index.js

// Main application logic for Apple Style Chatbot
import { pipeline, TextStreamer } from 'https://cdn.jsdelivr.net/npm/@huggingface/transformers@3.8.0';

class AppleChatbot {
    constructor() {
        this.generator = null;
        this.isGenerating = false;
        this.messages = [];
        this.settings = {
            maxTokens: 512,
            temperature: 0.7,
            streaming: true
        };
        this.init();
    }

    async init() {
        // Initialize UI elements
        this.loadingScreen = document.getElementById('loadingScreen');
        this.chatContainer = document.getElementById('chatContainer');
        this.inputArea = document.getElementById('inputArea');
        this.messagesList = document.getElementById('messagesList');
        this.messageInput = document.getElementById('messageInput');
        this.sendBtn = document.getElementById('sendBtn');
        this.clearBtn = document.getElementById('clearBtn');
        this.settingsBtn = document.getElementById('settingsBtn');
        this.progressFill = document.getElementById('progressFill');
        this.loadingStatus = document.getElementById('loadingStatus');
        this.charCount = document.getElementById('charCount');

        // Setup event listeners
        this.setupEventListeners();

        // Load model
        await this.loadModel();
    }

    setupEventListeners() {
        // Send button
        this.sendBtn.addEventListener('click', () => this.sendMessage());

        // Enter key to send (Shift+Enter for new line)
        this.messageInput.addEventListener('keydown', (e) => {
            if (e.key === 'Enter' && !e.shiftKey) {
                e.preventDefault();
                this.sendMessage();
            }
        });

        // Character count
        this.messageInput.addEventListener('input', (e) => {
            const length = e.target.value.length;
            this.charCount.textContent = `${length} / 1000`;
            this.sendBtn.disabled = length === 0 || this.isGenerating;

            // Auto-resize textarea
            e.target.style.height = 'auto';
            e.target.style.height = Math.min(e.target.scrollHeight, 120) + 'px';
        });

        // Clear button
        this.clearBtn.addEventListener('click', () => this.clearChat());

        // Settings
        this.settingsBtn.addEventListener('click', () => this.openSettings());
        document.getElementById('closeSettings').addEventListener('click', () => this.closeSettings());
        document.getElementById('saveSettings').addEventListener('click', () => this.saveSettings());

        // Settings inputs
        document.getElementById('maxTokens').addEventListener('input', (e) => {
            document.getElementById('maxTokensValue').textContent = e.target.value;
        });

        document.getElementById('temperature').addEventListener('input', (e) => {
            document.getElementById('temperatureValue').textContent = e.target.value;
        });

        // Close modal on backdrop click
        document.getElementById('settingsModal').addEventListener('click', (e) => {
            if (e.target.id === 'settingsModal') {
                this.closeSettings();
            }
        });
    }

    async loadModel() {
        try {
            this.updateProgress(10, 'Downloading model...');
            
            // Initialize the text generation pipeline with progress callback
            this.generator = await pipeline(
                'text-generation',
                'onnx-community/gemma-3-270m-it-ONNX',
                {
                    dtype: 'fp32',
                    progress_callback: (progress) => {
                        const percentage = Math.round(progress.progress * 100);
                        const status = progress.status || 'Loading...';
                        this.updateProgress(percentage, status);
                    }
                }
            );

            this.updateProgress(100, 'Model ready!');

            // Hide loading screen and show chat
            setTimeout(() => {
                this.loadingScreen.style.display = 'none';
                this.chatContainer.style.display = 'block';
                this.inputArea.style.display = 'block';
                this.messageInput.focus();
            }, 500);

        } catch (error) {
            console.error('Error loading model:', error);
            this.showError('Failed to load AI model. Please refresh the page and try again.');
        }
    }

    updateProgress(progress, status) {
        this.progressFill.style.width = `${progress}%`;
        this.loadingStatus.textContent = status;
    }

    async sendMessage() {
        const text = this.messageInput.value.trim();
        if (!text || this.isGenerating || !this.generator) return;

        // Add user message
        this.addMessage('user', text);
        this.messages.push({ role: 'user', content: text });

        // Clear input
        this.messageInput.value = '';
        this.charCount.textContent = '0 / 1000';
        this.sendBtn.disabled = true;
        this.messageInput.style.height = 'auto';

        // Show typing indicator
        const typingMessage = this.showTypingIndicator();

        try {
            this.isGenerating = true;

            // Generate response
            const response = await this.generateResponse();

            // Remove typing indicator
            typingMessage.remove();

            // Add assistant response
            this.addMessage('assistant', response);
            this.messages.push({ role: 'assistant', content: response });

        } catch (error) {
            console.error('Error generating response:', error);
            typingMessage.remove();
            this.addMessage('assistant', 'Sorry, I encountered an error while generating a response. Please try again.');
        } finally {
            this.isGenerating = false;
            this.sendBtn.disabled = false;
            this.messageInput.focus();
        }
    }

    async generateResponse() {
        if (!this.generator) throw new Error('Generator not initialized');

        const generationParams = {
            max_new_tokens: this.settings.maxTokens,
            do_sample: this.settings.temperature > 0,
            temperature: this.settings.temperature,
        };

        // Create prompt from messages
        const prompt = this.createPrompt();
        
        // Generate response
        const output = await this.generator(prompt, generationParams);
        
        // Extract the assistant's response
        const generatedText = output[0].generated_text;
        const response = generatedText.replace(prompt, '').trim();
        
        return response || 'I apologize, but I couldn\'t generate a response.';
    }

    createPrompt() {
        // Create a simple prompt from the conversation history
        let prompt = '';
        for (const msg of this.messages) {
            if (msg.role === 'user') {
                prompt += `User: ${msg.content}\n`;
            } else {
                prompt += `Assistant: ${msg.content}\n`;
            }
        }
        prompt += 'Assistant: ';
        return prompt;
    }

    addMessage(role, content) {
        const messageDiv = document.createElement('div');
        messageDiv.className = `message ${role}`;

        const avatar = document.createElement('div');
        avatar.className = 'message-avatar';
        avatar.innerHTML = role === 'user'
            ? '<svg width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M20 21v-2a4 4 0 0 0-4-4H8a4 4 0 0 0-4 4v2" /><circle cx="12" cy="7" r="4" /></svg>'
            : '<svg width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M12 2L2 7V17L12 22L22 17V7L12 2Z" /></svg>';

        const messageContent = document.createElement('div');
        messageContent.className = 'message-content';

        const messageText = document.createElement('div');
        messageText.className = 'message-text';
        messageText.textContent = content;

        const messageTime = document.createElement('div');
        messageTime.className = 'message-time';
        messageTime.textContent = this.getCurrentTime();

        messageContent.appendChild(messageText);
        messageContent.appendChild(messageTime);
        messageDiv.appendChild(avatar);
        messageDiv.appendChild(messageContent);

        this.messagesList.appendChild(messageDiv);

        // Scroll to bottom
        this.chatContainer.scrollTop = this.chatContainer.scrollHeight;
    }

    showTypingIndicator() {
        const messageDiv = document.createElement('div');
        messageDiv.className = 'message assistant';

        const avatar = document.createElement('div');
        avatar.className = 'message-avatar';
        avatar.innerHTML = '<svg width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><path d="M12 2L2 7V17L12 22L22 17V7L12 2Z" /></svg>';

        const messageContent = document.createElement('div');
        messageContent.className = 'message-content';

        const typingIndicator = document.createElement('div');
        typingIndicator.className = 'message-text typing-indicator';
        typingIndicator.innerHTML = `
            <div class="typing-dot"></div>
            <div class="typing-dot"></div>
            <div class="typing-dot"></div>
        `;

        const messageTime = document.createElement('div');
        messageTime.className = 'message-time';
        messageTime.textContent = 'Typing...';

        messageContent.appendChild(typingIndicator);
        messageContent.appendChild(messageTime);
        messageDiv.appendChild(avatar);
        messageDiv.appendChild(messageContent);

        this.messagesList.appendChild(messageDiv);
        this.chatContainer.scrollTop = this.chatContainer.scrollHeight;

        return messageDiv;
    }

    getCurrentTime() {
        const now = new Date();
        const hours = now.getHours().toString().padStart(2, '0');
        const minutes = now.getMinutes().toString().padStart(2, '0');
        return `${hours}:${minutes}`;
    }

    clearChat() {
        if (confirm('Are you sure you want to clear all messages?')) {
            // Keep only the welcome message
            this.messagesList.innerHTML = `
                <div class="message assistant">
                    <div class="message-avatar">
                        <svg width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                            <path d="M12 2L2 7V17L12 22L22 17V7L12 2Z" />
                        </svg>
                    </div>
                    <div class="message-content">
                        <div class="message-text">
                            Hello! I'm your AI assistant powered by Gemma-3. How can I help you today?
                        </div>
                        <div class="message-time">${this.getCurrentTime()}</div>
                    </div>
                </div>
            `;
            this.messages = [];
            this.messageInput.focus();
        }
    }

    openSettings() {
        document.getElementById('settingsModal').classList.add('active');
        document.getElementById('maxTokens').value = this.settings.maxTokens;
        document.getElementById('maxTokensValue').textContent = this.settings.maxTokens;
        document.getElementById('temperature').value = this.settings.temperature;
        document.getElementById('temperatureValue').textContent = this.settings.temperature;
        document.getElementById('streaming').checked = this.settings.streaming;
    }

    closeSettings() {
        document.getElementById('settingsModal').classList.remove('active');
    }

    saveSettings() {
        this.settings.maxTokens = parseInt(document.getElementById('maxTokens').value);
        this.settings.temperature = parseFloat(document.getElementById('temperature').value);
        this.settings.streaming = document.getElementById('streaming').checked;
        this.closeSettings();
    }

    showError(message) {
        this.loadingStatus.textContent = message;
        this.loadingStatus.style.color = 'var(--error)';
    }
}

// Initialize the chatbot when the page loads
document.addEventListener('DOMContentLoaded', () => {
    new AppleChatbot();
});