from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from app.core.database import get_db
from app.core.security import (
    hash_password, verify_password,
    create_access_token, create_refresh_token, decode_token,
)
from app.models.user import User
from app.schemas.auth import (
    RegisterRequest, LoginRequest, TokenResponse,
    RefreshRequest, UserOut,
)

router = APIRouter(prefix="/auth", tags=["auth"])


@router.post("/register", response_model=UserOut, status_code=status.HTTP_201_CREATED)
async def register(payload: RegisterRequest, db: AsyncSession = Depends(get_db)):
    result = await db.execute(
        select(User).where(
            (User.username == payload.username) | (User.email == payload.email)
        )
    )
    if result.scalar_one_or_none():
        raise HTTPException(status_code=400, detail="用户名或邮箱已被使用")

    user = User(
        username=payload.username,
        email=payload.email,
        hashed_password=hash_password(payload.password),
    )
    db.add(user)
    await db.flush()
    await db.refresh(user)
    return user


@router.post("/login", response_model=TokenResponse)
async def login(payload: LoginRequest, db: AsyncSession = Depends(get_db)):
    result = await db.execute(select(User).where(User.username == payload.username))
    user = result.scalar_one_or_none()

    if not user or not verify_password(payload.password, user.hashed_password):
        raise HTTPException(status_code=401, detail="用户名或密码错误")

    if not user.is_active:
        raise HTTPException(status_code=403, detail="账号已被禁用")

    return TokenResponse(
        access_token=create_access_token(user.id),
        refresh_token=create_refresh_token(user.id),
    )


@router.post("/refresh", response_model=TokenResponse)
async def refresh(payload: RefreshRequest, db: AsyncSession = Depends(get_db)):
    token_data = decode_token(payload.refresh_token)

    if token_data is None or token_data.get("type") != "refresh":
        raise HTTPException(status_code=401, detail="Refresh token 无效或已过期")

    user_id = int(token_data["sub"])
    result = await db.execute(select(User).where(User.id == user_id))
    user = result.scalar_one_or_none()

    if not user or not user.is_active:
        raise HTTPException(status_code=401, detail="用户不存在")

    return TokenResponse(
        access_token=create_access_token(user.id),
        refresh_token=create_refresh_token(user.id),
    )


@router.get("/me", response_model=UserOut)
async def get_me(current_user: User = Depends(__import__("app.api.deps", fromlist=["get_current_user"]).get_current_user)):
    return current_user