const { Preview } = Box;
const preview = new Preview();

/**
 * Shows a preview.
 *
 * @public
 * @param {string} fileId - File ID to preview
 * @param {string} accessToken - Box API access token
 * @param {Object} [options] - Options
 * @return {void}
 */
preview.show(fileId, accessToken, options);

/**
 * Hides the preview.
 *
 * @return {void}
 */
preview.hide();

/**
 * Prints the current file, if printable.
 *
 * @return {void}
 */
preview.print();

/**
 * Downloads the current file.
 *
 * @return {void}
 */
preview.download();

/**
 * Resizes the current preview, if applicable. This function only needs to
 * be called when preview's viewport has changed while the window has not.
 * If the window is resizing, then preview will automatically resize itself.
 *
 * @return {void}
 */
preview.resize();

/**
 * Adds an event listener to the preview. Listeners should be added
 * before calling show() so no events are missed.
 *
 * @param {string} eventName - Name of the event
 * @param {Function} listener - Callback function
 * @return {void}
 */
preview.addListener();

/**
 * Removes an event listener from the preview.
 *
 * @param {string} eventName - Name of the event
 * @param {Function} listener - Callback function
 * @return {void}
 */
preview.removeListener(eventName, listener);

/**
 * Removes all event listeners from the preview.
 *
 * @return {void}
 */
preview.removeAllListeners();

// Example token generator function that resolves to a single access token
var singleTokenGenerator = function() {
  return someApi.getToken().then(function(data) {
    return data.token;
  });
};

// Example token generator function that resolves to a map of tokens
var mapTokenGenerator = function() {
  return Promise.resolve({
    file_1234: "some_token_abcd",
    file_2345: "some_token_bcde"
  });
};

const listener = (value) => {
  // Do something with value
};

// Attach listener before calling show otherwise events can be missed
var preview = new Box.Preview();
preview.addListener(EVENTNAME, listener);

// Show a preview
preview.show(...);

// Remove listener when needed
preview.removeListener(EVENTNAME, listener);

error: 'message', // Error message if any error occurred while loading
viewer: {...},    // Instance of the current viewer object if no error occurred
metrics: {...},   // Performance metrics
file: {...}       // Box file object with properties defined in file.js

message: 'message', // Message to show
type: 'warning'    // 'warning', 'notice', or 'error'

event: EVENTNAME,         // Event name
data: DATA,               // Event data object
viewerName: VIEWERNAME,   // Name of the viewer. See VIEWERNAME above
fileId: fileId            // The file ID

var preview = new Box.Preview();
preview.addListener("viewer", viewer => {
  viewer.addListener("rotate", () => {
    // Do something when a viewer rotates a preview
  });
});

preview.addListener("load", data => {
  const viewer = data.viewer;
  viewer.addListener("rotate", () => {
    // Do something when a viewer rotates a preview
  });
});

preview.addListener("viewerevent", data => {
  if (data.viewerName === "Image") {
    if (data.event === "rotate") {
      // Do something when an image preview is rotated
    }
  } else if (data.viewerName === "Image360") {
    if (data.event === "rotate") {
      // Do something different when a 360-degree image is rotated
    }
  } else {
  }
});

preview.addListener("rotate", data => {
  if (data.viewerName === "Image") {
    // Do something when an image preview is rotated
  } else if (data.viewerName === "Image360") {
    // Do something different when a 360-degree image is rotated
  } else {
  }
});