/**
 * Popup Script - UI Logic
 * 
 * Responsibilities:
 * - Handle button clicks (Scan, Download)
 * - Communicate with content script to scan products
 * - Communicate with background service worker to start downloads
 * - Update UI with progress information
 * - Display logs
 */

// ============================================================================
// DOM ELEMENTS
// ============================================================================

const scanBtn = document.getElementById('scanBtn');
const downloadBtn = document.getElementById('downloadBtn');
const concurrencyInput = document.getElementById('concurrency');
const clearLogBtn = document.getElementById('clearLogBtn');
const debugBtn = document.getElementById('debugBtn');

const totalProductsEl = document.getElementById('totalProducts');
const currentProductEl = document.getElementById('currentProduct');
const imagesDownloadedEl = document.getElementById('imagesDownloaded');
const errorCountEl = document.getElementById('errorCount');
const progressBarEl = document.getElementById('progressBar');
const logBoxEl = document.getElementById('logBox');
const statusMsgEl = document.getElementById('statusMsg');

// ============================================================================
// STATE
// ============================================================================

let products = [];
let currentState = {
  products: [],
  currentProductIndex: -1,
  totalImagesDownloaded: 0,
  errorCount: 0,
  isRunning: false,
  logs: [],
};

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

scanBtn.addEventListener('click', handleScanClick);
downloadBtn.addEventListener('click', handleDownloadClick);
clearLogBtn.addEventListener('click', handleClearLogClick);
debugBtn.addEventListener('click', handleDebugClick);

// ============================================================================
// SCANNING LOGIC
// ============================================================================

async function handleDebugClick() {
  try {
    debugBtn.disabled = true;
    updateLog('Running debug diagnostics...', 'info');

    // Get current active tab
    const tabs = await chrome.tabs.query({ active: true, currentWindow: true });
    if (!tabs.length) {
      throw new Error('No active tab found');
    }

    const tabId = tabs[0].id;

    // Send debug message
    let response;
    try {
      response = await chrome.tabs.sendMessage(tabId, {
        action: 'debug',
      });
    } catch (e) {
      updateLog('Content script not loaded, injecting...', 'warning');
      
      await chrome.scripting.executeScript({
        target: { tabId: tabId },
        files: ['content.js'],
      });

      await new Promise(resolve => setTimeout(resolve, 500));
      response = await chrome.tabs.sendMessage(tabId, { action: 'debug' });
    }

    if (response.success) {
      updateLog('=== DEBUG INFO ===', 'info');
      updateLog(`Total links on page: ${response.allLinks}`, 'info');
      updateLog(`a[href*="/item/"] = ${response.linkItem}`, 'info');
      updateLog(`a[href*="/product"] = ${response.linkProduct}`, 'info');
      updateLog(`div[onclick*="/item/"] = ${response.divOnclick}`, 'info');
      updateLog(`div.item = ${response.divItem}`, 'info');
      updateLog(`All images on page: ${response.allImages}`, 'info');
      
      // Show sample links
      if (response.sampleLinks && response.sampleLinks.length > 0) {
        updateLog('--- Sample links on page (first 20) ---', 'info');
        response.sampleLinks.forEach((link, i) => {
          // Show only the relevant part of href
          const shortLink = link.length > 80 ? link.substring(0, 80) + '...' : link;
          updateLog(`  [${i + 1}] ${shortLink}`, 'info');
        });
      }
      
      updateLog('=== END DEBUG ===', 'info');

      if (response.allLinks === 0) {
        updateLog('⚠️ No links found! Page might not be fully loaded.', 'warning');
      } else if (response.allLinks > 0 && response.linkItem === 0 && response.linkProduct === 0) {
        updateLog('⚠️ Found links but none match /fs/, /f/, /item/ patterns.', 'warning');
        updateLog('✅ Scanner will search for product containers instead.', 'info');
      }
    }
  } catch (error) {
    updateLog(`Debug error: ${error.message}`, 'error');
  } finally {
    debugBtn.disabled = false;
  }
}

async function handleScanClick() {
  try {
    scanBtn.disabled = true;
    setStatus('Scanning page...', 'working');
    updateLog('Starting page scan...', 'info');

    // Get current active tab
    const tabs = await chrome.tabs.query({ active: true, currentWindow: true });
    if (!tabs.length) {
      throw new Error('No active tab found');
    }

    const tabId = tabs[0].id;
    const tabUrl = tabs[0].url;

    // Verify content script is injected
    let response;
    try {
      response = await chrome.tabs.sendMessage(tabId, {
        action: 'scanPage',
      });
    } catch (e) {
      // Content script might not be loaded, try injecting it
      updateLog('Content script not found, injecting...', 'warning');
      
      try {
        await chrome.scripting.executeScript({
          target: { tabId: tabId },
          files: ['content.js'],
        });
      } catch (err) {
        throw new Error(`Cannot inject script on this page. URL: ${tabUrl}. Some pages (chrome://, extensions://, etc) don't allow scripts.`);
      }

      // Give it a moment to load
      await new Promise(resolve => setTimeout(resolve, 500));

      // Try again
      response = await chrome.tabs.sendMessage(tabId, {
        action: 'scanPage',
      });
    }

    if (!response.success) {
      throw new Error('Failed to scan page');
    }

    products = response.products || [];
    const count = products.length;

    updateLog(`Found ${count} products`, 'success');
    totalProductsEl.textContent = count;

    if (count > 0) {
      downloadBtn.disabled = false;
      setStatus(`Ready to download ${count} products`, 'idle');
      
      // Send products to background
      await chrome.runtime.sendMessage({
        action: 'updateProducts',
        products: products,
      });
    } else {
      setStatus('No products found. Check page structure and selectors.', 'error');
    }
  } catch (error) {
    console.error('Scan error:', error);
    updateLog(`Error: ${error.message}`, 'error');
    setStatus(`Scan failed: ${error.message}`, 'error');
  } finally {
    scanBtn.disabled = false;
  }
}

// ============================================================================
// DOWNLOAD LOGIC
// ============================================================================

async function handleDownloadClick() {
  try {
    if (products.length === 0) {
      setStatus('No products to download. Scan the page first.', 'error');
      return;
    }

    downloadBtn.disabled = true;
    const maxConcurrency = parseInt(concurrencyInput.value) || 2;
    
    updateLog(`Starting download of ${products.length} products...`, 'info');
    updateLog(`Max concurrent: ${maxConcurrency}`, 'info');

    await chrome.runtime.sendMessage({
      action: 'startDownload',
      maxConcurrency: maxConcurrency,
    });

    setStatus('Downloads in progress...', 'working');
    
    // Start polling for updates
    pollForUpdates();
  } catch (error) {
    console.error('Download error:', error);
    updateLog(`Error: ${error.message}`, 'error');
    setStatus(`Download failed: ${error.message}`, 'error');
    downloadBtn.disabled = false;
  }
}

// ============================================================================
// STATE UPDATES & POLLING
// ============================================================================

async function pollForUpdates() {
  while (currentState.isRunning) {
    try {
      const response = await chrome.runtime.sendMessage({
        action: 'getState',
      });

      if (response && response.state) {
        currentState = response.state;
        updateUI();
      }
    } catch (error) {
      // Extension context invalidated or popup closed
      break;
    }

    // Poll every 500ms
    await new Promise(resolve => setTimeout(resolve, 500));
  }

  // Final update
  updateUI();
  downloadBtn.disabled = false;
  setStatus('Download complete!', 'success');
}

/**
 * Update UI with current state
 */
function updateUI() {
  totalProductsEl.textContent = currentState.products.length;
  imagesDownloadedEl.textContent = currentState.totalImagesDownloaded;
  errorCountEl.textContent = currentState.errorCount;

  // Update current product display
  if (currentState.currentProductIndex >= 0 && currentState.products[currentState.currentProductIndex]) {
    const product = currentState.products[currentState.currentProductIndex];
    currentProductEl.textContent = product.productCode || `Product ${currentState.currentProductIndex + 1}`;
  } else {
    currentProductEl.textContent = '—';
  }

  // Update progress bar
  if (currentState.products.length > 0) {
    const progress = ((currentState.currentProductIndex + 1) / currentState.products.length) * 100;
    progressBarEl.style.width = Math.max(0, Math.min(100, progress)) + '%';
  }

  // Update logs
  const logEntries = currentState.logs || [];
  logBoxEl.innerHTML = '';

  logEntries.forEach(entry => {
    const div = document.createElement('div');
    div.className = `log-entry ${entry.type}`;
    div.textContent = entry.message;
    logBoxEl.appendChild(div);
  });

  // Auto-scroll to bottom
  logBoxEl.scrollTop = logBoxEl.scrollHeight;
}

// ============================================================================
// UI HELPERS
// ============================================================================

function updateLog(message, type = 'info') {
  const entry = document.createElement('div');
  entry.className = `log-entry ${type}`;
  
  const timestamp = new Date().toLocaleTimeString();
  entry.textContent = `[${timestamp}] ${message}`;
  
  logBoxEl.appendChild(entry);
  logBoxEl.scrollTop = logBoxEl.scrollHeight;
}

function setStatus(message, status = 'idle') {
  statusMsgEl.textContent = message;
  statusMsgEl.className = `status ${status}`;
}

function handleClearLogClick() {
  logBoxEl.innerHTML = '';
  updateLog('Log cleared', 'info');
}

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

async function initializePopup() {
  try {
    // Get initial state from background
    const response = await chrome.runtime.sendMessage({
      action: 'getState',
    });

    if (response && response.state) {
      currentState = response.state;
      products = currentState.products;
    }

    updateUI();

    // If download is in progress, start polling
    if (currentState.isRunning) {
      downloadBtn.disabled = true;
      setStatus('Download in progress...', 'working');
      pollForUpdates();
    } else {
      // Enable download button if we have products
      if (products.length > 0) {
        downloadBtn.disabled = false;
      }
      setStatus('Ready to scan', 'idle');
    }
  } catch (error) {
    console.error('Initialization error:', error);
    updateLog('Failed to connect to background', 'error');
  }
}

// Initialize when popup opens
document.addEventListener('DOMContentLoaded', initializePopup);

// Cleanup listeners on popup close
window.addEventListener('beforeunload', () => {
  // Popup is closing
});

console.log('[Popup] Script loaded');