# -*- coding: utf-8 -*-
"""接口层依赖：数据库句柄与当前登录用户（JWT + RBAC，全异步）。

``Database`` 实例由 ``main.py`` 在启动时创建并挂在 ``app.state.db`` 上，
路由通过 ``Depends(get_db)`` 取用；测试时可替换为临时目录实例。
"""
from __future__ import annotations

from fastapi import Depends, HTTPException, Request

from .. import config
from ..infrastructure.repositories import Database
from ..jwt import decode_access_token

BEARER_PREFIX = "Bearer "


def extract_bearer_token(request: Request) -> str:
    """从 Authorization 头提取 Bearer token，没有则返回空串。"""
    auth_header = request.headers.get("Authorization", "")
    if auth_header.startswith(BEARER_PREFIX):
        return auth_header[len(BEARER_PREFIX):].strip()
    return ""


async def get_db():
    """每请求一个独立 Database/AsyncSession（绑定共享引擎）。

    之前直接返回 app.state.db（单例 AsyncSession）被并发请求复用，会间歇报
    ``sqlalchemy.exc.InvalidRequestError: concurrent operations are not permitted``。
    改为每请求各建一个 Database 并在请求结束关闭，根除该竞态。
    """
    db = Database()
    try:
        yield db
    finally:
        await db.close()


async def _resolve_identity(user: dict, db: Database) -> dict:
    """单账号角色（多身份已收敛）：role 由 users.role 提供，仅计算权限与数据范围。"""
    user["permissions"] = await db.roles.permissions_for(
        user.get("role", "opc_member"), None,
    )
    user["scope_region_ids"] = await db.regions.visible_region_ids(user.get("region_id"))
    user["scope_level"] = await db.regions.level(user.get("region_id"))
    return user


async def get_current_user(
    request: Request,
    db: Database = Depends(get_db),
) -> dict:
    """校验调用方 JWT，返回当前用户记录（含 role/权限/数据范围）。"""
    token = extract_bearer_token(request)
    if not token:
        raise HTTPException(status_code=401, detail="No token provided")

    payload = decode_access_token(token)
    if payload is None:
        raise HTTPException(status_code=401, detail="Invalid or expired token")

    user_id = payload.get("sub")
    if not await db.tokens.session_valid(
        payload.get("jti", ""),
        user_id,
        payload.get("ver", 0),
    ):
        raise HTTPException(status_code=401, detail="Invalid or expired token")

    user = await db.users.get_by_id(user_id)
    if user is None or user.get("status") != "active":
        raise HTTPException(status_code=401, detail="Invalid or expired token")

    return await _resolve_identity(user, db)


async def optional_current_user(
    request: Request,
    db: Database = Depends(get_db),
) -> dict | None:
    """可选登录：有有效 JWT 则返回用户，否则返回 None（不报错）。"""
    token = extract_bearer_token(request)
    if not token:
        return None
    payload = decode_access_token(token)
    if payload is None:
        return None
    if not await db.tokens.session_valid(
        payload.get("jti", ""), payload.get("sub", ""), payload.get("ver", 0),
    ):
        return None
    user = await db.users.get_by_id(payload.get("sub"))
    if user is None or user.get("status") != "active":
        return None
    return await _resolve_identity(user, db)


def require_port(user: dict = Depends(get_current_user)) -> dict:
    """按端口隔离的资源（如智能体）—— 单角色后不再按端口隔离，仅要求已登录。

    账号唯一角色：智能体不再按端口隔离，统一归到该账号（port=""）。为兼容
    既有 AgentRepository 的 port 过滤，这里补一个恒定空串。
    """
    user.setdefault("port", "")
    return user