// js/main.js

// --- IMPORTS ---
import { apiCall } from './api.js';
import { showMessage } from './utils.js';
import {
    renderAuthView,
    renderAdminDashboard,
    renderEmployeeDashboard,
    renderEditModal,
    renderChangePasswordModal,
    renderResetPasswordModal,
    renderRequestHistoryModal,
    handleViewNotesClick,
    renderArchiveView,
    renderTimeOffHistoryView,
    updatePendingRequestsList,
    renderEditTimeOffModal,
    renderCalendarView
} from './ui.js';

// --- STATE MANAGEMENT ---
let user = null;
let authToken = null;
let lastAdminTab = 'overview';
let lastEmployeeTab = 'dashboard';
export { lastAdminTab };

// --- NOTIFICATION LOGIC ---

// This helper function converts the VAPID public key for the browser
function urlBase64ToUint8Array(base64String) {
    const padding = '='.repeat((4 - base64String.length % 4) % 4);
    const base64 = (base64String + padding).replace(/\-/g, '+').replace(/_/g, '/');
    const rawData = window.atob(base64);
    const outputArray = new Uint8Array(rawData.length);
    for (let i = 0; i < rawData.length; ++i) {
        outputArray[i] = rawData.charCodeAt(i);
    }
    return outputArray;
}

// This function handles the actual subscription process
async function subscribeToNotifications() {
    try {
        // This key is not a secret, it's safe to have here.
        const publicVapidKey = 'BI1mWxe0yAsMw_iDjmb4Te2ByWwKuHhWsLYFilk7prozsnCEbtNHEJfNh_zIiNumLgWFKSvD6pMhnRbjhXVY_pU';
        const token = localStorage.getItem('authToken');

        if (!token || !publicVapidKey) {
            return console.error('Auth token or VAPID key is missing.');
        }

        const register = await navigator.serviceWorker.register('/sw.js', { scope: '/' });
        const subscription = await register.pushManager.subscribe({
            userVisibleOnly: true,
            applicationServerKey: urlBase64ToUint8Array(publicVapidKey)
        });

        const res = await apiCall('/subscribe', 'POST', subscription);
        
        // If the subscription is saved successfully, set a flag so we don't do it again
        if (res.success) {
            localStorage.setItem('subscriptionSent', 'true');
            showMessage('You are now subscribed to notifications!', 'success');
        }
    } catch (error) {
        console.error('Error subscribing to notifications:', error);
        showMessage('Failed to subscribe. Please ensure notifications are allowed for this site.', 'error');
    }
}

// NEW: This function creates the pop-up prompt for the user
function setupNotifications() {
    // Don't do anything if service workers aren't supported
    if (!('serviceWorker' in navigator)) return;

    // Case 1: Permission is already granted
    if (Notification.permission === 'granted') {
        // Only try to subscribe if we haven't already sent the subscription to the server
        if (!localStorage.getItem('subscriptionSent')) {
            subscribeToNotifications();
        }
        return;
    }

    // Case 2: Permission has been denied, so we don't ask again
    if (Notification.permission === 'denied') {
        return;
    }

    // Case 3: Permission is 'default' (user hasn't chosen yet)
    // Only ask if we haven't prompted them before
    if (!localStorage.getItem('notificationPrompted')) {
        setTimeout(() => {
            if (confirm("Enable notifications to receive important updates?")) {
                subscribeToNotifications();
            }
            // Remember that we've prompted them so we don't ask again on the next login
            localStorage.setItem('notificationPrompted', 'true');
        }, 2000);
    }
}

// --- EVENT HANDLERS ---
async function handleAuthSubmit(e) {
    e.preventDefault();
    const username = e.target.elements.username.value;
    const password = e.target.elements.password.value;
    const res = await apiCall('/login', 'POST', { username, password });

    if (res && res.success) {
        localStorage.setItem('authToken', res.data.token);
        localStorage.setItem('user', JSON.stringify(res.data.user));
        initializeApp();
    } else {
        showMessage(res?.data?.message || 'Login failed. Please check your credentials.', 'error');
    }
}

function handleSignOut(message) {
    localStorage.clear(); // This already clears everything, which is what we want.
    authToken = null;
    user = null;
    if (message) {
        showMessage(message, 'success');
    }
    initializeApp();
}

const handlePunch = () => {
    apiCall('/punch', 'POST').then(res => res.success && renderEmployeeDashboard());
};

async function handleChangePassword(e) {
    e.preventDefault();
    const currentPassword = e.target.elements['modal-current-pw'].value;
    const newPassword = e.target.elements['modal-new-pw'].value;
    const res = await apiCall('/user/change-password', 'POST', { currentPassword, newPassword });
    if (res.success) {
        showMessage(res.data.message, 'success');
        document.getElementById('modal-container').innerHTML = '';
    }
}

async function handleTimeOffRequest(e) {
    e.preventDefault();
    const startDate = e.target.elements['start-date'].value;
    const endDate = e.target.elements['end-date'].value;
    const reason = e.target.elements['reason'].value;
    if (new Date(endDate) < new Date(startDate)) {
        return showMessage('End date cannot be before start date.', 'error');
    }
    const res = await apiCall('/user/request-time-off', 'POST', { startDate, endDate, reason });
    if (res.success) {
        showMessage(res.data.message, 'success');
        e.target.reset();
        renderEmployeeDashboard();
    }
}

async function handleViewRequestHistoryClick() {
    const res = await apiCall('/user/time-off-requests/history');
    if (res.success) {
        renderRequestHistoryModal(res.data);
    }
}

async function loadEmployeeCalendar() {
    const iframe = document.getElementById('employee-calendar-iframe');
    const empty = document.getElementById('employee-calendar-empty');
    const link = document.getElementById('employee-calendar-link');
    if (!iframe || !empty || !link) return;
    const res = await apiCall('/calendar-url');
    if (!res.success) return;
    const url = res.data?.url || '';
    if (!url) {
        iframe.removeAttribute('src');
        empty.classList.remove('hidden');
        link.classList.add('hidden');
        return;
    }
    iframe.src = url;
    link.href = url;
    link.classList.remove('hidden');
    empty.classList.add('hidden');
}

async function handleEditSubmit(e) {
    e.preventDefault();
    const id = e.target.elements['edit-id'].value;
    const punch_in_time = new Date(e.target.elements['edit-in'].value).toISOString();
    const punch_out_value = e.target.elements['edit-out'].value;
    const punch_out_time = punch_out_value ? new Date(punch_out_value).toISOString() : null;
    const res = await apiCall(`/admin/logs/${id}`, 'PUT', { punch_in_time, punch_out_time });
    if (res.success) {
        document.getElementById('modal-container').innerHTML = '';
        renderAdminDashboard();
        showMessage('Entry updated successfully.', 'success');
    }
}

const handleArchive = () => {
    if (confirm('Are you sure you want to archive all completed time entries? This action cannot be undone.')) {
        apiCall('/admin/archive', 'POST').then(res => {
            if (res.success) {
                showMessage('Records archived successfully.', 'success');
                renderAdminDashboard();
            }
        });
    }
};

async function handleCreateUser(e) {
    e.preventDefault();
    const username = e.target.elements['new-username'].value;
    const password = e.target.elements['new-password'].value;
    const role = e.target.elements['new-user-role'].value;
    const res = await apiCall('/admin/create-user', 'POST', { username, password, role });
    if (res.success) {
        showMessage(res.data.message, 'success');
        e.target.reset();
        renderAdminDashboard();
    }
}

async function handleAddPunch(e) {
    e.preventDefault();
    const selected = e.target.elements['add-punch-user'];
    const userId = selected.value;
    const username = selected.options[selected.selectedIndex].dataset.username;
    const punchInTime = new Date(e.target.elements['add-punch-in'].value).toISOString();
    const punchOutValue = e.target.elements['add-punch-out'].value;
    const punchOutTime = punchOutValue ? new Date(punchOutValue).toISOString() : null;
    const res = await apiCall('/admin/add-punch', 'POST', { userId, username, punchInTime, punchOutTime });
    if (res.success) {
        showMessage(res.data.message, 'success');
        e.target.reset();
        renderAdminDashboard();
    }
}

async function handleAddNote(e) {
    e.preventDefault();
    const userId = e.target.elements['note-user-select'].value;
    const noteText = e.target.elements['note-text'].value;
    if (!userId) {
        return showMessage('Please select an employee.', 'error');
    }
    const res = await apiCall('/admin/notes', 'POST', { userId, noteText });
    if (res.success) {
        showMessage(res.data.message, 'success');
        e.target.reset();
    }
}

async function handleCalendarSettingsSubmit(e) {
    e.preventDefault();
    const input = document.getElementById('calendar-embed-url');
    if (!input) return;
    const url = input.value.trim();
    const res = await apiCall('/admin/calendar-url', 'POST', { url });
    if (res.success) {
        showMessage(res.data.message || 'Calendar settings updated.', 'success');
        await loadCalendarSettings();
    }
}

async function handleCalendarSettingsClear() {
    const res = await apiCall('/admin/calendar-url', 'POST', { url: '' });
    if (res.success) {
        const input = document.getElementById('calendar-embed-url');
        if (input) input.value = '';
        updateCalendarPreview('');
        showMessage(res.data.message || 'Calendar settings cleared.', 'success');
    }
}

function updateCalendarPreview(url) {
    const iframe = document.getElementById('calendar-preview-iframe');
    const empty = document.getElementById('calendar-preview-empty');
    if (!iframe || !empty) return;
    if (!url) {
        iframe.removeAttribute('src');
        empty.classList.remove('hidden');
        return;
    }
    iframe.src = url;
    empty.classList.add('hidden');
}

async function loadCalendarSettings() {
    const input = document.getElementById('calendar-embed-url');
    if (!input) return;
    const res = await apiCall('/admin/calendar-url');
    if (res.success) {
        const url = res.data?.url || '';
        input.value = url;
        updateCalendarPreview(url);
    }
}

async function handleResetPassword(e) {
    e.preventDefault();
    const username = e.target.elements['reset-username'].value;
    const newPassword = e.target.elements['reset-new-pw'].value;
    const res = await apiCall('/admin/reset-password', 'POST', { username, newPassword });
    if (res.success) {
        showMessage(res.data.message, 'success');
        document.getElementById('modal-container').innerHTML = '';
    }
}

function handleAdminDashboardClick(e) {
    const target = e.target.closest('button');
    if (!target) return;

    const { id, userid, username, role, noteId } = target.dataset;

    switch (target.id) {
        case 'view-archives-btn':
            renderArchiveView();
            return;
        case 'archive-btn':
            handleArchive();
            return;
        case 'view-time-off-history-btn':
            renderTimeOffHistoryView();
            return;
        case 'view-notes-btn':
            handleViewNotesClick();
            return;
        case 'view-calendar-btn':
            renderCalendarView();
            return;
    }

    if (target.classList.contains('approve-request-btn') || target.classList.contains('deny-request-btn')) {
        const status = target.classList.contains('approve-request-btn') ? 'approved' : 'denied';
        if (confirm(`Set this request to "${status}"?`)) {
            apiCall('/admin/update-time-off-status', 'POST', { requestId: id, status: status })
                .then(res => {
                    if (res.success) {
                        showMessage(`Request ${status}.`, 'success');
                        apiCall('/admin/time-off-requests/pending').then(requestsRes => {
                            if (requestsRes.success) {
                                updatePendingRequestsList(requestsRes.data);
                            }
                        });
                    }
                });
        }
        return;
    }

    if (target.classList.contains('admin-delete-request-btn')) {
        if (confirm('Are you sure you want to permanently delete this request? This cannot be undone.')) {
            apiCall(`/admin/time-off-requests/${id}`, 'DELETE')
                .then(res => {
                    if (res.success) {
                        showMessage('Request deleted.', 'success');
                        apiCall('/admin/time-off-requests/pending').then(requestsRes => {
                            if (requestsRes.success) {
                                updatePendingRequestsList(requestsRes.data);
                            }
                        });
                    }
                });
        }
        return;
    }

    if (target.classList.contains('edit-btn')) renderEditModal(id, handleEditSubmit);
    if (target.classList.contains('delete-btn') && confirm('Delete this time entry?')) apiCall(`/admin/logs/${id}`, 'DELETE').then(res => res.success && renderAdminDashboard());
    if (target.classList.contains('archive-log-btn') && confirm('Archive this time entry?')) apiCall(`/admin/logs/archive/${id}`, 'POST').then(res => res.success && renderAdminDashboard());
    if (target.classList.contains('force-clock-out-btn') && confirm(`Force clock out ${username}?`)) apiCall('/admin/force-clock-out', 'POST', { userId: userid }).then(res => res.success && renderAdminDashboard());
    if (target.classList.contains('reset-pw-btn')) renderResetPasswordModal(username, handleResetPassword);
    if (target.classList.contains('change-role-btn')) { const newRole = role === 'admin' ? 'employee' : 'admin'; if (confirm(`Change ${username} to ${newRole}?`)) apiCall('/admin/update-role', 'POST', { username, newRole }).then(res => res.success && renderAdminDashboard()); }
    if (target.classList.contains('delete-user-btn') && confirm(`PERMANENTLY DELETE user '${username}'?`)) apiCall(`/admin/delete-user/${username}`, 'DELETE').then(res => res.success && renderAdminDashboard());
    if (target.classList.contains('delete-note-btn')) { if (confirm('Delete this note?')) { apiCall(`/admin/notes/${noteId}`, 'DELETE').then(res => { if (res.success) { showMessage('Note deleted.', 'success'); handleViewNotesClick(); } }); } }
}

async function handleEditTimeOffSubmit(e) {
    e.preventDefault();
    const id = e.target.elements['edit-request-id'].value;
    const startDate = e.target.elements['edit-start-date'].value;
    const endDate = e.target.elements['edit-end-date'].value;
    const reason = e.target.elements['edit-reason'].value;

    if (new Date(endDate) < new Date(startDate)) {
        return showMessage('End date cannot be before start date.', 'error');
    }

    const res = await apiCall(`/user/time-off-requests/${id}`, 'PUT', { startDate, endDate, reason });
    if (res.success) {
        showMessage(res.data.message, 'success');
        document.getElementById('modal-container').innerHTML = '';
        renderEmployeeDashboard();
    }
}

function handleTimeOffHistoryClick(e) {
    const target = e.target.closest('button');
    if (!target) return;

    const { id } = target.dataset;

    if (target.classList.contains('set-pending-btn')) {
        if (confirm('Are you sure you want to move this request back to pending?')) {
            apiCall('/admin/update-time-off-status', 'POST', { requestId: id, status: 'pending' })
                .then(res => {
                    if (res.success) {
                        showMessage('Request status set to pending.', 'success');
                        renderTimeOffHistoryView();
                    }
                });
        }
    }

    if (target.classList.contains('admin-delete-request-btn')) {
        if (confirm('Are you sure you want to permanently delete this request? This cannot be undone.')) {
            apiCall(`/admin/time-off-requests/${id}`, 'DELETE')
                .then(res => {
                    if (res.success) {
                        showMessage('Request deleted.', 'success');
                        renderTimeOffHistoryView();
                    }
                });
        }
    }
}

// --- LISTENER ATTACHMENT FUNCTIONS ---
export function attachAuthFormListener() {
    const form = document.getElementById('auth-form');
    if (form) form.addEventListener('submit', handleAuthSubmit);
}

export function attachEmployeeDashboardListeners() {
    const dashboard = document.getElementById('employee-dashboard');
    if (!dashboard) return;

    dashboard.addEventListener('click', async (e) => {
        const target = e.target;
        if (target.id === 'punch-btn') handlePunch();
        if (target.id === 'change-password-btn') renderChangePasswordModal(handleChangePassword);
        if (target.id === 'view-request-history-btn') handleViewRequestHistoryClick();
        if (target.classList.contains('delete-request-btn')) {
            const id = target.dataset.id;
            if (confirm('Are you sure you want to delete this time off request?')) {
                const res = await apiCall(`/user/time-off-requests/${id}`, 'DELETE');
                if (res.success) {
                    showMessage(res.data.message, 'success');
                    renderEmployeeDashboard();
                }
            }
        }
        if (target.classList.contains('edit-request-btn')) {
            const id = target.dataset.id;
            const res = await apiCall('/user/time-off-requests/history');
            if (res.success) {
                const requestToEdit = res.data.find(r => r.id == id);
                if (requestToEdit) {
                    renderEditTimeOffModal(requestToEdit, handleEditTimeOffSubmit);
                }
            }
        }
    });

    const timeOffForm = document.getElementById('time-off-form');
    if (timeOffForm) {
        timeOffForm.addEventListener('submit', handleTimeOffRequest);
    }

    setupEmployeeTabs();
    if (lastEmployeeTab !== 'dashboard') {
        const tabsContainer = document.getElementById('employee-tabs-nav');
        tabsContainer?.querySelectorAll('.tab-btn').forEach(btn => btn.classList.remove('active-tab'));
        tabsContainer?.querySelector(`.tab-btn[data-tab="${lastEmployeeTab}"]`)?.classList.add('active-tab');
        document.getElementById('tab-content-employee-dashboard')?.classList.add('hidden');
        document.getElementById(`tab-content-employee-${lastEmployeeTab}`)?.classList.remove('hidden');
    }
    if (lastEmployeeTab === 'calendar') loadEmployeeCalendar();
}

export function attachAdminDashboardListeners() {
    document.getElementById('admin-dashboard')?.addEventListener('click', handleAdminDashboardClick);
    document.getElementById('create-user-form')?.addEventListener('submit', handleCreateUser);
    document.getElementById('add-punch-form')?.addEventListener('submit', handleAddPunch);
    document.getElementById('add-note-form')?.addEventListener('submit', handleAddNote);
    document.getElementById('calendar-settings-form')?.addEventListener('submit', handleCalendarSettingsSubmit);
    document.getElementById('calendar-clear-btn')?.addEventListener('click', handleCalendarSettingsClear);
    document.getElementById('calendar-embed-url')?.addEventListener('input', (e) => updateCalendarPreview(e.target.value.trim()));
    setupTabbedInterface();
    const adminContent = document.getElementById('admin-tabs-content');
    if (adminContent) {
        adminContent.classList.toggle('calendar-full-bleed', lastAdminTab === 'calendar');
    }
    if (lastAdminTab === 'calendar') renderCalendarView();
    if (lastAdminTab === 'settings') loadCalendarSettings();
}

export function attachTimeOffHistoryListeners() {
    const historyView = document.getElementById('admin-time-off-history-view');
    if (historyView) {
        historyView.addEventListener('click', handleTimeOffHistoryClick);
    }
}

// --- APP INITIALIZER ---
function initializeApp() {
    authToken = localStorage.getItem('authToken');
    const userString = localStorage.getItem('user');
    user = userString ? JSON.parse(userString) : null;

    const userControls = document.getElementById('nav-user-controls');
    if (authToken && user) {
        userControls.classList.remove('hidden');
        userControls.querySelector('#welcome-message').textContent = `Welcome, ${user.username}`;
        if (user.role === 'admin') {
            renderAdminDashboard();
        } else {
            renderEmployeeDashboard();
        }
        // Ask for notification permission after user is logged in
        setupNotifications();
    } else {
        userControls.classList.add('hidden');
        renderAuthView();
    }
}

// --- HELPERS ---
function setupTabbedInterface() {
    const tabsContainer = document.getElementById('admin-tabs-nav');
    const contentContainer = document.getElementById('admin-tabs-content');

    if (!tabsContainer || !contentContainer) return;

    tabsContainer.addEventListener('click', (e) => {
        const clickedTab = e.target.closest('.tab-btn');
        if (!clickedTab) return;

        const tabTarget = clickedTab.dataset.tab;
        lastAdminTab = tabTarget;

        tabsContainer.querySelectorAll('.tab-btn').forEach(btn => {
            btn.classList.remove('active-tab');
        });
        clickedTab.classList.add('active-tab');

        contentContainer.querySelectorAll('[id^="tab-content-"]').forEach(panel => {
            panel.classList.add('hidden');
        });
        document.getElementById(`tab-content-${tabTarget}`).classList.remove('hidden');
        contentContainer.classList.toggle('calendar-full-bleed', tabTarget === 'calendar');
        if (tabTarget === 'calendar') {
            renderCalendarView();
        }
        if (tabTarget === 'settings') {
            loadCalendarSettings();
        }
    });
}

function setupEmployeeTabs() {
    const tabsContainer = document.getElementById('employee-tabs-nav');
    const contentContainer = document.getElementById('employee-tabs-content');
    if (!tabsContainer || !contentContainer) return;

    tabsContainer.addEventListener('click', (e) => {
        const clickedTab = e.target.closest('.tab-btn');
        if (!clickedTab) return;

        const tabTarget = clickedTab.dataset.tab;
        lastEmployeeTab = tabTarget;

        tabsContainer.querySelectorAll('.tab-btn').forEach(btn => btn.classList.remove('active-tab'));
        clickedTab.classList.add('active-tab');

        contentContainer.querySelectorAll('[id^="tab-content-employee-"]').forEach(panel => {
            panel.classList.add('hidden');
        });
        document.getElementById(`tab-content-employee-${tabTarget}`).classList.remove('hidden');

        if (tabTarget === 'calendar') loadEmployeeCalendar();
    });
}

// --- START THE APP ---
// Register the service worker when the page loads
if ('serviceWorker' in navigator) {
    window.addEventListener('load', () => {
        navigator.serviceWorker.register('/sw.js')
            .then(registration => console.log('Service Worker registered! Scope:', registration.scope))
            .catch(err => console.error('Service Worker registration failed:', err));
    });
}

document.getElementById('sign-out-btn').addEventListener('click', () => handleSignOut('You have been signed out.'));
document.addEventListener('visibilitychange', () => {
    if (document.visibilityState === 'visible' && localStorage.getItem('user')) {
        initializeApp();
    }
});

initializeApp();