/* global opts */
function rememberGallerySelection(id_gallery) {}

function getGallerySelectedIndex(id_gallery) {}

function request(url, data, handler, errorHandler) {
  const xhr = new XMLHttpRequest();
  xhr.open('POST', url, true);
  xhr.setRequestHeader('Content-Type', 'application/json');
  xhr.onreadystatechange = function () {
    if (xhr.readyState === 4) {
      if (xhr.status === 200) {
        try {
          const js = JSON.parse(xhr.responseText);
          handler(js);
        } catch (error) {
          console.error(error);
          errorHandler();
        }
      } else {
        errorHandler();
      }
    }
  };
  const js = JSON.stringify(data);
  xhr.send(js);
}

function pad2(x) {
  return x < 10 ? `0${x}` : x;
}

function formatTime(secs) {
  if (secs > 3600) return `${pad2(Math.floor(secs / 60 / 60))}:${pad2(Math.floor(secs / 60) % 60)}:${pad2(Math.floor(secs) % 60)}`;
  if (secs > 60) return `${pad2(Math.floor(secs / 60))}:${pad2(Math.floor(secs) % 60)}`;
  return `${Math.floor(secs)}s`;
}

function setTitle(progress) {
  let title = 'SD.Next';
  if (progress) title += ` ${progress.split(' ')[0].trim()}`;
  if (document.title != title) document.title = title;
}

function randomId() {
  return `task(${Math.random().toString(36).slice(2, 7)}${Math.random().toString(36).slice(2, 7)}${Math.random().toString(36).slice(2, 7)})`;
}

// starts sending progress requests to "/internal/progress" uri, creating progressbar above progressbarContainer element and
// preview inside gallery element. Cleans up all created stuff when the task is over and calls atEnd.
// calls onProgress every time there is a progress update
function requestProgress(id_task, progressbarContainer, gallery, atEnd = null, onProgress = null, once = false) {
  let hasStarted = false;
  const dateStart = new Date();
  const prevProgress = null;
  const parentProgressbar = progressbarContainer.parentNode;
  const parentGallery = gallery ? gallery.parentNode : null;
  const divProgress = document.createElement('div');
  divProgress.className = 'progressDiv';
  divProgress.id = 'progressbar';
  divProgress.style.display = opts.show_progressbar ? 'block' : 'none';
  const divInner = document.createElement('div');
  divInner.className = 'progress';
  divProgress.appendChild(divInner);
  parentProgressbar.insertBefore(divProgress, progressbarContainer);
  localStorage.setItem('task', id_task);
  let livePreview;
  if (parentGallery) {
    livePreview = document.createElement('div');
    livePreview.className = 'livePreview';
    parentGallery.insertBefore(livePreview, gallery);
  }

  const removeProgressBar = function () {
    console.debug('task end:   ', id_task);
    localStorage.removeItem('task');
    setTitle('');
    if (divProgress) parentProgressbar.removeChild(divProgress);
    if (parentGallery) parentGallery.removeChild(livePreview);
    if (atEnd) atEnd();
  };

  const fun = function (id_task, id_live_preview) {
    request('./internal/progress', { id_task, id_live_preview }, (res) => {
      const elapsedFromStart = (new Date() - dateStart) / 1000;
      if (res.completed) {
        removeProgressBar();
        return;
      }
      var rect = progressbarContainer.getBoundingClientRect();
      if (rect.width) divProgress.style.width = `${rect.width}px`;
      progressText = '';
      divInner.style.width = `${(res.progress || 0) * 100.0}%`;
      divInner.style.background = res.progress ? '' : 'transparent';
      if (res.progress > 0) progressText = `${((res.progress || 0) * 100.0).toFixed(0)}%`;
      if (res.eta) progressText += ` ETA: ${formatTime(res.eta)}`;
      setTitle(progressText);
      if (res.textinfo && res.textinfo.indexOf('\n') == -1) progressText = `${res.textinfo} ${progressText}`;
      divInner.textContent = progressText;
      hasStarted |= res.active;
      if (!res.active && (hasStarted || once)) {
        removeProgressBar();
        return;
      }
      if (res.completed) {
        removeProgressBar();
        return;
      }
      if (elapsedFromStart > 30 && !res.queued && res.progress == prevProgress) {
        removeProgressBar();
        return;
      }
      if (res.live_preview && gallery) {
        var rect = gallery.getBoundingClientRect();
        if (rect.width) {
          livePreview.style.width = `${rect.width}px`;
          livePreview.style.height = `${rect.height}px`;
        }
        const img = new Image();
        img.onload = function () {
          livePreview.appendChild(img);
          if (livePreview.childElementCount > 2) livePreview.removeChild(livePreview.firstElementChild);
        };
        img.src = res.live_preview;
      }
      if (onProgress) onProgress(res);
      setTimeout(() => fun(id_task, res.id_live_preview), opts.live_preview_refresh_period || 250);
    }, () => {
      removeProgressBar();
    });
  };
  fun(id_task, 0);
}