// State variables
let promptHistory = [];
const HISTORY_KEY = 'gemma_code_llm_history';
const THEME_KEY = 'gemma_code_llm_theme';

// DOM Elements
const statusBadge = document.getElementById('statusBadge');
const statusDot = statusBadge.querySelector('.status-dot');
const statusText = statusBadge.querySelector('.status-text');

const temperatureInput = document.getElementById('temperature');
const tempVal = document.getElementById('tempVal');
const topPInput = document.getElementById('top_p');
const topPVal = document.getElementById('topPVal');
const maxTokensInput = document.getElementById('max_new_tokens');
const maxTokensVal = document.getElementById('maxTokensVal');
const safetyInput = document.getElementById('safety');

const instructionInput = document.getElementById('instructionInput');
const contextInput = document.getElementById('contextInput');
const generateBtn = document.getElementById('generateBtn');
const btnText = generateBtn.querySelector('.btn-text');
const btnArrow = generateBtn.querySelector('.btn-arrow');
const btnSpinner = generateBtn.querySelector('.btn-spinner');

const codeOutput = document.getElementById('codeOutput');
const preOutput = codeOutput.parentElement;
const skeletonLoader = document.getElementById('skeletonLoader');
const copyBtn = document.getElementById('copyBtn');
const latencyTimer = document.getElementById('latencyTimer');

const historyList = document.getElementById('historyList');
const clearHistoryBtn = document.getElementById('clearHistoryBtn');
const themeToggleBtn = document.getElementById('themeToggleBtn');
const toastContainer = document.getElementById('toastContainer');

// Initialize App
document.addEventListener('DOMContentLoaded', () => {
    initSliders();
    initTheme();
    loadHistory();
    checkHealth();
    initTemplateTags();
    
    // Periodically check server status (every 10 seconds)
    setInterval(checkHealth, 10000);
});

// Slider values updating
function initSliders() {
    temperatureInput.addEventListener('input', (e) => {
        tempVal.textContent = parseFloat(e.target.value).toFixed(1);
    });
    
    topPInput.addEventListener('input', (e) => {
        topPVal.textContent = parseFloat(e.target.value).toFixed(2);
    });
    
    maxTokensInput.addEventListener('input', (e) => {
        maxTokensVal.textContent = parseInt(e.target.value);
    });
}

// Light / Dark Theme setup
function initTheme() {
    const savedTheme = localStorage.getItem(THEME_KEY);
    if (savedTheme === 'light') {
        document.body.classList.remove('dark-theme');
        document.body.classList.add('light-theme');
    } else {
        document.body.classList.remove('light-theme');
        document.body.classList.add('dark-theme');
    }
    
    themeToggleBtn.addEventListener('click', () => {
        if (document.body.classList.contains('dark-theme')) {
            document.body.classList.remove('dark-theme');
            document.body.classList.add('light-theme');
            localStorage.setItem(THEME_KEY, 'light');
            showToast('Switched to light theme', 'info');
        } else {
            document.body.classList.remove('light-theme');
            document.body.classList.add('dark-theme');
            localStorage.setItem(THEME_KEY, 'dark');
            showToast('Switched to dark theme', 'info');
        }
    });
}

// Check backend server health
async function checkHealth() {
    statusDot.className = 'status-dot loading animate-pulse';
    statusText.textContent = 'Checking status...';
    
    try {
        const response = await fetch('/health');
        if (response.ok) {
            const data = await response.json();
            if (data.status === 'ok') {
                statusDot.className = 'status-dot online';
                statusText.textContent = 'Connected';
            } else {
                setOfflineStatus('Unhealthy');
            }
        } else {
            setOfflineStatus('Offline');
        }
    } catch (err) {
        setOfflineStatus('Offline');
    }
}

function setOfflineStatus(reason) {
    statusDot.className = 'status-dot error';
    statusText.textContent = reason;
}

// Templates Handling
function initTemplateTags() {
    const tagBtns = document.querySelectorAll('.tag-btn');
    tagBtns.forEach(btn => {
        btn.addEventListener('click', () => {
            instructionInput.value = btn.getAttribute('data-inst');
            contextInput.value = btn.getAttribute('data-ctx');
            
            // Highlight inputs briefly
            instructionInput.focus();
            showToast('Loaded template prompt', 'info');
        });
    });
}

// History caching and UI rendering
function loadHistory() {
    const cached = localStorage.getItem(HISTORY_KEY);
    if (cached) {
        try {
            promptHistory = JSON.parse(cached);
        } catch (e) {
            promptHistory = [];
        }
    }
    renderHistory();
}

function saveHistory() {
    localStorage.setItem(HISTORY_KEY, JSON.stringify(promptHistory));
    renderHistory();
}

function renderHistory() {
    historyList.innerHTML = '';
    
    if (promptHistory.length === 0) {
        historyList.innerHTML = '<div class="no-history">No past instructions yet.</div>';
        return;
    }
    
    promptHistory.slice().reverse().forEach((item, index) => {
        // True index in original array
        const realIndex = promptHistory.length - 1 - index;
        
        const historyItem = document.createElement('div');
        historyItem.className = 'history-item';
        historyItem.innerHTML = `
            <div class="history-text" title="${escapeHtml(item.instruction)}">${escapeHtml(item.instruction)}</div>
            <div class="history-meta">
                <span>t=${item.temperature} • max=${item.max_new_tokens}</span>
                <button class="delete-history-item" data-index="${realIndex}" title="Delete Item">
                    <svg width="12" height="12" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
                        <polyline points="3 6 5 6 21 6"></polyline>
                        <path d="M19 6v14a2 2 0 0 1-2 2H7a2 2 0 0 1-2-2V6m3 0V4a2 2 0 0 1 2-2h4a2 2 0 0 1 2 2v2"></path>
                    </svg>
                </button>
            </div>
        `;
        
        // Populate inputs when clicking history item
        historyItem.addEventListener('click', (e) => {
            // Ignore click if it was on the delete button
            if (e.target.closest('.delete-history-item')) return;
            
            loadHistoryItem(item);
        });
        
        // Hook up single item delete
        const delBtn = historyItem.querySelector('.delete-history-item');
        delBtn.addEventListener('click', (e) => {
            e.stopPropagation();
            deleteHistoryItem(realIndex);
        });
        
        historyList.appendChild(historyItem);
    });
}

function loadHistoryItem(item) {
    instructionInput.value = item.instruction;
    contextInput.value = item.context || '';
    
    temperatureInput.value = item.temperature;
    tempVal.textContent = parseFloat(item.temperature).toFixed(1);
    
    topPInput.value = item.top_p;
    topPVal.textContent = parseFloat(item.top_p).toFixed(2);
    
    maxTokensInput.value = item.max_new_tokens;
    maxTokensVal.textContent = parseInt(item.max_new_tokens);
    
    safetyInput.checked = item.safety !== false;
    
    // Render the output immediately
    codeOutput.textContent = item.response;
    // Auto detect python vs other languages in simple regex
    detectLanguageAndHighlight(item.response);
    
    // Display metadata
    if (item.time_taken) {
        latencyTimer.textContent = `${item.time_taken.toFixed(2)}s`;
        latencyTimer.classList.remove('hidden');
    } else {
        latencyTimer.classList.add('hidden');
    }
    
    copyBtn.disabled = false;
    showToast('Loaded prompt details from history', 'success');
}

function deleteHistoryItem(index) {
    promptHistory.splice(index, 1);
    saveHistory();
    showToast('Removed item from history', 'info');
}

clearHistoryBtn.addEventListener('click', () => {
    if (promptHistory.length === 0) return;
    if (confirm('Are you sure you want to clear your entire playground history?')) {
        promptHistory = [];
        saveHistory();
        showToast('Cleared all history', 'info');
    }
});

// Prompt execution triggers
generateBtn.addEventListener('click', async () => {
    const instruction = instructionInput.value.trim();
    const context = contextInput.value.trim();
    
    if (!instruction) {
        showToast('Instruction is required', 'error');
        instructionInput.focus();
        return;
    }
    
    // Toggle Loading UI
    setGeneratingState(true);
    
    const requestData = {
        instruction: instruction,
        input: context,
        temperature: parseFloat(temperatureInput.value),
        top_p: parseFloat(topPInput.value),
        max_new_tokens: parseInt(maxTokensInput.value),
        safety: safetyInput.checked
    };
    
    const startTime = performance.now();
    
    try {
        const response = await fetch('/generate', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json'
            },
            body: JSON.stringify(requestData)
        });
        
        if (response.ok) {
            const data = await response.json();
            const clientTime = (performance.now() - startTime) / 1000;
            const serverTime = data.time_taken || clientTime;
            
            // Render Result
            codeOutput.textContent = data.completion;
            detectLanguageAndHighlight(data.completion);
            
            // UI actions
            latencyTimer.textContent = `${serverTime.toFixed(2)}s`;
            latencyTimer.classList.remove('hidden');
            copyBtn.disabled = false;
            
            // Add to history
            addToHistory(instruction, context, requestData, data.completion, serverTime);
            showToast('Generation complete', 'success');
        } else {
            const errData = await response.json();
            const errMsg = errData.detail || 'Inference error occurred.';
            showToast(`Server Error: ${errMsg}`, 'error');
            setPlaceholderOutput(`/* Generation Error: \n${errMsg}\n*/`);
        }
    } catch (err) {
        showToast('Network error: Is the backend server running?', 'error');
        setPlaceholderOutput(`/* Network Connection Failed.\nPlease make sure the FastAPI server is running on port 8000.\n*/`);
    } finally {
        setGeneratingState(false);
    }
});

function setGeneratingState(isGenerating) {
    if (isGenerating) {
        generateBtn.disabled = true;
        btnText.textContent = 'Generating...';
        btnArrow.classList.add('hidden');
        btnSpinner.classList.remove('hidden');
        
        preOutput.classList.add('hidden');
        skeletonLoader.classList.remove('hidden');
        copyBtn.disabled = true;
        latencyTimer.classList.add('hidden');
    } else {
        generateBtn.disabled = false;
        btnText.textContent = 'Generate Code';
        btnArrow.classList.remove('hidden');
        btnSpinner.classList.add('hidden');
        
        skeletonLoader.classList.add('hidden');
        preOutput.classList.remove('hidden');
    }
}

function setPlaceholderOutput(text) {
    codeOutput.textContent = text;
    codeOutput.className = 'language-javascript';
    Prism.highlightElement(codeOutput);
}

function detectLanguageAndHighlight(codeText) {
    // Basic language detection from output signature
    codeOutput.className = 'language-python'; // Default
    
    if (codeText.includes('import ') || codeText.includes('def ')) {
        codeOutput.className = 'language-python';
    } else if (codeText.includes('const ') || codeText.includes('let ') || codeText.includes('function ')) {
        codeOutput.className = 'language-javascript';
    } else if (codeText.includes('echo ') || codeText.includes('sudo ') || codeText.startsWith('#!/bin/')) {
        codeOutput.className = 'language-bash';
    }
    
    Prism.highlightElement(codeOutput);
}

function addToHistory(instruction, context, params, response, timeTaken) {
    // Check if duplicate instruction exists, remove it to bubble it to top
    promptHistory = promptHistory.filter(item => item.instruction !== instruction);
    
    promptHistory.push({
        instruction: instruction,
        context: context,
        temperature: params.temperature,
        top_p: params.top_p,
        max_new_tokens: params.max_new_tokens,
        safety: params.safety,
        response: response,
        time_taken: timeTaken,
        timestamp: Date.now()
    });
    
    // Cap history length at 25 items
    if (promptHistory.length > 25) {
        promptHistory.shift();
    }
    
    saveHistory();
}

// Copy Code Clipboard trigger
copyBtn.addEventListener('click', async () => {
    const code = codeOutput.textContent;
    if (!code) return;
    
    try {
        await navigator.clipboard.writeText(code);
        copyBtn.classList.add('copied');
        copyBtn.querySelector('span').textContent = 'Copied!';
        showToast('Code copied to clipboard', 'success');
        
        setTimeout(() => {
            copyBtn.classList.remove('copied');
            copyBtn.querySelector('span').textContent = 'Copy';
        }, 2000);
    } catch (err) {
        showToast('Failed to copy code to clipboard', 'error');
    }
});

// Toast notification trigger
function showToast(message, type = 'info') {
    const toast = document.createElement('div');
    toast.className = `toast ${type}`;
    
    // Select Icon based on Type
    let icon = '';
    if (type === 'success') {
        icon = `<svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="20 6 9 17 4 12"></polyline></svg>`;
    } else if (type === 'error') {
        icon = `<svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="10"></circle><line x1="12" y1="8" x2="12" y2="12"></line><line x1="12" y1="16" x2="12.01" y2="16"></line></svg>`;
    } else {
        icon = `<svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="10"></circle><line x1="12" y1="16" x2="12" y2="12"></line><line x1="12" y1="8" x2="12.01" y2="8"></line></svg>`;
    }
    
    toast.innerHTML = `
        ${icon}
        <span class="toast-message">${message}</span>
        <button class="toast-close">&times;</button>
    `;
    
    // Close toast button click event
    toast.querySelector('.toast-close').addEventListener('click', () => {
        toast.style.opacity = '0';
        setTimeout(() => toast.remove(), 300);
    });
    
    toastContainer.appendChild(toast);
    
    // Auto-remove toast after 4 seconds
    setTimeout(() => {
        if (toast.parentElement) {
            toast.style.opacity = '0';
            toast.style.transform = 'translateY(10px)';
            setTimeout(() => toast.remove(), 300);
        }
    }, 4000);
}

// Helper to escape HTML characters
function escapeHtml(text) {
    if (!text) return '';
    return text
        .replace(/&/g, '&amp;')
        .replace(/</g, '&lt;')
        .replace(/>/g, '&gt;')
        .replace(/"/g, '&quot;')
        .replace(/'/g, '&#039;');
}