import Overlay from './Overlay';
import Dialog from './Dialog';
import ProgressDialog from './ProgressDialog';

/**
 * The OverlayAPI is responsible for pre-pending templates to
 * the body of the document, which is useful for displaying templates
 * which need to block the full screen.
 *
 * @memberof api/overlays
 * @constructor
*/

class OverlayAPI {
    constructor() {
        this.activeOverlays = [];

        this.dismissLastOverlay = this.dismissLastOverlay.bind(this);

        document.addEventListener('keyup', (event) => {
            if (event.key === 'Escape') {
                this.dismissLastOverlay();
            }
        });
    }

    /**
     * private
     */
    showOverlay(overlay) {
        if (this.activeOverlays.length) {
            this.activeOverlays[this.activeOverlays.length - 1].container.classList.add('invisible');
        }

        this.activeOverlays.push(overlay);

        overlay.once('destroy', () => {
            this.activeOverlays.splice(this.activeOverlays.indexOf(overlay), 1);

            if (this.activeOverlays.length) {
                this.activeOverlays[this.activeOverlays.length - 1].container.classList.remove('invisible');
            }
        });

        overlay.show();
    }

    /**
     * private
     */
    dismissLastOverlay() {
        let lastOverlay = this.activeOverlays[this.activeOverlays.length - 1];
        if (lastOverlay && lastOverlay.dismissable) {
            lastOverlay.dismiss();
        }
    }

    /**
     * A description of option properties that can be passed into the overlay
     * @typedef options
        * @property {object} element DOMElement that is to be inserted/shown on the overlay
        * @property {string} size prefered size of the overlay (large, small, fit)
        * @property {array} buttons optional button objects with label and callback properties
        * @property {function} onDestroy callback to be called when overlay is destroyed
        * @property {boolean} dismissable allow user to dismiss overlay by using esc, and clicking away
        * from overlay. Unless set to false, all overlays will be dismissable by default.
    */
    overlay(options) {
        let overlay = new Overlay(options);

        this.showOverlay(overlay);

        return overlay;
    }

    /**
     * Displays a blocking (modal) dialog. This dialog can be used for
     * displaying messages that require the user's
     * immediate attention.
     * @param {model} options defines options for the dialog
     * @returns {object} with an object with a dismiss function that can be called from the calling code
     * to dismiss/destroy the dialog
     *
     * A description of the model options that may be passed to the
     * dialog method. Note that the DialogModel described
     * here is shared with the Notifications framework.
     * @see NotificationService
     *
    * @typedef options
        * @property {string} title the title to use for the dialog
        * @property {string} iconClass class to apply to icon that is shown on dialog
        * @property {string} message text that indicates a current message,
        * @property {buttons[]} buttons a list of buttons with title and callback properties that will
        * be added to the dialog.
    */
    dialog(options) {
        let dialog = new Dialog(options);

        this.showOverlay(dialog);

        return dialog;
    }


    /**
     * Displays a blocking (modal) progress dialog. This dialog can be used for
     * displaying messages that require the user's attention, and show progress
     * @param {model} options defines options for the dialog
     * @returns {object} with an object with a dismiss function that can be called from the calling code
     * to dismiss/destroy the dialog and an updateProgress function that takes progressPercentage(Number 0-100)
     * and progressText (string)
     *
     * A description of the model options that may be passed to the
     * dialog method. Note that the DialogModel described
     * here is shared with the Notifications framework.
     * @see NotificationService
     *
    * @typedef options
        * @property {number} progressPerc the initial progress value (0-100) or {string} 'unknown' for anonymous progress
        * @property {string} progressText the initial text to be shown under the progress bar
        * @property {buttons[]} buttons a list of buttons with title and callback properties that will
        * be added to the dialog.
    */
    progressDialog(options) {
        let progressDialog = new ProgressDialog(options);

        this.showOverlay(progressDialog);

        return progressDialog;
    }
}

export default OverlayAPI;