"""认证 API"""
import hmac
import secrets
from urllib.parse import parse_qsl, urlencode, urlsplit, urlunsplit

from fastapi import APIRouter, Depends, HTTPException, Header, Request, Response
from pydantic import BaseModel
from sqlalchemy.orm import Session
from app.core.database import get_db
from app.core.casdoor import casdoor_sdk
from app.core.errors import internal_error
from app.core.security import create_access_token, verify_casdoor_token, verify_token
from app.core.config import settings
from app.models.user import User
from app.schemas.auth import Token, UserInfo
from datetime import datetime

router = APIRouter(prefix="/api/auth", tags=["认证"])
OAUTH_STATE_COOKIE = "h3c_oauth_state"
OAUTH_STATE_TTL_SECONDS = 300


def _with_oauth_state(url: str, state: str) -> str:
    """Replace the SDK-generated state with the browser-bound state value."""
    parts = urlsplit(url)
    query = [(key, value) for key, value in parse_qsl(parts.query, keep_blank_values=True) if key != "state"]
    query.append(("state", state))
    return urlunsplit((parts.scheme, parts.netloc, parts.path, urlencode(query), parts.fragment))


@router.get("/login")
def login(response: Response):
    """获取 Casdoor 登录 URL"""
    state = secrets.token_urlsafe(32)
    response.set_cookie(
        key=OAUTH_STATE_COOKIE,
        value=state,
        max_age=OAUTH_STATE_TTL_SECONDS,
        httponly=True,
        secure=not settings.DEBUG,
        samesite="lax",
        path="/api/auth",
    )
    login_url = casdoor_sdk.get_auth_link(settings.CASDOOR_REDIRECT_URL)
    return {"url": _with_oauth_state(login_url, state)}


class CallbackRequest(BaseModel):
    code: str
    state: str


@router.post("/callback", response_model=Token)
def callback(
    body: CallbackRequest,
    request: Request,
    response: Response,
    db: Session = Depends(get_db),
):
    """Casdoor 登录回调"""
    try:
        expected_state = request.cookies.get(OAUTH_STATE_COOKIE)
        response.delete_cookie(OAUTH_STATE_COOKIE, path="/api/auth")
        if not expected_state or not hmac.compare_digest(body.state, expected_state):
            raise HTTPException(status_code=400, detail="登录状态校验失败，请重新登录")

        token_response = casdoor_sdk.get_oauth_token(code=body.code)
        if isinstance(token_response, dict) and "error" in token_response:
            raise HTTPException(status_code=400, detail=token_response.get("error_description", token_response["error"]))

        access_token = token_response.get("access_token") if isinstance(token_response, dict) else token_response
        identity_token = token_response.get("id_token") if isinstance(token_response, dict) else None
        if not access_token:
            raise HTTPException(status_code=400, detail="Casdoor 未返回 access_token")

        casdoor_user = verify_casdoor_token(identity_token or access_token)

        user = db.query(User).filter(User.casdoor_id == casdoor_user["sub"]).first()
        if not user:
            user = User(
                casdoor_id=casdoor_user["sub"],
                username=casdoor_user.get("preferred_username") or casdoor_user.get("name", ""),
                display_name=casdoor_user.get("displayName") or casdoor_user.get("name", ""),
                email=casdoor_user.get("email"),
                role="user"
            )
            db.add(user)
        else:
            # 每次登录同步 Casdoor 信息（姓名、邮箱等可能更新）
            user.display_name = casdoor_user.get("displayName") or casdoor_user.get("name", user.display_name or "")
            user.email = casdoor_user.get("email", user.email)

        user.last_login = datetime.utcnow()
        db.commit()

        jwt_token = create_access_token({
            "sub": str(user.id),
            "username": user.username,
            "role": user.role or "user",
        })
        return {"access_token": jwt_token}
    except HTTPException:
        raise
    except Exception as e:
        raise internal_error("Casdoor login callback", e)


@router.get("/permissions")
def get_my_permissions(
    authorization: str = Header(None, alias="Authorization"),
    db: Session = Depends(get_db)
):
    """获取当前用户的权限码列表"""
    from app.middleware.permission_middleware import get_role_permissions
    if not authorization or not authorization.startswith("Bearer "):
        raise HTTPException(status_code=401, detail="未授权")
    token = authorization[7:]
    payload = verify_token(token)
    if not payload:
        raise HTTPException(status_code=401, detail="无效的令牌")
    role = payload.get('role', 'user')
    perms = get_role_permissions(role, db)
    return {"role": role, "permissions": perms}


@router.get("/profile")
def get_profile(
    authorization: str = Header(None, alias="Authorization"),
    db: Session = Depends(get_db)
):
    """获取当前用户信息"""
    if not authorization or not authorization.startswith("Bearer "):
        raise HTTPException(status_code=401, detail="未授权")
    token = authorization[7:]
    payload = verify_token(token)
    if not payload:
        raise HTTPException(status_code=401, detail="无效的令牌")

    user = db.query(User).filter(User.id == int(payload["sub"])).first()
    if not user:
        raise HTTPException(status_code=404, detail="用户不存在")

    return user