/*
 * Copyright (C) 2016 Apple Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

class ControlsVisibilitySupport extends MediaControllerSupport
{

    constructor(mediaController)
    {
        super(mediaController);

        this._controlsAttributeObserver = new MutationObserver(this._updateControls.bind(this));
        this._controlsAttributeObserver.observe(mediaController.media, { attributes: true, attributeFilter: ["controls"] });

        this._updateControls();
    }

    // Protected

    destroy()
    {
        this._controlsAttributeObserver.disconnect();
    }

    get mediaEvents()
    {
        return ["loadedmetadata", "play", "pause"];
    }

    get tracksToMonitor()
    {
        return [this.mediaController.media.videoTracks];
    }

    handleEvent()
    {
        this._updateControls();
    }

    // Private

    _updateControls()
    {
        const media = this.mediaController.media;
        const isVideo = media instanceof HTMLVideoElement && media.videoTracks.length > 0;
        let shouldShowControls = media.controls && !!media.currentSrc;
        if (isVideo)
            shouldShowControls = shouldShowControls && media.readyState > HTMLMediaElement.HAVE_NOTHING;

        const controls = this.mediaController.controls;
        controls.startButton.visible = shouldShowControls;
        controls.controlsBar.visible = shouldShowControls;
        controls.controlsBar.fadesWhileIdle = isVideo ? !media.paused : false;
    }

}
