refactor: separate provider capability policy

backend/app/services/provider_router.py

@@ -1,7 +1,6 @@
 """Provider routing with failover - 基于适配器注册表的智能路由。"""
 
 import time
-from enum import Enum
 from typing import TYPE_CHECKING, Literal, TypeVar
 
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -13,6 +12,13 @@ from app.services.adapters.text.models import StoryOutput
 from app.services.cost_tracker import cost_tracker
 from app.services.provider_cache import get_providers
 from app.services.provider_metrics import health_checker, metrics_collector
+from app.services.provider_policy import (
+    API_KEY_MAP,
+    DEFAULT_PROVIDERS,
+    ProviderType,
+    RoutingStrategy,
+    get_provider_names_from_settings,
+)
 
 if TYPE_CHECKING:
     from app.db.admin_models import Provider
@@ -21,50 +27,9 @@ logger = get_logger(__name__)
 
 T = TypeVar("T")
 
-ProviderType = Literal["text", "image", "tts", "storybook"]
-
-
-class RoutingStrategy(str, Enum):
-    """路由策略枚举。"""
-
-    PRIORITY = "priority"  # 按优先级排序（默认）
-    COST = "cost"  # 按成本排序
-    LATENCY = "latency"  # 按延迟排序
-    ROUND_ROBIN = "round_robin"  # 轮询
-
-
-# 默认配置映射（当 DB 无配置时使用）
-# 这是“代码级”的默认策略，对应 .env 为空的情况
-DEFAULT_PROVIDERS: dict[ProviderType, list[str]] = {
-    "text": ["gemini", "openai"],
-    "image": ["cqtai"],
-    "tts": ["minimax", "elevenlabs", "edge_tts"],
-    "storybook": ["storybook_primary"],
-}
-
-# API Key 映射：adapter_name -> settings 属性名
-API_KEY_MAP: dict[str, str] = {
-    # Text
-    "gemini": "text_api_key",       # Gemini 还是复用 text_api_key 字段
-    "text_primary": "text_api_key", # 兼容旧别名
-    "openai": "openai_api_key",
-
-    # Image
-    "cqtai": "cqtai_api_key",
-    "image_primary": "image_api_key", # 兼容旧别名
-
-    # TTS
-    "minimax": "minimax_api_key",
-    "elevenlabs": "elevenlabs_api_key",
-    "edge_tts": "tts_api_key",      # EdgeTTS 复用 tts_api_key (通常为空)
-    "tts_primary": "tts_api_key",   # 兼容旧别名
-}
-
 # 轮询计数器
 _round_robin_counters: dict[ProviderType, int] = {
-    "text": 0,
-    "image": 0,
-    "tts": 0,
+    provider_type: 0 for provider_type in DEFAULT_PROVIDERS
 }
 
 # 延迟缓存（内存中，简化实现）
@@ -115,6 +80,13 @@ def _get_default_config(adapter_name: str) -> AdapterConfig | None:
             model=settings.image_model or "nano-banana-pro",
             timeout_ms=120000,
         )
+    if adapter_name == "antigravity":
+        return AdapterConfig(
+            api_key=getattr(settings, "antigravity_api_key", ""),
+            api_base=getattr(settings, "antigravity_api_base", ""),
+            model=settings.antigravity_model,
+            timeout_ms=120000,
+        )
     if adapter_name == "image_primary":
         # 如果还有地方在用 image_primary，暂时映射到快或者其他
         # 但既然我们全面整改，最好也删了。这里暂时保留一个空的 fallback 以防报错
@@ -196,15 +168,7 @@ async def _get_providers_with_config(
     if db_providers:
         return [(p.adapter, _build_config_from_provider(p), p) for p in db_providers]
 
-    settings_map = {
-        "text": settings.text_providers,
-        "image": settings.image_providers,
-        "tts": settings.tts_providers,
-        "storybook": settings.storybook_providers,
-    }
-    names = settings_map.get(provider_type) or DEFAULT_PROVIDERS[provider_type]
-    if settings.enable_demo_providers and "demo" not in names:
-        names = ["demo", *names]
+    names = get_provider_names_from_settings(provider_type, settings)
 
     result = []
     for name in names: