// ================ PAGE NAVIGATION ================

const pages = {
    'page-a': document.getElementById('page-a'),
    'page-b': document.getElementById('page-b'),
    'page-c': document.getElementById('page-c'), // Achievement
    'page-d': document.getElementById('page-d'), // Records
    'page-e': document.getElementById('page-e'), // Customise
    'page-f': document.getElementById('page-f')  // Help
};

function showPage(pageId) {
    for (const key in pages) {
        pages[key].classList.add('hidden');
    }
    if (pages[pageId]) {
        pages[pageId].classList.remove('hidden');
    }
}

// ================ VIDEO MANAGER CLASS ================

class VideoManager {
    constructor() {
        this.videoElement = null;
        this.canvasElement = null;
        this.ctx = null;
        this.captureCanvas = null;
        this.captureCtx = null;
        this.stream = null;
        this.ws = null;
        this.isStreaming = false;
        this.sessionId = null;
        this.frameRate = 30;
        this.frameInterval = null;
        this.renderLoopId = null;

        // Status smoothing for stable display
        this.currentStatus = false;  // Default: not focused
        this.previousStatus = false;  // Track previous status to detect changes
        this.statusBuffer = [];  // Buffer for last N frames
        this.bufferSize = 5;  // Number of frames to average (smaller = more responsive)

        // Latest detection data for rendering
        this.latestDetectionData = null;
        this.lastConfidence = 0;
        this.detectionHoldMs = 30;
    }

    async initCamera() {
        try {
            this.stream = await navigator.mediaDevices.getUserMedia({
                video: {
                    width: { ideal: 640 },
                    height: { ideal: 480 },
                    facingMode: 'user'
                }
            });

            this.videoElement = document.createElement('video');
            this.videoElement.srcObject = this.stream;
            this.videoElement.autoplay = true;
            this.videoElement.playsInline = true;

            this.canvasElement = document.createElement('canvas');
            this.canvasElement.width = 640;
            this.canvasElement.height = 480;
            this.ctx = this.canvasElement.getContext('2d');

            this.captureCanvas = document.createElement('canvas');
            this.captureCanvas.width = 640;
            this.captureCanvas.height = 480;
            this.captureCtx = this.captureCanvas.getContext('2d');

            const displayArea = document.getElementById('display-area');
            displayArea.innerHTML = '';
            displayArea.appendChild(this.canvasElement);

            await this.videoElement.play();
            this.startRenderLoop();

            return true;
        } catch (error) {
            console.error('Camera init error:', error);
            throw error;
        }
    }

    connectWebSocket() {
        const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
        const wsUrl = `${protocol}//${window.location.host}/ws/video`;

        this.ws = new WebSocket(wsUrl);

        this.ws.onopen = () => {
            console.log('WebSocket connected');
            this.startSession();
        };

        this.ws.onmessage = (event) => {
            const data = JSON.parse(event.data);
            this.handleServerMessage(data);
        };

        this.ws.onerror = (error) => {
            console.error('WebSocket error:', error);
        };

        this.ws.onclose = () => {
            console.log('WebSocket closed');
        };
    }

    startStreaming() {
        this.isStreaming = true;
        this.connectWebSocket();

        this.frameInterval = setInterval(() => {
            if (this.ws && this.ws.readyState === WebSocket.OPEN) {
                this.captureAndSendFrame();
            }
        }, 1000 / this.frameRate);
    }

    captureAndSendFrame() {
        if (!this.videoElement || !this.captureCanvas || !this.captureCtx) return;

        this.captureCtx.drawImage(this.videoElement, 0, 0, 640, 480);

        const imageData = this.captureCanvas.toDataURL('image/jpeg', 0.8);
        const base64Data = imageData.split(',')[1];

        if (this.ws && this.ws.readyState === WebSocket.OPEN) {
            this.ws.send(JSON.stringify({
                type: 'frame',
                image: base64Data
            }));
        }
    }

    handleServerMessage(data) {
        switch (data.type) {
            case 'detection':
                // Update status with smoothing
                this.updateStatus(data.focused);

                // Render with smoothed status
                this.renderDetections(data);

                // Update timeline and notifications with smoothed status
                timeline.addEvent(this.currentStatus);
                checkDistraction(this.currentStatus);
                break;
            case 'session_started':
                this.sessionId = data.session_id;
                console.log('Session started:', this.sessionId);
                break;
            case 'session_ended':
                console.log('Session ended:', data.summary);
                showSessionSummary(data.summary);
                break;
            case 'ack':
                // Frame acknowledged but not processed
                break;
            case 'error':
                console.error('Server error:', data.message);
                break;
        }
    }

    updateStatus(newFocused) {
        // Add to buffer
        this.statusBuffer.push(newFocused);

        // Keep buffer size limited
        if (this.statusBuffer.length > this.bufferSize) {
            this.statusBuffer.shift();
        }

        // Don't update status until buffer is full (prevents initial flickering)
        if (this.statusBuffer.length < this.bufferSize) {
            return false;  // Status hasn't changed
        }

        // Calculate majority vote with moderate thresholds for better responsiveness
        const focusedCount = this.statusBuffer.filter(f => f).length;
        const focusedRatio = focusedCount / this.statusBuffer.length;

        // Store previous status
        this.previousStatus = this.currentStatus;

        // Moderate thresholds: quicker to change, still avoids rapid flipping
        // For 8 frames: need 6+ focused to become FOCUSED, or 6+ not focused to become NOT FOCUSED
        if (focusedRatio >= 0.75) {
            this.currentStatus = true;
        } else if (focusedRatio <= 0.25) {
            this.currentStatus = false;
        }
        // Between 0.25-0.75: keep current status (hysteresis to avoid jitter)

        // Log only when status actually changes
        const statusChanged = this.currentStatus !== this.previousStatus;
        if (statusChanged) {
            console.log(`Status changed: ${this.previousStatus ? 'FOCUSED' : 'NOT FOCUSED'} -> ${this.currentStatus ? 'FOCUSED' : 'NOT FOCUSED'} (ratio: ${focusedRatio.toFixed(2)})`);
        }

        // Return whether status changed
        return statusChanged;
    }

    renderDetections(data) {
        this.latestDetectionData = {
            detections: data.detections || [],
            confidence: data.confidence || 0,
            focused: data.focused,
            timestamp: performance.now()
        };
        this.lastConfidence = data.confidence || 0;
    }

    startRenderLoop() {
        if (this.renderLoopId) return;

        const render = () => {
            if (this.videoElement && this.ctx) {
                this.ctx.drawImage(this.videoElement, 0, 0, 640, 480);

                const now = performance.now();
                const latest = this.latestDetectionData;
                const hasFresh = latest && (now - latest.timestamp) <= this.detectionHoldMs;

                // Draw detection boxes using last known data (prevents flicker)
                if (hasFresh && latest.detections.length > 0) {
                    latest.detections.forEach(det => {
                        const [x1, y1, x2, y2] = det.bbox;
                        this.ctx.strokeStyle = this.currentStatus ? '#00FF00' : '#FF0000';
                        this.ctx.lineWidth = 3;
                        this.ctx.strokeRect(x1, y1, x2 - x1, y2 - y1);

                        this.ctx.fillStyle = this.currentStatus ? '#00FF00' : '#FF0000';
                        this.ctx.font = '16px Nunito';
                        const label = `${det.class_name} ${(det.confidence * 100).toFixed(1)}%`;
                        this.ctx.fillText(label, x1, y1 - 5);
                    });
                }

                const statusText = this.currentStatus ? 'FOCUSED' : 'NOT FOCUSED';
                this.ctx.fillStyle = this.currentStatus ? '#00FF00' : '#FF0000';
                this.ctx.font = 'bold 24px Nunito';
                this.ctx.fillText(statusText, 10, 30);

                this.ctx.font = '16px Nunito';
                this.ctx.fillText(`Confidence: ${(this.lastConfidence * 100).toFixed(1)}%`, 10, 55);
            }

            this.renderLoopId = requestAnimationFrame(render);
        };

        this.renderLoopId = requestAnimationFrame(render);
    }

    stopRenderLoop() {
        if (this.renderLoopId) {
            cancelAnimationFrame(this.renderLoopId);
            this.renderLoopId = null;
        }
    }

    startSession() {
        if (this.ws && this.ws.readyState === WebSocket.OPEN) {
            this.ws.send(JSON.stringify({ type: 'start_session' }));
        }
    }

    stopStreaming() {
        this.isStreaming = false;
        this.stopRenderLoop();

        if (this.frameInterval) {
            clearInterval(this.frameInterval);
            this.frameInterval = null;
        }

        if (this.ws) {
            this.ws.send(JSON.stringify({ type: 'end_session' }));
            this.ws.close();
            this.ws = null;
        }

        if (this.stream) {
            this.stream.getTracks().forEach(track => track.stop());
            this.stream = null;
        }

        if (this.canvasElement && this.ctx) {
            this.ctx.clearRect(0, 0, 640, 480);
        }

        // Reset status
        this.currentStatus = false;
        this.statusBuffer = [];
        this.latestDetectionData = null;
        this.lastConfidence = 0;
    }

    setFrameRate(rate) {
        this.frameRate = Math.max(1, Math.min(60, rate));

        if (this.isStreaming && this.frameInterval) {
            clearInterval(this.frameInterval);
            this.frameInterval = setInterval(() => {
                if (this.ws && this.ws.readyState === WebSocket.OPEN) {
                    this.captureAndSendFrame();
                }
            }, 1000 / this.frameRate);
        }
    }
}

// ================ TIMELINE MANAGER CLASS ================

class TimelineManager {
    constructor(maxEvents = 60) {
        this.events = [];
        this.maxEvents = maxEvents;
        this.container = document.getElementById('timeline-visuals');
    }

    addEvent(isFocused) {
        const timestamp = Date.now();
        this.events.push({ timestamp, isFocused });

        if (this.events.length > this.maxEvents) {
            this.events.shift();
        }

        this.render();
    }

    render() {
        if (!this.container) return;

        this.container.innerHTML = '';

        this.events.forEach((event, index) => {
            const block = document.createElement('div');
            block.className = 'timeline-block';
            block.style.backgroundColor = event.isFocused ? '#00FF00' : '#FF0000';
            block.style.width = '10px';
            block.style.height = '20px';
            block.style.display = 'inline-block';
            block.style.marginRight = '2px';
            block.title = event.isFocused ? 'Focused' : 'Distracted';
            this.container.appendChild(block);
        });
    }

    clear() {
        this.events = [];
        this.render();
    }
}

// ================ NOTIFICATION SYSTEM ================

let distractionStartTime = null;
let notificationTimeout = null;
let currentSettings = null;

async function loadCurrentSettings() {
    try {
        const response = await fetch('/api/settings');
        currentSettings = await response.json();
    } catch (error) {
        console.error('Failed to load settings:', error);
        currentSettings = {
            notification_enabled: true,
            notification_threshold: 30
        };
    }
}

function checkDistraction(isFocused) {
    if (!currentSettings || !currentSettings.notification_enabled) return;

    if (!isFocused) {
        if (!distractionStartTime) {
            distractionStartTime = Date.now();
        }

        const distractionDuration = (Date.now() - distractionStartTime) / 1000;

        if (distractionDuration >= currentSettings.notification_threshold && !notificationTimeout) {
            sendNotification('Focus Guard Alert', 'You seem distracted. Time to refocus!');
            notificationTimeout = setTimeout(() => {
                notificationTimeout = null;
            }, 60000);
        }
    } else {
        distractionStartTime = null;
    }
}

async function sendNotification(title, body) {
    if ('Notification' in window) {
        if (Notification.permission === 'granted') {
            new Notification(title, { body });
        } else if (Notification.permission !== 'denied') {
            const permission = await Notification.requestPermission();
            if (permission === 'granted') {
                new Notification(title, { body });
            }
        }
    }
}

// ================ SESSION SUMMARY MODAL ================

function showSessionSummary(summary) {
    const modal = document.createElement('div');
    modal.className = 'modal-overlay';
    modal.innerHTML = `
        <div class="modal-content">
            <h2>Session Complete!</h2>
            <div class="summary-stats">
                <div class="summary-item">
                    <span class="summary-label">Duration:</span>
                    <span class="summary-value">${formatDuration(summary.duration_seconds)}</span>
                </div>
                <div class="summary-item">
                    <span class="summary-label">Focus Score:</span>
                    <span class="summary-value">${(summary.focus_score * 100).toFixed(1)}%</span>
                </div>
                <div class="summary-item">
                    <span class="summary-label">Total Frames:</span>
                    <span class="summary-value">${summary.total_frames}</span>
                </div>
                <div class="summary-item">
                    <span class="summary-label">Focused Frames:</span>
                    <span class="summary-value">${summary.focused_frames}</span>
                </div>
            </div>
            <button class="btn-main" onclick="closeModal()">Close</button>
        </div>
    `;

    document.body.appendChild(modal);
}

function closeModal() {
    const modal = document.querySelector('.modal-overlay');
    if (modal) {
        modal.remove();
    }
}

function formatDuration(seconds) {
    const hours = Math.floor(seconds / 3600);
    const minutes = Math.floor((seconds % 3600) / 60);
    const secs = seconds % 60;

    if (hours > 0) {
        return `${hours}h ${minutes}m ${secs}s`;
    } else if (minutes > 0) {
        return `${minutes}m ${secs}s`;
    } else {
        return `${secs}s`;
    }
}

// ================ GLOBAL INSTANCES ================

const videoManager = new VideoManager();
const timeline = new TimelineManager();

// ================ EVENT LISTENERS ================

// Page navigation
document.getElementById('menu-start').addEventListener('click', () => showPage('page-b'));
document.getElementById('menu-achievement').addEventListener('click', () => {
    showPage('page-c');
    loadAchievements();
});
document.getElementById('menu-records').addEventListener('click', () => {
    showPage('page-d');
    loadRecords('today');
});
document.getElementById('menu-customise').addEventListener('click', () => {
    showPage('page-e');
    loadSettings();
});
document.getElementById('menu-help').addEventListener('click', () => showPage('page-f'));

document.getElementById('start-button').addEventListener('click', () => showPage('page-b'));

// Page B controls
document.getElementById('btn-cam-start').addEventListener('click', async () => {
    try {
        await videoManager.initCamera();
        videoManager.startStreaming();
        timeline.clear();
        await loadCurrentSettings();
    } catch (error) {
        console.error('Failed to start camera:', error);
        alert('Camera access denied. Please allow camera permissions and ensure you are using HTTPS or localhost.');
    }
});

document.getElementById('btn-cam-stop').addEventListener('click', () => {
    videoManager.stopStreaming();
});

document.getElementById('btn-floating').addEventListener('click', () => {
    alert('Floating window feature coming soon!');
});

document.getElementById('btn-models').addEventListener('click', () => {
    alert('Model selection feature coming soon!');
});

// Frame control
const frameSlider = document.getElementById('frame-slider');
const frameInput = document.getElementById('frame-input');

frameSlider.addEventListener('input', (e) => {
    const rate = parseInt(e.target.value);
    frameInput.value = rate;
    videoManager.setFrameRate(rate);
});

frameInput.addEventListener('input', (e) => {
    const rate = parseInt(e.target.value);
    frameSlider.value = rate;
    videoManager.setFrameRate(rate);
});

// ================ ACHIEVEMENT PAGE ================

async function loadAchievements() {
    try {
        const response = await fetch('/api/stats/summary');
        const stats = await response.json();

        document.getElementById('total-sessions').textContent = stats.total_sessions;
        document.getElementById('total-hours').textContent =
            (stats.total_focus_time / 3600).toFixed(1) + 'h';
        document.getElementById('avg-focus').textContent =
            (stats.avg_focus_score * 100).toFixed(1) + '%';
        document.getElementById('current-streak').textContent = stats.streak_days;

        loadBadges(stats);
    } catch (error) {
        console.error('Failed to load achievements:', error);
    }
}

function loadBadges(stats) {
    const badges = [
        { name: 'First Session', condition: stats.total_sessions >= 1, icon: '' },
        { name: '10 Sessions', condition: stats.total_sessions >= 10, icon: '' },
        { name: '50 Sessions', condition: stats.total_sessions >= 50, icon: '' },
        { name: '10 Hour Focus', condition: stats.total_focus_time >= 36000, icon: '' },
        { name: '7 Day Streak', condition: stats.streak_days >= 7, icon: '' },
        { name: '90% Avg Focus', condition: stats.avg_focus_score >= 0.9, icon: '' }
    ];

    const container = document.getElementById('badges-container');
    container.innerHTML = '';

    badges.forEach(badge => {
        const badgeEl = document.createElement('div');
        badgeEl.className = 'badge ' + (badge.condition ? 'earned' : 'locked');
        badgeEl.innerHTML = `
            <div class="badge-icon">${badge.icon}</div>
            <div class="badge-name">${badge.name}</div>
        `;
        container.appendChild(badgeEl);
    });
}

// ================ RECORDS PAGE ================

async function loadRecords(filter = 'today') {
    try {
        const response = await fetch(`/api/sessions?filter=${filter}`);
        const sessions = await response.json();

        renderSessionsTable(sessions);
        renderChart(sessions);
    } catch (error) {
        console.error('Failed to load records:', error);
    }
}

function renderSessionsTable(sessions) {
    const tbody = document.getElementById('sessions-tbody');
    tbody.innerHTML = '';

    sessions.forEach(session => {
        const row = document.createElement('tr');
        const date = new Date(session.start_time).toLocaleString();
        const duration = formatDuration(session.duration_seconds);
        const score = (session.focus_score * 100).toFixed(1) + '%';

        row.innerHTML = `
            <td>${date}</td>
            <td>${duration}</td>
            <td>${score}</td>
            <td><button class="btn-view" onclick="viewSessionDetails(${session.id})">View</button></td>
        `;
        tbody.appendChild(row);
    });

    if (sessions.length === 0) {
        const row = document.createElement('tr');
        row.innerHTML = '<td colspan="4" style="text-align: center;">No sessions found</td>';
        tbody.appendChild(row);
    }
}

function renderChart(sessions) {
    const canvas = document.getElementById('focus-chart');
    const ctx = canvas.getContext('2d');

    canvas.width = 800;
    canvas.height = 300;

    ctx.clearRect(0, 0, canvas.width, canvas.height);

    if (sessions.length === 0) {
        ctx.fillStyle = '#888';
        ctx.font = '20px Nunito';
        ctx.fillText('No data available', canvas.width / 2 - 80, canvas.height / 2);
        return;
    }

    const barWidth = Math.min((canvas.width - 40) / sessions.length - 10, 80);
    const maxScore = 1.0;

    sessions.forEach((session, index) => {
        const x = index * (barWidth + 10) + 20;
        const barHeight = (session.focus_score / maxScore) * (canvas.height - 60);
        const y = canvas.height - barHeight - 30;

        ctx.fillStyle = session.focus_score > 0.7 ? '#28a745' :
            session.focus_score > 0.4 ? '#ffc107' : '#dc3545';
        ctx.fillRect(x, y, barWidth, barHeight);

        ctx.fillStyle = '#333';
        ctx.font = '12px Nunito';
        const scoreText = (session.focus_score * 100).toFixed(0) + '%';
        ctx.fillText(scoreText, x + barWidth / 2 - 15, y - 5);
    });
}

function viewSessionDetails(sessionId) {
    alert(`Session details for ID ${sessionId} - Feature coming soon!`);
}

// Filter buttons
document.getElementById('filter-today').addEventListener('click', () => {
    setActiveFilter('filter-today');
    loadRecords('today');
});

document.getElementById('filter-week').addEventListener('click', () => {
    setActiveFilter('filter-week');
    loadRecords('week');
});

document.getElementById('filter-month').addEventListener('click', () => {
    setActiveFilter('filter-month');
    loadRecords('month');
});

document.getElementById('filter-all').addEventListener('click', () => {
    setActiveFilter('filter-all');
    loadRecords('all');
});

function setActiveFilter(activeId) {
    document.querySelectorAll('.filter-btn').forEach(btn => {
        btn.classList.remove('active');
    });
    document.getElementById(activeId).classList.add('active');
}

// ================ SETTINGS PAGE ================

async function loadSettings() {
    try {
        const response = await fetch('/api/settings');
        if (!response.ok) {
            throw new Error(`HTTP ${response.status}: ${response.statusText}`);
        }

        const settings = await response.json();
        console.log('Loaded settings:', settings);

        // Apply settings with fallback to defaults
        document.getElementById('sensitivity-slider').value = settings.sensitivity || 6;
        document.getElementById('sensitivity-value').textContent = settings.sensitivity || 6;
        document.getElementById('default-framerate').value = settings.frame_rate || 30;
        document.getElementById('framerate-value').textContent = settings.frame_rate || 30;
        document.getElementById('enable-notifications').checked = settings.notification_enabled !== false;
        document.getElementById('notification-threshold').value = settings.notification_threshold || 30;
    } catch (error) {
        console.error('Failed to load settings:', error);
        alert('Failed to load settings: ' + error.message);
    }
}

async function saveSettings() {
    const settings = {
        sensitivity: parseInt(document.getElementById('sensitivity-slider').value),
        frame_rate: parseInt(document.getElementById('default-framerate').value),
        notification_enabled: document.getElementById('enable-notifications').checked,
        notification_threshold: parseInt(document.getElementById('notification-threshold').value)
    };

    console.log('Saving settings:', settings);

    try {
        const response = await fetch('/api/settings', {
            method: 'PUT',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify(settings)
        });

        if (response.ok) {
            const result = await response.json();
            console.log('Settings saved:', result);
            alert('Settings saved successfully!');
            await loadCurrentSettings();
        } else {
            const error = await response.text();
            console.error('Save failed with status:', response.status, error);
            alert(`Failed to save settings: ${response.status} ${response.statusText}`);
        }
    } catch (error) {
        console.error('Failed to save settings:', error);
        alert('Failed to save settings: ' + error.message);
    }
}

// Settings UI handlers
document.getElementById('sensitivity-slider').addEventListener('input', (e) => {
    document.getElementById('sensitivity-value').textContent = e.target.value;
});

document.getElementById('default-framerate').addEventListener('input', (e) => {
    document.getElementById('framerate-value').textContent = e.target.value;
});

document.getElementById('save-settings').addEventListener('click', saveSettings);

document.getElementById('export-data').addEventListener('click', async () => {
    try {
        const response = await fetch('/api/sessions?filter=all');
        const sessions = await response.json();

        const dataStr = JSON.stringify(sessions, null, 2);
        const dataBlob = new Blob([dataStr], { type: 'application/json' });
        const url = URL.createObjectURL(dataBlob);

        const link = document.createElement('a');
        link.href = url;
        link.download = `focus-guard-data-${new Date().toISOString().split('T')[0]}.json`;
        link.click();

        URL.revokeObjectURL(url);
    } catch (error) {
        console.error('Failed to export data:', error);
        alert('Failed to export data');
    }
});

document.getElementById('clear-history').addEventListener('click', async () => {
    if (confirm('Are you sure you want to clear all history? This cannot be undone.')) {
        alert('Clear history feature requires backend implementation');
    }
});

// ================ INITIALIZATION ================

// Request notification permission on load
if ('Notification' in window && Notification.permission === 'default') {
    Notification.requestPermission();
}

// Load settings on startup
loadCurrentSettings();

console.log(' Focus Guard initialized');