after %s reduction cycles": "Automatische Preisreduzierung angewendet: %s -> %s nach %s Reduktionszyklen"
+    "Auto price reduction kept price %s after attempting %s reduction cycles": "Automatische Preisreduzierung hat Preis %s beibehalten nach dem Versuch von %s Reduktionszyklen"
+  _repost_cycle_ready:
+    "Auto price reduction delayed for [%s]: waiting %s more reposts (completed %s, applied %s reductions)": "Automatische Preisreduzierung für [%s] verzögert: Warte %s weitere erneute Veröffentlichungen (abgeschlossen %s, angewendet %s Reduktionen)"
+    "Auto price reduction already applied for [%s]: %s reductions match %s eligible reposts": "Automatische Preisreduzierung für [%s] bereits angewendet: %s Reduktionen entsprechen %s berechtigten erneuten Veröffentlichungen"
+  _day_delay_elapsed:
+    "Auto price reduction delayed for [%s]: waiting %s days (elapsed %s)": "Automatische Preisreduzierung für [%s] verzögert: Warte %s Tage (vergangen %s)"
+    "Auto price reduction delayed for [%s]: waiting %s days but publish timestamp missing": "Automatische Preisreduzierung für [%s] verzögert: Warte %s Tage, aber Zeitstempel der Veröffentlichung fehlt"
 
   publish_ad:
     "Publishing ad '%s'...": "Veröffentliche Anzeige '%s'..."
@@ -531,6 +542,24 @@ kleinanzeigen_bot/update_checker.py:
     ? "You are on a different commit than the release for channel '%s' (tag: %s). This may mean you are ahead, behind, or on a different branch. Local commit: %s (%s UTC), Release commit: %s (%s UTC)"
     : "Sie befinden sich auf einem anderen Commit als das Release für Kanal '%s' (Tag: %s). Dies kann bedeuten, dass Sie voraus, hinterher oder auf einem anderen Branch sind. Lokaler Commit: %s (%s UTC), Release-Commit: %s (%s UTC)"
 
+#################################################
+kleinanzeigen_bot/model/config_model.py:
+#################################################
+  _validate_config:
+    "strategy must be specified when auto_price_reduction is enabled": "strategy muss angegeben werden, wenn auto_price_reduction aktiviert ist"
+    "amount must be specified when auto_price_reduction is enabled": "amount muss angegeben werden, wenn auto_price_reduction aktiviert ist"
+    "min_price must be specified when auto_price_reduction is enabled": "min_price muss angegeben werden, wenn auto_price_reduction aktiviert ist"
+    "Percentage reduction amount must not exceed %s": "Prozentuale Reduktionsmenge darf %s nicht überschreiten"
+
+#################################################
+kleinanzeigen_bot/model/ad_model.py:
+#################################################
+  _validate_auto_price_reduction_constraints:
+    "price must be specified when auto_price_reduction is enabled": "price muss angegeben werden, wenn auto_price_reduction aktiviert ist"
+    "min_price must not exceed price": "min_price darf price nicht überschreiten"
+  calculate_auto_price:
+    "min_price must be specified when auto_price_reduction is enabled": "min_price muss angegeben werden, wenn auto_price_reduction aktiviert ist"
+
 #################################################
 kleinanzeigen_bot/model/update_check_state.py:
 #################################################

src/kleinanzeigen_bot/utils/pydantics.py

@@ -192,6 +192,14 @@ def __get_message_template(error_code:str) -> str | None:
         case "decimal_max_digits": return _("Decimal input should have no more than {max_digits} digit{expected_plural} in total")
         case "decimal_max_places": return _("Decimal input should have no more than {decimal_places} decimal place{expected_plural}")
         case "decimal_whole_digits": return _("Decimal input should have no more than {whole_digits} digit{expected_plural} before the decimal point")
-        case "complex_type": return _("Input should be a valid python complex object, a number, or a valid complex string following the rules at https://docs.python.org/3/library/functions.html#complex")
-        case "complex_str_parsing": return _("Input should be a valid complex string following the rules at https://docs.python.org/3/library/functions.html#complex")
+        case "complex_type":
+            return _(
+                "Input should be a valid python complex object, a number, or a valid complex string "
+                "following the rules at https://docs.python.org/3/library/functions.html#complex"
+            )
+        case "complex_str_parsing":
+            return _(
+                "Input should be a valid complex string following the rules at "
+                "https://docs.python.org/3/library/functions.html#complex"
+            )
         case _: return None

tests/unit/test_ad_model.py

@@ -1,11 +1,18 @@
 # SPDX-FileCopyrightText: © Sebastian Thomschke and contributors
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # SPDX-ArtifactOfProjectHomePage: https://github.com/Second-Hand-Friends/kleinanzeigen-bot/
+from __future__ import annotations
+
 import math
 
-from kleinanzeigen_bot.model.ad_model import AdPartial
+import pytest
+
+from kleinanzeigen_bot.model.ad_model import MAX_DESCRIPTION_LENGTH, Ad, AdPartial, ShippingOption, calculate_auto_price
+from kleinanzeigen_bot.model.config_model import AdDefaults, AutoPriceReductionConfig
+from kleinanzeigen_bot.utils.pydantics import ContextualModel, ContextualValidationError
 
 
+@pytest.mark.unit
 def test_update_content_hash() -> None:
     minimal_ad_cfg = {
         "id": "123456789",
@@ -41,6 +48,37 @@ def test_update_content_hash() -> None:
     }).update_content_hash().content_hash != minimal_ad_cfg_hash
 
 
+@pytest.mark.unit
+def test_price_reduction_count_does_not_influence_content_hash() -> None:
+    base_ad_cfg = {
+        "id": "123456789",
+        "title": "Test Ad Title",
+        "category": "160",
+        "description": "Test Description",
+        "price_type": "NEGOTIABLE",
+    }
+
+    hash_without_reposts = AdPartial.model_validate(base_ad_cfg | {"price_reduction_count": 0}).update_content_hash().content_hash
+    hash_with_reposts = AdPartial.model_validate(base_ad_cfg | {"price_reduction_count": 5}).update_content_hash().content_hash
+    assert hash_without_reposts == hash_with_reposts
+
+
+@pytest.mark.unit
+def test_repost_count_does_not_influence_content_hash() -> None:
+    base_ad_cfg = {
+        "id": "123456789",
+        "title": "Test Ad Title",
+        "category": "160",
+        "description": "Test Description",
+        "price_type": "NEGOTIABLE",
+    }
+
+    hash_without_reposts = AdPartial.model_validate(base_ad_cfg | {"repost_count": 0}).update_content_hash().content_hash
+    hash_with_reposts = AdPartial.model_validate(base_ad_cfg | {"repost_count": 5}).update_content_hash().content_hash
+    assert hash_without_reposts == hash_with_reposts
+
+
+@pytest.mark.unit
 def test_shipping_costs() -> None:
     minimal_ad_cfg = {
         "id": "123456789",
@@ -60,3 +98,337 @@ def test_shipping_costs() -> None:
     assert AdPartial.model_validate(minimal_ad_cfg | {"shipping_costs": " "}).shipping_costs is None
     assert AdPartial.model_validate(minimal_ad_cfg | {"shipping_costs": None}).shipping_costs is None
     assert AdPartial.model_validate(minimal_ad_cfg).shipping_costs is None
+
+
+class ShippingOptionWrapper(ContextualModel):
+    option:ShippingOption
+
+
+@pytest.mark.unit
+def test_shipping_option_must_not_be_blank() -> None:
+    with pytest.raises(ContextualValidationError, match = "must be non-empty and non-blank"):
+        ShippingOptionWrapper.model_validate({"option": " "})
+
+
+@pytest.mark.unit
+def test_description_length_limit() -> None:
+    cfg = {
+        "title": "Description Length",
+        "category": "160",
+        "description": "x" * (MAX_DESCRIPTION_LENGTH + 1)
+    }
+
+    with pytest.raises(ContextualValidationError, match = f"description length exceeds {MAX_DESCRIPTION_LENGTH} characters"):
+        AdPartial.model_validate(cfg)
+
+
+@pytest.fixture
+def base_ad_cfg() -> dict[str, object]:
+    return {
+        "title": "Test Ad Title",
+        "category": "160",
+        "description": "Test Description",
+        "price_type": "NEGOTIABLE",
+        "contact": {"name": "Test User", "zipcode": "12345"},
+        "shipping_type": "PICKUP",
+        "sell_directly": False,
+        "type": "OFFER",
+        "active": True
+    }
+
+
+@pytest.fixture
+def complete_ad_cfg(base_ad_cfg:dict[str, object]) -> dict[str, object]:
+    return base_ad_cfg | {
+        "republication_interval": 7,
+        "price": 100,
+        "auto_price_reduction": {
+            "enabled": True,
+            "strategy": "FIXED",
+            "amount": 5,
+            "min_price": 50,
+            "delay_reposts": 0,
+            "delay_days": 0
+        }
+    }
+
+
+class SparseDumpAdPartial(AdPartial):
+    def model_dump(self, *args:object, **kwargs:object) -> dict[str, object]:
+        data = super().model_dump(*args, **kwargs)  # type: ignore[arg-type]
+        data.pop("price_reduction_count", None)
+        data.pop("repost_count", None)
+        return data
+
+
+@pytest.mark.unit
+def test_auto_reduce_requires_price(base_ad_cfg:dict[str, object]) -> None:
+    cfg = base_ad_cfg.copy() | {
+        "auto_price_reduction": {
+            "enabled": True,
+            "strategy": "FIXED",
+            "amount": 5,
+            "min_price": 50
+        }
+    }
+    with pytest.raises(ContextualValidationError, match = "price must be specified"):
+        AdPartial.model_validate(cfg).to_ad(AdDefaults())
+
+
+@pytest.mark.unit
+def test_auto_reduce_requires_strategy(base_ad_cfg:dict[str, object]) -> None:
+    cfg = base_ad_cfg.copy() | {
+        "price": 100,
+        "auto_price_reduction": {
+            "enabled": True,
+            "min_price": 50
+        }
+    }
+    with pytest.raises(ContextualValidationError, match = "strategy must be specified"):
+        AdPartial.model_validate(cfg).to_ad(AdDefaults())
+
+
+@pytest.mark.unit
+def test_prepare_ad_model_fills_missing_counters(base_ad_cfg:dict[str, object]) -> None:
+    cfg = base_ad_cfg.copy() | {
+        "price": 120,
+        "shipping_type": "SHIPPING",
+        "sell_directly": False
+    }
+    ad = AdPartial.model_validate(cfg).to_ad(AdDefaults())
+
+    assert ad.auto_price_reduction.delay_reposts == 0
+    assert ad.auto_price_reduction.delay_days == 0
+    assert ad.price_reduction_count == 0
+    assert ad.repost_count == 0
+
+
+@pytest.mark.unit
+def test_min_price_must_not_exceed_price(base_ad_cfg:dict[str, object]) -> None:
+    cfg = base_ad_cfg.copy() | {
+        "price": 100,
+        "auto_price_reduction": {
+            "enabled": True,
+            "strategy": "FIXED",
+            "amount": 5,
+            "min_price": 120
+        }
+    }
+    with pytest.raises(ContextualValidationError, match = "min_price must not exceed price"):
+        AdPartial.model_validate(cfg)
+
+
+@pytest.mark.unit
+def test_min_price_validation_defers_to_pydantic_for_invalid_types(base_ad_cfg:dict[str, object]) -> None:
+    # Test that invalid price/min_price types are handled gracefully
+    # The safe Decimal comparison should catch conversion errors and defer to Pydantic
+    cfg = base_ad_cfg.copy() | {
+        "price": "not_a_number",
+        "auto_price_reduction": {
+            "enabled": True,
+            "strategy": "FIXED",
+            "amount": 5,
+            "min_price": 100
+        }
+    }
+    # Should raise Pydantic validation error for invalid price type, not our custom validation error
+    with pytest.raises(ContextualValidationError):
+        AdPartial.model_validate(cfg)
+
+    # Test with invalid min_price type
+    cfg2 = base_ad_cfg.copy() | {
+        "price": 100,
+        "auto_price_reduction": {
+            "enabled": True,
+            "strategy": "FIXED",
+            "amount": 5,
+            "min_price": "invalid"
+        }
+    }
+    # Should raise Pydantic validation error for invalid min_price type
+    with pytest.raises(ContextualValidationError):
+        AdPartial.model_validate(cfg2)
+
+
+@pytest.mark.unit
+def test_auto_reduce_requires_min_price(base_ad_cfg:dict[str, object]) -> None:
+    cfg = base_ad_cfg.copy() | {
+        "price": 100,
+        "auto_price_reduction": {
+            "enabled": True,
+            "strategy": "FIXED",
+            "amount": 5
+        }
+    }
+    with pytest.raises(ContextualValidationError, match = "min_price must be specified"):
+        AdPartial.model_validate(cfg).to_ad(AdDefaults())
+
+
+@pytest.mark.unit
+def test_to_ad_stabilizes_counters_when_defaults_omit(base_ad_cfg:dict[str, object]) -> None:
+    cfg = base_ad_cfg.copy() | {
+        "republication_interval": 7,
+        "price": 120
+    }
+    ad = AdPartial.model_validate(cfg).to_ad(AdDefaults())
+
+    assert ad.auto_price_reduction.delay_reposts == 0
+    assert ad.auto_price_reduction.delay_days == 0
+    assert ad.price_reduction_count == 0
+    assert ad.repost_count == 0
+
+
+@pytest.mark.unit
+def test_to_ad_sets_zero_when_counts_missing_from_dump(base_ad_cfg:dict[str, object]) -> None:
+    cfg = base_ad_cfg.copy() | {
+        "republication_interval": 7,
+        "price": 130
+    }
+    ad = SparseDumpAdPartial.model_validate(cfg).to_ad(AdDefaults())
+
+    assert ad.price_reduction_count == 0
+    assert ad.repost_count == 0
+
+
+@pytest.mark.unit
+def test_ad_model_auto_reduce_requires_price(complete_ad_cfg:dict[str, object]) -> None:
+    cfg = complete_ad_cfg.copy() | {"price": None}
+    with pytest.raises(ContextualValidationError, match = "price must be specified"):
+        Ad.model_validate(cfg)
+
+
+@pytest.mark.unit
+def test_ad_model_auto_reduce_requires_strategy(complete_ad_cfg:dict[str, object]) -> None:
+    cfg_copy = complete_ad_cfg.copy()
+    cfg_copy["auto_price_reduction"] = {
+        "enabled": True,
+        "min_price": 50
+    }
+    with pytest.raises(ContextualValidationError, match = "strategy must be specified"):
+        Ad.model_validate(cfg_copy)
+
+
+@pytest.mark.unit
+def test_price_reduction_delay_inherited_from_defaults(complete_ad_cfg:dict[str, object]) -> None:
+    # When auto_price_reduction is not specified in ad config, it inherits from defaults
+    cfg = complete_ad_cfg.copy()
+    cfg.pop("auto_price_reduction", None)  # Remove to inherit from defaults
+    defaults = AdDefaults(
+        auto_price_reduction = AutoPriceReductionConfig(
+            enabled = True,
+            strategy = "FIXED",
+            amount = 5,
+            min_price = 50,
+            delay_reposts = 4,
+            delay_days = 0
+        )
+    )
+    ad = AdPartial.model_validate(cfg).to_ad(defaults)
+    assert ad.auto_price_reduction.delay_reposts == 4
+
+
+@pytest.mark.unit
+def test_price_reduction_delay_override_zero(complete_ad_cfg:dict[str, object]) -> None:
+    cfg = complete_ad_cfg.copy()
+    # Type-safe way to modify nested dict
+    cfg["auto_price_reduction"] = {
+        "enabled": True,
+        "strategy": "FIXED",
+        "amount": 5,
+        "min_price": 50,
+        "delay_reposts": 0,
+        "delay_days": 0
+    }
+    defaults = AdDefaults(
+        auto_price_reduction = AutoPriceReductionConfig(
+            enabled = True,
+            strategy = "FIXED",
+            amount = 5,
+            min_price = 50,
+            delay_reposts = 4,
+            delay_days = 0
+        )
+    )
+    ad = AdPartial.model_validate(cfg).to_ad(defaults)
+    assert ad.auto_price_reduction.delay_reposts == 0
+
+
+@pytest.mark.unit
+def test_ad_model_auto_reduce_requires_min_price(complete_ad_cfg:dict[str, object]) -> None:
+    cfg_copy = complete_ad_cfg.copy()
+    cfg_copy["auto_price_reduction"] = {
+        "enabled": True,
+        "strategy": "FIXED",
+        "amount": 5
+    }
+    with pytest.raises(ContextualValidationError, match = "min_price must be specified"):
+        Ad.model_validate(cfg_copy)
+
+
+@pytest.mark.unit
+def test_ad_model_min_price_must_not_exceed_price(complete_ad_cfg:dict[str, object]) -> None:
+    cfg_copy = complete_ad_cfg.copy()
+    cfg_copy["price"] = 100
+    cfg_copy["auto_price_reduction"] = {
+        "enabled": True,
+        "strategy": "FIXED",
+        "amount": 5,
+        "min_price": 150,
+        "delay_reposts": 0,
+        "delay_days": 0
+    }
+    with pytest.raises(ContextualValidationError, match = "min_price must not exceed price"):
+        Ad.model_validate(cfg_copy)
+
+
+@pytest.mark.unit
+def test_calculate_auto_price_with_missing_strategy() -> None:
+    """Test calculate_auto_price when strategy is None but enabled is True (defensive check)"""
+    # Use model_construct to bypass validation and reach defensive lines 234-235
+    config = AutoPriceReductionConfig.model_construct(
+        enabled = True, strategy = None, amount = None, min_price = 50
+    )
+    result = calculate_auto_price(
+        base_price = 100,
+        auto_price_reduction = config,
+        target_reduction_cycle = 1
+    )
+    assert result == 100  # Should return base price when strategy is None
+
+
+@pytest.mark.unit
+def test_calculate_auto_price_with_missing_amount() -> None:
+    """Test calculate_auto_price when amount is None but enabled is True (defensive check)"""
+    # Use model_construct to bypass validation and reach defensive lines 234-235
+    config = AutoPriceReductionConfig.model_construct(
+        enabled = True, strategy = "FIXED", amount = None, min_price = 50
+    )
+    result = calculate_auto_price(
+        base_price = 100,
+        auto_price_reduction = config,
+        target_reduction_cycle = 1
+    )
+    assert result == 100  # Should return base price when amount is None
+
+
+@pytest.mark.unit
+def test_calculate_auto_price_raises_when_min_price_none_and_enabled() -> None:
+    """Test that calculate_auto_price raises ValueError when min_price is None during calculation (defensive check)"""
+    # Use model_construct to bypass validation and reach defensive line 237-238
+    config = AutoPriceReductionConfig.model_construct(
+        enabled = True, strategy = "FIXED", amount = 10, min_price = None
+    )
+
+    with pytest.raises(ValueError, match = "min_price must be specified when auto_price_reduction is enabled"):
+        calculate_auto_price(
+            base_price = 100,
+            auto_price_reduction = config,
+            target_reduction_cycle = 1
+        )
+
+
+@pytest.mark.unit
+def test_auto_price_reduction_config_requires_amount_when_enabled() -> None:
+    """Test AutoPriceReductionConfig validator requires amount when enabled"""
+    with pytest.raises(ValueError, match = "amount must be specified when auto_price_reduction is enabled"):
+        AutoPriceReductionConfig(enabled = True, strategy = "FIXED", amount = None, min_price = 50)

tests/unit/test_init.py

@@ -5,7 +5,7 @@ import copy, io, json, logging, os, tempfile  # isort: skip
 from collections.abc import Generator
 from contextlib import redirect_stdout
 from datetime import timedelta
-from pathlib import Path
+from pathlib import Path, PureWindowsPath
 from typing import Any, cast
 from unittest.mock import AsyncMock, MagicMock, patch
 
@@ -1072,6 +1072,124 @@ class TestKleinanzeigenBotShippingOptions:
             # Verify the file was created in the temporary directory
             assert ad_file.exists()
 
+    @pytest.mark.asyncio
+    async def test_cross_drive_path_fallback_windows(self, test_bot:KleinanzeigenBot, base_ad_config:dict[str, Any]) -> None:
+        """Test that cross-drive path handling falls back to absolute path on Windows."""
+        # Create ad config
+        ad_cfg = Ad.model_validate(base_ad_config | {
+            "updated_on": "2024-01-01T00:00:00",
+            "created_on": "2024-01-01T00:00:00",
+            "auto_price_reduction": {
+                "enabled": True,
+                "strategy": "FIXED",
+                "amount": 10,
+                "min_price": 50,
+                "delay_reposts": 0,
+                "delay_days": 0
+            },
+            "price": 100,
+            "repost_count": 1,
+            "price_reduction_count": 0
+        })
+        ad_cfg.update_content_hash()
+        ad_cfg_orig = ad_cfg.model_dump()
+
+        # Simulate Windows cross-drive scenario
+        # Config on D:, ad file on C:
+        test_bot.config_file_path = "D:\\project\\config.yaml"
+        ad_file = "C:\\temp\\test_ad.yaml"
+
+        # Create a sentinel exception to abort publish_ad early
+        class _SentinelException(Exception):
+            pass
+
+        # Track what path argument __apply_auto_price_reduction receives
+        recorded_path:list[str] = []
+
+        def mock_apply_auto_price_reduction(ad_cfg:Ad, ad_cfg_orig:dict[str, Any], ad_file_relative:str) -> None:
+            recorded_path.append(ad_file_relative)
+            raise _SentinelException("Abort early for test")
+
+        # Mock Path to use PureWindowsPath for testing cross-drive behavior
+        with patch("kleinanzeigen_bot.Path", PureWindowsPath), \
+                patch.object(test_bot, "_KleinanzeigenBot__apply_auto_price_reduction", side_effect = mock_apply_auto_price_reduction), \
+                patch.object(test_bot, "web_open", new_callable = AsyncMock), \
+                patch.object(test_bot, "delete_ad", new_callable = AsyncMock):
+            # Call publish_ad and expect sentinel exception
+            try:
+                await test_bot.publish_ad(ad_file, ad_cfg, ad_cfg_orig, [], AdUpdateStrategy.REPLACE)
+                pytest.fail("Expected _SentinelException to be raised")
+            except _SentinelException:
+                # This is expected - the test aborts early
+                pass
+
+        # Verify the path argument is the absolute path (fallback behavior)
+        assert len(recorded_path) == 1
+        assert recorded_path[0] == ad_file, f"Expected absolute path fallback, got: {recorded_path[0]}"
+
+    @pytest.mark.asyncio
+    async def test_auto_price_reduction_only_on_replace_not_update(
+        self,
+        test_bot:KleinanzeigenBot,
+        base_ad_config:dict[str, Any],
+        tmp_path:Path
+    ) -> None:
+        """Test that auto price reduction is ONLY applied on REPLACE mode, not UPDATE."""
+        # Create ad with auto price reduction enabled
+        ad_cfg = Ad.model_validate(base_ad_config | {
+            "id": 12345,
+            "price": 200,
+            "auto_price_reduction": {
+                "enabled": True,
+                "strategy": "FIXED",
+                "amount": 50,
+                "min_price": 50,
+                "delay_reposts": 0,
+                "delay_days": 0
+            },
+            "repost_count": 1,
+            "price_reduction_count": 0,
+            "updated_on": "2024-01-01T00:00:00",
+            "created_on": "2024-01-01T00:00:00"
+        })
+        ad_cfg.update_content_hash()
+        ad_cfg_orig = ad_cfg.model_dump()
+
+        # Mock the private __apply_auto_price_reduction method
+        with patch.object(test_bot, "_KleinanzeigenBot__apply_auto_price_reduction") as mock_apply:
+            # Mock other dependencies
+            mock_response = {"statusCode": 200, "statusMessage": "OK", "content": "{}"}
+            with patch.object(test_bot, "web_find", new_callable = AsyncMock), \
+                    patch.object(test_bot, "web_input", new_callable = AsyncMock), \
+                    patch.object(test_bot, "web_click", new_callable = AsyncMock), \
+                    patch.object(test_bot, "web_open", new_callable = AsyncMock), \
+                    patch.object(test_bot, "web_select", new_callable = AsyncMock), \
+                    patch.object(test_bot, "web_check", new_callable = AsyncMock, return_value = False), \
+                    patch.object(test_bot, "web_await", new_callable = AsyncMock), \
+                    patch.object(test_bot, "web_sleep", new_callable = AsyncMock), \
+                    patch.object(test_bot, "web_execute", new_callable = AsyncMock, return_value = mock_response), \
+                    patch.object(test_bot, "web_request", new_callable = AsyncMock, return_value = mock_response), \
+                    patch.object(test_bot, "web_scroll_page_down", new_callable = AsyncMock), \
+                    patch.object(test_bot, "web_find_all", new_callable = AsyncMock, return_value = []), \
+                    patch.object(test_bot, "check_and_wait_for_captcha", new_callable = AsyncMock), \
+                    patch("builtins.input", return_value = ""), \
+                    patch("kleinanzeigen_bot.utils.misc.ainput", new_callable = AsyncMock, return_value = ""):
+
+                test_bot.page = MagicMock()
+                test_bot.page.url = "https://www.kleinanzeigen.de/p-anzeige-aufgeben-bestaetigung.html?adId=12345"
+                test_bot.config.publishing.delete_old_ads = "BEFORE_PUBLISH"
+
+                # Test REPLACE mode - should call __apply_auto_price_reduction
+                await test_bot.publish_ad(str(tmp_path / "ad.yaml"), ad_cfg, ad_cfg_orig, [], AdUpdateStrategy.REPLACE)
+                assert mock_apply.call_count == 1, "Auto price reduction should be called on REPLACE"
+
+                # Reset mock
+                mock_apply.reset_mock()
+
+                # Test MODIFY mode - should NOT call __apply_auto_price_reduction
+                await test_bot.publish_ad(str(tmp_path / "ad.yaml"), ad_cfg, ad_cfg_orig, [], AdUpdateStrategy.MODIFY)
+                assert mock_apply.call_count == 0, "Auto price reduction should NOT be called on MODIFY"
+
     @pytest.mark.asyncio
     async def test_special_attributes_with_non_string_values(self, test_bot:KleinanzeigenBot, base_ad_config:dict[str, Any]) -> None:
         """Test that special attributes with non-string values are converted to strings."""
@@ -1462,3 +1580,45 @@ def test_file_logger_writes_message(tmp_path:Path, caplog:pytest.LogCaptureFixtu
     with open(log_path, "r", encoding = "utf-8") as f:
         contents = f.read()
     assert "Logger test log message" in contents
+
+
+class TestPriceReductionPersistence:
+    """Tests for price_reduction_count persistence logic."""
+
+    @pytest.mark.unit
+    def test_persistence_logic_saves_when_count_positive(self) -> None:
+        """Test the conditional logic that decides whether to persist price_reduction_count."""
+        # Simulate the logic from publish_ad lines 1076-1079
+        ad_cfg_orig:dict[str, Any] = {}
+
+        # Test case 1: price_reduction_count = 3 (should persist)
+        price_reduction_count = 3
+        if price_reduction_count is not None and price_reduction_count > 0:
+            ad_cfg_orig["price_reduction_count"] = price_reduction_count
+
+        assert "price_reduction_count" in ad_cfg_orig
+        assert ad_cfg_orig["price_reduction_count"] == 3
+
+    @pytest.mark.unit
+    def test_persistence_logic_skips_when_count_zero(self) -> None:
+        """Test that price_reduction_count == 0 does not get persisted."""
+        ad_cfg_orig:dict[str, Any] = {}
+
+        # Test case 2: price_reduction_count = 0 (should NOT persist)
+        price_reduction_count = 0
+        if price_reduction_count is not None and price_reduction_count > 0:
+            ad_cfg_orig["price_reduction_count"] = price_reduction_count
+
+        assert "price_reduction_count" not in ad_cfg_orig
+
+    @pytest.mark.unit
+    def test_persistence_logic_skips_when_count_none(self) -> None:
+        """Test that price_reduction_count == None does not get persisted."""
+        ad_cfg_orig:dict[str, Any] = {}
+
+        # Test case 3: price_reduction_count = None (should NOT persist)
+        price_reduction_count = None
+        if price_reduction_count is not None and price_reduction_count > 0:
+            ad_cfg_orig["price_reduction_count"] = price_reduction_count
+
+        assert "price_reduction_count" not in ad_cfg_orig

tests/unit/test_price_reduction.py

@@ -0,0 +1,550 @@
+# SPDX-FileCopyrightText: © Sebastian Thomschke and contributors
+# SPDX-License-Identifier: AGPL-3.0-or-later
+# SPDX-ArtifactOfProjectHomePage: https://github.com/Second-Hand-Friends/kleinanzeigen-bot/
+import logging
+from datetime import datetime, timedelta, timezone
+from gettext import gettext as _
+from types import SimpleNamespace
+from typing import Any, Protocol, runtime_checkable
+
+import pytest
+
+import kleinanzeigen_bot
+from kleinanzeigen_bot.model.ad_model import calculate_auto_price
+from kleinanzeigen_bot.model.config_model import AutoPriceReductionConfig
+from kleinanzeigen_bot.utils.pydantics import ContextualValidationError
+
+
+@runtime_checkable
+class _ApplyAutoPriceReduction(Protocol):
+    def __call__(self, ad_cfg:SimpleNamespace, ad_cfg_orig:dict[str, Any], ad_file_relative:str) -> None:
+        ...
+
+
+@pytest.fixture
+def apply_auto_price_reduction() -> _ApplyAutoPriceReduction:
+    # Return the module-level function directly (no more name-mangling!)
+    return kleinanzeigen_bot.apply_auto_price_reduction  # type: ignore[return-value]
+
+
+@pytest.mark.unit
+def test_initial_posting_uses_base_price() -> None:
+    config = AutoPriceReductionConfig(enabled = True, strategy = "PERCENTAGE", amount = 10, min_price = 50)
+    assert calculate_auto_price(
+        base_price = 100,
+        auto_price_reduction = config,
+        target_reduction_cycle = 0
+    ) == 100
+
+
+@pytest.mark.unit
+def test_auto_price_returns_none_without_base_price() -> None:
+    config = AutoPriceReductionConfig(enabled = True, strategy = "PERCENTAGE", amount = 10, min_price = 10)
+    assert calculate_auto_price(
+        base_price = None,
+        auto_price_reduction = config,
+        target_reduction_cycle = 3
+    ) is None
+
+
+@pytest.mark.unit
+def test_negative_price_reduction_count_is_treated_like_zero() -> None:
+    config = AutoPriceReductionConfig(enabled = True, strategy = "PERCENTAGE", amount = 25, min_price = 50)
+    assert calculate_auto_price(
+        base_price = 100,
+        auto_price_reduction = config,
+        target_reduction_cycle = -3
+    ) == 100
+
+
+@pytest.mark.unit
+def test_missing_price_reduction_returns_base_price() -> None:
+    assert calculate_auto_price(
+        base_price = 150,
+        auto_price_reduction = None,
+        target_reduction_cycle = 4
+    ) == 150
+
+
+@pytest.mark.unit
+def test_percentage_reduction_on_float_rounds_half_up() -> None:
+    config = AutoPriceReductionConfig(enabled = True, strategy = "PERCENTAGE", amount = 12.5, min_price = 50)
+    assert calculate_auto_price(
+        base_price = 99.99,
+        auto_price_reduction = config,
+        target_reduction_cycle = 1
+    ) == 87
+
+
+@pytest.mark.unit
+def test_fixed_reduction_on_float_rounds_half_up() -> None:
+    config = AutoPriceReductionConfig(enabled = True, strategy = "FIXED", amount = 12.4, min_price = 50)
+    assert calculate_auto_price(
+        base_price = 80.51,
+        auto_price_reduction = config,
+        target_reduction_cycle = 1
+    ) == 68
+
+
+@pytest.mark.unit
+def test_percentage_price_reduction_over_time() -> None:
+    config = AutoPriceReductionConfig(enabled = True, strategy = "PERCENTAGE", amount = 10, min_price = 50)
+    assert calculate_auto_price(
+        base_price = 100,
+        auto_price_reduction = config,
+        target_reduction_cycle = 1
+    ) == 90
+    assert calculate_auto_price(
+        base_price = 100,
+        auto_price_reduction = config,
+        target_reduction_cycle = 2
+    ) == 81
+    assert calculate_auto_price(
+        base_price = 100,
+        auto_price_reduction = config,
+        target_reduction_cycle = 3
+    ) == 73
+
+
+@pytest.mark.unit
+def test_fixed_price_reduction_over_time() -> None:
+    config = AutoPriceReductionConfig(enabled = True, strategy = "FIXED", amount = 15, min_price = 50)
+    assert calculate_auto_price(
+        base_price = 100,
+        auto_price_reduction = config,
+        target_reduction_cycle = 1
+    ) == 85
+    assert calculate_auto_price(
+        base_price = 100,
+        auto_price_reduction = config,
+        target_reduction_cycle = 2
+    ) == 70
+    assert calculate_auto_price(
+        base_price = 100,
+        auto_price_reduction = config,
+        target_reduction_cycle = 3
+    ) == 55
+
+
+@pytest.mark.unit
+def test_min_price_boundary_is_respected() -> None:
+    config = AutoPriceReductionConfig(enabled = True, strategy = "FIXED", amount = 20, min_price = 50)
+    assert calculate_auto_price(
+        base_price = 100,
+        auto_price_reduction = config,
+        target_reduction_cycle = 5
+    ) == 50
+
+
+@pytest.mark.unit
+def test_min_price_zero_is_allowed() -> None:
+    config = AutoPriceReductionConfig(enabled = True, strategy = "FIXED", amount = 5, min_price = 0)
+    assert calculate_auto_price(
+        base_price = 20,
+        auto_price_reduction = config,
+        target_reduction_cycle = 5
+    ) == 0
+
+
+@pytest.mark.unit
+def test_missing_min_price_raises_error() -> None:
+    # min_price validation happens at config initialization when enabled=True
+    with pytest.raises(ContextualValidationError, match = "min_price must be specified"):
+        AutoPriceReductionConfig.model_validate({"enabled": True, "strategy": "PERCENTAGE", "amount": 50, "min_price": None})
+
+
+@pytest.mark.unit
+def test_percentage_above_100_raises_error() -> None:
+    with pytest.raises(ContextualValidationError, match = "Percentage reduction amount must not exceed 100"):
+        AutoPriceReductionConfig.model_validate({"enabled": True, "strategy": "PERCENTAGE", "amount": 150, "min_price": 50})
+
+
+@pytest.mark.unit
+def test_feature_disabled_path_leaves_price_unchanged() -> None:
+    config = AutoPriceReductionConfig(enabled = False, strategy = "PERCENTAGE", amount = 25, min_price = 50)
+    price = calculate_auto_price(
+        base_price = 100,
+        auto_price_reduction = config,
+        target_reduction_cycle = 4
+    )
+    assert price == 100
+
+
+@pytest.mark.unit
+def test_apply_auto_price_reduction_logs_drop(
+    caplog:pytest.LogCaptureFixture,
+    apply_auto_price_reduction:_ApplyAutoPriceReduction
+) -> None:
+    ad_cfg = SimpleNamespace(
+        price = 200,
+        auto_price_reduction = AutoPriceReductionConfig(
+            enabled = True, strategy = "PERCENTAGE", amount = 25, min_price = 50, delay_reposts = 0, delay_days = 0
+        ),
+        price_reduction_count = 0,
+        repost_count = 1
+    )
+
+    ad_orig:dict[str, Any] = {}
+
+    with caplog.at_level(logging.INFO):
+        apply_auto_price_reduction(ad_cfg, ad_orig, "ad_test.yaml")
+
+    expected = _("Auto price reduction applied: %s -> %s after %s reduction cycles") % (200, 150, 1)
+    assert any(expected in message for message in caplog.messages)
+    assert ad_cfg.price == 150
+    assert ad_cfg.price_reduction_count == 1
+    # Note: price_reduction_count is NOT persisted to ad_orig until after successful publish
+    assert "price_reduction_count" not in ad_orig
+
+
+@pytest.mark.unit
+def test_apply_auto_price_reduction_logs_unchanged_price_at_floor(
+    caplog:pytest.LogCaptureFixture,
+    apply_auto_price_reduction:_ApplyAutoPriceReduction
+) -> None:
+    # Test scenario: price has been reduced to just above min_price,
+    # and the next reduction would drop it below, so it gets clamped
+    ad_cfg = SimpleNamespace(
+        price = 95,
+        auto_price_reduction = AutoPriceReductionConfig(
+            enabled = True, strategy = "FIXED", amount = 10, min_price = 90, delay_reposts = 0, delay_days = 0
+        ),
+        price_reduction_count = 0,
+        repost_count = 1
+    )
+
+    ad_orig:dict[str, Any] = {}
+
+    with caplog.at_level(logging.INFO):
+        apply_auto_price_reduction(ad_cfg, ad_orig, "ad_test.yaml")
+
+    # Price: 95 - 10 = 85, clamped to 90 (floor)
+    # So the effective price is 90, not 95, meaning reduction was applied
+    expected = _("Auto price reduction applied: %s -> %s after %s reduction cycles") % (95, 90, 1)
+    assert any(expected in message for message in caplog.messages)
+    assert ad_cfg.price == 90
+    assert ad_cfg.price_reduction_count == 1
+    assert "price_reduction_count" not in ad_orig
+
+
+@pytest.mark.unit
+def test_apply_auto_price_reduction_warns_when_price_missing(
+    caplog:pytest.LogCaptureFixture,
+    apply_auto_price_reduction:_ApplyAutoPriceReduction
+) -> None:
+    ad_cfg = SimpleNamespace(
+        price = None,
+        auto_price_reduction = AutoPriceReductionConfig(
+            enabled = True, strategy = "PERCENTAGE", amount = 25, min_price = 10, delay_reposts = 0, delay_days = 0
+        ),
+        price_reduction_count = 2,
+        repost_count = 2
+    )
+
+    ad_orig:dict[str, Any] = {}
+
+    with caplog.at_level(logging.WARNING):
+        apply_auto_price_reduction(ad_cfg, ad_orig, "ad_warning.yaml")
+
+    expected = _("Auto price reduction is enabled for [%s] but no price is configured.") % ("ad_warning.yaml",)
+    assert any(expected in message for message in caplog.messages)
+    assert ad_cfg.price is None
+
+
+@pytest.mark.unit
+def test_apply_auto_price_reduction_warns_when_min_price_equals_price(
+    caplog:pytest.LogCaptureFixture,
+    apply_auto_price_reduction:_ApplyAutoPriceReduction
+) -> None:
+    ad_cfg = SimpleNamespace(
+        price = 100,
+        auto_price_reduction = AutoPriceReductionConfig(
+            enabled = True, strategy = "PERCENTAGE", amount = 25, min_price = 100, delay_reposts = 0, delay_days = 0
+        ),
+        price_reduction_count = 0,
+        repost_count = 1
+    )
+
+    ad_orig:dict[str, Any] = {}
+
+    with caplog.at_level(logging.WARNING):
+        apply_auto_price_reduction(ad_cfg, ad_orig, "ad_equal_prices.yaml")
+
+    expected = _("Auto price reduction is enabled for [%s] but min_price equals price (%s) - no reductions will occur.") % ("ad_equal_prices.yaml", 100)
+    assert any(expected in message for message in caplog.messages)
+    assert ad_cfg.price == 100
+    assert ad_cfg.price_reduction_count == 0
+
+
+@pytest.mark.unit
+def test_apply_auto_price_reduction_respects_repost_delay(
+    caplog:pytest.LogCaptureFixture,
+    apply_auto_price_reduction:_ApplyAutoPriceReduction
+) -> None:
+    ad_cfg = SimpleNamespace(
+        price = 200,
+        auto_price_reduction = AutoPriceReductionConfig(
+            enabled = True, strategy = "PERCENTAGE", amount = 25, min_price = 50, delay_reposts = 3, delay_days = 0
+        ),
+        price_reduction_count = 0,
+        repost_count = 2
+    )
+
+    ad_orig:dict[str, Any] = {}
+
+    with caplog.at_level(logging.INFO):
+        apply_auto_price_reduction(ad_cfg, ad_orig, "ad_delay.yaml")
+
+    assert ad_cfg.price == 200
+    delayed_message = _("Auto price reduction delayed for [%s]: waiting %s more reposts (completed %s, applied %s reductions)") % ("ad_delay.yaml", 2, 2, 0)
+    assert any(delayed_message in message for message in caplog.messages)
+
+
+@pytest.mark.unit
+def test_apply_auto_price_reduction_after_repost_delay_reduces_once(
+    apply_auto_price_reduction:_ApplyAutoPriceReduction
+) -> None:
+    ad_cfg = SimpleNamespace(
+        price = 100,
+        auto_price_reduction = AutoPriceReductionConfig(
+            enabled = True, strategy = "PERCENTAGE", amount = 10, min_price = 50, delay_reposts = 2, delay_days = 0
+        ),
+        price_reduction_count = 0,
+        repost_count = 3
+    )
+
+    ad_cfg_orig:dict[str, Any] = {}
+    apply_auto_price_reduction(ad_cfg, ad_cfg_orig, "ad_after_delay.yaml")
+
+    assert ad_cfg.price == 90
+    assert ad_cfg.price_reduction_count == 1
+    # Note: price_reduction_count is NOT persisted to ad_orig until after successful publish
+    assert "price_reduction_count" not in ad_cfg_orig
+
+
+@pytest.mark.unit
+def test_apply_auto_price_reduction_waits_when_reduction_already_applied(
+    caplog:pytest.LogCaptureFixture,
+    apply_auto_price_reduction:_ApplyAutoPriceReduction
+) -> None:
+    ad_cfg = SimpleNamespace(
+        price = 100,
+        auto_price_reduction = AutoPriceReductionConfig(
+            enabled = True, strategy = "PERCENTAGE", amount = 10, min_price = 50, delay_reposts = 0, delay_days = 0
+        ),
+        price_reduction_count = 3,
+        repost_count = 3
+    )
+
+    ad_orig:dict[str, Any] = {}
+
+    with caplog.at_level(logging.DEBUG):
+        apply_auto_price_reduction(ad_cfg, ad_orig, "ad_already.yaml")
+
+    expected = _("Auto price reduction already applied for [%s]: %s reductions match %s eligible reposts") % ("ad_already.yaml", 3, 3)
+    assert any(expected in message for message in caplog.messages)
+    assert ad_cfg.price == 100
+    assert ad_cfg.price_reduction_count == 3
+    assert "price_reduction_count" not in ad_orig
+
+
+@pytest.mark.unit
+def test_apply_auto_price_reduction_respects_day_delay(
+    monkeypatch:pytest.MonkeyPatch,
+    caplog:pytest.LogCaptureFixture,
+    apply_auto_price_reduction:_ApplyAutoPriceReduction
+) -> None:
+    reference = datetime(2025, 1, 1, tzinfo = timezone.utc)
+    ad_cfg = SimpleNamespace(
+        price = 150,
+        auto_price_reduction = AutoPriceReductionConfig(
+            enabled = True, strategy = "PERCENTAGE", amount = 25, min_price = 50, delay_reposts = 0, delay_days = 3
+        ),
+        price_reduction_count = 0,
+        repost_count = 1,
+        updated_on = reference,
+        created_on = reference
+    )
+
+    monkeypatch.setattr("kleinanzeigen_bot.misc.now", lambda: reference + timedelta(days = 1))
+
+    ad_orig:dict[str, Any] = {}
+
+    with caplog.at_level("INFO"):
+        apply_auto_price_reduction(ad_cfg, ad_orig, "ad_delay_days.yaml")
+
+    assert ad_cfg.price == 150
+    delayed_message = _("Auto price reduction delayed for [%s]: waiting %s days (elapsed %s)") % ("ad_delay_days.yaml", 3, 1)
+    assert any(delayed_message in message for message in caplog.messages)
+
+
+@pytest.mark.unit
+def test_apply_auto_price_reduction_runs_after_delays(
+    monkeypatch:pytest.MonkeyPatch,
+    apply_auto_price_reduction:_ApplyAutoPriceReduction
+) -> None:
+    reference = datetime(2025, 1, 1, tzinfo = timezone.utc)
+    ad_cfg = SimpleNamespace(
+        price = 120,
+        auto_price_reduction = AutoPriceReductionConfig(
+            enabled = True, strategy = "PERCENTAGE", amount = 25, min_price = 60, delay_reposts = 2, delay_days = 3
+        ),
+        price_reduction_count = 0,
+        repost_count = 3,
+        updated_on = reference - timedelta(days = 5),
+        created_on = reference - timedelta(days = 10)
+    )
+
+    monkeypatch.setattr("kleinanzeigen_bot.misc.now", lambda: reference)
+
+    ad_orig:dict[str, Any] = {}
+    apply_auto_price_reduction(ad_cfg, ad_orig, "ad_ready.yaml")
+
+    assert ad_cfg.price == 90
+
+
+@pytest.mark.unit
+def test_apply_auto_price_reduction_delayed_when_timestamp_missing(
+    caplog:pytest.LogCaptureFixture,
+    apply_auto_price_reduction:_ApplyAutoPriceReduction
+) -> None:
+    ad_cfg = SimpleNamespace(
+        price = 200,
+        auto_price_reduction = AutoPriceReductionConfig(
+            enabled = True, strategy = "FIXED", amount = 20, min_price = 50, delay_reposts = 0, delay_days = 2
+        ),
+        price_reduction_count = 0,
+        repost_count = 1,
+        updated_on = None,
+        created_on = None
+    )
+
+    ad_orig:dict[str, Any] = {}
+
+    with caplog.at_level("INFO"):
+        apply_auto_price_reduction(ad_cfg, ad_orig, "ad_missing_time.yaml")
+
+    expected = _("Auto price reduction delayed for [%s]: waiting %s days but publish timestamp missing") % ("ad_missing_time.yaml", 2)
+    assert any(expected in message for message in caplog.messages)
+
+
+@pytest.mark.unit
+def test_fractional_reduction_increments_counter_even_when_price_unchanged(
+    caplog:pytest.LogCaptureFixture,
+    apply_auto_price_reduction:_ApplyAutoPriceReduction
+) -> None:
+    # Test that small fractional reductions increment the counter even when rounded price doesn't change
+    # This allows cumulative reductions to eventually show visible effect
+    ad_cfg = SimpleNamespace(
+        price = 100,
+        auto_price_reduction = AutoPriceReductionConfig(
+            enabled = True, strategy = "FIXED", amount = 0.3, min_price = 50, delay_reposts = 0, delay_days = 0
+        ),
+        price_reduction_count = 0,
+        repost_count = 1
+    )
+
+    ad_orig:dict[str, Any] = {}
+
+    with caplog.at_level(logging.INFO):
+        apply_auto_price_reduction(ad_cfg, ad_orig, "ad_fractional.yaml")
+
+    # Price: 100 - 0.3 = 99.7, rounds to 100 (no visible change)
+    # But counter should still increment for future cumulative reductions
+    expected = _("Auto price reduction kept price %s after attempting %s reduction cycles") % (100, 1)
+    assert any(expected in message for message in caplog.messages)
+    assert ad_cfg.price == 100
+    assert ad_cfg.price_reduction_count == 1  # Counter incremented despite no visible price change
+    assert "price_reduction_count" not in ad_orig
+
+
+@pytest.mark.unit
+def test_reduction_value_zero_raises_error() -> None:
+    with pytest.raises(ContextualValidationError, match = "Input should be greater than 0"):
+        AutoPriceReductionConfig.model_validate({"enabled": True, "strategy": "PERCENTAGE", "amount": 0, "min_price": 50})
+
+
+@pytest.mark.unit
+def test_reduction_value_negative_raises_error() -> None:
+    with pytest.raises(ContextualValidationError, match = "Input should be greater than 0"):
+        AutoPriceReductionConfig.model_validate({"enabled": True, "strategy": "FIXED", "amount": -5, "min_price": 50})
+
+
+@pytest.mark.unit
+def test_percentage_reduction_100_percent() -> None:
+    config = AutoPriceReductionConfig(enabled = True, strategy = "PERCENTAGE", amount = 100, min_price = 0)
+    assert calculate_auto_price(
+        base_price = 150,
+        auto_price_reduction = config,
+        target_reduction_cycle = 1
+    ) == 0
+
+
+@pytest.mark.unit
+def test_extreme_reduction_cycles() -> None:
+    # Test that extreme cycle counts don't cause performance issues or errors
+    config = AutoPriceReductionConfig(enabled = True, strategy = "PERCENTAGE", amount = 10, min_price = 0)
+    result = calculate_auto_price(
+        base_price = 1000,
+        auto_price_reduction = config,
+        target_reduction_cycle = 100
+    )
+    # With commercial rounding (round after each step), price stabilizes at 5
+    # because 5 * 0.9 = 4.5 rounds back to 5 with ROUND_HALF_UP
+    assert result == 5
+
+
+@pytest.mark.unit
+def test_commercial_rounding_each_step() -> None:
+    """Test that commercial rounding is applied after each reduction step, not just at the end."""
+    config = AutoPriceReductionConfig(enabled = True, strategy = "PERCENTAGE", amount = 10, min_price = 0)
+    # With 135 EUR and 2x 10% reduction:
+    # Step 1: 135 * 0.9 = 121.5 → rounds to 122 EUR
+    # Step 2: 122 * 0.9 = 109.8 → rounds to 110 EUR
+    # (Without intermediate rounding, it would be: 135 * 0.9^2 = 109.35 → 109 EUR)
+    result = calculate_auto_price(
+        base_price = 135,
+        auto_price_reduction = config,
+        target_reduction_cycle = 2
+    )
+    assert result == 110  # Commercial rounding result
+
+
+@pytest.mark.unit
+def test_extreme_reduction_cycles_with_floor() -> None:
+    # Test that extreme cycles stop at min_price and don't cause issues
+    config = AutoPriceReductionConfig(enabled = True, strategy = "PERCENTAGE", amount = 10, min_price = 50)
+    result = calculate_auto_price(
+        base_price = 1000,
+        auto_price_reduction = config,
+        target_reduction_cycle = 1000
+    )
+    # Should stop at min_price, not go to 0, regardless of cycle count
+    assert result == 50
+
+
+@pytest.mark.unit
+def test_fractional_min_price_is_rounded_up_with_ceiling() -> None:
+    # Test that fractional min_price is rounded UP using ROUND_CEILING
+    # This prevents the price from going below min_price due to int() conversion
+    # Example: min_price=90.5 should become floor of 91, not 90
+    config = AutoPriceReductionConfig(enabled = True, strategy = "FIXED", amount = 10, min_price = 90.5)
+
+    # Start at 100, reduce by 10 = 90
+    # But min_price=90.5 rounds UP to 91 with ROUND_CEILING
+    # So the result should be 91, not 90
+    result = calculate_auto_price(
+        base_price = 100,
+        auto_price_reduction = config,
+        target_reduction_cycle = 1
+    )
+    assert result == 91  # Rounded up from 90.5 floor
+
+    # Verify with another fractional value
+    config2 = AutoPriceReductionConfig(enabled = True, strategy = "FIXED", amount = 5, min_price = 49.1)
+    result2 = calculate_auto_price(
+        base_price = 60,
+        auto_price_reduction = config2,
+        target_reduction_cycle = 3  # 60 - 5 - 5 - 5 = 45, clamped to ceil(49.1) = 50
+    )
+    assert result2 == 50  # Rounded up from 49.1 floor

tests/unit/test_pydantics.py

@@ -151,6 +151,14 @@ class TestFormatValidationError:
                 [{"loc": ("decimal_max_digits",), "msg": "dummy", "type": "decimal_max_digits", "ctx": {"max_digits": 10, "expected_plural": "s"}}],
                 "Decimal input should have no more than 10 digits in total",
             ),
+            (
+                [{"loc": ("decimal_max_places",), "msg": "dummy", "type": "decimal_max_places", "ctx": {"decimal_places": 2, "expected_plural": "s"}}],
+                "Decimal input should have no more than 2 decimal places",
+            ),
+            (
+                [{"loc": ("decimal_whole_digits",), "msg": "dummy", "type": "decimal_whole_digits", "ctx": {"whole_digits": 3, "expected_plural": ""}}],
+                "Decimal input should have no more than 3 digits before the decimal point",
+            ),
             # Complex number related errors
             (
                 [{"loc": ("complex",), "msg": "dummy", "type": "complex_type"}],