import { HttpInterceptorFn, HttpErrorResponse } from '@angular/common/http';
import { inject } from '@angular/core';
import { Router } from '@angular/router';
import { catchError, throwError } from 'rxjs';
import { AuthService } from '../services/auth.service';

// 防重复重定向机制
let lastRedirectTime = 0;
const REDIRECT_DEBOUNCE_MS = 1000;

export const AuthInterceptor: HttpInterceptorFn = (req, next) => {
  const router = inject(Router);
  const authService = inject(AuthService);
  
  console.log(`拦截请求: ${req.method} ${req.url}`);
  
  // 克隆请求以添加认证头
  let authReq = req;
  
  // 检查是否为公开端点（不需要认证）
  const isPublicEndpoint = req.url.includes('/auth/login') || req.url.includes('/auth/health');
  
  // 为需要认证的API请求添加Bearer认证头
  if (req.url.includes('/api/') && !isPublicEndpoint) {
    const token = authService.getAuthToken();
    console.log(`🔍 [AuthInterceptor] 处理API请求: ${req.method} ${req.url}`);
    console.log(`🔍 [AuthInterceptor] Token存在: ${!!token}, 长度: ${token?.length}`);
    
    if (token) {
      console.log('🔍 [AuthInterceptor] API请求，添加Bearer认证头');
      authReq = req.clone({
        setHeaders: {
          Authorization: `Bearer ${token}`
        }
      });
      console.log(`🔍 [AuthInterceptor] 添加后的请求头:`, authReq.headers.get('Authorization')?.substring(0, 30) + '...');
    } else {
      console.warn('🔍 [AuthInterceptor] API请求需要认证，但用户未登录，不添加认证头');
      // 不添加认证头，后端会返回401错误，错误处理会跳转到登录页
    }
  } else {
    console.log('🔍 [AuthInterceptor] 公开端点或非API请求，不添加认证头');
  }
  
  return next(authReq).pipe(
    catchError((error: HttpErrorResponse) => {
      console.log(`请求错误: ${error.status} ${req.method} ${req.url}`);
      console.log('错误详情:', error.error);
      
      // 处理认证错误
      if (error.status === 401 || error.status === 403 || 
          (error.error && (error.error.error?.includes('认证') || error.error.error?.includes('缺少认证')))) {
        console.warn('认证失败，跳转到登录页面:', error.error);
        console.log('当前路由:', router.url);
        
        // 清除本地存储的认证信息
        authService.logout();
        
        // 跳转到登录页面，除非当前已经在登录页面
        if (!router.url.includes('/login')) {
          // 防重复重定向：检查上次重定向时间
          const now = Date.now();
          if (now - lastRedirectTime > REDIRECT_DEBOUNCE_MS) {
            lastRedirectTime = now;
            console.log('重定向到登录页面');
            router.navigate(['/login'], {
              queryParams: { returnUrl: router.url }
            });
          } else {
            console.log('跳过重复重定向（防抖期内）');
          }
        } else {
          console.log('已经在登录页面，不重定向');
        }
      }
      
      return throwError(() => error);
    })
  );
};