// ===== Application State =====
let tasks = [];
let categories = [];
let workspaces = [];
let currentView = 'all';
let currentFilter = { priority: 'all', workspace: null, date: null, search: '' };
let currentSort = 'date-desc';
let editingTaskId = null;
let viewMode = 'list';
let sortableInstance = null;
let lastDeletedTask = null;
let focusModeEnabled = false;
let smartFilter = 'all';
let calendarMonth = new Date();
let calendarViewVisible = false;
let streakCount = 0;
let myDayTasks = [];

// Pomodoro
let pomodoroRunning = false;
let pomodoroTimer = null;
let pomodoroTime = 25 * 60;
let pomodoroPhase = 'focus';
let pomodoroSessions = 0;
let pomodoroTodayMinutes = 0;

// ===== Initialize =====
document.addEventListener('DOMContentLoaded', () => {
    setTimeout(() => {
        document.getElementById('loading-screen').classList.add('hidden');
        loadFromLocalStorage();
        initializeEventListeners();
        setQuickAddDefaults();
        renderTasks();
        renderCategories();
        renderWorkspaces();
        updateWorkspaceSelect();
        updateCounts();
        updateProgress();
        updateInsights();
        applySettings();
        checkDarkMode();
        updateUserStats();
        loadStreak();
        updatePomodoroDisplay();
        initParticles();
    }, 1200);
});

// ===== Local Storage =====
function saveToLocalStorage() {
    localStorage.setItem('tasks', JSON.stringify(tasks));
    localStorage.setItem('categories', JSON.stringify(categories));
    localStorage.setItem('workspaces', JSON.stringify(workspaces));
    localStorage.setItem('pomodoroSessions', pomodoroSessions.toString());
    localStorage.setItem('pomodoroTodayMinutes', pomodoroTodayMinutes.toString());
}

function loadFromLocalStorage() {
    try {
        tasks = JSON.parse(localStorage.getItem('tasks')) || [];
        categories = JSON.parse(localStorage.getItem('categories')) || [];
        workspaces = JSON.parse(localStorage.getItem('workspaces')) || [];
        pomodoroSessions = parseInt(localStorage.getItem('pomodoroSessions')) || 0;
        pomodoroTodayMinutes = parseInt(localStorage.getItem('pomodoroTodayMinutes')) || 0;
        const savedUserName = localStorage.getItem('userName');
        if (savedUserName) {
            document.getElementById('user-name').textContent = savedUserName;
            document.getElementById('user-name-input').value = savedUserName;
        }
    } catch (e) {
        tasks = [];
        categories = [];
        workspaces = [];
    }
}

// ===== Streak =====
function loadStreak() {
    const lastDate = localStorage.getItem('lastCompleteDate');
    const today = new Date().toISOString().split('T')[0];
    if (lastDate === today) {
        streakCount = parseInt(localStorage.getItem('streakCount')) || 0;
    } else if (lastDate === getYesterday()) {
        streakCount = parseInt(localStorage.getItem('streakCount')) || 0;
    } else {
        streakCount = 0;
        localStorage.setItem('streakCount', '0');
    }
    updateStreakDisplay();
}

function getYesterday() {
    const d = new Date();
    d.setDate(d.getDate() - 1);
    return d.toISOString().split('T')[0];
}

function updateStreakDisplay() {
    const existing = document.querySelector('.streak-badge');
    if (existing) existing.remove();
    if (streakCount > 0) {
        const badge = document.createElement('span');
        badge.className = 'streak-badge';
        badge.innerHTML = `<i class="fas fa-fire"></i> ${streakCount} day${streakCount > 1 ? 's' : ''}`;
        document.querySelector('.user-info h3').after(badge);
    }
}

function checkStreak() {
    const today = new Date().toISOString().split('T')[0];
    const lastDate = localStorage.getItem('lastCompleteDate');
    if (lastDate === today) return;
    if (lastDate === getYesterday()) {
        streakCount++;
    } else {
        streakCount = 1;
    }
    localStorage.setItem('lastCompleteDate', today);
    localStorage.setItem('streakCount', streakCount.toString());
    updateStreakDisplay();
}

// ===== My Day =====
function addToMyDay(taskId) {
    const task = tasks.find(t => t.id === taskId);
    if (!task) return;
    if (!myDayTasks.includes(taskId)) {
        myDayTasks.push(taskId);
        localStorage.setItem('myDayTasks', JSON.stringify(myDayTasks));
        showToast('Added to My Day', 'success');
    }
}

function loadMyDay() {
    try {
        myDayTasks = JSON.parse(localStorage.getItem('myDayTasks')) || [];
    } catch { myDayTasks = []; }
}

// ===== Event Listeners =====
function initializeEventListeners() {
    document.querySelectorAll('.nav-item').forEach(item => {
        item.addEventListener('click', (e) => {
            switchView(e.currentTarget.dataset.view);
        });
    });

    document.getElementById('add-task-btn').addEventListener('click', () => openTaskModal());
    document.getElementById('close-modal').addEventListener('click', closeTaskModal);
    document.getElementById('cancel-btn').addEventListener('click', closeTaskModal);
    document.getElementById('task-form').addEventListener('submit', saveTask);

    document.getElementById('task-recurring').addEventListener('change', (e) => {
        document.getElementById('recurring-options').style.display = e.target.checked ? 'block' : 'none';
    });

    document.getElementById('add-category-btn').addEventListener('click', openCategoryModal);
    document.getElementById('add-workspace-btn').addEventListener('click', openWorkspaceModal);
    document.getElementById('close-workspace-modal').addEventListener('click', closeWorkspaceModal);
    document.getElementById('cancel-workspace-btn').addEventListener('click', closeWorkspaceModal);
    document.getElementById('workspace-form').addEventListener('submit', saveWorkspace);
    document.getElementById('close-category-modal').addEventListener('click', closeCategoryModal);
    document.getElementById('cancel-category-btn').addEventListener('click', closeCategoryModal);
    document.getElementById('category-form').addEventListener('submit', saveCategory);

    document.querySelectorAll('.color-option').forEach(option => {
        option.addEventListener('click', function() {
            document.querySelectorAll('.color-option').forEach(o => o.classList.remove('active'));
            this.classList.add('active');
        });
    });

    document.getElementById('settings-btn').addEventListener('click', openSettingsModal);
    document.getElementById('close-settings-modal').addEventListener('click', closeSettingsModal);

    document.getElementById('pomodoro-toggle-btn').addEventListener('click', togglePomodoroPanel);
    document.getElementById('pomodoro-start').addEventListener('click', togglePomodoro);
    document.getElementById('pomodoro-reset').addEventListener('click', resetPomodoro);
    document.getElementById('pomodoro-skip').addEventListener('click', skipPomodoro);

    document.getElementById('focus-mode-btn').addEventListener('click', toggleFocusMode);
    document.getElementById('template-btn').addEventListener('click', openTemplateModal);
    document.getElementById('close-template-modal').addEventListener('click', closeTemplateModal);
    document.getElementById('smart-filter-btn').addEventListener('click', cycleSmartFilter);

    document.getElementById('stats-btn').addEventListener('click', openStatsModal);
    document.getElementById('close-stats-modal').addEventListener('click', closeStatsModal);

    document.getElementById('shortcuts-btn').addEventListener('click', openShortcutsModal);
    document.getElementById('close-shortcuts-modal').addEventListener('click', closeShortcutsModal);

    document.getElementById('user-name-input').addEventListener('change', (e) => {
        const name = e.target.value.trim() || 'Welcome Back!';
        document.getElementById('user-name').textContent = name;
        localStorage.setItem('userName', name);
    });

    document.getElementById('search-input').addEventListener('input', handleSearch);

    document.getElementById('quick-add-form').addEventListener('submit', handleQuickAddSubmit);
    document.getElementById('complete-visible-btn').addEventListener('click', completeVisibleTasks);
    document.getElementById('clear-completed-btn').addEventListener('click', clearCompletedTasks);

    document.getElementById('filter-btn').addEventListener('click', toggleFilterPanel);
    document.getElementById('view-toggle').addEventListener('click', toggleViewMode);
    document.getElementById('calendar-toggle').addEventListener('click', toggleCalendarView);
    document.getElementById('calendar-prev').addEventListener('click', () => {
        calendarMonth = new Date(calendarMonth.getFullYear(), calendarMonth.getMonth() - 1, 1);
        renderCalendar();
    });
    document.getElementById('calendar-next').addEventListener('click', () => {
        calendarMonth = new Date(calendarMonth.getFullYear(), calendarMonth.getMonth() + 1, 1);
        renderCalendar();
    });

    document.querySelectorAll('.filter-option').forEach(option => {
        option.addEventListener('click', handleFilter);
    });

    document.querySelectorAll('.sort-option').forEach(option => {
        option.addEventListener('click', handleSort);
    });

    document.getElementById('add-subtask-btn').addEventListener('click', (e) => {
        e.preventDefault();
        addSubtaskInput();
    });

    document.getElementById('theme-toggle').addEventListener('click', toggleDarkMode);
    document.getElementById('dark-mode-toggle').addEventListener('change', toggleDarkMode);
    document.getElementById('animations-toggle').addEventListener('change', (e) => {
        localStorage.setItem('animationsEnabled', e.target.checked ? 'true' : 'false');
        applySettings();
    });
    document.getElementById('notifications-toggle').addEventListener('change', (e) => {
        localStorage.setItem('notificationsEnabled', e.target.checked ? 'true' : 'false');
        if (e.target.checked) checkNotifications();
    });
    document.getElementById('sound-toggle').addEventListener('change', (e) => {
        localStorage.setItem('soundEnabled', e.target.checked ? 'true' : 'false');
    });

    document.getElementById('export-data-btn').addEventListener('click', exportData);
    document.getElementById('import-data-btn').addEventListener('click', () => {
        document.getElementById('import-file-input').click();
    });
    document.getElementById('import-file-input').addEventListener('change', importData);
    document.getElementById('clear-data-btn').addEventListener('click', clearAllData);

    document.getElementById('sidebar-toggle').addEventListener('click', () => {
        document.getElementById('sidebar').classList.toggle('active');
    });

    document.querySelectorAll('.modal').forEach(modal => {
        modal.addEventListener('click', (e) => {
            if (e.target === modal) modal.classList.remove('active');
        });
    });
}

// ===== Pomodoro =====
function togglePomodoroPanel() {
    const panel = document.getElementById('pomodoro-container');
    panel.classList.toggle('active');
}

function togglePomodoro() {
    if (pomodoroRunning) {
        clearInterval(pomodoroTimer);
        pomodoroRunning = false;
        document.getElementById('pomodoro-start').innerHTML = '<i class="fas fa-play"></i>';
        document.getElementById('pomodoro-start').classList.remove('active');
    } else {
        pomodoroRunning = true;
        document.getElementById('pomodoro-start').innerHTML = '<i class="fas fa-pause"></i>';
        document.getElementById('pomodoro-start').classList.add('active');
        pomodoroTimer = setInterval(() => {
            pomodoroTime--;
            updatePomodoroDisplay();
            if (pomodoroTime <= 0) {
                clearInterval(pomodoroTimer);
                pomodoroRunning = false;
                document.getElementById('pomodoro-start').innerHTML = '<i class="fas fa-play"></i>';
                document.getElementById('pomodoro-start').classList.remove('active');
                pomodoroComplete();
            }
        }, 1000);
    }
}

function resetPomodoro() {
    clearInterval(pomodoroTimer);
    pomodoroRunning = false;
    pomodoroPhase = 'focus';
    pomodoroTime = 25 * 60;
    document.getElementById('pomodoro-start').innerHTML = '<i class="fas fa-play"></i>';
    document.getElementById('pomodoro-start').classList.remove('active');
    document.getElementById('pomodoro-status').textContent = 'Focus';
    updatePomodoroDisplay();
}

function skipPomodoro() {
    clearInterval(pomodoroTimer);
    pomodoroRunning = false;
    pomodoroComplete();
}

function pomodoroComplete() {
    if (pomodoroPhase === 'focus') {
        pomodoroSessions++;
        pomodoroTodayMinutes += 25;
        saveToLocalStorage();
        document.getElementById('pomodoro-sessions').textContent = pomodoroSessions;
        document.getElementById('pomodoro-today-min').textContent = pomodoroTodayMinutes;

        if (pomodoroSessions % 4 === 0) {
            pomodoroPhase = 'long-break';
            pomodoroTime = 15 * 60;
            showToast('Long break time! Great work! 🎉', 'success');
            triggerConfetti();
        } else {
            pomodoroPhase = 'short-break';
            pomodoroTime = 5 * 60;
            showToast('Good job! Take a short break ☕', 'success');
        }
        document.getElementById('pomodoro-status').textContent = pomodoroPhase === 'short-break' ? 'Short Break' : 'Long Break';
    } else {
        pomodoroPhase = 'focus';
        pomodoroTime = 25 * 60;
        document.getElementById('pomodoro-status').textContent = 'Focus';
        showToast('Break over! Time to focus 🎯', 'info');
    }
    updatePomodoroDisplay();
}

function updatePomodoroDisplay() {
    const mins = Math.floor(pomodoroTime / 60);
    const secs = pomodoroTime % 60;
    document.getElementById('pomodoro-timer').textContent =
        `${String(mins).padStart(2, '0')}:${String(secs).padStart(2, '0')}`;
    document.getElementById('pomodoro-sessions').textContent = pomodoroSessions;
    document.getElementById('pomodoro-today-min').textContent = pomodoroTodayMinutes;
}

// ===== Stats =====
function openStatsModal() {
    const total = tasks.length;
    const completed = tasks.filter(t => t.completed).length;
    const pending = total - completed;

    document.getElementById('stats-total').textContent = total;
    document.getElementById('stats-completed').textContent = completed;
    document.getElementById('stats-pending').textContent = pending;
    document.getElementById('stats-streak').textContent = streakCount;

    renderChart();
    document.getElementById('stats-modal').classList.add('active');
}

function closeStatsModal() {
    document.getElementById('stats-modal').classList.remove('active');
}

function renderChart() {
    const container = document.getElementById('chart-bars');
    container.innerHTML = '';
    const days = [];
    for (let i = 6; i >= 0; i--) {
        const d = new Date();
        d.setDate(d.getDate() - i);
        days.push(d.toISOString().split('T')[0]);
    }
    const maxVal = Math.max(1, ...days.map(day =>
        tasks.filter(t => {
            if (!t.createdAt) return false;
            const taskDay = t.createdAt.split('T')[0];
            return taskDay === day && t.completed;
        }).length
    ));
    days.forEach(day => {
        const count = tasks.filter(t => {
            if (!t.createdAt) return false;
            return t.createdAt.split('T')[0] === day && t.completed;
        }).length;
        const bar = document.createElement('div');
        bar.className = 'chart-bar';
        const pct = (count / maxVal) * 100;
        bar.style.height = `${Math.max(pct, 4)}%`;
        const dateObj = new Date(day + 'T00:00:00');
        const label = dateObj.toLocaleDateString('en-US', { weekday: 'short' });
        bar.innerHTML = `
            <span class="chart-bar-value">${count}</span>
            <span class="chart-bar-label">${label}</span>
        `;
        container.appendChild(bar);
    });
}

// ===== Shortcuts Modal =====
function openShortcutsModal() {
    document.getElementById('shortcuts-modal').classList.add('active');
}

function closeShortcutsModal() {
    document.getElementById('shortcuts-modal').classList.remove('active');
}

// ===== View Management =====
function switchView(view) {
    currentView = view;
    currentFilter.category = null;
    currentFilter.workspace = null;
    currentFilter.date = null;

    document.querySelectorAll('.nav-item').forEach(item => item.classList.remove('active'));
    document.querySelector(`[data-view="${view}"]`).classList.add('active');
    document.querySelectorAll('.category-item').forEach(item => item.classList.remove('active'));

    const titles = {
        all: { title: 'All Tasks', subtitle: 'Manage your tasks efficiently' },
        myday: { title: 'My Day', subtitle: 'Tasks you want to focus on today' },
        today: { title: 'Today', subtitle: 'Tasks due today' },
        upcoming: { title: 'Upcoming', subtitle: 'Tasks coming up' },
        overdue: { title: 'Overdue', subtitle: 'Tasks that need attention' },
        completed: { title: 'Completed', subtitle: 'Finished tasks' },
        important: { title: 'Important', subtitle: 'High priority tasks' }
    };

    document.getElementById('view-title').textContent = titles[view].title;
    document.getElementById('view-subtitle').textContent = titles[view].subtitle;

    renderTasks();
    updateProgress();
}

function toggleViewMode() {
    viewMode = viewMode === 'list' ? 'grid' : 'list';
    document.querySelector('#view-toggle i').className = viewMode === 'list' ? 'fas fa-th' : 'fas fa-list';
    localStorage.setItem('viewMode', viewMode);
    renderTasks();
}

// ===== Quick Actions =====
function setQuickAddDefaults() {
    const dateInput = document.getElementById('quick-add-date');
    if (dateInput) dateInput.value = new Date().toISOString().split('T')[0];
}

function handleQuickAddSubmit(e) {
    e.preventDefault();
    const title = document.getElementById('quick-add-title').value.trim();
    if (!title) { showToast('Please enter a task title', 'error'); return; }

    const parsedTask = parseNaturalLanguageTask(title);
    const newTask = {
        id: Date.now(),
        title: parsedTask.title,
        description: parsedTask.description,
        dueDate: parsedTask.dueDate || document.getElementById('quick-add-date').value,
        dueTime: parsedTask.dueTime || '',
        priority: parsedTask.priority || 'medium',
        category: parsedTask.category || '',
        workspace: '',
        tags: parsedTask.tags || [],
        important: parsedTask.important || false,
        recurring: false,
        recurrence: null,
        subtasks: [],
        completed: false,
        createdAt: new Date().toISOString()
    };

    tasks.unshift(newTask);
    saveToLocalStorage();
    renderTasks();
    updateCounts();
    updateProgress();
    updateInsights();
    renderCategories();
    updateUserStats();
    showToast('Task added!', 'success');
    playSound('create');
    document.getElementById('quick-add-form').reset();
    setQuickAddDefaults();
}

function parseNaturalLanguageTask(input) {
    const text = input.toLowerCase();
    const result = { title: input.trim(), description: '', dueDate: '', dueTime: '', priority: '', category: '', tags: [], important: false };

    if (text.includes('urgent') || text.includes('asap')) {
        result.priority = 'high'; result.important = true;
    } else if (text.includes('later')) {
        result.priority = 'low';
    } else if (text.includes('important')) {
        result.priority = 'high'; result.important = true;
    }

    const today = new Date();
    const tomorrow = new Date(today); tomorrow.setDate(today.getDate() + 1);
    const nextWeek = new Date(today); nextWeek.setDate(today.getDate() + 7);

    if (text.includes('today')) result.dueDate = today.toISOString().split('T')[0];
    else if (text.includes('tomorrow')) result.dueDate = tomorrow.toISOString().split('T')[0];
    else if (text.includes('week')) result.dueDate = nextWeek.toISOString().split('T')[0];

    if (text.includes('work')) { result.category = 'work'; result.tags.push('work'); }
    else if (text.includes('personal')) { result.category = 'personal'; result.tags.push('personal'); }

    const match = input.match(/@([a-zA-Z0-9-_]+)/);
    if (match) result.tags.push(match[1]);

    return result;
}

function completeVisibleTasks() {
    const visibleTasks = getFilteredTasks().filter(task => !task.completed);
    if (visibleTasks.length === 0) { showToast('No visible tasks to complete', 'info'); return; }
    visibleTasks.forEach(task => { task.completed = true; });
    saveToLocalStorage();
    renderTasks();
    updateCounts();
    updateProgress();
    updateInsights();
    renderCategories();
    updateUserStats();
    showToast(`Completed ${visibleTasks.length} task${visibleTasks.length !== 1 ? 's' : ''}`, 'success');
}

function toggleFocusMode() {
    focusModeEnabled = !focusModeEnabled;
    document.body.classList.toggle('focus-mode', focusModeEnabled);
    document.getElementById('focus-mode-btn').innerHTML =
        focusModeEnabled ? '<i class="fas fa-bullseye"></i> Focus On' : '<i class="fas fa-bullseye"></i> Focus Mode';
    showToast(focusModeEnabled ? 'Focus mode enabled' : 'Focus mode disabled', 'info');
}

function openTemplateModal() {
    const list = document.getElementById('template-list');
    list.innerHTML = '';
    const templates = [
        { name: 'Deep Work', tasks: ['Block 90 minutes for focused work', 'Close all distractions', 'Review progress'] },
        { name: 'Weekly Review', tasks: ['Review completed tasks', 'Plan next week', 'Update notes'] },
        { name: 'Trip Prep', tasks: ['Pack passport', 'Check travel documents', 'Confirm bookings'] },
        { name: 'Daily Standup', tasks: ['What I did yesterday', 'What I will do today', 'Any blockers'] }
    ];

    templates.forEach(template => {
        const card = document.createElement('div');
        card.className = 'template-card';
        card.innerHTML = `<strong>${template.name}</strong><div>${template.tasks.join('<br>')}</div><button class="btn btn-primary btn-sm" data-template='${JSON.stringify(template.tasks)}'>Apply</button>`;
        list.appendChild(card);
    });

    list.querySelectorAll('button').forEach(btn => {
        btn.addEventListener('click', () => {
            const tasksToAdd = JSON.parse(btn.dataset.template);
            tasksToAdd.forEach(taskText => {
                const parsed = parseNaturalLanguageTask(taskText);
                tasks.unshift({
                    id: Date.now() + Math.floor(Math.random() * 9999),
                    title: parsed.title,
                    description: parsed.description,
                    dueDate: parsed.dueDate || '',
                    dueTime: parsed.dueTime || '',
                    priority: parsed.priority || 'medium',
                    category: parsed.category || '',
                    workspace: '',
                    reminder: '',
                    tags: parsed.tags || [],
                    important: parsed.important || false,
                    recurring: false,
                    recurrence: null,
                    subtasks: [],
                    completed: false,
                    createdAt: new Date().toISOString()
                });
            });
            saveToLocalStorage();
            renderTasks();
            updateCounts();
            updateProgress();
            updateInsights();
            renderCategories();
            updateUserStats();
            closeTemplateModal();
            showToast('Template applied!', 'success');
        });
    });
    document.getElementById('template-modal').classList.add('active');
}

function closeTemplateModal() {
    document.getElementById('template-modal').classList.remove('active');
}

function cycleSmartFilter() {
    const filters = ['all', 'high', 'today', 'important'];
    const index = filters.indexOf(smartFilter);
    smartFilter = filters[(index + 1) % filters.length];
    showToast(`Smart filter: ${smartFilter}`, 'info');
    renderTasks();
}

function clearCompletedTasks() {
    const completedCount = tasks.filter(task => task.completed).length;
    if (completedCount === 0) { showToast('No completed tasks to clear', 'info'); return; }
    tasks = tasks.filter(task => !task.completed);
    saveToLocalStorage();
    renderTasks();
    updateCounts();
    updateProgress();
    updateInsights();
    renderCategories();
    updateUserStats();
    showToast('Completed tasks cleared', 'success');
}

function updateInsights() {
    const today = new Date().toISOString().split('T')[0];
    const activeTasks = tasks.filter(task => !task.completed).length;
    const overdueTasks = tasks.filter(task => task.dueDate && task.dueDate < today && !task.completed).length;
    const dueSoonTasks = tasks.filter(task => {
        if (!task.dueDate || task.completed) return false;
        const diffDays = Math.round((new Date(`${task.dueDate}T00:00:00`) - new Date(`${today}T00:00:00`)) / (86400000));
        return diffDays >= 0 && diffDays <= 2;
    }).length;

    document.getElementById('insight-active').textContent = `${activeTasks} task${activeTasks !== 1 ? 's' : ''}`;
    document.getElementById('insight-overdue').textContent = `${overdueTasks} task${overdueTasks !== 1 ? 's' : ''}`;
    document.getElementById('insight-soon').textContent = `${dueSoonTasks} task${dueSoonTasks !== 1 ? 's' : ''}`;
}

function getTaskDueState(task) {
    if (task.completed || !task.dueDate) return { className: '', label: '' };
    const today = new Date();
    const todayStart = new Date(today.getFullYear(), today.getMonth(), today.getDate());
    const dueDate = new Date(`${task.dueDate}T00:00:00`);
    const diffDays = Math.round((dueDate - todayStart) / 86400000);
    if (diffDays < 0) return { className: 'overdue', label: 'Overdue' };
    if (diffDays <= 2) return { className: 'due-soon', label: diffDays === 0 ? 'Due today' : `${diffDays} day${diffDays === 1 ? '' : 's'} left` };
    return { className: '', label: '' };
}

// ===== Task Management =====
function openTaskModal(taskId = null) {
    const modal = document.getElementById('task-modal');
    const form = document.getElementById('task-form');
    const modalTitle = document.getElementById('modal-title');

    form.reset();
    document.getElementById('subtasks-container').innerHTML = '';
    document.getElementById('recurring-options').style.display = 'none';

    if (taskId) {
        editingTaskId = taskId;
        const task = tasks.find(t => t.id === taskId);
        if (!task) return;
        modalTitle.textContent = 'Edit Task';
        document.getElementById('task-title').value = task.title;
        document.getElementById('task-description').value = task.description || '';
        document.getElementById('task-date').value = task.dueDate || '';
        document.getElementById('task-time').value = task.dueTime || '';
        document.getElementById('task-priority').value = task.priority;
        document.getElementById('task-category').value = task.category || '';
        document.getElementById('task-workspace').value = task.workspace || '';
        document.getElementById('task-reminder').value = task.reminder || '';
        document.getElementById('task-tags').value = task.tags ? task.tags.join(', ') : '';
        document.getElementById('task-important').checked = task.important || false;
        document.getElementById('task-recurring').checked = task.recurring || false;
        if (task.recurring) {
            document.getElementById('recurring-options').style.display = 'block';
            document.getElementById('task-recurrence').value = task.recurrence || 'daily';
        }
        if (task.subtasks && task.subtasks.length > 0) {
            task.subtasks.forEach(subtask => addSubtaskInput(subtask.text));
        }
    } else {
        editingTaskId = null;
        modalTitle.textContent = 'Add New Task';
    }

    updateCategorySelect();
    updateWorkspaceSelect();
    modal.classList.add('active');
}

function closeTaskModal() {
    document.getElementById('task-modal').classList.remove('active');
    editingTaskId = null;
}

function saveTask(e) {
    e.preventDefault();
    const title = document.getElementById('task-title').value.trim();
    if (!title) { showToast('Please enter a task title', 'error'); return; }

    const taskData = {
        title,
        description: document.getElementById('task-description').value.trim(),
        dueDate: document.getElementById('task-date').value,
        dueTime: document.getElementById('task-time').value,
        priority: document.getElementById('task-priority').value,
        category: document.getElementById('task-category').value,
        workspace: document.getElementById('task-workspace').value,
        reminder: document.getElementById('task-reminder').value,
        tags: document.getElementById('task-tags').value.trim().split(',').map(t => t.trim()).filter(Boolean),
        important: document.getElementById('task-important').checked,
        recurring: document.getElementById('task-recurring').checked,
        recurrence: document.getElementById('task-recurring').checked ? document.getElementById('task-recurrence').value : null,
        subtasks: [],
        completed: false
    };

    document.querySelectorAll('.subtask-item input[type="text"]').forEach(input => {
        if (input.value.trim()) {
            taskData.subtasks.push({ id: Date.now() + Math.floor(Math.random() * 9999), text: input.value.trim(), completed: false });
        }
    });

    if (editingTaskId) {
        const taskIndex = tasks.findIndex(t => t.id === editingTaskId);
        if (taskIndex !== -1) {
            tasks[taskIndex] = { ...tasks[taskIndex], ...taskData };
            showToast('Task updated!', 'success');
        }
    } else {
        tasks.unshift({ id: Date.now(), createdAt: new Date().toISOString(), ...taskData });
        showToast('Task created!', 'success');
        playSound('create');
    }

    saveToLocalStorage();
    renderTasks();
    updateCounts();
    updateProgress();
    updateInsights();
    renderCategories();
    updateUserStats();
    closeTaskModal();
}

function deleteTask(taskId) {
    const task = tasks.find(t => t.id === taskId);
    if (!task) return;
    lastDeletedTask = { task: { ...task }, index: tasks.findIndex(t => t.id === taskId) };
    tasks = tasks.filter(t => t.id !== taskId);
    saveToLocalStorage();
    renderTasks();
    updateCounts();
    updateProgress();
    updateInsights();
    renderCategories();
    updateUserStats();
    showToast('Task deleted!', 'success', 'Undo', restoreLastDeletedTask);
    playSound('delete');
}

function restoreLastDeletedTask() {
    if (!lastDeletedTask) return;
    const { task, index } = lastDeletedTask;
    if (index >= 0) tasks.splice(index, 0, task);
    else tasks.unshift(task);
    lastDeletedTask = null;
    saveToLocalStorage();
    renderTasks();
    updateCounts();
    updateProgress();
    updateInsights();
    renderCategories();
    updateUserStats();
    showToast('Task restored!', 'info');
}

function toggleTaskComplete(taskId) {
    const task = tasks.find(t => t.id === taskId);
    if (!task) return;
    task.completed = !task.completed;

    if (task.completed) {
        showToast('Task completed! 🎉', 'success');
        playSound('complete');
        triggerConfetti();
        checkStreak();
        if (task.recurring && task.recurrence) createRecurringTask(task);
    } else {
        showToast('Task reopened!', 'info');
    }

    saveToLocalStorage();
    renderTasks();
    updateCounts();
    updateProgress();
    updateInsights();
    renderCategories();
    updateUserStats();
}

function createRecurringTask(originalTask) {
    const newTask = { ...originalTask };
    newTask.id = Date.now();
    newTask.completed = false;
    newTask.createdAt = new Date().toISOString();
    if (newTask.dueDate) {
        const currentDate = new Date(newTask.dueDate);
        if (newTask.recurrence === 'daily') currentDate.setDate(currentDate.getDate() + 1);
        else if (newTask.recurrence === 'weekly') currentDate.setDate(currentDate.getDate() + 7);
        else if (newTask.recurrence === 'monthly') currentDate.setMonth(currentDate.getMonth() + 1);
        newTask.dueDate = currentDate.toISOString().split('T')[0];
    }
    tasks.unshift(newTask);
    saveToLocalStorage();
}

function toggleTaskImportant(taskId) {
    const task = tasks.find(t => t.id === taskId);
    if (!task) return;
    task.important = !task.important;
    saveToLocalStorage();
    renderTasks();
    updateCounts();
    updateInsights();
    showToast(task.important ? 'Marked as important!' : 'Removed from important!', 'info');
}

function toggleSubtask(taskId, subtaskId) {
    const task = tasks.find(t => t.id === taskId);
    if (!task || !task.subtasks) return;
    const subtask = task.subtasks.find(s => s.id === subtaskId);
    if (!subtask) return;
    subtask.completed = !subtask.completed;
    saveToLocalStorage();
    renderTasks();
}

// ===== Render =====
function renderTasks() {
    const container = document.getElementById('tasks-container');
    const emptyState = document.getElementById('empty-state');
    if (!container || !emptyState) return;

    container.classList.remove('list-view', 'grid-view');
    container.classList.add(viewMode === 'grid' ? 'grid-view' : 'list-view');

    let filteredTasks = getFilteredTasks();

    if (filteredTasks.length === 0) {
        emptyState.style.display = 'flex';
        container.querySelectorAll('.task-card').forEach(card => card.remove());
        if (sortableInstance) { sortableInstance.destroy(); sortableInstance = null; }
        return;
    }

    emptyState.style.display = 'none';
    container.innerHTML = '';

    filteredTasks.forEach(task => {
        container.appendChild(createTaskCard(task));
    });

    if (currentView === 'all' && !sortableInstance) {
        sortableInstance = Sortable.create(container, {
            animation: 200,
            ghostClass: 'dragging',
            onEnd: function(evt) {
                const movedTask = filteredTasks[evt.oldIndex];
                filteredTasks.splice(evt.oldIndex, 1);
                filteredTasks.splice(evt.newIndex, 0, movedTask);
                const allTaskIds = filteredTasks.map(t => t.id);
                tasks.sort((a, b) => {
                    const ai = allTaskIds.indexOf(a.id);
                    const bi = allTaskIds.indexOf(b.id);
                    if (ai === -1) return 1;
                    if (bi === -1) return -1;
                    return ai - bi;
                });
                saveToLocalStorage();
            }
        });
    } else if (currentView !== 'all' && sortableInstance) {
        sortableInstance.destroy();
        sortableInstance = null;
    }
}

function escapeHtml(text) {
    const div = document.createElement('div');
    div.textContent = text;
    return div.innerHTML;
}

function createTaskCard(task) {
    const card = document.createElement('div');
    const dueState = getTaskDueState(task);
    card.className = `task-card ${task.completed ? 'completed' : ''} ${dueState.className}`;

    const category = categories.find(c => c.id === task.category);
    const workspace = workspaces.find(w => w.id === task.workspace);
    const categoryBadge = category ?
        `<span class="task-category-badge" style="background:${category.color}15;color:${category.color}"><i class="fas ${category.icon}"></i>${escapeHtml(category.name)}</span>` : '';

    const tagsHtml = task.tags && task.tags.length > 0 ?
        `<div class="task-tags">${task.tags.map(tag => `<span class="task-tag">${escapeHtml(tag)}</span>`).join('')}</div>` : '';

    const dueDateHtml = task.dueDate ?
        `<div class="task-meta-item"><i class="fas fa-calendar"></i><span>${formatDate(task.dueDate)}</span></div>` : '';

    const dueTimeHtml = task.dueTime ?
        `<div class="task-meta-item"><i class="fas fa-clock"></i><span>${task.dueTime}</span></div>` : '';

    const workspaceBadge = workspace ?
        `<div class="task-meta-item"><i class="fas fa-folder"></i><span>${escapeHtml(workspace.name)}</span></div>` : '';

    const recurringBadge = task.recurring ?
        `<div class="task-meta-item"><i class="fas fa-redo"></i><span>${task.recurrence}</span></div>` : '';

    const dueStateBadge = dueState.label ?
        `<div class="task-meta-item due-state ${dueState.className}"><i class="fas fa-bolt"></i><span>${escapeHtml(dueState.label)}</span></div>` : '';

    let subtasksHtml = '';
    if (task.subtasks && task.subtasks.length > 0) {
        const completedSubtasks = task.subtasks.filter(s => s.completed).length;
        const subtasksItems = task.subtasks.map(subtask => {
            const checked = subtask.completed ? 'checked' : '';
            return `<div class="task-subtask"><input type="checkbox" ${checked} data-task-id="${task.id}" data-subtask-id="${subtask.id}" class="subtask-checkbox"><span style="${subtask.completed ? 'text-decoration:line-through' : ''}">${escapeHtml(subtask.text)}</span></div>`;
        }).join('');
        subtasksHtml = `<div class="task-subtasks"><div style="font-size:12px;color:var(--text-tertiary);margin-bottom:8px">${completedSubtasks}/${task.subtasks.length} subtasks</div>${subtasksItems}</div>`;
    }

    const isMyDay = myDayTasks.includes(task.id);

    card.innerHTML = `
        <div class="task-header">
            <div class="task-checkbox ${task.completed ? 'checked' : ''}" data-task-id="${task.id}"></div>
            <div class="task-content">
                <h3 class="task-title">${escapeHtml(task.title)}</h3>
                ${task.description ? `<p class="task-description">${escapeHtml(task.description)}</p>` : ''}
                <div class="task-meta">
                    <span class="task-priority ${task.priority}">${task.priority}</span>
                    ${categoryBadge}
                    ${dueDateHtml}
                    ${dueTimeHtml}
                    ${workspaceBadge}
                    ${recurringBadge}
                    ${dueStateBadge}
                    ${isMyDay ? '<span class="task-priority" style="background:rgba(245,158,11,0.1);color:var(--warning);font-size:10px"><i class="fas fa-sun"></i> My Day</span>' : ''}
                </div>
                ${tagsHtml}
                ${subtasksHtml}
            </div>
            <div class="task-actions">
                <button class="task-action-btn" data-task-id="${task.id}" data-action="myday" title="Add to My Day"><i class="fas fa-sun"></i></button>
                <button class="task-action-btn ${task.important ? 'important' : ''}" data-task-id="${task.id}" data-action="important" title="Important"><i class="fas fa-star"></i></button>
                <button class="task-action-btn" data-task-id="${task.id}" data-action="edit" title="Edit"><i class="fas fa-edit"></i></button>
                <button class="task-action-btn delete" data-task-id="${task.id}" data-action="delete" title="Delete"><i class="fas fa-trash"></i></button>
            </div>
        </div>
    `;

    card.querySelector('.task-checkbox').addEventListener('click', function() {
        toggleTaskComplete(Number(this.dataset.taskId));
    });

    card.querySelectorAll('.task-action-btn').forEach(btn => {
        btn.addEventListener('click', (e) => {
            e.stopPropagation();
            const action = btn.dataset.action;
            const taskId = Number(btn.dataset.taskId);
            if (action === 'important') toggleTaskImportant(taskId);
            else if (action === 'edit') openTaskModal(taskId);
            else if (action === 'delete') deleteTask(taskId);
            else if (action === 'myday') addToMyDay(taskId);
        });
    });

    card.querySelectorAll('.subtask-checkbox').forEach(cb => {
        cb.addEventListener('change', (e) => {
            toggleSubtask(Number(e.target.dataset.taskId), parseFloat(e.target.dataset.subtaskId));
        });
    });

    return card;
}

function getFilteredTasks() {
    let filtered = [...tasks];
    const today = new Date().toISOString().split('T')[0];

    if (smartFilter === 'high') filtered = filtered.filter(task => task.priority === 'high' || task.important);
    else if (smartFilter === 'today') filtered = filtered.filter(task => task.dueDate === today || !task.dueDate);
    else if (smartFilter === 'important') filtered = filtered.filter(task => task.important);

    loadMyDay();
    switch (currentView) {
        case 'myday':
            filtered = filtered.filter(t => myDayTasks.includes(t.id));
            break;
        case 'today':
            filtered = filtered.filter(t => t.dueDate === today && !t.completed);
            break;
        case 'upcoming':
            filtered = filtered.filter(t => t.dueDate && t.dueDate > today && !t.completed);
            break;
        case 'overdue':
            filtered = filtered.filter(t => t.dueDate && t.dueDate < today && !t.completed);
            break;
        case 'completed':
            filtered = filtered.filter(t => t.completed);
            break;
        case 'important':
            filtered = filtered.filter(t => t.important && !t.completed);
            break;
    }

    if (currentFilter.priority !== 'all') filtered = filtered.filter(t => t.priority === currentFilter.priority);
    if (currentFilter.category) filtered = filtered.filter(t => t.category === currentFilter.category);
    if (currentFilter.workspace) filtered = filtered.filter(t => t.workspace === currentFilter.workspace);
    if (currentFilter.date) filtered = filtered.filter(t => t.dueDate === currentFilter.date);

    if (currentFilter.search) {
        const search = currentFilter.search.toLowerCase();
        filtered = filtered.filter(t =>
            t.title.toLowerCase().includes(search) ||
            (t.description && t.description.toLowerCase().includes(search)) ||
            (t.tags && t.tags.some(tag => tag.toLowerCase().includes(search)))
        );
    }

    filtered.sort((a, b) => {
        switch (currentSort) {
            case 'date-desc': return new Date(b.createdAt) - new Date(a.createdAt);
            case 'date-asc': return new Date(a.createdAt) - new Date(b.createdAt);
            case 'priority': return ({ high: 3, medium: 2, low: 1 })[b.priority] - ({ high: 3, medium: 2, low: 1 })[a.priority];
            case 'alphabetical': return a.title.localeCompare(b.title);
            case 'duedate':
                if (!a.dueDate) return 1;
                if (!b.dueDate) return -1;
                return new Date(a.dueDate) - new Date(b.dueDate);
            default: return 0;
        }
    });

    return filtered;
}

// ===== Categories =====
function openCategoryModal() {
    document.getElementById('category-modal').classList.add('active');
}

function closeCategoryModal() {
    document.getElementById('category-modal').classList.remove('active');
    document.getElementById('category-form').reset();
    document.querySelectorAll('.color-option').forEach(o => o.classList.remove('active'));
    document.querySelector('.color-option').classList.add('active');
}

function saveCategory(e) {
    e.preventDefault();
    const name = document.getElementById('category-name').value.trim();
    if (!name) { showToast('Please enter a category name', 'error'); return; }
    categories.push({
        id: Date.now().toString(),
        name,
        icon: document.getElementById('category-icon').value,
        color: document.querySelector('.color-option.active').dataset.color
    });
    saveToLocalStorage();
    renderCategories();
    updateCategorySelect();
    closeCategoryModal();
    showToast('Category created!', 'success');
}

function renderCategories() {
    const container = document.getElementById('categories-list');
    container.innerHTML = '';
    categories.forEach(category => {
        const item = document.createElement('button');
        item.className = 'category-item';
        item.dataset.categoryId = category.id;
        item.addEventListener('click', function() { filterByCategory(category.id, this); });
        const count = tasks.filter(t => t.category === category.id && !t.completed).length;
        item.innerHTML = `<div class="category-icon" style="background:${category.color}15;color:${category.color}"><i class="fas ${category.icon}"></i></div><span>${escapeHtml(category.name)}</span><span class="count">${count}</span>`;
        container.appendChild(item);
    });
}

function filterByCategory(categoryId, element) {
    currentFilter.category = categoryId;
    document.querySelectorAll('.category-item').forEach(item => item.classList.remove('active'));
    if (element) element.classList.add('active');
    renderTasks();
}

function renderWorkspaces() {
    const container = document.getElementById('workspaces-list');
    container.innerHTML = '';
    workspaces.forEach(workspace => {
        const item = document.createElement('button');
        item.className = 'category-item';
        item.innerHTML = `<span>${escapeHtml(workspace.name)}</span><span class="count">${tasks.filter(t => t.workspace === workspace.id).length}</span>`;
        item.addEventListener('click', () => {
            currentFilter.workspace = workspace.id;
            currentFilter.category = null;
            document.querySelectorAll('.category-item').forEach(el => el.classList.remove('active'));
            renderTasks();
        });
        container.appendChild(item);
    });
}

function openWorkspaceModal() { document.getElementById('workspace-modal').classList.add('active'); }
function closeWorkspaceModal() { document.getElementById('workspace-modal').classList.remove('active'); document.getElementById('workspace-form').reset(); }

function saveWorkspace(e) {
    e.preventDefault();
    const name = document.getElementById('workspace-name').value.trim();
    if (!name) return;
    workspaces.push({ id: Date.now().toString(), name });
    saveToLocalStorage();
    renderWorkspaces();
    updateWorkspaceSelect();
    closeWorkspaceModal();
    showToast('Workspace created!', 'success');
}

function updateWorkspaceSelect() {
    const select = document.getElementById('task-workspace');
    const currentValue = select.value;
    select.innerHTML = '<option value="">No Workspace</option>';
    workspaces.forEach(w => {
        const o = document.createElement('option');
        o.value = w.id; o.textContent = w.name; select.appendChild(o);
    });
    if (currentValue) select.value = currentValue;
}

function updateCategorySelect() {
    const select = document.getElementById('task-category');
    const currentValue = select.value;
    select.innerHTML = '<option value="">No Category</option>';
    categories.forEach(c => {
        const o = document.createElement('option');
        o.value = c.id; o.textContent = c.name; select.appendChild(o);
    });
    if (currentValue) select.value = currentValue;
}

// ===== Filter & Sort =====
function toggleFilterPanel() { document.getElementById('filter-panel').classList.toggle('active'); }

function handleFilter(e) {
    const filterType = e.currentTarget.dataset.filter;
    const filterValue = e.currentTarget.dataset.value;
    currentFilter[filterType] = filterValue;
    e.currentTarget.parentElement.querySelectorAll('.filter-option').forEach(o => o.classList.remove('active'));
    e.currentTarget.classList.add('active');
    renderTasks();
}

function handleSort(e) {
    currentSort = e.currentTarget.dataset.sort;
    document.querySelectorAll('.sort-option').forEach(o => o.classList.remove('active'));
    e.currentTarget.classList.add('active');
    renderTasks();
}

function handleSearch(e) {
    currentFilter.search = e.target.value.trim();
    renderTasks();
}

// ===== Subtasks =====
function addSubtaskInput(subtaskText = '') {
    const container = document.getElementById('subtasks-container');
    const item = document.createElement('div');
    item.className = 'subtask-item';
    const input = document.createElement('input');
    input.type = 'text';
    input.placeholder = 'Enter subtask';
    input.value = subtaskText;
    const removeBtn = document.createElement('button');
    removeBtn.type = 'button';
    removeBtn.innerHTML = '<i class="fas fa-times"></i>';
    removeBtn.addEventListener('click', () => item.remove());
    item.appendChild(input);
    item.appendChild(removeBtn);
    container.appendChild(item);
}

// ===== Settings =====
function openSettingsModal() { document.getElementById('settings-modal').classList.add('active'); }
function closeSettingsModal() { document.getElementById('settings-modal').classList.remove('active'); }

function toggleDarkMode() {
    document.body.classList.toggle('dark-mode');
    const isDark = document.body.classList.contains('dark-mode');
    localStorage.setItem('darkMode', isDark ? 'enabled' : 'disabled');
    document.getElementById('dark-mode-toggle').checked = isDark;
    document.querySelector('#theme-toggle i').className = isDark ? 'fas fa-sun' : 'fas fa-moon';
}

function applySettings() {
    const animationsEnabled = localStorage.getItem('animationsEnabled') !== 'false';
    const notificationsEnabled = localStorage.getItem('notificationsEnabled') !== 'false';
    const soundEnabled = localStorage.getItem('soundEnabled') !== 'false';
    const savedViewMode = localStorage.getItem('viewMode');
    document.body.classList.toggle('no-animations', !animationsEnabled);
    document.getElementById('animations-toggle').checked = animationsEnabled;
    document.getElementById('notifications-toggle').checked = notificationsEnabled;
    document.getElementById('sound-toggle').checked = soundEnabled;
    if (savedViewMode === 'grid' || savedViewMode === 'list') {
        viewMode = savedViewMode;
        const icon = document.querySelector('#view-toggle i');
        if (icon) icon.className = viewMode === 'list' ? 'fas fa-th' : 'fas fa-list';
    }
}

function checkDarkMode() {
    if (localStorage.getItem('darkMode') === 'enabled') {
        document.body.classList.add('dark-mode');
        document.getElementById('dark-mode-toggle').checked = true;
        document.querySelector('#theme-toggle i').className = 'fas fa-sun';
    }
}

function exportData() {
    const data = { tasks, categories, workspaces, exportDate: new Date().toISOString(), version: '3.0' };
    const blob = new Blob([JSON.stringify(data, null, 2)], { type: 'application/json' });
    const url = URL.createObjectURL(blob);
    const link = document.createElement('a');
    link.href = url;
    link.download = `taskmaster-backup-${Date.now()}.json`;
    link.click();
    URL.revokeObjectURL(url);
    showToast('Data exported!', 'success');
}

function importData(e) {
    const file = e.target.files[0];
    if (!file) return;
    const reader = new FileReader();
    reader.onload = (event) => {
        try {
            const data = JSON.parse(event.target.result);
            if (data.tasks && data.categories) {
                tasks = data.tasks;
                categories = data.categories;
                workspaces = data.workspaces || [];
                saveToLocalStorage();
                renderTasks();
                renderCategories();
                renderWorkspaces();
                updateWorkspaceSelect();
                updateCounts();
                updateProgress();
                updateInsights();
                updateUserStats();
                showToast('Data imported!', 'success');
            } else {
                showToast('Invalid data format!', 'error');
            }
        } catch (err) {
            showToast('Error: ' + err.message, 'error');
        }
    };
    reader.readAsText(file);
    e.target.value = '';
}

function clearAllData() {
    if (confirm('Are you sure you want to clear all data? This cannot be undone!')) {
        tasks = [];
        categories = [];
        workspaces = [];
        saveToLocalStorage();
        renderTasks();
        renderCategories();
        updateCounts();
        updateProgress();
        updateInsights();
        updateUserStats();
        showToast('All data cleared!', 'success');
    }
}

// ===== Utility =====
function toggleCalendarView() {
    calendarViewVisible = !calendarViewVisible;
    document.getElementById('calendar-view-panel').hidden = !calendarViewVisible;
    document.getElementById('tasks-container').hidden = calendarViewVisible;
    if (calendarViewVisible) renderCalendar();
}

function renderCalendar() {
    const grid = document.getElementById('calendar-grid');
    const label = document.getElementById('calendar-label');
    label.textContent = calendarMonth.toLocaleDateString('en-US', { month: 'long', year: 'numeric' });
    const year = calendarMonth.getFullYear();
    const month = calendarMonth.getMonth();
    const firstDay = new Date(year, month, 1).getDay();
    const daysInMonth = new Date(year, month + 1, 0).getDate();
    const cells = [];
    for (let i = 0; i < firstDay; i++) cells.push('<div class="calendar-cell muted"></div>');
    for (let day = 1; day <= daysInMonth; day++) {
        const dateKey = `${year}-${String(month + 1).padStart(2, '0')}-${String(day).padStart(2, '0')}`;
        const dayTasks = tasks.filter(task => task.dueDate === dateKey && !task.completed);
        const isSelected = currentFilter.date === dateKey;
        cells.push(`<div class="calendar-cell ${isSelected ? 'active' : ''}" data-date="${dateKey}"><strong>${day}</strong><div class="calendar-task-count">${dayTasks.length} task${dayTasks.length === 1 ? '' : 's'}</div></div>`);
    }
    grid.innerHTML = cells.join('');
    grid.querySelectorAll('.calendar-cell[data-date]').forEach(cell => {
        cell.addEventListener('click', () => {
            currentFilter.date = cell.dataset.date;
            renderCalendar();
            renderTasks();
        });
    });
}

function updateCounts() {
    const today = new Date().toISOString().split('T')[0];
    loadMyDay();
    document.getElementById('all-count').textContent = tasks.filter(t => !t.completed).length;
    document.getElementById('myday-count').textContent = myDayTasks.length;
    document.getElementById('today-count').textContent = tasks.filter(t => t.dueDate === today && !t.completed).length;
    document.getElementById('upcoming-count').textContent = tasks.filter(t => t.dueDate && t.dueDate > today && !t.completed).length;
    document.getElementById('overdue-count').textContent = tasks.filter(t => t.dueDate && t.dueDate < today && !t.completed).length;
    document.getElementById('completed-count').textContent = tasks.filter(t => t.completed).length;
    document.getElementById('important-count').textContent = tasks.filter(t => t.important && !t.completed).length;
    document.getElementById('stat-completed').textContent = tasks.filter(t => t.completed).length;
    document.getElementById('stat-pending').textContent = tasks.filter(t => !t.completed).length;
}

function updateProgress() {
    const today = new Date().toISOString().split('T')[0];
    const todayTasks = tasks.filter(t => t.dueDate === today);
    const completedToday = todayTasks.filter(t => t.completed).length;
    const totalToday = todayTasks.length;
    const percentage = totalToday > 0 ? Math.round((completedToday / totalToday) * 100) : 0;
    document.getElementById('progress-text').textContent = `${percentage}%`;
    document.getElementById('progress-fill').style.width = `${percentage}%`;
}

function updateUserStats() {
    const today = new Date().toISOString().split('T')[0];
    const todayTasks = tasks.filter(t => t.dueDate === today && !t.completed).length;
    document.getElementById('user-stats').textContent = `${todayTasks} task${todayTasks !== 1 ? 's' : ''} today`;
}

function formatDate(dateString) {
    const date = new Date(dateString);
    const today = new Date();
    const tomorrow = new Date(today);
    tomorrow.setDate(tomorrow.getDate() + 1);
    const todayStr = today.toISOString().split('T')[0];
    const tomorrowStr = tomorrow.toISOString().split('T')[0];
    if (dateString === todayStr) return 'Today';
    else if (dateString === tomorrowStr) return 'Tomorrow';
    else if (dateString < todayStr) return '⚠️ Overdue';
    else return date.toLocaleDateString('en-US', { month: 'short', day: 'numeric', year: 'numeric' });
}

function showToast(message, type = 'success', actionLabel = '', actionHandler = null) {
    const toast = document.getElementById('toast');
    const toastMessage = document.getElementById('toast-message');
    const toastIcon = toast.querySelector('i');
    const toastAction = document.getElementById('toast-action');

    toastMessage.textContent = message;
    if (actionLabel && actionHandler) {
        toastAction.textContent = actionLabel;
        toastAction.style.display = 'inline-flex';
        toastAction.onclick = actionHandler;
    } else {
        toastAction.textContent = '';
        toastAction.style.display = 'none';
        toastAction.onclick = null;
    }

    toastIcon.className = type === 'success' ? 'fas fa-check-circle' : type === 'error' ? 'fas fa-exclamation-circle' : 'fas fa-info-circle';
    toast.style.background = type === 'success' ? 'var(--success)' : type === 'error' ? 'var(--danger)' : 'var(--info)';
    toast.classList.add('show');
    setTimeout(() => toast.classList.remove('show'), 3500);
}

function scheduleReminders() {
    const now = new Date();
    tasks.filter(task => task.reminder && !task.completed).forEach(task => {
        const reminderTime = new Date(task.reminder);
        if (reminderTime > now) {
            setTimeout(() => {
                if (Notification.permission === 'granted') {
                    new Notification('Task Reminder', { body: task.title });
                }
            }, reminderTime - now);
        }
    });
}

function playSound(type) {
    if (localStorage.getItem('soundEnabled') === 'false') return;
    try {
        const audioCtx = new (window.AudioContext || window.webkitAudioContext)();
        const osc = audioCtx.createOscillator();
        const gain = audioCtx.createGain();
        osc.connect(gain);
        gain.connect(audioCtx.destination);
        if (type === 'complete') { osc.frequency.value = 800; gain.gain.value = 0.1; osc.start(); osc.stop(audioCtx.currentTime + 0.1); }
        else if (type === 'create') { osc.frequency.value = 600; gain.gain.value = 0.05; osc.start(); osc.stop(audioCtx.currentTime + 0.05); }
        else if (type === 'delete') { osc.frequency.value = 400; gain.gain.value = 0.05; osc.start(); osc.stop(audioCtx.currentTime + 0.05); }
    } catch (e) {}
}

function triggerConfetti() {
    const canvas = document.getElementById('confetti-canvas');
    const ctx = canvas.getContext('2d');
    canvas.width = window.innerWidth;
    canvas.height = window.innerHeight;

    const confetti = [];
    const count = 60;
    const colors = ['#6366f1', '#a855f7', '#ec4899', '#f59e0b', '#22c55e', '#06b6d4'];

    for (let i = 0; i < count; i++) {
        confetti.push({
            x: Math.random() * canvas.width,
            y: Math.random() * canvas.height - canvas.height,
            r: Math.random() * 6 + 3,
            d: Math.random() * count,
            color: colors[Math.floor(Math.random() * colors.length)],
            tilt: Math.random() * 10 - 10,
            tiltAngleIncremental: Math.random() * 0.07 + 0.05,
            tiltAngle: 0
        });
    }

    let frameCount = 0;
    function draw() {
        frameCount++;
        ctx.clearRect(0, 0, canvas.width, canvas.height);
        confetti.forEach((c, i) => {
            ctx.beginPath();
            ctx.lineWidth = c.r / 2;
            ctx.strokeStyle = c.color;
            c.tiltAngle += c.tiltAngleIncremental;
            c.y += (Math.cos(c.d) + 3 + c.r / 2) / 2;
            c.tilt = Math.sin(c.tiltAngle - i / 3) * 15;
            ctx.moveTo(c.x + c.tilt + c.r, c.y);
            ctx.lineTo(c.x + c.tilt, c.y + c.tilt + c.r);
            ctx.stroke();
            if (c.y > canvas.height) confetti.splice(i, 1);
        });
        if (confetti.length > 0 && frameCount < 150) {
            requestAnimationFrame(draw);
        } else {
            ctx.clearRect(0, 0, canvas.width, canvas.height);
        }
    }
    draw();
}

function initParticles() {
    const canvas = document.getElementById('particles-canvas');
    const ctx = canvas.getContext('2d');
    canvas.width = window.innerWidth;
    canvas.height = window.innerHeight;

    const particles = [];
    const count = 40;

    for (let i = 0; i < count; i++) {
        particles.push({
            x: Math.random() * canvas.width,
            y: Math.random() * canvas.height,
            vx: (Math.random() - 0.5) * 0.5,
            vy: (Math.random() - 0.5) * 0.5,
            r: Math.random() * 2 + 1,
            opacity: Math.random() * 0.5 + 0.1
        });
    }

    function animate() {
        ctx.clearRect(0, 0, canvas.width, canvas.height);
        const isDark = document.body.classList.contains('dark-mode');
        particles.forEach(p => {
            p.x += p.vx;
            p.y += p.vy;
            if (p.x < 0) p.x = canvas.width;
            if (p.x > canvas.width) p.x = 0;
            if (p.y < 0) p.y = canvas.height;
            if (p.y > canvas.height) p.y = 0;

            ctx.beginPath();
            ctx.arc(p.x, p.y, p.r, 0, Math.PI * 2);
            ctx.fillStyle = isDark ? `rgba(255,255,255,${p.opacity * 0.3})` : `rgba(99,102,241,${p.opacity * 0.3})`;
            ctx.fill();
        });
        requestAnimationFrame(animate);
    }
    animate();

    window.addEventListener('resize', () => {
        canvas.width = window.innerWidth;
        canvas.height = window.innerHeight;
    });
}

// ===== Keyboard =====
document.addEventListener('keydown', (e) => {
    if ((e.ctrlKey || e.metaKey) && e.key === 'n') { e.preventDefault(); openTaskModal(); }
    if ((e.ctrlKey || e.metaKey) && e.key === 'd') { e.preventDefault(); toggleDarkMode(); }
    if ((e.ctrlKey || e.metaKey) && e.key === 'f') { e.preventDefault(); document.getElementById('search-input').focus(); }
    if ((e.ctrlKey || e.metaKey) && e.key === 'p') { e.preventDefault(); togglePomodoroPanel(); }
    if ((e.ctrlKey || e.metaKey) && e.key === 'Shift' && e.key === 'F') { e.preventDefault(); toggleFocusMode(); }
    if (e.key === 'Escape') {
        document.querySelectorAll('.modal.active').forEach(modal => modal.classList.remove('active'));
    }
});

// ===== Notifications =====
function checkNotifications() {
    if (localStorage.getItem('notificationsEnabled') === 'false') return;
    if (!('Notification' in window)) return;
    if (Notification.permission === 'granted') {
        const today = new Date().toISOString().split('T')[0];
        const todayTasks = tasks.filter(t => t.dueDate === today && !t.completed);
        if (todayTasks.length > 0) {
            new Notification('TaskMaster Pro', {
                body: `You have ${todayTasks.length} task${todayTasks.length !== 1 ? 's' : ''} due today!`
            });
        }
    } else if (Notification.permission !== 'denied') {
        Notification.requestPermission();
    }
}

setTimeout(() => {
    checkNotifications();
    scheduleReminders();
    loadMyDay();
}, 2000);