"use client";

import React, { useEffect, useState } from "react";
import { useRouter, useSearchParams } from "next/navigation";
import { CheckCircle, XCircle, Loader2, AlertTriangle } from "lucide-react";
import type { OAuthCallbackParams } from "@/app/types/google-oauth";
import { baseUrl } from '@/lib/env';

// 根据后端实际返回格式定义响应类型
interface GoogleOAuthResponse {
  code: number;
  message: string;
  data: {
    token: string;
    user: {
      userId: string;
      userName: string;
      name: string;
      email: string;
      authType: "GOOGLE";
      avatar: string;
      isNewUser: boolean;
    };
    message: string;
  };
  successful: boolean;
}

export default function OAuthCallback() {
  const router = useRouter();
  const searchParams = useSearchParams();
  const [status, setStatus] = useState<"loading" | "success" | "error" | "conflict">("loading");
  const [message, setMessage] = useState("");
  const [conflictData, setConflictData] = useState<any>(null);

  useEffect(() => {
    const handleOAuthCallback = async () => {
      try {
        console.log('🎯 Google OAuth 回调页面开始处理...');
        console.log('📍 回调页面调试信息:');
        console.log('  - 完整回调 URL:', window.location.href);
        console.log('  - 回调域名:', window.location.hostname);
        console.log('  - 回调协议:', window.location.protocol);
        console.log('  - 回调路径:', window.location.pathname);
        console.log('  - URL 查询参数:', window.location.search);
        
        // 获取URL参数
        const params: OAuthCallbackParams = {
          code: searchParams.get("code") || undefined,
          state: searchParams.get("state") || undefined,
          error: searchParams.get("error") || undefined,
          error_description: searchParams.get("error_description") || undefined,
        };

        console.log('📦 获取到的URL参数:', params);

        // 检查是否有错误
        if (params.error) {
          console.error('OAuth错误:', params.error, params.error_description);
          setStatus("error");
          setMessage(params.error_description || `OAuth error: ${params.error}`);
          return;
        }

        // 验证必需参数
        if (!params.code || !params.state) {
          console.error('缺少必需的OAuth参数:', { code: !!params.code, state: !!params.state });
          setStatus("error");
          setMessage("Missing required OAuth parameters");
          return;
        }

        // 解析state参数获取邀请码等信息
        let stateData: any = {};
        try {
          stateData = JSON.parse(params.state);
          console.log('解析后的State数据:', stateData);
        } catch (e) {
          console.warn('无法解析state参数:', params.state, e);
        }

        // 从 sessionStorage 获取邀请码
        let inviteCode: string | undefined = undefined;
        try {
          const sessionInviteCode = sessionStorage.getItem("inviteCode");
          if (sessionInviteCode) {
            inviteCode = sessionInviteCode;
            console.log('从 sessionStorage 获取到邀请码:', inviteCode);
          }
        } catch (e) {
          console.warn('无法从 sessionStorage 获取邀请码:', e);
        }

        // 优先级：sessionStorage > state参数 > undefined
        const finalInviteCode = inviteCode || stateData.inviteCode || undefined;

        console.log('开始处理Google OAuth回调, code:', params.code?.substring(0, 20) + '...');
        console.log('State数据:', stateData);
        console.log('最终使用的邀请码:', finalInviteCode);

        // 根据 jiekou.md 文档调用统一的 Python OAuth 接口
        // 使用统一配置中的 baseUrl
        console.log('🔧 调用 Python OAuth 接口:', baseUrl);

        const response = await fetch(`${baseUrl}/api/oauth/google`, {
          method: 'POST',
          headers: {
            'Content-Type': 'application/json',
            'Accept': 'application/json',
          },
          body: JSON.stringify({
            code: params.code,
            state: params.state,
            invite_code: finalInviteCode || null
          })
        });

        console.log('Python OAuth接口响应状态:', response.status);
        const result: GoogleOAuthResponse = await response.json();

        console.log('🔍 后端返回的完整数据:', result);

        // 根据后端实际返回格式判断成功状态
        // 后端返回: { code: 0, successful: true } 表示成功
        const isSuccess = response.ok && result.successful && result.code === 0;

        if (!isSuccess) {
          console.error('Python OAuth接口处理失败:', result);

          // 处理常见错误码
          if (result.message?.includes('GOOGLE_TOKEN_EXCHANGE_FAILED')) {
            throw new Error('Google authorization failed. Please try again.');
          } else if (result.message?.includes('INVALID_ID_TOKEN')) {
            throw new Error('Invalid Google token. Please try again.');
          } else if (result.message?.includes('UPSTREAM_AUTH_ERROR')) {
            throw new Error('Authentication service error. Please try again later.');
          }

          // 根据后端返回格式处理错误
          const errorMessage = result.message || `OAuth failed (code: ${result.code})`;
          throw new Error(errorMessage);
        }

        console.log('🎉 Google OAuth成功:', {
          userId: result.data?.user?.userId,
          email: result.data?.user?.email,
          isNewUser: result.data?.user?.isNewUser,
          code: result.code,
          successful: result.successful
        });

        // 处理成功结果
        console.log('✅ Google登录成功，完整响应:', result);
        setStatus("success");
        setMessage(result.data.message || "Login successful! Redirecting to dashboard...");

        // 根据后端实际响应格式保存用户信息
        const { token, user } = result.data;

        // 保存用户信息到localStorage
        const userData = {
          userId: user.userId,
          userName: user.userName,
          name: user.name,
          email: user.email,
          authType: user.authType,
          avatar: user.avatar,
          isNewUser: user.isNewUser
        };

        console.log('💾 保存用户数据到 localStorage:', userData);
        localStorage.setItem('currentUser', JSON.stringify(userData));

        if (token) {
          console.log('🔑 保存 token 到 localStorage');
          localStorage.setItem('token', token);
        }

        console.log('⏰ 准备在2秒后跳转到 /movies');

        // 2秒后跳转到主页
        setTimeout(() => {
          const returnUrl = '/movies';
          console.log('🚀 开始跳转到:', returnUrl);
          window.location.href = returnUrl;
        }, 2000);

      } catch (error: any) {
        console.error("OAuth callback error:", error);
        
        // 检查是否是网络连接错误
        if (error.code === 'ECONNREFUSED' || error.message?.includes('fetch failed')) {
          console.error('网络连接失败，可能是后端服务不可用');
          setStatus("error");
          setMessage('Backend service unavailable. Please try again later.');
          return;
        }

        // 检查是否是 JSON 解析错误
        if (error.message?.includes('JSON') || error.name === 'SyntaxError') {
          console.error('响应数据解析失败:', error);
          setStatus("error");
          setMessage('Invalid response format from backend services');
          return;
        }

        // 处理邮箱冲突错误
        if (error.type === 'EMAIL_CONFLICT') {
          setStatus("conflict");
          setMessage(error.message);
          setConflictData(error.data);
        } else {
          setStatus("error");
          setMessage(error.message || "OAuth callback processing failed");
        }
      }
    };

    handleOAuthCallback();
  }, [searchParams, router]);

  const handleBindAccount = async () => {
    try {
      // 这里应该实现账户绑定逻辑
      // 需要调用 /api/auth/google/bind 接口
      console.log("Account binding not yet implemented");
      setMessage("Account binding feature is not yet implemented");
    } catch (error: any) {
      console.error("Account binding failed:", error);
      setMessage(error.message || "Account binding failed");
    }
  };

  const handleReturnToLogin = () => {
    router.push("/login");
  };

  const renderContent = () => {
    switch (status) {
      case "loading":
        return (
          <div className="flex flex-col items-center justify-center space-y-4">
            <div className="relative">
              <div className="absolute inset-0 bg-gradient-to-r from-cyan-400 to-purple-600 rounded-full blur-lg opacity-30 animate-pulse"></div>
              <Loader2 className="h-16 w-16 animate-spin text-cyan-400 relative z-10" />
            </div>
            <p className="text-lg text-gray-300">Processing OAuth callback...</p>
          </div>
        );

      case "success":
        return (
          <div className="flex flex-col items-center justify-center space-y-4">
            <div className="relative">
              <div className="absolute inset-0 bg-gradient-to-r from-cyan-400 to-purple-600 rounded-full blur-lg opacity-30"></div>
              <CheckCircle className="h-16 w-16 text-cyan-400 relative z-10" />
            </div>
            <h2 className="text-2xl font-semibold bg-gradient-to-r from-cyan-400 to-purple-600 bg-clip-text text-transparent">
              Login Successful
            </h2>
            <p className="text-gray-300 text-center max-w-md">{message}</p>
          </div>
        );

      case "conflict":
        return (
          <div className="flex flex-col items-center justify-center space-y-4">
            <div className="relative">
              <div className="absolute inset-0 bg-gradient-to-r from-yellow-400 to-orange-500 rounded-full blur-lg opacity-30"></div>
              <AlertTriangle className="h-16 w-16 text-yellow-400 relative z-10" />
            </div>
            <h2 className="text-2xl font-semibold bg-gradient-to-r from-yellow-400 to-orange-500 bg-clip-text text-transparent">
              Account Conflict
            </h2>
            <p className="text-gray-300 text-center max-w-md">{message}</p>
            {conflictData && (
              <div className="text-center space-y-4">
                <p className="text-sm text-gray-400">
                  Email: {conflictData.existingUser?.email}
                </p>
                <div className="flex gap-3">
                  <button
                    onClick={handleBindAccount}
                    className="px-4 py-2 bg-gradient-to-r from-cyan-400 to-purple-600 text-white rounded-lg hover:from-cyan-500 hover:to-purple-700 transition-all duration-300"
                  >
                    Bind Account
                  </button>
                  <button
                    onClick={handleReturnToLogin}
                    className="px-4 py-2 border border-white/20 text-white rounded-lg hover:bg-white/10 transition-all duration-300"
                  >
                    Return to Login
                  </button>
                </div>
              </div>
            )}
          </div>
        );

      case "error":
        return (
          <div className="flex flex-col items-center justify-center space-y-4">
            <div className="relative">
              <div className="absolute inset-0 bg-gradient-to-r from-red-500 to-orange-500 rounded-full blur-lg opacity-30"></div>
              <XCircle className="h-16 w-16 text-red-400 relative z-10" />
            </div>
            <h2 className="text-2xl font-semibold bg-gradient-to-r from-red-500 to-orange-500 bg-clip-text text-transparent">
              OAuth Failed
            </h2>
            <p className="text-gray-300 text-center max-w-md">{message}</p>
            <button
              onClick={handleReturnToLogin}
              className="mt-4 px-6 py-2 bg-gradient-to-r from-cyan-400 to-purple-600 text-white rounded-lg hover:from-cyan-500 hover:to-purple-700 transition-all duration-300 shadow-lg hover:shadow-xl transform hover:scale-105"
            >
              Return to Login
            </button>
          </div>
        );
    }
  };

  return (
    <div className="min-h-screen flex items-center justify-center bg-gradient-to-br from-black via-gray-900 to-black px-4">
      <div className="bg-gradient-to-br from-gray-900/90 to-black/90 backdrop-blur-sm rounded-2xl shadow-2xl p-8 max-w-md w-full border border-gray-700/50 relative overflow-hidden">
        <div className="absolute inset-0 bg-gradient-to-br from-cyan-400/10 to-purple-600/10 pointer-events-none"></div>
        <div className="relative z-10">
          {status === "loading" && (
            <div className="text-center mb-8">
              <h1 className="text-3xl font-bold text-white mb-2 bg-gradient-to-r from-cyan-400 to-purple-600 bg-clip-text text-transparent">
                OAuth Callback
              </h1>
              <p className="text-gray-300">
                Please wait while we process your authentication
              </p>
            </div>
          )}
          {renderContent()}
        </div>
      </div>
    </div>
  );
}