from contextlib import asynccontextmanager
from fastapi import FastAPI, Request
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse, FileResponse
import os
import time
import json

from app.config import CORS_ORIGINS, WEBUI_PATH, HOST, PORT
from app.database import init_db
from app.routers import api_router
from app.utils.logger import logger
from app.utils.auth import decode_access_token


@asynccontextmanager
async def lifespan(app: FastAPI):
    """应用生命周期管理"""
    # 启动时
    logger.info("应用启动中...")
    init_db()
    logger.info("数据库初始化完成")
    yield
    # 关闭时
    logger.info("应用关闭中...")


# 创建 FastAPI 应用
app = FastAPI(
    title="爱莉希雅待办事项 API",
    description="Elysia ToDo - 个人信息管理应用",
    version="1.0.0",
    lifespan=lifespan,
)

# 配置 CORS
app.add_middleware(
    CORSMiddleware,
    allow_origins=CORS_ORIGINS,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


# 请求日志中间件
@app.middleware("http")
async def log_requests(request: Request, call_next):
    start_time = time.time()

    # 记录请求信息
    request_method = request.method
    request_path = request.url.path
    query_params = dict(request.query_params) if request.query_params else None

    # 构建日志信息
    log_parts = [f"请求开始 -> {request_method} {request_path}"]
    if query_params:
        log_parts.append(f"Query参数: {json.dumps(query_params, ensure_ascii=False)}")

    # 尝试读取请求体（仅对有 body 的方法）
    body_info = None
    if request.method in ["POST", "PUT", "PATCH"]:
        try:
            body_bytes = await request.body()
            if body_bytes:
                try:
                    body_json = json.loads(body_bytes)
                    body_info = json.dumps(body_json, ensure_ascii=False)
                except json.JSONDecodeError:
                    body_info = body_bytes.decode('utf-8', errors='replace')[:200]
                log_parts.append(f"Body: {body_info}")
        except Exception:
            pass

    logger.info(" | ".join(log_parts))

    # 执行请求
    response = await call_next(request)

    # 计算耗时
    process_time = (time.time() - start_time) * 1000

    # 记录响应信息
    logger.info(
        f"请求完成 <- {request_method} {request_path} | "
        f"状态码: {response.status_code} | 耗时: {process_time:.2f}ms"
    )

    return response


# 认证中间件（保护所有 /api/* 路由，除了 /api/auth/* 和 /health）
@app.middleware("http")
async def auth_middleware(request: Request, call_next):
    path = request.url.path

    # 不拦截：健康检查、静态文件、auth 路由
    if path == "/health" or not path.startswith("/api/") or path.startswith("/api/auth/"):
        return await call_next(request)

    auth_header = request.headers.get("Authorization", "")
    token = auth_header.replace("Bearer ", "")
    if not token:
        return JSONResponse(status_code=401, content={"detail": "未登录"})

    try:
        decode_access_token(token)
    except Exception:
        return JSONResponse(status_code=401, content={"detail": "登录已过期，请重新登录"})

    return await call_next(request)


# 全局异常处理器
@app.exception_handler(Exception)
async def global_exception_handler(request: Request, exc: Exception):
    # 使用 exc_info=True 记录完整堆栈信息
    logger.error(
        f"全局异常: {request.method} {request.url.path} | 错误: {str(exc)}",
        exc_info=True
    )
    return JSONResponse(
        status_code=500,
        content={
            "success": False,
            "message": "服务器内部错误",
            "error_code": "INTERNAL_ERROR"
        }
    )


# 注册路由
app.include_router(api_router)


# 健康检查（必须在 static mount 之前注册，否则会被静态文件拦截）
@app.get("/health")
async def health_check():
    """健康检查"""
    return {"status": "ok", "message": "服务运行正常"}


# SPA 静态文件回退路由（支持前端 History 模式路由）
if os.path.exists(WEBUI_PATH):

    @app.get("/")
    async def serve_index():
        return FileResponse(os.path.join(WEBUI_PATH, "index.html"))

    @app.get("/{full_path:path}")
    async def spa_fallback(request: Request, full_path: str):
        """SPA 回退：先尝试提供真实文件，找不到则返回 index.html"""
        # 规范化路径并防止路径穿越攻击
        safe_path = os.path.normpath(os.path.join(WEBUI_PATH, full_path))
        if not safe_path.startswith(os.path.normpath(WEBUI_PATH)):
            return FileResponse(os.path.join(WEBUI_PATH, "index.html"))
        if os.path.isfile(safe_path):
            return FileResponse(safe_path)
        return FileResponse(os.path.join(WEBUI_PATH, "index.html"))

    logger.info(f"SPA 静态文件服务已配置: {WEBUI_PATH}")
else:
    logger.warning(f"WebUI 目录不存在: {WEBUI_PATH}")


if __name__ == "__main__":
    import uvicorn
    logger.info(f"启动服务: {HOST}:{PORT}")
    uvicorn.run(app, host=HOST, port=PORT)