class UI {
  static allowedToolbarItems = [
    'sidebar-thumbnails',
    'sidebar-document-ouline',
    'sidebar-bookmarks',
    'pager',
    'pan',
    'zoom-out',
    'zoom-in',
    'zoom-mode',
    'spacer',
    'search',
  ]

  // Load the PSPDFKit UI by setting a target element as the container to render in
  // and a arraybuffer which represents the document that should be displayed.
  static Instance
  static loadPSPDFKit(arrayBuffer, container, licenseKey, locale) {
    UI.Instance = PSPDFKit.load({
      locale: locale,
      licenseKey: licenseKey,
      styleSheets: ['/css/site.css'],
      container: container,
      document: arrayBuffer,
      annotationPresets: UI.getPresets(),
      electronicSignatures: {
        creationModes: ['DRAW', 'TYPE', 'IMAGE'],
      },
      initialViewState: new PSPDFKit.ViewState({
        sidebarMode: PSPDFKit.SidebarMode.THUMBNAILS,
      }),
      isEditableAnnotation: function (annotation) {
        // Check if the annotation is a signature
        // This will allow new signatures, but not allow edits.
        if (annotation.isSignature || annotation.description == 'FRAME') {
          return false
        }

        return true

        //return !annotation.isSignature;
      },
      customRenderers: {
        Annotation: UI.annotationRenderer,
      },
    })

    return UI.Instance;
  }

  static configurePSPDFKit(instance, handler) {
    const toolbarItems = UI.getToolbarItems(instance, handler)
    instance.setToolbarItems(toolbarItems)
  }

  static annotationRenderer(data) {
    // leave everything as is
    return null
  }

  static getToolbarItems(instance, handler) {
    const customItems = UI.getCustomItems(handler)
    const defaultItems = UI.getDefaultItems(instance.toolbarItems)
    return defaultItems.concat(customItems)
  }

  static createElementFromHTML(html) {
    const el = document.createElement('div')
    el.innerHTML = html.trim()

    return el.firstChild
  }

  static getCustomItems = function (callback) {
    return []
    return [
      {
        type: 'custom',
        id: 'button-reset',
        className: 'button-reset',
        title: 'Zurücksetzen',
        onPress() {
          callback('RESET')
        },
        icon: `<svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" fill="currentColor" class="bi bi-arrow-counterclockwise" viewBox="0 0 16 16">
                        <path fill-rule="evenodd" d="M8 3a5 5 0 1 1-4.546 2.914.5.5 0 0 0-.908-.417A6 6 0 1 0 8 2v1z"/>
                        <path d="M8 4.466V.534a.25.25 0 0 0-.41-.192L5.23 2.308a.25.25 0 0 0 0 .384l2.36 1.966A.25.25 0 0 0 8 4.466z"/>
                      </svg>`,
      },
      {
        type: 'custom',
        id: 'button-reject',
        className: 'button-reject',
        title: 'Ablehnen',
        onPress() {
          callback('REJECT')
        },
        icon: `<svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" fill="currentColor" class="bi bi-hand-thumbs-down" viewBox="0 0 16 16">
                        <path d="M8.864 15.674c-.956.24-1.843-.484-1.908-1.42-.072-1.05-.23-2.015-.428-2.59-.125-.36-.479-1.012-1.04-1.638-.557-.624-1.282-1.179-2.131-1.41C2.685 8.432 2 7.85 2 7V3c0-.845.682-1.464 1.448-1.546 1.07-.113 1.564-.415 2.068-.723l.048-.029c.272-.166.578-.349.97-.484C6.931.08 7.395 0 8 0h3.5c.937 0 1.599.478 1.934 1.064.164.287.254.607.254.913 0 .152-.023.312-.077.464.201.262.38.577.488.9.11.33.172.762.004 1.15.069.13.12.268.159.403.077.27.113.567.113.856 0 .289-.036.586-.113.856-.035.12-.08.244-.138.363.394.571.418 1.2.234 1.733-.206.592-.682 1.1-1.2 1.272-.847.283-1.803.276-2.516.211a9.877 9.877 0 0 1-.443-.05 9.364 9.364 0 0 1-.062 4.51c-.138.508-.55.848-1.012.964zM11.5 1H8c-.51 0-.863.068-1.14.163-.281.097-.506.229-.776.393l-.04.025c-.555.338-1.198.73-2.49.868-.333.035-.554.29-.554.55V7c0 .255.226.543.62.65 1.095.3 1.977.997 2.614 1.709.635.71 1.064 1.475 1.238 1.977.243.7.407 1.768.482 2.85.025.362.36.595.667.518l.262-.065c.16-.04.258-.144.288-.255a8.34 8.34 0 0 0-.145-4.726.5.5 0 0 1 .595-.643h.003l.014.004.058.013a8.912 8.912 0 0 0 1.036.157c.663.06 1.457.054 2.11-.163.175-.059.45-.301.57-.651.107-.308.087-.67-.266-1.021L12.793 7l.353-.354c.043-.042.105-.14.154-.315.048-.167.075-.37.075-.581 0-.211-.027-.414-.075-.581-.05-.174-.111-.273-.154-.315l-.353-.354.353-.354c.047-.047.109-.176.005-.488a2.224 2.224 0 0 0-.505-.804l-.353-.354.353-.354c.006-.005.041-.05.041-.17a.866.866 0 0 0-.121-.415C12.4 1.272 12.063 1 11.5 1"/>
                      </svg>`,
      },
      {
        type: 'custom',
        id: 'button-finish',
        className: 'button-finish',
        title: 'Abschließen',
        onPress() {
          callback('FINISH')
        },
      },
    ]
  }

  static getDefaultItems(items) {
    return items.filter((item) => UI.allowedToolbarItems.includes(item.type))
  }

  static getPresets() {
    const annotationPresets = PSPDFKit.defaultAnnotationPresets
    annotationPresets.ink = {
      lineWidth: 10,
    }

    annotationPresets.widget = {
      readOnly: true,
    }

    return annotationPresets
  }
}