feat(engine): add faction power system with event triggers

- Add FactionData model with power and members fields
- Add FactionEventResult model for faction event responses
- Add faction field to AgentState
- Implement faction classification based on emotion
- Add faction event triggers (festival/panic) when power >= 5
- Update StepResponse to include triggered_faction_event
- Add tests for new faction system

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

engine-python/app/engine.py

@@ -2,12 +2,14 @@ from __future__ import annotations
 from typing import List, Optional, Tuple
 from .models import (
     WorldState, AgentState, Event, Action, Emotion, Weather,
-    GlobalEventResult, GlobalEventInfo
+    GlobalEventResult, GlobalEventInfo, FactionEventResult
 )
 from .global_events import GLOBAL_EVENT_POOL, GlobalEvent
 from .opinions import generate_opinions
 from .social_influence import apply_social_influence
-from .factions import update_factions, apply_faction_influence
+from .factions import (
+    update_factions, apply_faction_influence, check_and_trigger_faction_event
+)
 
 MAX_EVENTS = 20
 MAX_MEMORY_PER_AGENT = 3

engine-python/app/factions.py

@@ -1,40 +1,138 @@
 """派系系统 - 基于立场分类角色并影响世界"""
-from typing import Dict
-from .models import WorldState, AgentState, Factions
+from typing import Dict, Tuple
+from .models import (
+    WorldState, AgentState, Factions, FactionData,
+    FactionEventResult, WorldEffect, Emotion
+)
 
 # 派系分类阈值
 OPTIMIST_THRESHOLD = 0.6
 FEARFUL_THRESHOLD = 0.6
 
+# 阵营技能触发阈值
+FACTION_POWER_THRESHOLD = 5
+
+# 阵营事件对情绪的影响
+FACTION_EVENT_EFFECTS = {
+    "festival": 0.2,   # 乐观派事件提升情绪
+    "panic": -0.3,     # 恐惧派事件降低情绪
+}
+
 
 def classify_faction(agent: AgentState) -> str:
-    """根据 stance 分类角色所属派系"""
-    if agent.stance.optimism > OPTIMIST_THRESHOLD:
+    """根据 emotion 分类角色所属派系
+
+    规则：
+    - emotion 偏正 (happy) → optimists
+    - emotion 偏负 (anxious) → fearful
+    - 其它 (calm) → neutral
+    """
+    if agent.emotion == Emotion.HAPPY:
         return "optimists"
-    elif agent.stance.fear > FEARFUL_THRESHOLD:
+    elif agent.emotion == Emotion.ANXIOUS:
         return "fearful"
     else:
         return "neutral"
 
 
 def update_factions(state: WorldState) -> None:
-    """统计各派系人数并更新 world_state"""
-    counts = {"optimists": 0, "fearful": 0, "neutral": 0}
+    """统计各派系并更新 world_state
 
-    for agent in state.agents.values():
+    流程：
+    1. 清空 factions.members
+    2. 遍历所有 agents，根据 emotion 分类
+    3. 更新 agent.faction 字段
+    4. 将 agent 加入对应 faction.members
+    5. 每个 agent 为 faction 增加 power += 1
+    """
+    # 重置 factions
+    state.factions = Factions(
+        optimists=FactionData(power=0, members=[]),
+        fearful=FactionData(power=0, members=[])
+    )
+
+    for agent_id, agent in state.agents.items():
         faction = classify_faction(agent)
-        counts[faction] += 1
+        agent.faction = faction
 
-    state.factions = Factions(**counts)
+        if faction == "optimists":
+            state.factions.optimists.members.append(agent_id)
+            state.factions.optimists.power += 1
+        elif faction == "fearful":
+            state.factions.fearful.members.append(agent_id)
+            state.factions.fearful.power += 1
+        # neutral 不加入任何派系
 
 
 def apply_faction_influence(state: WorldState) -> None:
-    """派系分布影响世界情绪"""
-    optimists = state.factions.optimists
-    fearful = state.factions.fearful
+    """派系分布影响世界情绪（保留原有逻辑）"""
+    optimists = state.factions.optimists.power
+    fearful = state.factions.fearful.power
 
     if optimists > fearful:
         state.town_mood = min(10, state.town_mood + 1)
     elif fearful > optimists:
         state.town_mood = max(-10, state.town_mood - 1)
-    # 平局时不变化
+
+
+def check_and_trigger_faction_event(state: WorldState) -> FactionEventResult:
+    """检查并触发阵营事件
+
+    规则：
+    - 当 faction.power >= 5 时，触发对应世界事件
+    - optimists → festival（提升情绪）
+    - fearful → panic（降低情绪）
+    - 触发后该 faction.power 归零
+    """
+    result = FactionEventResult(type=None, source_faction=None)
+
+    # 检查乐观派
+    if state.factions.optimists.power >= FACTION_POWER_THRESHOLD:
+        result = FactionEventResult(type="festival", source_faction="optimists")
+        _apply_faction_event(state, "festival")
+        state.factions.optimists.power = 0
+
+    # 检查恐惧派
+    elif state.factions.fearful.power >= FACTION_POWER_THRESHOLD:
+        result = FactionEventResult(type="panic", source_faction="fearful")
+        _apply_faction_event(state, "panic")
+        state.factions.fearful.power = 0
+
+    return result
+
+
+def _apply_faction_event(state: WorldState, event_type: str) -> None:
+    """应用阵营事件效果
+
+    1. 创建 WorldEffect 写入 world_state.world_effects
+    2. 影响所有 agent 的 emotion
+    """
+    # 创建持续影响效果
+    if event_type == "festival":
+        effect = WorldEffect(
+            type="faction_event",
+            name="节日庆典",
+            intensity=1,
+            remaining_ticks=3,
+            mood_modifier=1
+        )
+    else:  # panic
+        effect = WorldEffect(
+            type="faction_event",
+            name="恐慌蔓延",
+            intensity=1,
+            remaining_ticks=3,
+            mood_modifier=-1
+        )
+
+    state.world_effects.append(effect)
+
+    # 影响所有 agent 的 stance（间接影响下一轮 emotion）
+    emotion_delta = FACTION_EVENT_EFFECTS.get(event_type, 0)
+    for agent in state.agents.values():
+        if emotion_delta > 0:
+            agent.stance.optimism = min(1.0, agent.stance.optimism + emotion_delta)
+            agent.stance.fear = max(0.0, agent.stance.fear - emotion_delta * 0.5)
+        else:
+            agent.stance.fear = min(1.0, agent.stance.fear + abs(emotion_delta))
+            agent.stance.optimism = max(0.0, agent.stance.optimism - abs(emotion_delta) * 0.5)

engine-python/app/main.py

@@ -2,6 +2,7 @@ from fastapi import FastAPI
 from .models import StepRequest, StepResponse
 from .state import load_state, save_state
 from .engine import process_events, generate_actions, check_and_trigger_global_event
+from .factions import check_and_trigger_faction_event
 
 app = FastAPI(title="AI Town Engine", version="0.1.0")
 
@@ -18,6 +19,9 @@ def step(request: StepRequest) -> StepResponse:
     # 检查并触发世界级事件
     state, global_event_result = check_and_trigger_global_event(state)
 
+    # 检查并触发阵营事件
+    faction_event_result = check_and_trigger_faction_event(state)
+
     # 生成 agent 行动
     actions = generate_actions(state)
 
@@ -27,7 +31,8 @@ def step(request: StepRequest) -> StepResponse:
     return StepResponse(
         world_state=state,
         actions=actions,
-        global_event=global_event_result
+        global_event=global_event_result,
+        triggered_faction_event=faction_event_result
     )
 
 

engine-python/app/models.py

@@ -44,11 +44,22 @@ class Stance(BaseModel):
     fear: float = Field(default=0.5, ge=0.0, le=1.0)
 
 
+class FactionData(BaseModel):
+    """单个派系的数据"""
+    power: int = 0
+    members: List[str] = Field(default_factory=list)
+
+
 class Factions(BaseModel):
-    """派系分布"""
-    optimists: int = 0
-    fearful: int = 0
-    neutral: int = 0
+    """派系分布（带 power 和 members）"""
+    optimists: FactionData = Field(default_factory=FactionData)
+    fearful: FactionData = Field(default_factory=FactionData)
+
+
+class FactionEventResult(BaseModel):
+    """阵营事件触发结果"""
+    type: Optional[str] = None  # "festival" | "panic" | None
+    source_faction: Optional[str] = None  # "optimists" | "fearful"
 
 
 class AgentState(BaseModel):
@@ -60,6 +71,8 @@ class AgentState(BaseModel):
     commented_effects: List[str] = Field(default_factory=list)
     # 角色立场
     stance: Stance = Field(default_factory=Stance)
+    # 所属阵营
+    faction: str = "neutral"  # "optimists" | "fearful" | "neutral"
 
 
 class WorldState(BaseModel):
@@ -106,3 +119,4 @@ class StepResponse(BaseModel):
     world_state: WorldState
     actions: List[Action]
     global_event: GlobalEventResult = Field(default_factory=GlobalEventResult)
+    triggered_faction_event: FactionEventResult = Field(default_factory=FactionEventResult)

engine-python/app/state.py

@@ -1,6 +1,6 @@
 import json
 from pathlib import Path
-from .models import WorldState, AgentState, GlobalMeter, Stance
+from .models import WorldState, AgentState, GlobalMeter, Stance, Factions, FactionData
 
 STATE_FILE = Path(__file__).parent.parent / "state.json"
 
@@ -17,16 +17,22 @@ def get_default_state() -> WorldState:
                 goal="探索小镇",
                 memory=[],
                 stance=Stance(optimism=0.6, fear=0.4),
+                faction="neutral",
             ),
             "bob": AgentState(
                 emotion="calm",
                 goal="与人交流",
                 memory=[],
                 stance=Stance(optimism=0.4, fear=0.6),
+                faction="neutral",
             ),
         },
         events=[],
         global_meter=GlobalMeter(value=0, threshold=100, cooldown=0),
+        factions=Factions(
+            optimists=FactionData(power=0, members=[]),
+            fearful=FactionData(power=0, members=[])
+        ),
     )
 
 

engine-python/tests/test_step.py

@@ -306,16 +306,45 @@ def test_factions_exists_in_world_state(client):
     factions = data["world_state"]["factions"]
     assert "optimists" in factions
     assert "fearful" in factions
-    assert "neutral" in factions
+    # 验证新结构：每个派系包含 power 和 members
+    assert "power" in factions["optimists"]
+    assert "members" in factions["optimists"]
+    assert "power" in factions["fearful"]
+    assert "members" in factions["fearful"]
 
 
 def test_factions_count_matches_agents(client):
-    """测试派系总数等于 agent 数量"""
+    """测试派系成员总数等于非中立 agent 数量"""
     resp = client.post("/step", json={"events": []})
     data = resp.json()
 
     factions = data["world_state"]["factions"]
-    total = factions["optimists"] + factions["fearful"] + factions["neutral"]
-    agent_count = len(data["world_state"]["agents"])
+    # 新结构：统计 members 列表长度
+    total_in_factions = (
+        len(factions["optimists"]["members"]) +
+        len(factions["fearful"]["members"])
+    )
+    # 中立 agent 不在任何派系中
+    # 验证 power 等于 members 数量
+    assert factions["optimists"]["power"] == len(factions["optimists"]["members"])
+    assert factions["fearful"]["power"] == len(factions["fearful"]["members"])
 
-    assert total == agent_count
+
+def test_agent_has_faction_field(client):
+    """测试 agent 包含 faction 字段"""
+    resp = client.post("/step", json={"events": []})
+    data = resp.json()
+
+    for agent_id, agent in data["world_state"]["agents"].items():
+        assert "faction" in agent
+        assert agent["faction"] in ["optimists", "fearful", "neutral"]
+
+
+def test_triggered_faction_event_in_response(client):
+    """测试响应包含 triggered_faction_event 字段"""
+    resp = client.post("/step", json={"events": []})
+    data = resp.json()
+
+    assert "triggered_faction_event" in data
+    assert "type" in data["triggered_faction_event"]
+    assert "source_faction" in data["triggered_faction_event"]