"""
认证装饰器与 session 校验
"""
from functools import wraps

from flask import request, redirect, url_for, session, jsonify

from utils.db import get_db


def is_session_user_valid():
    """校验 session 中的 user_id 是否仍存在；不存在则清空 session。"""
    uid = session.get('user_id')
    if not uid:
        return False
    try:
        conn = get_db()
        with conn.cursor() as cur:
            cur.execute("SELECT id FROM users WHERE id = %s", (uid,))
            row = cur.fetchone()
        conn.close()
        if not row:
            session.clear()
            return False
        return True
    except Exception:
        session.clear()
        return False


def get_current_admin_role():
    """返回当前登录用户的管理角色：super_admin / admin / None。"""
    uid = session.get('user_id')
    if not uid:
        return None, None
    try:
        conn = get_db()
        with conn.cursor() as cur:
            cur.execute(
                "SELECT id, username, is_admin, role, created_by_id FROM users WHERE id = %s",
                (uid,)
            )
            row = cur.fetchone()
        conn.close()
        if not row or not row.get('is_admin'):
            return None, row
        role = row.get('role') or ('super_admin' if row.get('created_by_id') is None else 'admin')
        return role, row
    except Exception:
        return None, None


def is_current_user_admin():
    role, _ = get_current_admin_role()
    return role in ('super_admin', 'admin')


def _is_ajax_request():
    return request.headers.get('X-Requested-With') == 'XMLHttpRequest'


def login_required(f):
    @wraps(f)
    def decorated(*args, **kwargs):
        if not session.get('user_id') or not is_session_user_valid():
            if _is_ajax_request():
                return jsonify({'success': False, 'error': '未登录'}), 401
            return redirect(url_for('auth.login'))
        return f(*args, **kwargs)
    return decorated


def admin_required(f):
    @wraps(f)
    def decorated(*args, **kwargs):
        if not session.get('user_id') or not is_session_user_valid():
            if _is_ajax_request():
                return jsonify({'success': False, 'error': '未登录'}), 401
            return redirect(url_for('auth.login'))

        try:
            role, _ = get_current_admin_role()
            if role not in ('super_admin', 'admin'):
                if _is_ajax_request():
                    return jsonify({'success': False, 'error': '需要管理员权限'}), 403
                return redirect(url_for('auth.login'))
        except Exception as exc:
            if _is_ajax_request():
                return jsonify({'success': False, 'error': str(exc)}), 500
            return redirect(url_for('auth.login'))
        return f(*args, **kwargs)
    return decorated