from fastapi import Depends, HTTPException, status
from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from models.database import get_db
from models.models import User
from .jwt_utils import decode_access_token
from .permissions import (
    ACCOUNTS_COOKIE,
    ACCOUNTS_CREATE,
    ACCOUNTS_DELETE,
    ACCOUNTS_START,
    ACCOUNTS_STOP,
    ACCOUNTS_UPDATE,
    ACCOUNTS_WRITE,
    ACCOUNTS_WRITE_GRANULAR,
    LINK_CARDS_WRITE,
    MESSAGES_WRITE,
    ORDERS_CREATE,
    ROLES_MANAGE,
    RULES_WRITE,
    SETTINGS_DATABASE,
    SYSTEM_LOGS_CLEAR,
    USERS_MANAGE,
    WRITE_PERMISSIONS,
)
from .roles import can_write, has_permission, is_admin

bearer_scheme = HTTPBearer(auto_error=False)


async def get_current_user(
    credentials: HTTPAuthorizationCredentials = Depends(bearer_scheme),
    db: AsyncSession = Depends(get_db),
) -> User:
    if not credentials or not credentials.credentials:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="未登录或令牌缺失")
    payload = decode_access_token(credentials.credentials)
    if not payload or not payload.get("sub"):
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="登录已过期，请重新登录")
    try:
        user_id = int(payload["sub"])
    except (TypeError, ValueError):
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="无效令牌")

    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=status.HTTP_401_UNAUTHORIZED, detail="用户不存在或已禁用")
    return user


def require_permission(permission: str):
    """FastAPI dependency factory that checks a single permission code."""

    async def _checker(user: User = Depends(get_current_user)) -> User:
        if has_permission(user.role, permission):
            return user
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail=f"缺少权限：{permission}",
        )

    return _checker


async def require_admin(user: User = Depends(get_current_user)) -> User:
    if not is_admin(user.role):
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="需要管理员权限")
    return user


async def require_write(user: User = Depends(get_current_user)) -> User:
    """Any write-capable permission (accounts/messages/rules) or legacy can_write."""
    if is_admin(user.role) or can_write(user.role):
        return user
    if any(has_permission(user.role, code) for code in WRITE_PERMISSIONS):
        return user
    raise HTTPException(
        status_code=status.HTTP_403_FORBIDDEN,
        detail="当前角色只读，无法执行此操作",
    )


def _require_any(*codes: str, detail: str):
    async def _checker(user: User = Depends(get_current_user)) -> User:
        if any(has_permission(user.role, code) for code in codes):
            return user
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail=detail)

    return _checker


# Backward-compatible: any account write capability.
require_accounts_write = _require_any(
    ACCOUNTS_WRITE,
    *ACCOUNTS_WRITE_GRANULAR,
    detail="缺少账号写权限",
)
require_accounts_create = require_permission(ACCOUNTS_CREATE)
require_accounts_update = require_permission(ACCOUNTS_UPDATE)
require_accounts_delete = require_permission(ACCOUNTS_DELETE)
require_accounts_start = require_permission(ACCOUNTS_START)
require_accounts_stop = require_permission(ACCOUNTS_STOP)
require_accounts_cookie = require_permission(ACCOUNTS_COOKIE)

require_messages_write = require_permission(MESSAGES_WRITE)
require_rules_write = require_permission(RULES_WRITE)
require_link_cards_write = require_permission(LINK_CARDS_WRITE)
require_system_logs_clear = require_permission(SYSTEM_LOGS_CLEAR)
require_settings_database = require_permission(SETTINGS_DATABASE)
require_orders_create = require_permission(ORDERS_CREATE)


async def require_user_manager(user: User = Depends(get_current_user)) -> User:
    if has_permission(user.role, USERS_MANAGE):
        return user
    raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="需要用户管理权限")


async def require_role_manager(user: User = Depends(get_current_user)) -> User:
    if has_permission(user.role, ROLES_MANAGE):
        return user
    raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="需要角色管理权限")