feat: add Budget Mode with price cache infrastructure and stale price warnings

code/deck_builder/builder.py

@@ -1367,6 +1367,68 @@ class DeckBuilder(
             self._full_cards_df = combined.copy()
         return combined
 
+    def apply_budget_pool_filter(self) -> None:
+        """M4: Remove cards priced above the per-card ceiling × (1 + tolerance) from the pool.
+
+        Must be called AFTER budget_config is set on the builder instance.
+        Fail-open: skipped if price column absent, no ceiling configured, or any exception occurs.
+        Include-list cards are never filtered regardless of price.
+        """
+        import logging
+        _logger = logging.getLogger(__name__)
+
+        budget_config = getattr(self, 'budget_config', None) or {}
+        ceiling = budget_config.get('card_ceiling')
+        if not ceiling or ceiling <= 0:
+            return
+
+        df = getattr(self, '_combined_cards_df', None)
+        if df is None or not hasattr(df, 'columns'):
+            return
+
+        if 'price' not in df.columns:
+            _logger.warning("BUDGET_POOL_FILTER: 'price' column absent — skipping pool filter")
+            return
+
+        # Tolerance: per-build user value > env var > constant default
+        tol = budget_config.get('pool_tolerance')
+        if tol is None:
+            import os as _os
+            env_tol = _os.getenv('BUDGET_POOL_TOLERANCE')
+            try:
+                tol = float(env_tol) if env_tol else bc.BUDGET_POOL_TOLERANCE
+            except ValueError:
+                tol = bc.BUDGET_POOL_TOLERANCE
+        max_price = ceiling * (1.0 + tol)
+
+        # Include-list cards always pass regardless of price
+        include_lower: set[str] = set()
+        try:
+            for nm in (getattr(self, 'include_cards', None) or []):
+                include_lower.add(str(nm).strip().lower())
+        except Exception:
+            pass
+
+        before = len(df)
+        try:
+            price_ok = df['price'].isna() | (df['price'] <= max_price)
+            if include_lower and 'name' in df.columns:
+                protected = df['name'].str.strip().str.lower().isin(include_lower)
+                df = df[price_ok | protected]
+            else:
+                df = df[price_ok]
+        except Exception as exc:
+            _logger.error(f"BUDGET_POOL_FILTER: filter failed: {exc}")
+            return
+
+        removed = before - len(df)
+        if removed:
+            _logger.info(
+                f"BUDGET_POOL_FILTER: removed {removed} cards above ${max_price:.2f} "
+                f"(ceiling=${ceiling:.2f}, tol={tol * 100:.0f}%)"
+            )
+        self._combined_cards_df = df
+
     # ---------------------------
     # Include/Exclude Processing (M1: Config + Validation + Persistence)
     # ---------------------------

code/deck_builder/builder_constants.py

@@ -163,6 +163,8 @@ PRICE_CACHE_SIZE: Final[int] = 128  # Size of price check LRU cache
 PRICE_CHECK_TIMEOUT: Final[int] = 30  # Timeout for price check requests in seconds
 PRICE_TOLERANCE_MULTIPLIER: Final[float] = 1.1  # Multiplier for price tolerance
 DEFAULT_MAX_CARD_PRICE: Final[float] = 20.0  # Default maximum price per card
+BUDGET_POOL_TOLERANCE: Final[float] = 0.15  # Default pool filter tolerance (15% overhead above per-card ceiling)
+BUDGET_TOTAL_TOLERANCE: Final[float] = 0.10  # End-of-build review threshold (10% grace on total deck cost)
 
 # Deck composition defaults
 DEFAULT_RAMP_COUNT: Final[int] = 8  # Default number of ramp pieces

code/deck_builder/phases/phase6_reporting.py

@@ -798,18 +798,24 @@ class ReportingMixin:
         except Exception:  # pragma: no cover - diagnostics only
             logger.debug("Failed to record theme telemetry", exc_info=True)
         return summary_payload
-    def export_decklist_csv(self, directory: str = 'deck_files', filename: str | None = None, suppress_output: bool = False) -> str:
-        """Export current decklist to CSV (enriched).
-        Filename pattern (default): commanderFirstWord_firstTheme_YYYYMMDD.csv
-        Included columns: Name, Count, Type, ManaCost, ManaValue, Colors, Power, Toughness, Role, Tags, Text.
-        Falls back gracefully if snapshot rows missing.
-        """
+    def export_decklist_csv(
+        self,
+        directory: str = 'deck_files',
+        filename: str | None = None,
+        suppress_output: bool = False,
+        price_lookup: Any | None = None,
+    ) -> str:
         """Export current decklist to CSV (enriched).
 
         Filename pattern (default): commanderFirstWord_firstTheme_YYYYMMDD.csv
         Included columns (enriched when possible):
-          Name, Count, Type, ManaCost, ManaValue, Colors, Power, Toughness, Role, Tags, Text
+          Name, Count, Type, ManaCost, ManaValue, Colors, Power, Toughness, Role, Tags, Text, Price
         Falls back gracefully if snapshot rows missing.
+
+        Args:
+            price_lookup: Optional callable (list[str] -> dict[str, float|None]) used to
+                          batch-look up prices at export time.  When omitted the Price column
+                          is written but left blank for every card.
         """
         os.makedirs(directory, exist_ok=True)
         def _slug(s: str) -> str:
@@ -882,9 +888,18 @@ class ReportingMixin:
 
         headers = [
             "Name","Count","Type","ManaCost","ManaValue","Colors","Power","Toughness",
-            "Role","SubRole","AddedBy","TriggerTag","Synergy","Tags","MetadataTags","Text","DFCNote","Owned"
+            "Role","SubRole","AddedBy","TriggerTag","Synergy","Tags","MetadataTags","Text","DFCNote","Owned","Price"
         ]
 
+        # Batch price lookup (no-op when price_lookup not provided)
+        card_names_list = list(self.card_library.keys())
+        prices_map: Dict[str, Any] = {}
+        if callable(price_lookup):
+            try:
+                prices_map = price_lookup(card_names_list) or {}
+            except Exception:
+                prices_map = {}
+
         header_suffix: List[str] = []
         try:
             commander_meta = self.get_commander_export_metadata()
@@ -1024,7 +1039,8 @@ class ReportingMixin:
                 metadata_tags_join,  # M5: Include metadata tags
                 text_field[:800] if isinstance(text_field, str) else str(text_field)[:800],
                 dfc_note,
-                owned_flag
+                owned_flag,
+                (f"{prices_map[name]:.2f}" if prices_map.get(name) is not None else '')
             ]))
 
         # Now sort (category precedence, then alphabetical name)
@@ -1038,6 +1054,19 @@ class ReportingMixin:
                     w.writerow(data_row + suffix_padding)
                 else:
                     w.writerow(data_row)
+            # Summary row: total price in the Price column (blank when no prices available)
+            if prices_map:
+                total_price = sum(
+                    v for v in prices_map.values() if v is not None
+                )
+                price_col_index = headers.index('Price')
+                summary_row = [''] * len(headers)
+                summary_row[0] = 'Total'
+                summary_row[price_col_index] = f'{total_price:.2f}'
+                if suffix_padding:
+                    w.writerow(summary_row + suffix_padding)
+                else:
+                    w.writerow(summary_row)
 
         self.output_func(f"Deck exported to {fname}")
         # Auto-generate matching plaintext list (best-effort; ignore failures)