from datetime import timedelta

from fastapi import APIRouter, Depends, HTTPException
from mysql.connector import Error as MySQLError

from ds.db import db
from schema.user_schema import UserRegisterRequest, UserLoginRequest, UserResponse
from schema.response_schema import APIResponse
from middle.auth_middleware import (
    get_password_hash,
    verify_password,
    create_access_token,
    ACCESS_TOKEN_EXPIRE_MINUTES,
    get_current_user
)

# 创建用户接口路由（前缀 /users、标签用于 Swagger 分类）
router = APIRouter(
    prefix="/users",
    tags=["用户管理"]
)


# ------------------------------
# 1. 用户注册接口
# ------------------------------
@router.post("/register", response_model=APIResponse, summary="用户注册")
async def user_register(request: UserRegisterRequest):
    """
    用户注册: 
    - 校验用户名是否已存在
    - 加密密码后插入数据库
    - 返回注册成功信息
    """
    conn = None
    cursor = None
    try:
        conn = db.get_connection()
        cursor = conn.cursor(dictionary=True)

        # 1. 检查用户名是否已存在（唯一索引）
        check_query = "SELECT username FROM users WHERE username = %s"
        cursor.execute(check_query, (request.username,))
        existing_user = cursor.fetchone()
        if existing_user:
            raise HTTPException(
                status_code=400,
                detail=f"用户名 '{request.username}' 已存在、请更换其他用户名"
            )

        # 2. 加密密码
        hashed_password = get_password_hash(request.password)

        # 3. 插入新用户到数据库
        insert_query = """
            INSERT INTO users (username, password)
            VALUES (%s, %s)
        """
        cursor.execute(insert_query, (request.username, hashed_password))
        conn.commit()  # 提交事务

        # 4. 返回注册成功响应
        return APIResponse(
            code=201,  # 201 表示资源创建成功
            message=f"用户 '{request.username}' 注册成功",
            data=None
        )
    except MySQLError as e:
        conn.rollback()  # 数据库错误时回滚事务
        raise Exception(f"注册失败: {str(e)}") from e
    finally:
        db.close_connection(conn, cursor)


# ------------------------------
# 2. 用户登录接口
# ------------------------------
@router.post("/login", response_model=APIResponse, summary="用户登录（获取 Token）")
async def user_login(request: UserLoginRequest):
    """
    用户登录: 
    - 校验用户名是否存在
    - 校验密码是否正确
    - 生成 JWT Token 并返回
    """
    conn = None
    cursor = None
    try:
        conn = db.get_connection()
        cursor = conn.cursor(dictionary=True)

        # 修复: SQL查询添加 created_at 和 updated_at 字段
        query = """
            SELECT id, username, password, created_at, updated_at 
            FROM users 
            WHERE username = %s
        """
        cursor.execute(query, (request.username,))
        user = cursor.fetchone()

        # 2. 校验用户名和密码
        if not user or not verify_password(request.password, user["password"]):
            raise HTTPException(
                status_code=401,
                detail="用户名或密码错误",
                headers={"WWW-Authenticate": "Bearer"},
            )

        # 3. 生成 Token（过期时间从配置读取）
        access_token_expires = timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
        access_token = create_access_token(
            data={"sub": user["username"]},
            expires_delta=access_token_expires
        )

        # 4. 返回 Token 和用户基本信息
        return APIResponse(
            code=200,
            message="登录成功",
            data={
                "access_token": access_token,
                "token_type": "bearer",
                "user": UserResponse(
                    id=user["id"],
                    username=user["username"],
                    created_at=user.get("created_at"),
                    updated_at=user.get("updated_at")
                )
            }
        )
    except MySQLError as e:
        raise Exception(f"登录失败: {str(e)}") from e
    finally:
        db.close_connection(conn, cursor)


# ------------------------------
# 3. 获取当前登录用户信息（需认证）
# ------------------------------
@router.get("/me", response_model=APIResponse, summary="获取当前用户信息")
async def get_current_user_info(
        current_user: UserResponse = Depends(get_current_user)  # 依赖认证中间件
):
    """
    获取当前登录用户信息: 
    - 需在请求头携带 Token（格式: Bearer <token>）
    - 认证通过后返回用户信息
    """
    return APIResponse(
        code=200,
        message="获取用户信息成功",
        data=current_user
    )