"use client";

import { useState } from "react";
import { signInWithPopup, GoogleAuthProvider } from "firebase/auth";
import { auth, googleProvider } from "@/lib/firebase";
import { useRouter } from "next/navigation";

interface GoogleSignInProps {
  type?: "login" | "register";
  onSuccess?: () => void;
  onError?: (error: string) => void;
}

export default function GoogleSignIn({ type = "login", onSuccess, onError }: GoogleSignInProps) {
  const [loading, setLoading] = useState(false);
  const router = useRouter();

  const handleGoogleSignIn = async () => {
    if (!auth) {
      const errorMsg = "Firebase is not initialized. Please check your configuration.";
      if (onError) {
        onError(errorMsg);
      } else {
        alert(errorMsg);
      }
      return;
    }

    setLoading(true);
    try {
      // Sign in with Google
      const result = await signInWithPopup(auth, googleProvider);
      const user = result.user;

      if (!user) {
        throw new Error("Failed to get user information");
      }

      // Get the ID token
      const idToken = await user.getIdToken();

      // Send token to backend for verification and user creation/update
      const response = await fetch("/api/auth/firebase", {
        method: "POST",
        headers: {
          "Content-Type": "application/json",
        },
        body: JSON.stringify({
          idToken,
          email: user.email,
          name: user.displayName,
          photoURL: user.photoURL,
          provider: "google",
        }),
      });

      // Check if response is OK before parsing JSON
      if (!response.ok) {
        // Try to get error message from response
        let errorMessage = "Authentication failed";
        try {
          const errorData = await response.json();
          errorMessage = errorData.error || errorData.message || `HTTP ${response.status}: ${response.statusText}`;
        } catch (e) {
          // If response is not JSON (e.g., HTML 404 page), use status text
          errorMessage = `HTTP ${response.status}: ${response.statusText || "Failed to connect to server"}`;
        }
        throw new Error(errorMessage);
      }

      const data = await response.json();

      // Store user in localStorage
      localStorage.setItem("user", JSON.stringify(data.user));
      localStorage.setItem("isAuthenticated", "true");
      localStorage.setItem("firebaseToken", idToken);

      // Call success callback if provided
      if (onSuccess) {
        onSuccess();
      }

      // Redirect based on role
      if (data.user.role === "admin") {
        router.push("/admin");
      } else {
        router.push("/account");
      }
    } catch (error: any) {
      console.error("Google Sign-In error:", error);
      const errorMessage = error.message || "Failed to sign in with Google";
      
      if (onError) {
        onError(errorMessage);
      } else {
        alert(errorMessage);
      }
    } finally {
      setLoading(false);
    }
  };

  return (
    <button
      type="button"
      onClick={handleGoogleSignIn}
      disabled={loading}
      className="flex items-center justify-center gap-2 px-4 py-2 border border-gray-300 rounded-lg hover:bg-gray-50 transition disabled:opacity-50 disabled:cursor-not-allowed w-full"
    >
      {loading ? (
        <>
          <div className="w-5 h-5 border-2 border-gray-300 border-t-blue-600 rounded-full animate-spin"></div>
          <span>Signing in...</span>
        </>
      ) : (
        <>
          <svg className="w-5 h-5" viewBox="0 0 24 24">
            <path
              fill="#4285F4"
              d="M22.56 12.25c0-.78-.07-1.53-.2-2.25H12v4.26h5.92c-.26 1.37-1.04 2.53-2.21 3.31v2.77h3.57c2.08-1.92 3.28-4.74 3.28-8.09z"
            />
            <path
              fill="#34A853"
              d="M12 23c2.97 0 5.46-.98 7.28-2.66l-3.57-2.77c-.98.66-2.23 1.06-3.71 1.06-2.86 0-5.29-1.93-6.16-4.53H2.18v2.84C3.99 20.53 7.7 23 12 23z"
            />
            <path
              fill="#FBBC05"
              d="M5.84 14.09c-.22-.66-.35-1.36-.35-2.09s.13-1.43.35-2.09V7.07H2.18C1.43 8.55 1 10.22 1 12s.43 3.45 1.18 4.93l2.85-2.22.81-.62z"
            />
            <path
              fill="#EA4335"
              d="M12 5.38c1.62 0 3.06.56 4.21 1.64l3.15-3.15C17.45 2.09 14.97 1 12 1 7.7 1 3.99 3.47 2.18 7.07l3.66 2.84c.87-2.6 3.3-4.53 6.16-4.53z"
            />
          </svg>
          <span>Continue with Google</span>
        </>
      )}
    </button>
  );
}