"""
AI Chat API Server — 主入口（纯基础设施层）

职责：
  - 注入运行时依赖（venv site-packages）
  - 读取 LLM_BACKEND 环境变量，动态加载对应平台模块
  - 注册 FastAPI 路由和中间件

平台代码位置（main.py 中不包含任何平台逻辑）：
  - 百炼 DashScope → api/chat_routes.py
  - 智谱 GLM-4.6V  → api/chat_routes_glm.py  +  utils/glm_adapter.py
"""

import os
import sys
from datetime import datetime, timezone
from pathlib import Path

# ── 注入 venv site-packages（兼容 start.sh 用系统 python3 启动）────────
# 必须在所有第三方 import 前执行
_venv_lib = Path(__file__).parent / ".venv" / "lib"
if _venv_lib.exists():
    for _sp in sorted(_venv_lib.glob("python*/site-packages"), reverse=True):
        if _sp.exists() and str(_sp) not in sys.path:
            sys.path.insert(0, str(_sp))
            print(f"[启动] venv 注入：{_sp}")
            break

# ── 第三方导入 ────────────────────────────────────────────────────────
from dotenv import load_dotenv
from fastapi import FastAPI, File, Request, UploadFile
from fastapi.responses import JSONResponse

sys.path.append("/home/mt/project/ai-chat-ui/server")

# ── 工具/日志（与平台无关）───────────────────────────────────────────
from utils.helpers import log_response
from utils.logger import get_logger

logger = get_logger()

# ── 加载环境变量 ──────────────────────────────────────────────────────
load_dotenv()

LLM_BACKEND = os.getenv("LLM_BACKEND", "dashscope").lower().strip()
if LLM_BACKEND not in {"dashscope", "glm"}:
    logger.warning(f"未知的 LLM_BACKEND='{LLM_BACKEND}'，回退到 dashscope")
    LLM_BACKEND = "dashscope"

# ── 动态加载平台模块 ──────────────────────────────────────────────────
if LLM_BACKEND == "glm":
    import api.chat_routes_glm as _platform
else:
    import api.chat_routes as _platform

_platform.init()  # 各平台自行完成初始化（API Key 校验等）

# 通用路由处理器（文件上传、会话管理等，与平台无关，统一用百炼路由中的实现）
from api.chat_routes import (delete_conversation_handler,
                             get_conversation_handler,
                             get_conversations_handler,
                             save_conversation_handler, serve_upload_handler,
                             stop_generation_handler, upload_file_handler)

# ── FastAPI 应用 ──────────────────────────────────────────────────────
app = FastAPI(
    title=f"AI Chat API（LLM_BACKEND={LLM_BACKEND}）",
    version="3.0.0",
)


@app.middleware("http")
async def logging_middleware(request: Request, call_next):
    start_time = datetime.now(timezone.utc)
    client_ip = request.client.host if request.client else "unknown"
    logger.info(f"→ {request.method} {request.url.path} | IP: {client_ip}")
    response = await call_next(request)
    ms = (datetime.now(timezone.utc) - start_time).total_seconds() * 1000
    icon = "✅" if response.status_code < 400 else "❌"
    logger.info(
        f"{icon} {request.method} {request.url.path} | 状态: {response.status_code} | 耗时: {ms:.0f}ms"
    )
    log_response(response.status_code, ms)
    response.headers["X-Process-Time"] = f"{ms:.2f}ms"
    return response


# ── 路由注册 ──────────────────────────────────────────────────────────


@app.get("/health")
async def health_check():
    return {
        "status": "healthy",
        "backend": LLM_BACKEND,
        "timestamp": datetime.now(timezone.utc).isoformat(),
    }


@app.post("/api/chat-ui/chat")
async def chat_endpoint(request: Request):
    """聊天接口（自动路由到当前平台）"""
    return await _platform.chat_handler(await request.json())


@app.get("/api/chat-ui/models")
async def get_models():
    """模型列表（由当前平台返回）"""
    result = _platform.models_handler()
    # 支持同步和异步两种返回
    if hasattr(result, "__await__"):
        return await result
    return result


# ── 通用路由（与平台无关）────────────────────────────────────────────


@app.get("/api/chat-ui/conversations")
async def get_conversations():
    return await get_conversations_handler()


@app.get("/api/chat-ui/conversations/{conversation_id}")
async def get_conversation(conversation_id: str):
    return await get_conversation_handler(conversation_id)


@app.post("/api/chat-ui/conversations")
async def save_conversation(request: Request):
    return await save_conversation_handler(await request.json())


@app.delete("/api/chat-ui/conversations/{conversation_id}")
async def delete_conversation(conversation_id: str):
    return await delete_conversation_handler(conversation_id)


@app.post("/api/chat-ui/upload")
async def upload_file(file: UploadFile = File(...)):
    return await upload_file_handler(file=file)


@app.get("/uploads/{filename}")
async def serve_upload(filename: str):
    return serve_upload_handler(filename)


@app.post("/api/chat-ui/stop")
async def stop_generation():
    return await stop_generation_handler()


@app.post("/api/chat-ui/stop/{message_id}")
async def stop_generation_by_id(message_id: str):
    return await stop_generation_handler(message_id)


# ── 程序入口 ──────────────────────────────────────────────────────────
if __name__ == "__main__":
    import uvicorn

    port = int(os.getenv("PORT", 8000))
    print("=" * 55)
    print(f"  AI Chat Server v3.0  启动中...")
    print(f"  后端平台  : {LLM_BACKEND.upper()}  [LLM_BACKEND={LLM_BACKEND}]")
    print(f"  监听端口  : {port}")
    print(f"  切换平台  : 修改 .env 中 LLM_BACKEND=glm|dashscope，重启")
    print("=" * 55)
    uvicorn.run(app, host="0.0.0.0", port=port)