feat(api): implement combat loot integration with hybrid static/procedural system

Add CombatLootService that orchestrates loot generation from combat,
supporting both static item drops (consumables, materials) and procedural
equipment generation (weapons, armor with affixes).

Key changes:
- Extend LootEntry model with LootType enum (STATIC/PROCEDURAL)
- Create StaticItemLoader service for consumables/materials from YAML
- Create CombatLootService with full rarity formula incorporating:
  - Party average level
  - Enemy difficulty tier (EASY: +0%, MEDIUM: +5%, HARD: +15%, BOSS: +30%)
  - Character luck stat
  - Per-entry rarity bonus
- Integrate with CombatService._calculate_rewards() for automatic loot gen
- Add boss guaranteed drops via generate_boss_loot()

New enemy variants (goblin family proof-of-concept):
- goblin_scout (Easy) - static drops only
- goblin_warrior (Medium) - static + procedural weapon drops
- goblin_chieftain (Hard) - static + procedural weapon/armor drops

Static items added:
- consumables.yaml: health/mana potions, elixirs, food
- materials.yaml: trophy items, crafting materials

Tests: 59 new tests across 3 test files (all passing)
This commit is contained in:
2025-11-27 00:01:17 -06:00
parent a38906b445
commit fdd48034e4
14 changed files with 2257 additions and 26 deletions

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"""
Combat Loot Service - Orchestrates loot generation from combat encounters.
This service bridges the EnemyTemplate loot tables with both the StaticItemLoader
(for consumables and materials) and ItemGenerator (for procedural equipment).
The service calculates effective rarity based on:
- Party average level
- Enemy difficulty tier
- Character luck stat
- Optional loot bonus modifiers (from abilities, buffs, etc.)
"""
import random
from dataclasses import dataclass
from typing import List, Optional
from app.models.enemy import EnemyTemplate, LootEntry, LootType, EnemyDifficulty
from app.models.items import Item
from app.services.item_generator import get_item_generator, ItemGenerator
from app.services.static_item_loader import get_static_item_loader, StaticItemLoader
from app.utils.logging import get_logger
logger = get_logger(__file__)
# Difficulty tier rarity bonuses (converted to effective luck points)
# Higher difficulty enemies have better chances of dropping rare items
DIFFICULTY_RARITY_BONUS = {
EnemyDifficulty.EASY: 0.0,
EnemyDifficulty.MEDIUM: 0.05,
EnemyDifficulty.HARD: 0.15,
EnemyDifficulty.BOSS: 0.30,
}
# Multiplier for converting rarity bonus to effective luck points
# Each 0.05 bonus translates to +1 effective luck
LUCK_CONVERSION_FACTOR = 20
@dataclass
class LootContext:
"""
Context for loot generation calculations.
Provides all the factors that influence loot quality and rarity.
Attributes:
party_average_level: Average level of player characters in the encounter
enemy_difficulty: Difficulty tier of the enemy being looted
luck_stat: Party's luck stat (typically average or leader's luck)
loot_bonus: Additional bonus from abilities, buffs, or modifiers (0.0 to 1.0)
"""
party_average_level: int = 1
enemy_difficulty: EnemyDifficulty = EnemyDifficulty.EASY
luck_stat: int = 8
loot_bonus: float = 0.0
class CombatLootService:
"""
Service for generating combat loot drops.
Supports two types of loot:
- STATIC: Predefined items loaded from YAML (consumables, materials)
- PROCEDURAL: Generated equipment with affixes (weapons, armor)
The service handles:
- Rolling for drops based on drop_chance
- Loading static items via StaticItemLoader
- Generating procedural items via ItemGenerator
- Calculating effective rarity based on context
"""
def __init__(
self,
item_generator: Optional[ItemGenerator] = None,
static_loader: Optional[StaticItemLoader] = None
):
"""
Initialize the combat loot service.
Args:
item_generator: ItemGenerator instance (uses global singleton if None)
static_loader: StaticItemLoader instance (uses global singleton if None)
"""
self.item_generator = item_generator or get_item_generator()
self.static_loader = static_loader or get_static_item_loader()
logger.info("CombatLootService initialized")
def generate_loot_from_enemy(
self,
enemy: EnemyTemplate,
context: LootContext
) -> List[Item]:
"""
Generate all loot drops from a defeated enemy.
Iterates through the enemy's loot table, rolling for each entry
and generating appropriate items based on loot type.
Args:
enemy: The defeated enemy template
context: Loot generation context (party level, luck, etc.)
Returns:
List of Item objects to add to player inventory
"""
items = []
for entry in enemy.loot_table:
# Roll for drop chance
if random.random() >= entry.drop_chance:
continue
# Determine quantity
quantity = random.randint(entry.quantity_min, entry.quantity_max)
if entry.loot_type == LootType.STATIC:
# Static item: load from predefined templates
static_items = self._generate_static_items(entry, quantity)
items.extend(static_items)
elif entry.loot_type == LootType.PROCEDURAL:
# Procedural equipment: generate with ItemGenerator
procedural_items = self._generate_procedural_items(
entry, quantity, context
)
items.extend(procedural_items)
logger.info(
"Loot generated from enemy",
enemy_id=enemy.enemy_id,
enemy_difficulty=enemy.difficulty.value,
item_count=len(items),
party_level=context.party_average_level,
luck=context.luck_stat
)
return items
def _generate_static_items(
self,
entry: LootEntry,
quantity: int
) -> List[Item]:
"""
Generate static items from a loot entry.
Args:
entry: The loot table entry
quantity: Number of items to generate
Returns:
List of Item instances
"""
items = []
if not entry.item_id:
logger.warning(
"Static loot entry missing item_id",
entry=entry.to_dict()
)
return items
for _ in range(quantity):
item = self.static_loader.get_item(entry.item_id)
if item:
items.append(item)
else:
logger.warning(
"Failed to load static item",
item_id=entry.item_id
)
return items
def _generate_procedural_items(
self,
entry: LootEntry,
quantity: int,
context: LootContext
) -> List[Item]:
"""
Generate procedural items from a loot entry.
Calculates effective luck based on:
- Base luck stat
- Entry-specific rarity bonus
- Difficulty bonus
- Loot bonus from abilities/buffs
Args:
entry: The loot table entry
quantity: Number of items to generate
context: Loot generation context
Returns:
List of generated Item instances
"""
items = []
if not entry.item_type:
logger.warning(
"Procedural loot entry missing item_type",
entry=entry.to_dict()
)
return items
# Calculate effective luck for rarity roll
effective_luck = self._calculate_effective_luck(entry, context)
for _ in range(quantity):
item = self.item_generator.generate_loot_drop(
character_level=context.party_average_level,
luck_stat=effective_luck,
item_type=entry.item_type
)
if item:
items.append(item)
else:
logger.warning(
"Failed to generate procedural item",
item_type=entry.item_type,
level=context.party_average_level
)
return items
def _calculate_effective_luck(
self,
entry: LootEntry,
context: LootContext
) -> int:
"""
Calculate effective luck for rarity rolling.
Combines multiple factors:
- Base luck stat from party
- Entry-specific rarity bonus (defined per loot entry)
- Difficulty bonus (based on enemy tier)
- Loot bonus (from abilities, buffs, etc.)
The formula:
effective_luck = base_luck + (entry_bonus + difficulty_bonus + loot_bonus) * FACTOR
Args:
entry: The loot table entry
context: Loot generation context
Returns:
Effective luck stat for rarity calculations
"""
# Get difficulty bonus
difficulty_bonus = DIFFICULTY_RARITY_BONUS.get(
context.enemy_difficulty, 0.0
)
# Sum all bonuses
total_bonus = (
entry.rarity_bonus +
difficulty_bonus +
context.loot_bonus
)
# Convert bonus to effective luck points
bonus_luck = int(total_bonus * LUCK_CONVERSION_FACTOR)
effective_luck = context.luck_stat + bonus_luck
logger.debug(
"Effective luck calculated",
base_luck=context.luck_stat,
entry_bonus=entry.rarity_bonus,
difficulty_bonus=difficulty_bonus,
loot_bonus=context.loot_bonus,
total_bonus=total_bonus,
effective_luck=effective_luck
)
return effective_luck
def generate_boss_loot(
self,
enemy: EnemyTemplate,
context: LootContext,
guaranteed_drops: int = 1
) -> List[Item]:
"""
Generate loot from a boss enemy with guaranteed drops.
Boss enemies are guaranteed to drop at least one piece of equipment
in addition to their normal loot table rolls.
Args:
enemy: The boss enemy template
context: Loot generation context
guaranteed_drops: Number of guaranteed equipment drops
Returns:
List of Item objects including guaranteed drops
"""
# Generate normal loot first
items = self.generate_loot_from_enemy(enemy, context)
# Add guaranteed procedural drops for bosses
if enemy.is_boss():
context_for_boss = LootContext(
party_average_level=context.party_average_level,
enemy_difficulty=EnemyDifficulty.BOSS,
luck_stat=context.luck_stat,
loot_bonus=context.loot_bonus + 0.1 # Extra bonus for bosses
)
for _ in range(guaranteed_drops):
# Alternate between weapon and armor
item_type = random.choice(["weapon", "armor"])
effective_luck = self._calculate_effective_luck(
LootEntry(
loot_type=LootType.PROCEDURAL,
item_type=item_type,
rarity_bonus=0.15 # Boss-tier bonus
),
context_for_boss
)
item = self.item_generator.generate_loot_drop(
character_level=context.party_average_level,
luck_stat=effective_luck,
item_type=item_type
)
if item:
items.append(item)
logger.info(
"Boss loot generated",
enemy_id=enemy.enemy_id,
guaranteed_drops=guaranteed_drops,
total_items=len(items)
)
return items
# Global singleton
_service_instance: Optional[CombatLootService] = None
def get_combat_loot_service() -> CombatLootService:
"""
Get the global CombatLootService instance.
Returns:
Singleton CombatLootService instance
"""
global _service_instance
if _service_instance is None:
_service_instance = CombatLootService()
return _service_instance