const elements = {
  startBtn: document.getElementById('startBtn'),
  stopBtn: document.getElementById('stopBtn'),
  clearLogsBtn: document.getElementById('clearLogsBtn'),
  errorBanner: document.getElementById('errorBanner'),
  successBanner: document.getElementById('successBanner'),
  connectionStatus: document.getElementById('connectionStatus'),
  currentState: document.getElementById('currentState'),
  totalItems: document.getElementById('totalItems'),
  currentPage: document.getElementById('currentPage'),
  lastRunTime: document.getElementById('lastRunTime'),
  progressBar: document.getElementById('progressBar'),
  progressLabel: document.getElementById('progressLabel'),
  csvLabel: document.getElementById('csvLabel'),
  logOutput: document.getElementById('logOutput'),
};

let logCursor = 0;
let pollTimer = null;
let running = false;
let screenshotTimer = null;

function setBanner(element, message) {
  if (!message) {
    element.classList.add('hidden');
    element.textContent = '';
    return;
  }
  element.textContent = message;
  element.classList.remove('hidden');
}

function showError(message) {
  setBanner(elements.errorBanner, message);
  setBanner(elements.successBanner, '');
}

function showSuccess(message) {
  setBanner(elements.successBanner, message);
  setBanner(elements.errorBanner, '');
}

function clearBanners() {
  setBanner(elements.errorBanner, '');
  setBanner(elements.successBanner, '');
}

function setRunningState(isRunning) {
  running = isRunning;
  elements.startBtn.disabled = isRunning;
  elements.stopBtn.disabled = !isRunning;
  elements.connectionStatus.textContent = isRunning ? 'Running' : 'Ready';
  if (isRunning) {
    elements.connectionStatus.parentElement.querySelector('.dot').style.background = '#f59e0b';
  } else {
    elements.connectionStatus.parentElement.querySelector('.dot').style.background = '#22c55e';
  }
}

function updateStatusPanel(data) {
  elements.currentState.textContent = data.current_state || 'Idle';
  elements.totalItems.textContent = String(data.total_items_found ?? 0);
  elements.currentPage.textContent = String(data.current_page ?? 0);
  elements.lastRunTime.textContent = data.last_run_time || '-';
  const progress = Number(data.progress || 0);
  elements.progressBar.style.width = `${Math.max(0, Math.min(100, progress))}%`;
  elements.progressLabel.textContent = `${Math.max(0, Math.min(100, progress))}%`;
  if (data.last_error) {
    showError(data.last_error);
  }
}

function appendLogs(logs) {
  if (!Array.isArray(logs) || logs.length <= logCursor) {
    return;
  }
  const newLogs = logs.slice(logCursor);
  if (!newLogs.length) {
    return;
  }
  const current = elements.logOutput.textContent === 'Waiting for the next run...' ? '' : elements.logOutput.textContent;
  const merged = [current.trimEnd(), ...newLogs].filter(Boolean).join('\n');
  elements.logOutput.textContent = merged;
  elements.logOutput.scrollTop = elements.logOutput.scrollHeight;
  logCursor = logs.length;
}

async function fetchStatus() {
  try {
    const response = await fetch('/status', { cache: 'no-store' });
    const data = await response.json();
    setRunningState(Boolean(data.running));
    updateStatusPanel(data);
    appendLogs(data.logs || []);
    if (!data.running && pollTimer) {
      window.clearInterval(pollTimer);
      pollTimer = null;
    }
  } catch (error) {
    console.error(error);
  }
}

async function startBot() {
  clearBanners();

  try {
    const response = await fetch('/start', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({}),
    });
    const data = await response.json();
    if (!response.ok || !data.ok) {
      showError(data.error || 'Failed to start automation.');
      return;
    }

    showSuccess('Automation started.');
    logCursor = 0;
    elements.logOutput.textContent = 'Waiting for the next run...';
    setRunningState(true);
    if (!pollTimer) {
      pollTimer = window.setInterval(fetchStatus, 2000);
    }
    await fetchStatus();
  } catch (error) {
    showError(error.message || 'Unable to start the bot.');
  }
}

async function stopBot() {
  try {
    const response = await fetch('/stop', { method: 'POST' });
    const data = await response.json();
    showSuccess(data.message || 'Stop requested.');
    await fetchStatus();
  } catch (error) {
    showError(error.message || 'Unable to stop the bot.');
  }
}

function clearLogs() {
  logCursor = 0;
  elements.logOutput.textContent = 'Waiting for the next run...';
}

function boot() {
  elements.startBtn.addEventListener('click', startBot);
  elements.stopBtn.addEventListener('click', stopBot);
  elements.clearLogsBtn.addEventListener('click', clearLogs);

  setRunningState(false);
  fetchStatus();
  pollTimer = window.setInterval(fetchStatus, 2000);
  const img = document.getElementById('screenshotImg');
  if (img) {
    const refresh = () => {
      img.src = '/screenshot?ts=' + Date.now();
    };
    screenshotTimer = window.setInterval(refresh, 3000);
    refresh();
  }
}

document.addEventListener('DOMContentLoaded', boot);