"""
主页面蓝图：首页、管理后台页、静态文件
"""
import os
from flask import Blueprint, current_app, redirect, url_for, send_file, session
from werkzeug.utils import safe_join

from utils.auth import login_required, is_session_user_valid
from utils.render import render_html

main = Blueprint('main', __name__, url_prefix='')

BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
STATIC_DIR = os.path.join(BASE_DIR, 'static')


@main.route('/')
def index():
    if session.get('user_id') and is_session_user_valid():
        return redirect(url_for('main.admin_page'))
    return redirect(url_for('auth.login'))


@main.route('/admin')
@login_required
def admin_page():
    """管理后台页：服务端直接渲染当前用户有权限的菜单，避免客户端二次渲染造成闪烁。"""
    context = {}
    try:
        # 复用权限菜单加载逻辑；Java 权限接口不可用时降级为无菜单（JS 侧会走 API 兜底）
        from blueprints.admin_api import _load_current_backend_menu_items
        _, _, items, denied = _load_current_backend_menu_items()
        if denied is None and items:
            context['admin_menu_items'] = items
            context['admin_menu_rendered'] = True
        else:
            # 权限接口失败：真实页面同样会失败，服务端不渲染菜单，避免展示越权菜单
            context['admin_menu_rendered'] = False
            current_app.logger.warning('[admin] 服务端菜单渲染失败，降级为客户端加载: %s',
                                       (denied[0].get_json() if denied and len(denied) > 0 else None))
    except Exception as exc:
        # 兜底：任何异常都不得阻断管理页打开，JS 会自行请求菜单接口
        current_app.logger.exception('[admin] 服务端渲染菜单异常: %s', exc)
        context['admin_menu_rendered'] = False
    return render_html('admin.html', **context)


@main.route('/static/<path:filename>')
def serve_static(filename):
    """提供 static 目录及子目录下的静态文件访问"""
    filepath = safe_join(STATIC_DIR, filename)
    if filepath is None or not os.path.isfile(filepath):
        return '', 404
    return send_file(filepath, as_attachment=False)