// js/firebase/auth.js
import { auth, provider } from './config.js';
import { signInWithPopup, signOut as firebaseSignOut, onAuthStateChanged, signInWithEmailAndPassword, createUserWithEmailAndPassword } from "https://www.gstatic.com/firebasejs/10.7.1/firebase-auth.js";
import { syncManager } from './sync.js';

export class AuthManager {
    constructor() {
        this.user = null;
        this.unsubscribe = null;
        this.init();
    }

    init() {
        if (!auth) return;

        this.unsubscribe = onAuthStateChanged(auth, (user) => {
            this.user = user;
            this.updateUI(user);
            
            if (user) {
                console.log("User logged in:", user.uid);
                syncManager.initialize(user);
            } else {
                console.log("User logged out");
                syncManager.disconnect();
            }
        });
    }

    async signInWithGoogle() {
        if (!auth) {
            alert("Firebase is not configured. Please check console.");
            return;
        }

        try {
            const result = await signInWithPopup(auth, provider);
            // The onAuthStateChanged listener will handle the rest
            return result.user;
        } catch (error) {
            console.error("Login failed:", error);
            alert(`Login failed: ${error.message}`);
            throw error;
        }
    }

    async signInWithEmail(email, password) {
        if (!auth) {
            alert("Firebase is not configured.");
            return;
        }
        try {
            const result = await signInWithEmailAndPassword(auth, email, password);
            return result.user;
        } catch (error) {
            console.error("Email Login failed:", error);
            alert(`Login failed: ${error.message}`);
            throw error;
        }
    }

    async signUpWithEmail(email, password) {
        if (!auth) {
            alert("Firebase is not configured.");
            return;
        }
        try {
            const result = await createUserWithEmailAndPassword(auth, email, password);
            return result.user;
        } catch (error) {
            console.error("Sign Up failed:", error);
            alert(`Sign Up failed: ${error.message}`);
            throw error;
        }
    }

    async signOut() {
        if (!auth) return;

        try {
            await firebaseSignOut(auth);
            // The onAuthStateChanged listener will handle the rest
        } catch (error) {
            console.error("Logout failed:", error);
            throw error;
        }
    }

    updateUI(user) {
        const connectBtn = document.getElementById('firebase-connect-btn');
        const clearDataBtn = document.getElementById('firebase-clear-cloud-btn');
        const statusText = document.getElementById('firebase-status');
        const emailContainer = document.getElementById('email-auth-container');
        const emailToggleBtn = document.getElementById('toggle-email-auth-btn');

        if (!connectBtn) return; // UI might not be rendered yet

        if (user) {
            connectBtn.textContent = 'Sign Out';
            connectBtn.classList.add('danger');
            connectBtn.onclick = () => this.signOut();
            
            if (clearDataBtn) clearDataBtn.style.display = 'block';
            if (emailContainer) emailContainer.style.display = 'none';
            if (emailToggleBtn) emailToggleBtn.style.display = 'none';

            if (statusText) statusText.textContent = `Signed in as ${user.email}`;

        } else {
            connectBtn.textContent = 'Connect with Google';
            connectBtn.classList.remove('danger');
            connectBtn.onclick = () => this.signInWithGoogle();
            
            if (clearDataBtn) clearDataBtn.style.display = 'none';
            if (emailToggleBtn) emailToggleBtn.style.display = 'inline-block';

            if (statusText) statusText.textContent = 'Sync your library across devices';
        }
    }
}

export const authManager = new AuthManager();