// App State
const state = {
    currentChatId: null,
    chats: [],
    isGenerating: false,
    theme: localStorage.getItem('theme') || 'system',
    sidebarOpen: false
};

// DOM Elements
const elements = {
    chatContainer: document.getElementById('chat-container'),
    messagesWrapper: document.getElementById('messages-wrapper'),
    messageInput: document.getElementById('message-input'),
    sendBtn: document.getElementById('send-btn'),
    welcomeScreen: document.getElementById('welcome-screen'),
    sidebar: document.getElementById('sidebar'),
    toggleSidebar: document.getElementById('toggle-sidebar'),
    themeToggle: document.getElementById('theme-toggle'),
    newChatBtn: document.getElementById('new-chat-btn'),
    suggestionBtns: document.querySelectorAll('.suggestion-btn'),
    attachBtn: document.getElementById('attach-btn')
};

// Initialize
document.addEventListener('DOMContentLoaded', () => {
    initializeTheme();
    loadChats();
    setupEventListeners();
    setupTextareaAutoResize();
});

// Theme Management
function initializeTheme() {
    if (state.theme === 'dark' || (state.theme === 'system' && window.matchMedia('(prefers-color-scheme: dark)').matches)) {
        document.documentElement.classList.add('dark');
        document.getElementById('hljs-theme').href = 'https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/github-dark.min.css';
    } else {
        document.documentElement.classList.remove('dark');
        document.getElementById('hljs-theme').href = 'https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/github.min.css';
    }
}

function toggleTheme() {
    if (document.documentElement.classList.contains('dark')) {
        document.documentElement.classList.remove('dark');
        state.theme = 'light';
        document.getElementById('hljs-theme').href = 'https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/github.min.css';
    } else {
        document.documentElement.classList.add('dark');
        state.theme = 'dark';
        document.getElementById('hljs-theme').href = 'https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/github-dark.min.css';
    }
    localStorage.setItem('theme', state.theme);
    feather.replace();
}

// Chat Management
function loadChats() {
    const saved = localStorage.getItem('chats');
    if (saved) {
        state.chats = JSON.parse(saved);
        if (state.chats.length > 0 && !state.currentChatId) {
            loadChat(state.chats[0].id);
        }
    }
    
    if (!state.currentChatId) {
        createNewChat();
    }
    updateSidebar();
}

function saveChats() {
    localStorage.setItem('chats', JSON.stringify(state.chats));
    updateSidebar();
}

function createNewChat() {
    const id = Date.now().toString();
    const chat = {
        id,
        title: 'New Chat',
        messages: [],
        createdAt: new Date().toISOString(),
        updatedAt: new Date().toISOString()
    };
    state.chats.unshift(chat);
    state.currentChatId = id;
    saveChats();
    renderMessages();
    elements.messageInput.focus();
}

function loadChat(id) {
    state.currentChatId = id;
    renderMessages();
    updateSidebar();
    
    // On mobile, close sidebar
    if (window.innerWidth < 1024) {
        elements.sidebar.shadowRoot.querySelector('aside').classList.add('-translate-x-full');
    }
}

function deleteChat(id, event) {
    event.stopPropagation();
    state.chats = state.chats.filter(c => c.id !== id);
    if (state.currentChatId === id) {
        if (state.chats.length > 0) {
            loadChat(state.chats[0].id);
        } else {
            createNewChat();
        }
    }
    saveChats();
}

function updateChatTitle(chatId, firstMessage) {
    const chat = state.chats.find(c => c.id === chatId);
    if (chat && chat.title === 'New Chat') {
        chat.title = firstMessage.slice(0, 30) + (firstMessage.length > 30 ? '...' : '');
        saveChats();
    }
}
// Message Handling
async function sendMessage(content = null) {
    const text = content || elements.messageInput.value.trim();
    if (!text || state.isGenerating) return;

    elements.messageInput.value = '';
    elements.messageInput.style.height = 'auto';
    elements.welcomeScreen?.classList.add('hidden');

    const userMessage = {
        id: Date.now().toString(),
        role: 'user',
        content: text,
        timestamp: new Date().toISOString()
    };

    const chat = state.chats.find(c => c.id === state.currentChatId);
    if (!chat) return;
    
    chat.messages.push(userMessage);
    chat.updatedAt = new Date().toISOString();
    updateChatTitle(state.currentChatId, text);
    saveChats();
    
    renderMessages();
    scrollToBottom();

    // Show typing indicator
    showTypingIndicator();

    try {
        state.isGenerating = true;
        updateSendButton();
        
        // Build conversation context from previous messages
        // Limit to last 10 messages to avoid token limits
        const recentMessages = chat.messages.slice(-10);
        const contextPrompt = buildContextPrompt(recentMessages);
        
        // Use Pollinations AI with context
        // The approach: include context in the system/instruction part of the prompt
        const response = await fetch('https://text.pollinations.ai/', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
            },
            body: JSON.stringify({
                messages: [
                    {
                        role: "system",
                        content: "You are a helpful AI assistant. You have access to the conversation history and should maintain context throughout the conversation. Be concise but thorough in your responses."
                    },
                    ...recentMessages.slice(0, -1).map(m => ({
                        role: m.role,
                        content: m.content
                    })),
                    {
                        role: "user",
                        content: text
                    }
                ],
                model: "openai-large",
                seed: Math.floor(Math.random() * 1000),
                jsonMode: false
            })
        });
        
        if (!response.ok) {
            throw new Error(`HTTP error! status: ${response.status}`);
        }
        
        const data = await response.text();
        
        hideTypingIndicator();
        
        const assistantMessage = {
            id: (Date.now() + 1).toString(),
            role: 'assistant',
            content: data,
            timestamp: new Date().toISOString()
        };
        
        chat.messages.push(assistantMessage);
        chat.updatedAt = new Date().toISOString();
        saveChats();
        renderMessages();
        scrollToBottom();
        
    } catch (error) {
        console.error('Error:', error);
        hideTypingIndicator();
        showError('Failed to get response. Please try again. Error: ' + error.message);
    } finally {
        state.isGenerating = false;
        updateSendButton();
    }
}

function buildContextPrompt(messages) {
    // This function formats the conversation history for context
    // It's used as a fallback if the API doesn't support message arrays
    let context = "Previous conversation context:\n\n";
    
    for (let i = 0; i < messages.length - 1; i++) {
        const msg = messages[i];
        const role = msg.role === 'user' ? 'User' : 'Assistant';
        context += `${role}: ${msg.content}\n\n`;
    }
    
    const lastMessage = messages[messages.length - 1];
    context += `User: ${lastMessage.content}\n\nAssistant:`;
    
    return context;
}
// Rendering
function renderMessages() {
    const chat = state.chats.find(c => c.id === state.currentChatId);
    if (!chat) return;

    if (chat.messages.length === 0) {
        elements.welcomeScreen?.classList.remove('hidden');
        elements.messagesWrapper.innerHTML = '';
        elements.messagesWrapper.appendChild(elements.welcomeScreen);
        return;
    }

    elements.welcomeScreen?.classList.add('hidden');
    
    // Clear current messages (except welcome screen)
    Array.from(elements.messagesWrapper.children).forEach(child => {
        if (child.id !== 'welcome-screen') {
            child.remove();
        }
    });

    chat.messages.forEach((msg, index) => {
        const msgEl = document.createElement('chat-message');
        msgEl.setAttribute('content', msg.content);
        msgEl.setAttribute('role', msg.role);
        msgEl.setAttribute('timestamp', msg.timestamp);
        msgEl.classList.add('message-enter');
        msgEl.style.animationDelay = `${index * 0.1}s`;
        elements.messagesWrapper.appendChild(msgEl);
    });

    scrollToBottom();
}

function showTypingIndicator() {
    const indicator = document.createElement('typing-indicator');
    indicator.id = 'typing-indicator';
    elements.messagesWrapper.appendChild(indicator);
    scrollToBottom();
}

function hideTypingIndicator() {
    const indicator = document.getElementById('typing-indicator');
    indicator?.remove();
}

function showError(message) {
    const errorEl = document.createElement('div');
    errorEl.className = 'p-4 bg-red-50 dark:bg-red-900/20 border border-red-200 dark:border-red-800 rounded-xl text-red-600 dark:text-red-400 text-center message-enter';
    errorEl.textContent = message;
    elements.messagesWrapper.appendChild(errorEl);
    scrollToBottom();
}

function scrollToBottom() {
    elements.chatContainer.scrollTo({
        top: elements.chatContainer.scrollHeight,
        behavior: 'smooth'
    });
}

function updateSendButton() {
    elements.sendBtn.disabled = state.isGenerating;
    elements.sendBtn.innerHTML = state.isGenerating 
        ? '<div class="typing-dot w-2 h-2 bg-white rounded-full inline-block mx-0.5"></div><div class="typing-dot w-2 h-2 bg-white rounded-full inline-block mx-0.5"></div><div class="typing-dot w-2 h-2 bg-white rounded-full inline-block mx-0.5"></div>'
        : '<i data-feather="send" class="w-5 h-5"></i>';
    feather.replace();
}

function updateSidebar() {
    if (elements.sidebar) {
        elements.sidebar.setAttribute('chats', JSON.stringify(state.chats));
        elements.sidebar.setAttribute('active-chat', state.currentChatId);
    }
}

// Event Listeners
function setupEventListeners() {
    // Send button
    elements.sendBtn.addEventListener('click', () => sendMessage());
    
    // Enter key (Shift+Enter for new line)
    elements.messageInput.addEventListener('keydown', (e) => {
        if (e.key === 'Enter' && !e.shiftKey) {
            e.preventDefault();
            sendMessage();
        }
    });

    // Suggestion buttons
    elements.suggestionBtns.forEach(btn => {
        btn.addEventListener('click', () => {
            const text = btn.querySelector('.text-sm').textContent;
            elements.messageInput.value = text;
            sendMessage();
        });
    });

    // Theme toggle
    elements.themeToggle.addEventListener('click', toggleTheme);

    // New chat
    elements.newChatBtn.addEventListener('click', createNewChat);
    // Sidebar toggle (mobile)
    elements.toggleSidebar?.addEventListener('click', () => {
        if (elements.sidebar) {
            elements.sidebar.toggle();
        }
    });
// Attach button (placeholder)
    elements.attachBtn.addEventListener('click', () => {
        alert('File upload coming soon!');
    });

    // Handle sidebar events
    elements.sidebar?.addEventListener('chat-selected', (e) => {
        loadChat(e.detail.chatId);
    });
    
    elements.sidebar?.addEventListener('chat-deleted', (e) => {
        deleteChat(e.detail.chatId, e.detail.event);
    });

    elements.sidebar?.addEventListener('new-chat', () => {
        createNewChat();
    });
}

// Textarea Auto-resize
function setupTextareaAutoResize() {
    const textarea = elements.messageInput;
    
    textarea.addEventListener('input', () => {
        textarea.style.height = 'auto';
        textarea.style.height = Math.min(textarea.scrollHeight, 128) + 'px';
    });
}

// Expose to window for components
window.appState = state;
window.loadChat = loadChat;
window.deleteChat = deleteChat;
window.createNewChat = createNewChat;