from fastapi import APIRouter, Depends, HTTPException, Response, Cookie, status
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession
from app.database import get_db
from app.models.user import User
from app.schemas.auth import UserCreate, UserLogin, UserResponse, TokenResponse
from app.services.auth import (
    hash_password, verify_password,
    create_access_token, create_refresh_token, decode_token,
    get_current_user,
)
from app.config import get_settings

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


@router.post("/register", response_model=UserResponse, status_code=201)
async def register(data: UserCreate, db: AsyncSession = Depends(get_db)):
    # Check existing
    existing = await db.execute(
        select(User).where((User.email == data.email) | (User.username == data.username))
    )
    if existing.scalar_one_or_none():
        raise HTTPException(status_code=409, detail="Email or username already registered")

    user = User(
        email=data.email,
        username=data.username,
        password_hash=hash_password(data.password),
    )
    db.add(user)
    await db.commit()
    await db.refresh(user)
    return user


@router.post("/login", response_model=TokenResponse)
async def login(data: UserLogin, response: Response, db: AsyncSession = Depends(get_db)):
    result = await db.execute(select(User).where(User.email == data.email))
    user = result.scalar_one_or_none()
    if not user or not verify_password(data.password, user.password_hash):
        raise HTTPException(status_code=401, detail="Invalid credentials")

    access_token = create_access_token(user.id)
    refresh_token = create_refresh_token(user.id)

    response.set_cookie(
        key="refresh_token",
        value=refresh_token,
        httponly=True,
        secure=False,  # Set True in production with HTTPS
        samesite="lax",
        max_age=settings.refresh_token_expire_days * 86400,
        path="/api/auth",
    )

    return TokenResponse(access_token=access_token)


@router.post("/refresh", response_model=TokenResponse)
async def refresh(
    response: Response,
    refresh_token: str | None = Cookie(default=None),
    db: AsyncSession = Depends(get_db),
):
    if not refresh_token:
        raise HTTPException(status_code=401, detail="No refresh token")

    payload = decode_token(refresh_token)
    if payload.get("type") != "refresh":
        raise HTTPException(status_code=401, detail="Invalid token type")

    user_id = int(payload["sub"])
    result = await db.execute(select(User).where(User.id == user_id))
    user = result.scalar_one_or_none()
    if not user:
        raise HTTPException(status_code=401, detail="User not found")

    new_access = create_access_token(user.id)
    new_refresh = create_refresh_token(user.id)

    response.set_cookie(
        key="refresh_token",
        value=new_refresh,
        httponly=True,
        secure=False,
        samesite="lax",
        max_age=settings.refresh_token_expire_days * 86400,
        path="/api/auth",
    )

    return TokenResponse(access_token=new_access)


@router.post("/logout")
async def logout(response: Response):
    response.delete_cookie("refresh_token", path="/api/auth")
    return {"message": "Logged out"}


@router.get("/me", response_model=UserResponse)
async def me(user: User = Depends(get_current_user)):
    return user