/**
 * Iribl AI - Document Intelligence Application
 * With Dual Sidebars, Collapsible Sections, and Animated Dropdowns
 */

// ==================== App State ====================
const state = {
    token: localStorage.getItem('Iribl AI_token'),
    user: JSON.parse(localStorage.getItem('Iribl AI_user') || 'null'),
    documents: [],
    buckets: [],
    employees: [],
    messages: [],
    summaries: {},  // doc_id -> summary text cache
    selectedDocument: null,  // Currently selected document for summary display
    selectedBucket: '',
    chatBucket: '',
    isLoading: false,
    currentRole: 'admin',
    // Chat History
    chatHistory: JSON.parse(localStorage.getItem('Iribl AI_chat_history') || '[]'),
    currentChatId: null,
    // Upload cancellation
    uploadCancelled: false,
    currentUploadAbortController: null,
    // Stream abort controller for stopping generation
    streamAbortController: null
};

// ==================== DOM Elements ====================
const elements = {
    // Auth
    authModal: document.getElementById('authModal'),
    loginForm: document.getElementById('loginForm'),
    registerForm: document.getElementById('registerForm'),
    employeeLoginForm: document.getElementById('employeeLoginForm'),
    authTabs: document.getElementById('authTabs'),
    loginError: document.getElementById('loginError'),
    registerError: document.getElementById('registerError'),
    employeeLoginError: document.getElementById('employeeLoginError'),

    // Modals
    addEmployeeModal: document.getElementById('addEmployeeModal'),
    addEmployeeForm: document.getElementById('addEmployeeForm'),
    addEmployeeError: document.getElementById('addEmployeeError'),
    addEmployeeBtn: document.getElementById('addEmployeeBtn'),
    cancelAddEmployee: document.getElementById('cancelAddEmployee'),
    createBucketModal: document.getElementById('createBucketModal'),
    createBucketForm: document.getElementById('createBucketForm'),
    createBucketError: document.getElementById('createBucketError'),
    createBucketBtn: document.getElementById('createBucketBtn'),
    cancelCreateBucket: document.getElementById('cancelCreateBucket'),
    docViewerModal: document.getElementById('docViewerModal'),
    docViewerTitle: document.getElementById('docViewerTitle'),
    docViewerContent: document.getElementById('docViewerContent'),
    closeDocViewer: document.getElementById('closeDocViewer'),

    // Sidebars
    leftSidebar: document.getElementById('leftSidebar'),
    rightSidebar: document.getElementById('rightSidebar'),
    leftToggle: document.getElementById('leftToggle'),
    rightToggle: document.getElementById('rightToggle'),

    // App
    appContainer: document.getElementById('appContainer'),
    userName: document.getElementById('userName'),
    userAvatar: document.getElementById('userAvatar'),
    userRole: document.getElementById('userRole'),
    logoutBtn: document.getElementById('logoutBtn'),

    // Admin
    adminSection: document.getElementById('adminSection'),
    employeesList: document.getElementById('employeesList'),

    // Buckets
    bucketsList: document.getElementById('bucketsList'),

    // Custom Dropdowns
    uploadBucketWrapper: document.getElementById('uploadBucketWrapper'),
    uploadBucketTrigger: document.getElementById('uploadBucketTrigger'),
    uploadBucketOptions: document.getElementById('uploadBucketOptions'),
    uploadBucketSelect: document.getElementById('uploadBucketSelect'),
    chatBucketWrapper: document.getElementById('chatBucketWrapper'),
    chatBucketTrigger: document.getElementById('chatBucketTrigger'),
    chatBucketOptions: document.getElementById('chatBucketOptions'),
    chatBucketSelect: document.getElementById('chatBucketSelect'),

    // Upload
    uploadZone: document.getElementById('uploadZone'),
    fileInput: document.getElementById('fileInput'),
    uploadProgress: document.getElementById('uploadProgress'),
    uploadStatus: document.getElementById('uploadStatus'),
    progressFill: document.getElementById('progressFill'),
    cancelUploadBtn: document.getElementById('cancelUploadBtn'),

    // Documents
    documentsList: document.getElementById('documentsList'),
    docCount: document.getElementById('docCount'),

    // Chat
    chatMessages: document.getElementById('chatMessages'),
    welcomeScreen: document.getElementById('welcomeScreen'),
    chatInput: document.getElementById('chatInput'),
    sendBtn: document.getElementById('sendBtn'),
    stopBtn: document.getElementById('stopBtn'),
    typingIndicator: document.getElementById('typingIndicator'),
    toastContainer: document.getElementById('toastContainer'),

    // Summary Panel
    summaryPanel: document.getElementById('summaryPanel'),
    summaryTitle: document.getElementById('summaryTitle'),
    summaryText: document.getElementById('summaryText'),
    summaryClose: document.getElementById('summaryClose'),

    // Chat History
    newChatBtn: document.getElementById('newChatBtn'),
    clearChatBtn: document.getElementById('clearChatBtn'),
    clearChatBtnTop: document.getElementById('clearChatBtnTop'),
    chatHistoryList: document.getElementById('chatHistoryList'),
    chatHistoryCount: document.getElementById('chatHistoryCount'),

    // Mobile Navigation
    mobileNav: document.getElementById('mobileNav'),
    mobileBackdrop: document.getElementById('mobileBackdrop'),
    mobileLeftToggle: document.getElementById('mobileLeftToggle'),
    mobileChatToggle: document.getElementById('mobileChatToggle'),
    mobileRightToggle: document.getElementById('mobileRightToggle')
};

// ==================== Toast ====================
function showToast(message, type = 'info') {
    const icons = { success: '✅', error: '❌', info: 'ℹ️' };
    const toast = document.createElement('div');
    toast.className = `toast ${type}`;
    toast.innerHTML = `<span class="toast-icon">${icons[type]}</span><span class="toast-message">${message}</span><button class="toast-close">✕</button>`;
    elements.toastContainer.appendChild(toast);
    toast.querySelector('.toast-close').addEventListener('click', () => toast.remove());
    setTimeout(() => { if (toast.parentElement) toast.remove(); }, 4000);
}

// ==================== Sidebar Toggle ====================
function initSidebars() {
    elements.leftToggle.addEventListener('click', () => {
        elements.leftSidebar.classList.toggle('collapsed');
        const icon = elements.leftToggle.querySelector('.toggle-icon');
        icon.textContent = elements.leftSidebar.classList.contains('collapsed') ? '▶' : '◀';
    });

    elements.rightToggle.addEventListener('click', () => {
        elements.rightSidebar.classList.toggle('collapsed');
        const icon = elements.rightToggle.querySelector('.toggle-icon');
        icon.textContent = elements.rightSidebar.classList.contains('collapsed') ? '◀' : '▶';
    });
}

// ==================== Mobile Navigation ====================
function initMobileNavigation() {
    // Check if we're on mobile
    const isMobile = () => window.innerWidth <= 768;

    // Close all sidebars on mobile
    function closeMobileSidebars() {
        elements.leftSidebar.classList.remove('mobile-open');
        elements.rightSidebar.classList.remove('mobile-open');
        elements.mobileBackdrop.classList.remove('active');
        document.body.style.overflow = '';

        // Reset nav button active states
        elements.mobileLeftToggle.classList.remove('active');
        elements.mobileRightToggle.classList.remove('active');
        elements.mobileChatToggle.classList.add('active');
    }

    // Open left sidebar (Menu)
    function openLeftSidebar() {
        closeMobileSidebars();
        elements.leftSidebar.classList.add('mobile-open');
        elements.mobileBackdrop.classList.add('active');
        document.body.style.overflow = 'hidden';

        elements.mobileLeftToggle.classList.add('active');
        elements.mobileChatToggle.classList.remove('active');
    }

    // Open right sidebar (Docs)
    function openRightSidebar() {
        closeMobileSidebars();
        elements.rightSidebar.classList.add('mobile-open');
        elements.mobileBackdrop.classList.add('active');
        document.body.style.overflow = 'hidden';

        elements.mobileRightToggle.classList.add('active');
        elements.mobileChatToggle.classList.remove('active');
    }

    // Mobile nav button handlers
    elements.mobileLeftToggle.addEventListener('click', () => {
        if (elements.leftSidebar.classList.contains('mobile-open')) {
            closeMobileSidebars();
        } else {
            openLeftSidebar();
        }
    });

    elements.mobileChatToggle.addEventListener('click', () => {
        closeMobileSidebars();
    });

    elements.mobileRightToggle.addEventListener('click', () => {
        if (elements.rightSidebar.classList.contains('mobile-open')) {
            closeMobileSidebars();
        } else {
            openRightSidebar();
        }
    });

    // Close sidebar when backdrop is clicked
    elements.mobileBackdrop.addEventListener('click', closeMobileSidebars);

    // Close sidebar on window resize to desktop
    window.addEventListener('resize', () => {
        if (!isMobile()) {
            closeMobileSidebars();
            // Reset any mobile-specific classes
            elements.leftSidebar.classList.remove('mobile-open');
            elements.rightSidebar.classList.remove('mobile-open');
        }
    });

    // Close sidebar when starting a new chat or after uploading (for better UX)
    const originalStartNewChat = window.startNewChat;
    if (typeof originalStartNewChat === 'function') {
        window.startNewChat = function () {
            if (isMobile()) closeMobileSidebars();
            return originalStartNewChat.apply(this, arguments);
        };
    }

    // Handle swipe gestures (optional enhancement)
    let touchStartX = 0;
    let touchEndX = 0;

    document.addEventListener('touchstart', (e) => {
        touchStartX = e.changedTouches[0].screenX;
    }, { passive: true });

    document.addEventListener('touchend', (e) => {
        if (!isMobile()) return;

        touchEndX = e.changedTouches[0].screenX;
        const swipeDistance = touchEndX - touchStartX;
        const minSwipeDistance = 80;

        // Swipe right from left edge - open left sidebar
        if (touchStartX < 30 && swipeDistance > minSwipeDistance) {
            openLeftSidebar();
        }

        // Swipe left from right edge - open right sidebar
        if (touchStartX > window.innerWidth - 30 && swipeDistance < -minSwipeDistance) {
            openRightSidebar();
        }

        // Swipe to close sidebars
        if (elements.leftSidebar.classList.contains('mobile-open') && swipeDistance < -minSwipeDistance) {
            closeMobileSidebars();
        }

        if (elements.rightSidebar.classList.contains('mobile-open') && swipeDistance > minSwipeDistance) {
            closeMobileSidebars();
        }
    }, { passive: true });
}

// ==================== Collapsible Sections ====================
function initCollapsible() {
    document.querySelectorAll('.collapsible .section-header').forEach(header => {
        header.addEventListener('click', (e) => {
            // Don't toggle if clicking on action buttons
            if (e.target.closest('.btn')) return;

            const section = header.closest('.collapsible');
            section.classList.toggle('collapsed');
        });
    });
}

// ==================== Custom Dropdowns ====================
function initCustomDropdowns() {
    // Close dropdowns when clicking outside
    document.addEventListener('click', (e) => {
        document.querySelectorAll('.custom-select.open').forEach(select => {
            if (!select.contains(e.target)) {
                select.classList.remove('open');
            }
        });
    });

    // Upload bucket dropdown
    elements.uploadBucketTrigger.addEventListener('click', (e) => {
        e.stopPropagation();
        elements.uploadBucketWrapper.classList.toggle('open');
        elements.chatBucketWrapper.classList.remove('open');
    });

    // Chat bucket dropdown
    elements.chatBucketTrigger.addEventListener('click', (e) => {
        e.stopPropagation();
        elements.chatBucketWrapper.classList.toggle('open');
        elements.uploadBucketWrapper.classList.remove('open');
    });
}

function updateDropdownOptions() {
    // Upload dropdown options
    let uploadOptions = `<div class="select-option active" data-value=""><span class="option-icon">📂</span> No Bucket (General)</div>`;
    uploadOptions += state.buckets.map(b =>
        `<div class="select-option" data-value="${b.bucket_id}"><span class="option-icon">📁</span> ${b.name}</div>`
    ).join('');
    elements.uploadBucketOptions.innerHTML = uploadOptions;

    // Chat dropdown options
    let chatOptions = `<div class="select-option active" data-value=""><span class="option-icon">📂</span> All Documents</div>`;
    chatOptions += state.buckets.map(b =>
        `<div class="select-option" data-value="${b.bucket_id}"><span class="option-icon">📁</span> ${b.name}</div>`
    ).join('');
    elements.chatBucketOptions.innerHTML = chatOptions;

    // Add click handlers
    elements.uploadBucketOptions.querySelectorAll('.select-option').forEach(opt => {
        opt.addEventListener('click', () => {
            const value = opt.dataset.value;
            elements.uploadBucketSelect.value = value;
            elements.uploadBucketTrigger.querySelector('.select-value').textContent = opt.textContent.trim();
            elements.uploadBucketOptions.querySelectorAll('.select-option').forEach(o => o.classList.remove('active'));
            opt.classList.add('active');
            elements.uploadBucketWrapper.classList.remove('open');
        });
    });

    elements.chatBucketOptions.querySelectorAll('.select-option').forEach(opt => {
        opt.addEventListener('click', () => {
            const value = opt.dataset.value;
            elements.chatBucketSelect.value = value;
            state.chatBucket = value;
            elements.chatBucketTrigger.querySelector('.select-value').textContent = opt.textContent.trim();
            elements.chatBucketOptions.querySelectorAll('.select-option').forEach(o => o.classList.remove('active'));
            opt.classList.add('active');
            elements.chatBucketWrapper.classList.remove('open');
        });
    });
}

// ==================== Auth ====================
function showAuthModal() {
    elements.authModal.classList.add('active');
    elements.appContainer.style.filter = 'blur(5px)';
}

function hideAuthModal() {
    elements.authModal.classList.remove('active');
    elements.appContainer.style.filter = '';
}

function updateAuthUI() {
    if (state.user) {
        elements.userName.textContent = state.user.username;
        elements.userAvatar.textContent = state.user.username.charAt(0).toUpperCase();
        elements.userRole.textContent = state.user.role === 'admin' ? 'Admin' : 'Employee';

        if (state.user.role === 'admin') {
            elements.adminSection.classList.remove('hidden');
            loadEmployees();
        } else {
            elements.adminSection.classList.add('hidden');
        }
        hideAuthModal();
    } else {
        showAuthModal();
    }
}

// Role tabs
document.querySelectorAll('.role-tab').forEach(tab => {
    tab.addEventListener('click', () => {
        document.querySelectorAll('.role-tab').forEach(t => t.classList.remove('active'));
        tab.classList.add('active');
        state.currentRole = tab.dataset.role;

        if (state.currentRole === 'admin') {
            elements.authTabs.classList.remove('hidden');
            elements.loginForm.classList.remove('hidden');
            elements.registerForm.classList.add('hidden');
            elements.employeeLoginForm.classList.add('hidden');
        } else {
            elements.authTabs.classList.add('hidden');
            elements.loginForm.classList.add('hidden');
            elements.registerForm.classList.add('hidden');
            elements.employeeLoginForm.classList.remove('hidden');
        }
    });
});

// Auth tabs
document.querySelectorAll('.auth-tab').forEach(tab => {
    tab.addEventListener('click', () => {
        document.querySelectorAll('.auth-tab').forEach(t => t.classList.remove('active'));
        tab.classList.add('active');
        const tabName = tab.dataset.tab;
        elements.loginForm.classList.toggle('hidden', tabName !== 'login');
        elements.registerForm.classList.toggle('hidden', tabName !== 'register');
    });
});

// Admin Login
elements.loginForm.addEventListener('submit', async (e) => {
    e.preventDefault();
    const formData = new FormData(e.target);
    const btn = e.target.querySelector('.auth-btn');
    btn.querySelector('.btn-text').classList.add('hidden');
    btn.querySelector('.btn-loader').classList.remove('hidden');
    elements.loginError.classList.add('hidden');

    try {
        const response = await fetch('/api/auth/login', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ username: formData.get('username'), password: formData.get('password'), role: 'admin' })
        });
        const data = await response.json();
        if (response.ok) {
            state.token = data.token;
            state.user = { user_id: data.user_id, username: data.username, role: data.role };
            localStorage.setItem('Iribl AI_token', state.token);
            localStorage.setItem('Iribl AI_user', JSON.stringify(state.user));
            updateAuthUI();
            loadBuckets();
            loadDocuments();
            loadChatHistoryFromServer();
            showToast('Welcome back!', 'success');
        } else {
            elements.loginError.textContent = data.error;
            elements.loginError.classList.remove('hidden');
        }
    } catch (error) {
        elements.loginError.textContent = 'Connection error';
        elements.loginError.classList.remove('hidden');
    }
    btn.querySelector('.btn-text').classList.remove('hidden');
    btn.querySelector('.btn-loader').classList.add('hidden');
});

// Admin Register
elements.registerForm.addEventListener('submit', async (e) => {
    e.preventDefault();
    const formData = new FormData(e.target);
    const btn = e.target.querySelector('.auth-btn');
    btn.querySelector('.btn-text').classList.add('hidden');
    btn.querySelector('.btn-loader').classList.remove('hidden');
    elements.registerError.classList.add('hidden');

    try {
        const response = await fetch('/api/auth/register/admin', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ username: formData.get('username'), email: formData.get('email'), password: formData.get('password') })
        });
        const data = await response.json();
        if (response.ok) {
            state.token = data.token;
            state.user = { user_id: data.user_id, username: data.username, role: data.role };
            localStorage.setItem('Iribl AI_token', state.token);
            localStorage.setItem('Iribl AI_user', JSON.stringify(state.user));
            updateAuthUI();
            loadBuckets();
            loadDocuments();
            loadChatHistoryFromServer();
            showToast('Account created!', 'success');
        } else {
            elements.registerError.textContent = data.error;
            elements.registerError.classList.remove('hidden');
        }
    } catch (error) {
        elements.registerError.textContent = 'Connection error';
        elements.registerError.classList.remove('hidden');
    }
    btn.querySelector('.btn-text').classList.remove('hidden');
    btn.querySelector('.btn-loader').classList.add('hidden');
});

// Employee Login
elements.employeeLoginForm.addEventListener('submit', async (e) => {
    e.preventDefault();
    const formData = new FormData(e.target);
    const btn = e.target.querySelector('.auth-btn');
    btn.querySelector('.btn-text').classList.add('hidden');
    btn.querySelector('.btn-loader').classList.remove('hidden');
    elements.employeeLoginError.classList.add('hidden');

    try {
        const response = await fetch('/api/auth/login', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ username: formData.get('email'), password: formData.get('password'), role: 'employee' })
        });
        const data = await response.json();
        if (response.ok) {
            state.token = data.token;
            state.user = { user_id: data.user_id, username: data.username, role: data.role };
            localStorage.setItem('Iribl AI_token', state.token);
            localStorage.setItem('Iribl AI_user', JSON.stringify(state.user));
            updateAuthUI();
            loadBuckets();
            loadDocuments();
            loadChatHistoryFromServer();
            showToast('Welcome!', 'success');
        } else {
            elements.employeeLoginError.textContent = data.error;
            elements.employeeLoginError.classList.remove('hidden');
        }
    } catch (error) {
        elements.employeeLoginError.textContent = 'Connection error';
        elements.employeeLoginError.classList.remove('hidden');
    }
    btn.querySelector('.btn-text').classList.remove('hidden');
    btn.querySelector('.btn-loader').classList.add('hidden');
});

// Logout
elements.logoutBtn.addEventListener('click', () => {
    state.token = null;
    state.user = null;
    state.documents = [];
    state.buckets = [];
    state.messages = [];
    localStorage.removeItem('Iribl AI_token');
    localStorage.removeItem('Iribl AI_user');
    updateAuthUI();
    renderDocuments();
    renderMessages();
    showToast('Logged out', 'info');
});

// ==================== Employees ====================
async function loadEmployees() {
    if (!state.token || state.user?.role !== 'admin') return;
    try {
        const response = await fetch('/api/admin/employees', { headers: { 'Authorization': `Bearer ${state.token}` } });
        if (response.ok) {
            const data = await response.json();
            state.employees = data.employees;
            renderEmployees();
        }
    } catch (error) { console.error('Failed to load employees:', error); }
}

function renderEmployees() {
    if (state.employees.length === 0) {
        elements.employeesList.innerHTML = `<div class="empty-state small"><div class="empty-text">No employees</div></div>`;
        return;
    }
    elements.employeesList.innerHTML = state.employees.map(emp => `
        <div class="employee-item">
            <span class="employee-email">${emp.email || emp.username}</span>
            <button class="btn btn-ghost" onclick="deleteEmployee('${emp.user_id}')" title="Remove">🗑️</button>
        </div>
    `).join('');
}

elements.addEmployeeBtn.addEventListener('click', (e) => {
    e.stopPropagation();
    elements.addEmployeeModal.classList.add('active');
    elements.addEmployeeError.classList.add('hidden');
    elements.addEmployeeForm.reset();
});

elements.cancelAddEmployee.addEventListener('click', () => elements.addEmployeeModal.classList.remove('active'));

elements.addEmployeeForm.addEventListener('submit', async (e) => {
    e.preventDefault();
    const formData = new FormData(e.target);
    const btn = e.target.querySelector('.btn-primary');
    btn.querySelector('.btn-text').classList.add('hidden');
    btn.querySelector('.btn-loader').classList.remove('hidden');

    try {
        const response = await fetch('/api/admin/employees', {
            method: 'POST',
            headers: { 'Authorization': `Bearer ${state.token}`, 'Content-Type': 'application/json' },
            body: JSON.stringify({ email: formData.get('email'), password: formData.get('password') })
        });
        const data = await response.json();
        if (response.ok) {
            elements.addEmployeeModal.classList.remove('active');
            loadEmployees();
            showToast('Employee added!', 'success');
        } else {
            elements.addEmployeeError.textContent = data.error;
            elements.addEmployeeError.classList.remove('hidden');
        }
    } catch (error) {
        elements.addEmployeeError.textContent = 'Connection error';
        elements.addEmployeeError.classList.remove('hidden');
    }
    btn.querySelector('.btn-text').classList.remove('hidden');
    btn.querySelector('.btn-loader').classList.add('hidden');
});

async function deleteEmployee(employeeId) {
    try {
        const response = await fetch(`/api/admin/employees/${employeeId}`, { method: 'DELETE', headers: { 'Authorization': `Bearer ${state.token}` } });
        if (response.ok) {
            state.employees = state.employees.filter(e => e.user_id !== employeeId);
            renderEmployees();
            showToast('Employee removed', 'success');
        }
    } catch (error) { showToast('Failed to remove employee', 'error'); }
}

// ==================== Buckets ====================
async function loadBuckets() {
    if (!state.token) return;
    try {
        const response = await fetch('/api/buckets', { headers: { 'Authorization': `Bearer ${state.token}` } });
        if (response.ok) {
            const data = await response.json();
            state.buckets = data.buckets;
            renderBuckets();
            updateDropdownOptions();
        }
    } catch (error) { console.error('Failed to load buckets:', error); }
}

function renderBuckets() {
    let html = `<div class="bucket-item ${state.selectedBucket === '' ? 'active' : ''}" onclick="selectBucket('')">
        <span class="bucket-name">📂 All Documents</span>
    </div>`;

    html += state.buckets.map(b => `
        <div class="bucket-item ${state.selectedBucket === b.bucket_id ? 'active' : ''}" data-id="${b.bucket_id}">
            <span class="bucket-name" onclick="selectBucket('${b.bucket_id}')">📁 ${b.name}</span>
            <span class="bucket-count">${b.doc_count}</span>
            <button class="btn btn-ghost bucket-delete" onclick="event.stopPropagation(); deleteBucket('${b.bucket_id}')">🗑️</button>
        </div>
    `).join('');

    elements.bucketsList.innerHTML = html;
}

function selectBucket(bucketId) {
    state.selectedBucket = bucketId;
    state.chatBucket = bucketId;  // Sync chat bucket filter

    // Get bucket name for display
    const bucketName = bucketId ?
        (state.buckets.find(b => b.bucket_id === bucketId)?.name || 'Selected Bucket') :
        '';
    const displayName = bucketId ? bucketName : 'All Documents';
    const uploadDisplayName = bucketId ? bucketName : 'No Bucket (General)';

    // Sync upload bucket dropdown
    elements.uploadBucketSelect.value = bucketId;
    elements.uploadBucketTrigger.querySelector('.select-value').textContent = uploadDisplayName;
    elements.uploadBucketOptions.querySelectorAll('.select-option').forEach(opt => {
        opt.classList.toggle('active', opt.dataset.value === bucketId);
    });

    // Sync chat bucket dropdown
    elements.chatBucketSelect.value = bucketId;
    elements.chatBucketTrigger.querySelector('.select-value').textContent = displayName;
    elements.chatBucketOptions.querySelectorAll('.select-option').forEach(opt => {
        opt.classList.toggle('active', opt.dataset.value === bucketId);
    });

    // Render all filtered components
    renderBuckets();
    loadDocuments();
    renderChatHistory();  // Re-render to filter by bucket
}

elements.createBucketBtn.addEventListener('click', (e) => {
    e.stopPropagation();
    elements.createBucketModal.classList.add('active');
    elements.createBucketError.classList.add('hidden');
    elements.createBucketForm.reset();
});

elements.cancelCreateBucket.addEventListener('click', () => elements.createBucketModal.classList.remove('active'));

elements.createBucketForm.addEventListener('submit', async (e) => {
    e.preventDefault();
    const formData = new FormData(e.target);
    const btn = e.target.querySelector('.btn-primary');
    btn.querySelector('.btn-text').classList.add('hidden');
    btn.querySelector('.btn-loader').classList.remove('hidden');

    try {
        const response = await fetch('/api/buckets', {
            method: 'POST',
            headers: { 'Authorization': `Bearer ${state.token}`, 'Content-Type': 'application/json' },
            body: JSON.stringify({ name: formData.get('name'), description: formData.get('description') })
        });
        const data = await response.json();
        if (response.ok) {
            elements.createBucketModal.classList.remove('active');
            loadBuckets();
            showToast('Bucket created!', 'success');
        } else {
            elements.createBucketError.textContent = data.error;
            elements.createBucketError.classList.remove('hidden');
        }
    } catch (error) {
        elements.createBucketError.textContent = 'Connection error';
        elements.createBucketError.classList.remove('hidden');
    }
    btn.querySelector('.btn-text').classList.remove('hidden');
    btn.querySelector('.btn-loader').classList.add('hidden');
});

async function deleteBucket(bucketId) {
    try {
        const response = await fetch(`/api/buckets/${bucketId}`, { method: 'DELETE', headers: { 'Authorization': `Bearer ${state.token}` } });
        if (response.ok) {
            if (state.selectedBucket === bucketId) state.selectedBucket = '';
            loadBuckets();
            loadDocuments();
            showToast('Bucket deleted', 'success');
        }
    } catch (error) { showToast('Failed to delete bucket', 'error'); }
}

// ==================== Documents ====================
async function loadDocuments() {
    if (!state.token) return;
    try {
        let url = '/api/documents';
        if (state.selectedBucket) url += `?bucket_id=${state.selectedBucket}`;

        const response = await fetch(url, { headers: { 'Authorization': `Bearer ${state.token}` } });
        if (response.ok) {
            const data = await response.json();
            state.documents = data.documents;
            renderDocuments();
        }
    } catch (error) { console.error('Failed to load documents:', error); }
}

function renderDocuments() {
    elements.docCount.textContent = `(${state.documents.length})`;

    if (state.documents.length === 0) {
        elements.documentsList.innerHTML = `<div class="empty-state"><div class="empty-icon">📭</div><div class="empty-text">No documents yet</div></div>`;
        return;
    }

    const icons = { pdf: '📕', word: '📘', powerpoint: '📙', excel: '📗', image: '🖼️', text: '📄' };

    elements.documentsList.innerHTML = state.documents.map(doc => `
        <div class="document-item ${state.selectedDocument === doc.doc_id ? 'selected' : ''}" data-id="${doc.doc_id}" onclick="selectDocument('${doc.doc_id}')">
            <div class="doc-icon">${icons[doc.doc_type] || '📄'}</div>
            <div class="doc-info">
                <div class="doc-name">${doc.filename}</div>
                <div class="doc-meta">${formatDate(doc.created_at)}</div>
            </div>
            <button class="btn btn-ghost doc-view" onclick="event.stopPropagation(); viewDocument('${doc.doc_id}', '${doc.filename}')" title="View">👁️</button>
            <button class="btn btn-ghost doc-delete" onclick="event.stopPropagation(); deleteDocument('${doc.doc_id}')" title="Delete">🗑️</button>
        </div>
    `).join('');
}

function formatDate(timestamp) {
    const date = new Date(timestamp * 1000);
    const now = new Date();
    const diff = now - date;
    if (diff < 60000) return 'Just now';
    if (diff < 3600000) return `${Math.floor(diff / 60000)}m ago`;
    if (diff < 86400000) return `${Math.floor(diff / 3600000)}h ago`;
    return date.toLocaleDateString();
}

async function deleteDocument(docId) {
    try {
        const response = await fetch(`/api/documents/${docId}`, { method: 'DELETE', headers: { 'Authorization': `Bearer ${state.token}` } });
        if (response.ok) {
            state.documents = state.documents.filter(d => d.doc_id !== docId);
            // Clear selection if deleted doc was selected
            if (state.selectedDocument === docId) {
                state.selectedDocument = null;
                hideSummary();
            }
            // Remove from summaries cache
            delete state.summaries[docId];
            renderDocuments();
            loadBuckets();
            showToast('Document deleted', 'success');
        }
    } catch (error) { showToast('Failed to delete', 'error'); }
}

// ==================== Document Summary ====================
function selectDocument(docId) {
    state.selectedDocument = docId;
    renderDocuments();
    displaySummary(docId);
}

async function displaySummary(docId) {
    const doc = state.documents.find(d => d.doc_id === docId);
    if (!doc) return;

    // Check if summary is cached
    if (state.summaries[docId]) {
        showSummaryPanel(doc.filename, state.summaries[docId].summary);
    } else {
        // Show loading state
        showSummaryPanel(doc.filename, 'Generating summary...');
        // Fetch summary from server
        await fetchSummary(docId);
    }
}

async function fetchSummary(docId) {
    try {
        const response = await fetch(`/api/documents/${docId}/summary`, {
            headers: { 'Authorization': `Bearer ${state.token}` }
        });
        const data = await response.json();

        if (response.ok && data.summary) {
            // Cache the summary
            state.summaries[docId] = {
                summary: data.summary,
                filename: data.filename
            };
            // Update display if still selected
            if (state.selectedDocument === docId) {
                showSummaryPanel(data.filename, data.summary);
            }
        } else {
            // Show error state
            if (state.selectedDocument === docId) {
                showSummaryPanel(data.filename || 'Document', 'Unable to generate summary.');
            }
        }
    } catch (error) {
        console.error('Failed to fetch summary:', error);
        if (state.selectedDocument === docId) {
            const doc = state.documents.find(d => d.doc_id === docId);
            showSummaryPanel(doc?.filename || 'Document', 'Failed to load summary.');
        }
    }
}

function showSummaryPanel(filename, summaryText) {
    elements.summaryPanel.classList.remove('hidden');
    elements.summaryTitle.textContent = filename;
    elements.summaryText.textContent = summaryText;
}

function hideSummary() {
    elements.summaryPanel.classList.add('hidden');
    state.selectedDocument = null;
    renderDocuments();
}

function initSummaryPanel() {
    elements.summaryClose.addEventListener('click', hideSummary);
}

// ==================== Document Viewer ====================
async function viewDocument(docId, filename) {
    try {
        // Fetch the document with proper authorization
        const response = await fetch(`/api/documents/${docId}/view`, {
            headers: { 'Authorization': `Bearer ${state.token}` }
        });

        if (!response.ok) {
            showToast('Failed to load document', 'error');
            return;
        }

        // Get the blob and create a URL
        const blob = await response.blob();
        const blobUrl = URL.createObjectURL(blob);

        // Open in a new tab
        window.open(blobUrl, '_blank');
    } catch (error) {
        console.error('Failed to view document:', error);
        showToast('Failed to open document', 'error');
    }
}


elements.closeDocViewer.addEventListener('click', () => elements.docViewerModal.classList.remove('active'));

// ==================== Upload ====================
let currentPollInterval = null;  // Track the current polling interval for cancellation

function initUpload() {
    elements.uploadZone.addEventListener('click', () => elements.fileInput.click());
    elements.fileInput.addEventListener('change', (e) => {
        if (e.target.files.length > 0) uploadFiles(Array.from(e.target.files));
    });
    elements.uploadZone.addEventListener('dragover', (e) => { e.preventDefault(); elements.uploadZone.classList.add('dragover'); });
    elements.uploadZone.addEventListener('dragleave', () => elements.uploadZone.classList.remove('dragover'));
    elements.uploadZone.addEventListener('drop', (e) => {
        e.preventDefault();
        elements.uploadZone.classList.remove('dragover');
        if (e.dataTransfer.files.length > 0) uploadFiles(Array.from(e.dataTransfer.files));
    });

    // Cancel upload button
    elements.cancelUploadBtn.addEventListener('click', cancelUpload);
}

function cancelUpload() {
    state.uploadCancelled = true;

    // Abort any ongoing fetch request
    if (state.currentUploadAbortController) {
        state.currentUploadAbortController.abort();
        state.currentUploadAbortController = null;
    }

    // Clear any polling interval
    if (currentPollInterval) {
        clearInterval(currentPollInterval);
        currentPollInterval = null;
    }

    // Reset UI
    elements.uploadProgress.classList.add('hidden');
    elements.uploadZone.style.pointerEvents = '';
    elements.fileInput.value = '';
    elements.progressFill.style.width = '0%';

    showToast('Upload cancelled', 'info');
}

async function uploadFiles(files) {
    // Reset cancellation state
    state.uploadCancelled = false;

    elements.uploadProgress.classList.remove('hidden');
    elements.uploadZone.style.pointerEvents = 'none';

    const bucketId = elements.uploadBucketSelect.value;
    let completed = 0;

    // Process files sequentially to avoid overwhelming the client, 
    // but the server handles them in background.
    for (const file of files) {
        // Check if cancelled before processing each file
        if (state.uploadCancelled) {
            break;
        }

        elements.uploadStatus.textContent = `Uploading ${file.name}...`;
        elements.progressFill.style.width = '10%'; // Initial progress

        const formData = new FormData();
        formData.append('file', file);
        formData.append('bucket_id', bucketId);

        // Create abort controller for this request
        state.currentUploadAbortController = new AbortController();

        try {
            // Initial upload request
            const response = await fetch('/api/documents/upload', {
                method: 'POST',
                headers: { 'Authorization': `Bearer ${state.token}` },
                body: formData,
                signal: state.currentUploadAbortController.signal
            });

            if (response.status === 202) {
                // Async processing started
                const data = await response.json();
                await pollUploadStatus(data.doc_id, file.name);
                if (!state.uploadCancelled) {
                    completed++;
                }
            } else if (response.ok) {
                // Instant completion (legacy or small file)
                const data = await response.json();
                handleUploadSuccess(data);
                completed++;
            } else {
                const data = await response.json();
                showToast(`Failed: ${file.name} - ${data.error}`, 'error');
            }
        } catch (e) {
            if (e.name === 'AbortError') {
                // Upload was cancelled by user
                break;
            }
            console.error(e);
            showToast(`Failed to upload ${file.name}`, 'error');
        }
    }

    // Clean up abort controller
    state.currentUploadAbortController = null;

    // Only update UI if not cancelled (cancelUpload already handles UI reset)
    if (!state.uploadCancelled) {
        elements.uploadProgress.classList.add('hidden');
        elements.uploadZone.style.pointerEvents = '';
        elements.fileInput.value = '';
        elements.progressFill.style.width = '0%';

        // Load documents first, then show summary
        await loadDocuments();
        loadBuckets();
    }
}

async function pollUploadStatus(docId, filename) {
    return new Promise((resolve, reject) => {
        currentPollInterval = setInterval(async () => {
            // Check if cancelled
            if (state.uploadCancelled) {
                clearInterval(currentPollInterval);
                currentPollInterval = null;
                resolve();
                return;
            }

            try {
                const response = await fetch(`/api/documents/${docId}/status`, {
                    headers: { 'Authorization': `Bearer ${state.token}` }
                });

                if (response.ok) {
                    const statusData = await response.json();

                    // Update UI
                    elements.uploadStatus.textContent = `Processing ${filename}: ${statusData.message || '...'}`;
                    // Map 0-100 progress to UI width (keeping 10% buffer)
                    if (statusData.progress) {
                        elements.progressFill.style.width = `${Math.max(10, statusData.progress)}%`;
                    }

                    if (statusData.status === 'completed') {
                        clearInterval(currentPollInterval);
                        currentPollInterval = null;
                        if (statusData.result) {
                            handleUploadSuccess(statusData.result);
                        }
                        resolve();
                    } else if (statusData.status === 'failed') {
                        clearInterval(currentPollInterval);
                        currentPollInterval = null;
                        showToast(`Processing failed: ${filename} - ${statusData.error}`, 'error');
                        resolve(); // Resolve anyway to continue with next file
                    }
                } else {
                    // Status check failed - might be network glitch, ignore once
                }
            } catch (e) {
                console.error("Polling error", e);
                // Continue polling despite error
            }
        }, 2000); // Check every 2 seconds
    });
}

function handleUploadSuccess(data) {
    showToast(`Ready: ${data.filename}`, 'success');

    // Cache the summary
    if (data.summary) {
        state.summaries[data.doc_id] = {
            summary: data.summary,
            filename: data.filename
        };
    }

    // Auto-display this document
    state.selectedDocument = data.doc_id;
    // We will re-render documents shortly after this returns

    if (data.summary) {
        // Defer slightly to ensure DOM is ready if needed
        setTimeout(() => {
            showSummaryPanel(data.filename, data.summary);
        }, 500);
    }
}

// ==================== Chat ====================
function initChat() {
    elements.chatInput.addEventListener('input', () => {
        elements.chatInput.style.height = 'auto';
        elements.chatInput.style.height = Math.min(elements.chatInput.scrollHeight, 150) + 'px';
        elements.sendBtn.disabled = !elements.chatInput.value.trim();
    });
    elements.chatInput.addEventListener('keydown', (e) => {
        if (e.key === 'Enter' && !e.shiftKey) { e.preventDefault(); sendMessage(); }
    });
    elements.sendBtn.addEventListener('click', sendMessage);

    // Stop generation button
    elements.stopBtn.addEventListener('click', stopGeneration);
}

function stopGeneration() {
    if (state.streamAbortController) {
        state.streamAbortController.abort();
        state.streamAbortController = null;
    }

    // Hide stop button, show send button
    elements.stopBtn.classList.add('hidden');
    elements.sendBtn.classList.remove('hidden');
    elements.typingIndicator.classList.add('hidden');
    state.isLoading = false;

    // Add a note that generation was stopped
    if (state.messages.length > 0) {
        const lastMsg = state.messages[state.messages.length - 1];
        if (lastMsg.role === 'assistant' && lastMsg.content) {
            lastMsg.content += '\n\n*[Generation stopped]*';
            renderMessages();
            saveCurrentChat();
        }
    }

    showToast('Generation stopped', 'info');
}

async function sendMessage() {
    const message = elements.chatInput.value.trim();
    if (!message || state.isLoading) return;

    elements.chatInput.value = '';
    elements.chatInput.style.height = 'auto';
    elements.sendBtn.disabled = true;
    elements.welcomeScreen.classList.add('hidden');

    // Create a chat ID if this is the first message
    if (state.messages.length === 0 && !state.currentChatId) {
        state.currentChatId = Date.now().toString();
    }

    const targetChatId = state.currentChatId;
    addMessage('user', message);
    elements.typingIndicator.classList.remove('hidden');
    state.isLoading = true;
    scrollToBottom();

    // Show stop button, hide send button
    elements.sendBtn.classList.add('hidden');
    elements.stopBtn.classList.remove('hidden');

    // Create abort controller for this request
    state.streamAbortController = new AbortController();

    try {
        // Use streaming endpoint for instant response
        const response = await fetch('/api/chat/stream', {
            method: 'POST',
            headers: {
                'Authorization': `Bearer ${state.token}`,
                'Content-Type': 'application/json'
            },
            body: JSON.stringify({
                message: message,
                bucket_id: state.chatBucket || null,
                chat_id: state.currentChatId
            }),
            signal: state.streamAbortController.signal
        });

        if (!response.ok) {
            throw new Error('Stream request failed');
        }

        elements.typingIndicator.classList.add('hidden');

        // Create a placeholder message for streaming
        let streamingContent = '';
        let sources = [];

        // Add empty assistant message and get reference to its content element
        state.messages.push({ role: 'assistant', content: '', sources: [] });
        renderMessages();
        scrollToBottom();

        // Get direct reference to the streaming message element for fast updates
        const messageElements = elements.chatMessages.querySelectorAll('.message.assistant .message-content');
        const streamingElement = messageElements[messageElements.length - 1];

        const reader = response.body.getReader();
        const decoder = new TextDecoder();

        // Throttle DOM updates for smooth rendering (update every 50ms max)
        let lastUpdateTime = 0;
        let pendingUpdate = false;
        const UPDATE_INTERVAL = 50; // ms

        while (true) {
            const { done, value } = await reader.read();
            if (done) break;

            const text = decoder.decode(value);
            const lines = text.split('\n');

            for (const line of lines) {
                if (line.startsWith('data: ')) {
                    try {
                        const data = JSON.parse(line.slice(6));

                        if (data.type === 'sources') {
                            sources = data.sources || [];
                        } else if (data.type === 'chunk' || data.type === 'content') {
                            // Support both 'chunk' (legacy) and 'content' (specialized queries)
                            streamingContent += data.content;
                            // Update state for saving later
                            state.messages[state.messages.length - 1].content = streamingContent;
                            state.messages[state.messages.length - 1].sources = sources;

                            // Throttled DOM update for smooth rendering
                            const now = Date.now();
                            if (now - lastUpdateTime >= UPDATE_INTERVAL) {
                                if (streamingElement) {
                                    streamingElement.innerHTML = formatContent(streamingContent);
                                }
                                lastUpdateTime = now;
                                pendingUpdate = false;
                            } else {
                                pendingUpdate = true;
                            }
                            // No auto-scroll during streaming - stay at current position
                        } else if (data.type === 'done') {
                            // Final update with any pending content
                            if (pendingUpdate && streamingElement) {
                                streamingElement.innerHTML = formatContent(streamingContent);
                            }
                            // Streaming complete - do final render for proper formatting
                            renderMessages();
                            saveCurrentChat();
                            // No auto-scroll - user stays at current position
                        } else if (data.type === 'error') {
                            state.messages[state.messages.length - 1].content = data.content || 'Error generating response';
                            renderMessages();
                        }
                    } catch (e) {
                        // Skip malformed JSON
                    }
                }
            }
        }
    } catch (err) {
        elements.typingIndicator.classList.add('hidden');
        // Only show error if not aborted by user
        if (err.name !== 'AbortError') {
            addMessageToChat(targetChatId, 'assistant', 'Connection error. Please try again.');
        }
    }

    // Cleanup: hide stop button, show send button
    elements.stopBtn.classList.add('hidden');
    elements.sendBtn.classList.remove('hidden');
    state.streamAbortController = null;
    state.isLoading = false;
    // No auto-scroll - user stays at current position
}

function addMessage(role, content, sources = []) {
    // Create a new chat ID if this is the first message
    if (state.messages.length === 0 && !state.currentChatId) {
        state.currentChatId = Date.now().toString();
    }

    state.messages.push({ role, content, sources });
    renderMessages();

    // Auto-save after assistant responds (complete exchange)
    if (role === 'assistant') {
        saveCurrentChat();
    }
}

// Add message to a specific chat (handles case where user switched chats during loading)
function addMessageToChat(chatId, role, content, sources = []) {
    // If this is the current chat, add directly
    if (chatId === state.currentChatId) {
        state.messages.push({ role, content, sources });
        renderMessages();
        saveCurrentChat();
    } else {
        // Add to the chat in history
        const chatIndex = state.chatHistory.findIndex(c => c.id === chatId);
        if (chatIndex >= 0) {
            state.chatHistory[chatIndex].messages.push({ role, content, sources });
            saveChatHistory();
            syncChatToServer(state.chatHistory[chatIndex]);
            renderChatHistory();
            showToast('Response added to previous chat', 'info');
        }
    }
}

function renderMessages() {
    // Preserve summary panel state before re-rendering
    const summaryVisible = !elements.summaryPanel.classList.contains('hidden');
    const summaryTitle = elements.summaryTitle.textContent;
    const summaryText = elements.summaryText.textContent;

    if (state.messages.length === 0) {
        // Clear chat messages and show welcome screen
        elements.chatMessages.innerHTML = '';
        elements.welcomeScreen.classList.remove('hidden');
        elements.chatMessages.appendChild(elements.welcomeScreen);
        // Re-show summary if it was visible
        if (summaryVisible) {
            elements.summaryPanel.classList.remove('hidden');
        }
        return;
    }
    elements.welcomeScreen.classList.add('hidden');

    const html = state.messages.map((msg, i) => {
        const avatar = msg.role === 'user' ? (state.user?.username?.charAt(0).toUpperCase() || 'U') : '🧠';
        const isUserMessage = msg.role === 'user';
        return `<div class="message ${msg.role}"><div class="message-avatar">${avatar}</div><div class="message-content">${formatContent(msg.content, isUserMessage)}</div></div>`;
    }).join('');

    // Build full content with summary panel and welcome screen
    const summaryPanelHTML = `
        <div class="summary-panel ${summaryVisible ? '' : 'hidden'}" id="summaryPanel">
            <div class="summary-header">
                <span class="summary-icon">📄</span>
                <span class="summary-title" id="summaryTitle">${summaryTitle}</span>
            </div>
            <div class="summary-content" id="summaryContent">
                <div class="summary-text" id="summaryText">${summaryText}</div>
            </div>
            <button class="summary-close" id="summaryClose" title="Close summary">✕</button>
        </div>
    `;

    elements.chatMessages.innerHTML = summaryPanelHTML + html + elements.welcomeScreen.outerHTML;
    document.getElementById('welcomeScreen')?.classList.add('hidden');

    // Re-bind summary panel elements and event listener
    elements.summaryPanel = document.getElementById('summaryPanel');
    elements.summaryTitle = document.getElementById('summaryTitle');
    elements.summaryText = document.getElementById('summaryText');
    elements.summaryClose = document.getElementById('summaryClose');
    elements.summaryClose.addEventListener('click', hideSummary);
}

function formatContent(content, isUserMessage = false) {
    // Enhanced markdown parsing for beautiful formatting
    let html = content;

    // For user messages, escape HTML and preserve line breaks
    if (isUserMessage) {
        // Escape HTML to prevent XSS
        html = html
            .replace(/&/g, '&amp;')
            .replace(/</g, '&lt;')
            .replace(/>/g, '&gt;')
            .replace(/"/g, '&quot;')
            .replace(/'/g, '&#039;');
        // Convert line breaks to <br>
        html = html.replace(/\n/g, '<br>');
        return html;
    }

    // Escape HTML special characters first (except for already parsed markdown)
    // Skip this if content looks like it's already HTML
    if (!html.includes('<table') && !html.includes('<div')) {
        // Don't escape - let markdown do its thing
    }

    // Code blocks: ```code```
    html = html.replace(/```(\w*)\n?([\s\S]*?)```/g, (match, lang, code) => {
        return `<pre class="code-block${lang ? ' lang-' + lang : ''}"><code>${code.trim()}</code></pre>`;
    });

    // Tables: | Header | Header |
    html = html.replace(/(?:^|\n)(\|.+\|)\n(\|[-:\s|]+\|)\n((?:\|.+\|\n?)+)/gm, (match, headerRow, sepRow, bodyRows) => {
        const headers = headerRow.split('|').filter(cell => cell.trim()).map(cell =>
            `<th>${cell.trim()}</th>`
        ).join('');

        const rows = bodyRows.trim().split('\n').map(row => {
            const cells = row.split('|').filter(cell => cell.trim()).map(cell =>
                `<td>${cell.trim()}</td>`
            ).join('');
            return `<tr>${cells}</tr>`;
        }).join('');

        return `<div class="table-wrapper"><table><thead><tr>${headers}</tr></thead><tbody>${rows}</tbody></table></div>`;
    });

    // Headers: ### Header, ## Header, # Header
    html = html.replace(/^#### (.+)$/gm, '<h4>$1</h4>');
    html = html.replace(/^### (.+)$/gm, '<h3>$1</h3>');
    html = html.replace(/^## (.+)$/gm, '<h2>$1</h2>');
    html = html.replace(/^# (.+)$/gm, '<h1>$1</h1>');

    // Bold headers at start of line (NotebookLM style)
    html = html.replace(/^(\*\*[^*]+\*\*):?\s*$/gm, '<h4>$1</h4>');

    // Bold text: **text**
    html = html.replace(/\*\*([^*]+)\*\*/g, '<strong>$1</strong>');

    // Italic text: *text*
    html = html.replace(/(?<!\*)\*([^*]+)\*(?!\*)/g, '<em>$1</em>');

    // Inline code: `code`
    html = html.replace(/`([^`]+)`/g, '<code class="inline-code">$1</code>');

    // Horizontal rule: --- or ***
    html = html.replace(/^[-*]{3,}$/gm, '<hr class="divider">');

    // Numbered lists: 1. Item, 2. Item, etc.
    html = html.replace(/^(\d+)\.\s+(.+)$/gm, '<li class="numbered"><span class="list-num">$1.</span> $2</li>');

    // Bullet points: • Item or - Item or * Item at start of line
    html = html.replace(/^[\•\-\*]\s+(.+)$/gm, '<li class="bullet">$1</li>');

    // Sub-bullets with indentation (2+ spaces before bullet)
    html = html.replace(/^[\s]{2,}[\•\-\*]\s+(.+)$/gm, '<li class="sub-bullet">$1</li>');

    // Wrap consecutive numbered list items
    html = html.replace(/(<li class="numbered">[\s\S]*?<\/li>\n?)+/g, '<ol class="formatted-list">$&</ol>');

    // Wrap consecutive bullet items
    html = html.replace(/(<li class="bullet">[\s\S]*?<\/li>\n?)+/g, '<ul class="formatted-list">$&</ul>');

    // Wrap consecutive sub-bullet items
    html = html.replace(/(<li class="sub-bullet">[\s\S]*?<\/li>\n?)+/g, '<ul class="formatted-list sub-list">$&</ul>');

    // Blockquotes: > text
    html = html.replace(/^>\s+(.+)$/gm, '<blockquote>$1</blockquote>');
    // Merge consecutive blockquotes
    html = html.replace(/<\/blockquote>\n<blockquote>/g, '<br>');

    // Double newlines become paragraph breaks
    html = html.replace(/\n\n+/g, '</p><p>');

    // Single newlines become line breaks (but not inside lists)
    html = html.replace(/\n/g, '<br>');

    // Clean up br tags in lists, headers, tables
    html = html.replace(/<br><li/g, '<li');
    html = html.replace(/<\/li><br>/g, '</li>');
    html = html.replace(/<br><h/g, '<h');
    html = html.replace(/<\/h(\d)><br>/g, '</h$1>');
    html = html.replace(/<br><ul/g, '<ul');
    html = html.replace(/<br><ol/g, '<ol');
    html = html.replace(/<\/ul><br>/g, '</ul>');
    html = html.replace(/<\/ol><br>/g, '</ol>');
    html = html.replace(/<br><table/g, '<table');
    html = html.replace(/<\/table><br>/g, '</table>');
    html = html.replace(/<br><div class="table/g, '<div class="table');
    html = html.replace(/<\/div><br>/g, '</div>');
    html = html.replace(/<br><pre/g, '<pre');
    html = html.replace(/<\/pre><br>/g, '</pre>');
    html = html.replace(/<br><hr/g, '<hr');
    html = html.replace(/<hr[^>]*><br>/g, '<hr class="divider">');
    html = html.replace(/<br><blockquote/g, '<blockquote');
    html = html.replace(/<\/blockquote><br>/g, '</blockquote>');

    // Wrap in paragraph
    html = '<p>' + html + '</p>';

    // Clean up empty paragraphs
    html = html.replace(/<p><\/p>/g, '');
    html = html.replace(/<p>(\s|<br>)*<\/p>/g, '');
    html = html.replace(/<p><(h\d|ul|ol|table|div|pre|hr|blockquote)/g, '<$1');
    html = html.replace(/<\/(h\d|ul|ol|table|div|pre|blockquote)><\/p>/g, '</$1>');
    html = html.replace(/<p><hr/g, '<hr');

    return html;
}

function scrollToBottom() {
    elements.chatMessages.scrollTop = elements.chatMessages.scrollHeight;
}

// ==================== Token Verification ====================
async function verifyToken() {
    if (!state.token) { showAuthModal(); return; }
    try {
        const response = await fetch('/api/auth/verify', { headers: { 'Authorization': `Bearer ${state.token}` } });
        if (response.ok) {
            const data = await response.json();
            state.user = data;
            localStorage.setItem('Iribl AI_user', JSON.stringify(state.user));
            updateAuthUI();
            loadBuckets();
            loadDocuments();
            // Load chat history from server database
            loadChatHistoryFromServer();
        } else {
            state.token = null;
            state.user = null;
            localStorage.removeItem('Iribl AI_token');
            localStorage.removeItem('Iribl AI_user');
            showAuthModal();
        }
    } catch { showAuthModal(); }
}

// ==================== Chat History ====================
function generateChatTopic(messages) {
    // Get the first user message as the topic
    const firstUserMsg = messages.find(m => m.role === 'user');
    if (firstUserMsg) {
        // Truncate to first 40 chars
        let topic = firstUserMsg.content.substring(0, 40);
        if (firstUserMsg.content.length > 40) topic += '...';
        return topic;
    }
    return 'New Conversation';
}

function saveChatHistory() {
    localStorage.setItem('Iribl AI_chat_history', JSON.stringify(state.chatHistory));
}

// Sync chat to server
async function syncChatToServer(chatData) {
    if (!state.token) return;

    try {
        await fetch('/api/chats', {
            method: 'POST',
            headers: {
                'Authorization': `Bearer ${state.token}`,
                'Content-Type': 'application/json'
            },
            body: JSON.stringify(chatData)
        });
    } catch (error) {
        console.error('Failed to sync chat to server:', error);
    }
}

// Load chat history from server
async function loadChatHistoryFromServer() {
    if (!state.token) return;

    try {
        const response = await fetch('/api/chats', {
            headers: { 'Authorization': `Bearer ${state.token}` }
        });

        if (response.ok) {
            const data = await response.json();
            if (data.chats && data.chats.length > 0) {
                // Merge server chats with local (server takes priority)
                state.chatHistory = data.chats;
                saveChatHistory();  // Update local storage
                renderChatHistory();
            }
        }
    } catch (error) {
        console.error('Failed to load chats from server:', error);
    }
}

// Delete chat from server
async function deleteChatFromServer(chatId) {
    if (!state.token) return;

    try {
        await fetch(`/api/chats/${chatId}`, {
            method: 'DELETE',
            headers: { 'Authorization': `Bearer ${state.token}` }
        });
    } catch (error) {
        console.error('Failed to delete chat from server:', error);
    }
}

function saveCurrentChat() {
    // Only save if there are messages
    if (state.messages.length === 0) return null;

    const chatId = state.currentChatId || Date.now().toString();
    const topic = generateChatTopic(state.messages);

    // Check if this chat already exists
    const existingIndex = state.chatHistory.findIndex(c => c.id === chatId);

    const chatData = {
        id: chatId,
        topic: topic,
        messages: [...state.messages],
        timestamp: Date.now(),
        bucket: state.chatBucket
    };

    if (existingIndex >= 0) {
        // Update existing chat
        state.chatHistory[existingIndex] = chatData;
    } else {
        // Add new chat at the beginning
        state.chatHistory.unshift(chatData);
    }

    saveChatHistory();
    renderChatHistory();

    // Sync to server
    syncChatToServer(chatData);

    return chatId;
}

function startNewChat() {
    // Warn if AI is still generating
    if (state.isLoading) {
        showToast('AI is still responding - response will go to current chat', 'info');
    }

    // Save current chat first if it has messages
    if (state.messages.length > 0) {
        saveCurrentChat();
    }

    // Clear current chat
    state.messages = [];
    state.currentChatId = null;

    // Reset UI
    renderMessages();
    elements.welcomeScreen.classList.remove('hidden');
    hideSummary();
    renderChatHistory();

    showToast('Started new chat', 'info');
}

function loadChatFromHistory(chatId) {
    // Warn if AI is still generating
    if (state.isLoading) {
        showToast('AI is still responding - response will go to current chat', 'info');
    }

    // Save current chat first if it has messages
    if (state.messages.length > 0 && state.currentChatId !== chatId) {
        saveCurrentChat();
    }

    const chat = state.chatHistory.find(c => c.id === chatId);
    if (!chat) return;

    // Load the chat
    state.messages = [...chat.messages];
    state.currentChatId = chat.id;
    state.chatBucket = chat.bucket || '';

    // Update bucket dropdown
    if (elements.chatBucketSelect) {
        elements.chatBucketSelect.value = state.chatBucket;
        const bucketName = state.chatBucket ?
            state.buckets.find(b => b.bucket_id === state.chatBucket)?.name || 'Selected Bucket' :
            'All Documents';
        elements.chatBucketTrigger.querySelector('.select-value').textContent = bucketName;
    }

    // Render messages
    renderMessages();

    // Show/hide welcome screen based on whether chat has messages
    if (state.messages.length === 0) {
        elements.welcomeScreen.classList.remove('hidden');
    } else {
        elements.welcomeScreen.classList.add('hidden');
    }

    renderChatHistory();
    scrollToBottom();
}

function deleteChatFromHistory(chatId) {
    event.stopPropagation();

    state.chatHistory = state.chatHistory.filter(c => c.id !== chatId);

    // If deleting current chat, clear it
    if (state.currentChatId === chatId) {
        state.messages = [];
        state.currentChatId = null;
        renderMessages();
        elements.welcomeScreen.classList.remove('hidden');
    }

    saveChatHistory();
    renderChatHistory();

    // Delete from server
    deleteChatFromServer(chatId);

    showToast('Chat deleted', 'success');
}

function renderChatHistory() {
    // Filter chats by selected bucket
    let filteredChats = state.chatHistory;
    if (state.selectedBucket) {
        filteredChats = state.chatHistory.filter(chat =>
            chat.bucket === state.selectedBucket ||
            // Also include chats with no bucket for backwards compatibility
            (!chat.bucket && !state.selectedBucket)
        );
    }

    const count = filteredChats.length;
    const totalCount = state.chatHistory.length;

    // Show filtered count vs total if filtering is active
    elements.chatHistoryCount.textContent = state.selectedBucket && count !== totalCount ?
        `(${count}/${totalCount})` : `(${totalCount})`;

    if (count === 0) {
        elements.chatHistoryList.innerHTML = state.selectedBucket ?
            `<div class="empty-state small"><div class="empty-text">No chats in this bucket</div></div>` :
            `<div class="empty-state small"><div class="empty-text">No chats yet</div></div>`;
        return;
    }

    elements.chatHistoryList.innerHTML = filteredChats.map(chat => {
        const isActive = state.currentChatId === chat.id;
        const date = formatDate(chat.timestamp / 1000);
        return `
            <div class="chat-history-item ${isActive ? 'active' : ''}" onclick="loadChatFromHistory('${chat.id}')">
                <span class="chat-history-icon">💬</span>
                <div class="chat-history-info">
                    <div class="chat-history-topic">${chat.topic}</div>
                    <div class="chat-history-date">${date}</div>
                </div>
                <button class="btn btn-ghost chat-history-delete" onclick="deleteChatFromHistory('${chat.id}')" title="Delete">🗑️</button>
            </div>
        `;
    }).join('');
}

function clearCurrentChat() {
    // Warn if AI is still generating
    if (state.isLoading) {
        showToast('AI is still responding - response will go to current chat', 'info');
    }

    // If there's a current chat, clear its messages but keep it in history
    if (state.currentChatId) {
        const chatIndex = state.chatHistory.findIndex(c => c.id === state.currentChatId);
        if (chatIndex >= 0) {
            // Clear the messages in history
            state.chatHistory[chatIndex].messages = [];
            saveChatHistory();
            // Sync cleared chat to server
            syncChatToServer(state.chatHistory[chatIndex]);
        }
    }

    // Clear current chat messages
    state.messages = [];

    // Reset UI
    renderMessages();
    elements.welcomeScreen.classList.remove('hidden');
    hideSummary();
    renderChatHistory();

    showToast('Chat cleared', 'info');
}

function initChatHistory() {
    // New Chat button handler
    elements.newChatBtn.addEventListener('click', startNewChat);

    // Clear Chat button handler (sidebar)
    elements.clearChatBtn.addEventListener('click', (e) => {
        e.stopPropagation();
        clearCurrentChat();
    });

    // Clear Chat button handler (top)
    elements.clearChatBtnTop.addEventListener('click', clearCurrentChat);

    // Render existing history
    renderChatHistory();

    // Auto-save current chat when sending messages (hook into sendMessage)
    // This is handled by updating currentChatId after first message
}

// ==================== Init ====================
function init() {
    initSidebars();
    initMobileNavigation();
    initCollapsible();
    initCustomDropdowns();
    initUpload();
    initChat();
    initSummaryPanel();
    initChatHistory();
    verifyToken();
}

document.addEventListener('DOMContentLoaded', init);