// Frontend functionality for NutriBot chat interface
document.addEventListener('DOMContentLoaded', function() {
    const messageInput = document.getElementById('messageInput');
    const sendButton = document.getElementById('sendButton');
    const clearButton = document.getElementById('clearButton');
    const chatContainer = document.getElementById('chatContainer');
    const loadingIndicator = document.getElementById('loadingIndicator');
    
    let conversationHistory = [];
    
    // Function to add message to chat
    function addMessage(role, content) {
        const messageDiv = document.createElement('div');
        messageDiv.className = `message mb-4 ${role === 'user' ? 'text-right' : 'text-left'}`;
        
        const messageContent = document.createElement('div');
        messageContent.className = `inline-block max-w-xs md:max-w-md px-4 py-2 rounded-lg ${
            role === 'user' 
                ? 'bg-green-600 text-white' 
                : 'bg-gray-200 text-gray-800'
        }`;
        messageContent.textContent = content;
        
        messageDiv.appendChild(messageContent);
        chatContainer.appendChild(messageDiv);
        
        // Scroll to bottom
        chatContainer.scrollTop = chatContainer.scrollHeight;
        
        // Reinitialize feather icons
        feather.replace();
    }
    
    // Function to show typing indicator
    function showTypingIndicator() {
        const typingDiv = document.createElement('div');
        typingDiv.className = 'message mb-4 text-left';
        typingDiv.id = 'typingIndicator';
        
        const typingContent = document.createElement('div');
        typingContent.className = 'inline-block px-4 py-2 rounded-lg bg-gray-200';
        typingContent.innerHTML = `
            <div class="typing-indicator">
                <span></span>
                <span></span>
                <span></span>
            </div>
        `;
        
        typingDiv.appendChild(typingContent);
        chatContainer.appendChild(typingDiv);
        chatContainer.scrollTop = chatContainer.scrollHeight;
    }
    
    // Function to hide typing indicator
    function hideTypingIndicator() {
        const typingIndicator = document.getElementById('typingIndicator');
        if (typingIndicator) {
            typingIndicator.remove();
        }
    }
    
    // Function to send message to backend
    async function sendMessage() {
        const message = messageInput.value.trim();
        if (!message) return;
        
        // Clear initial welcome message if it exists
        if (conversationHistory.length === 0) {
            chatContainer.innerHTML = '';
        }
        
        // Add user message to chat
        addMessage('user', message);
        messageInput.value = '';
        
        // Add to conversation history
        conversationHistory.push({ role: 'user', content: message });
        
        // Show loading and typing indicators
        loadingIndicator.classList.remove('hidden');
        showTypingIndicator();
        
        try {
            const response = await fetch('http://localhost:8000/chat', {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json',
                },
                body: JSON.stringify({
                    message: message,
                    user_id: 'default_user'
                })
            });
            
            if (!response.ok) {
                throw new Error('Failed to get response from server');
            }
            
            const data = await response.json();
            const assistantMessage = data.response;
            
            // Hide typing indicator and loading
            hideTypingIndicator();
            loadingIndicator.classList.add('hidden');
            
            // Add assistant response to chat
            addMessage('assistant', assistantMessage);
            
            // Add to conversation history
            conversationHistory.push({ role: 'assistant', content: assistantMessage });
            
        } catch (error) {
            console.error('Error:', error);
            hideTypingIndicator();
            loadingIndicator.classList.add('hidden');
            addMessage('assistant', 'Sorry, I encountered an error. Please try again.');
        }
    }
    
    // Function to clear conversation
    function clearConversation() {
        conversationHistory = [];
        chatContainer.innerHTML = `
            <div class="text-center text-gray-500 py-8">
                <i data-feather="message-circle" class="mx-auto mb-2"></i>
                <p>Start a conversation with NutriBot below!</p>
            </div>
        `;
        feather.replace();
    }
    
    // Event listeners
    sendButton.addEventListener('click', sendMessage);
    
    messageInput.addEventListener('keypress', function(e) {
        if (e.key === 'Enter' && !e.shiftKey) {
            e.preventDefault();
            sendMessage();
        }
    });
    
    clearButton.addEventListener('click', clearConversation);
    
    // Focus on input field
    messageInput.focus();
});