import { Observable } from "../../Misc/observable";
import { Tools } from "../../Misc/tools";
import { Logger } from "../../Misc/logger";
import { Nullable } from "../../types";
import { Scene } from "../../scene";
import { Engine } from "../../Engines/engine";
import { Texture } from "../../Materials/Textures/texture";

import "../../Engines/Extensions/engine.videoTexture";
import "../../Engines/Extensions/engine.dynamicTexture";

/**
 * Settings for finer control over video usage
 */
export interface VideoTextureSettings {
    /**
     * Applies `autoplay` to video, if specified
     */
    autoPlay?: boolean;

    /**
     * Applies `loop` to video, if specified
     */
    loop?: boolean;

    /**
     * Automatically updates internal texture from video at every frame in the render loop
     */
    autoUpdateTexture: boolean;

    /**
     * Image src displayed during the video loading or until the user interacts with the video.
     */
    poster?: string;
}

/**
 * If you want to display a video in your scene, this is the special texture for that.
 * This special texture works similar to other textures, with the exception of a few parameters.
 * @see https://doc.babylonjs.com/how_to/video_texture
 */
export class VideoTexture extends Texture {
    /**
     * Tells whether textures will be updated automatically or user is required to call `updateTexture` manually
     */
    public readonly autoUpdateTexture: boolean;

    /**
     * The video instance used by the texture internally
     */
    public readonly video: HTMLVideoElement;

    private _onUserActionRequestedObservable: Nullable<Observable<Texture>> = null;

    /**
     * Event triggerd when a dom action is required by the user to play the video.
     * This happens due to recent changes in browser policies preventing video to auto start.
     */
    public get onUserActionRequestedObservable(): Observable<Texture> {
        if (!this._onUserActionRequestedObservable) {
            this._onUserActionRequestedObservable = new Observable<Texture>();
        }
        return this._onUserActionRequestedObservable;
    }

    private _generateMipMaps: boolean;
    private _engine: Engine;
    private _stillImageCaptured = false;
    private _displayingPosterTexture = false;
    private _settings: VideoTextureSettings;
    private _createInternalTextureOnEvent: string;
    private _frameId = -1;
    private _currentSrc: Nullable<string | string[] | HTMLVideoElement> = null;

    /**
     * Creates a video texture.
     * If you want to display a video in your scene, this is the special texture for that.
     * This special texture works similar to other textures, with the exception of a few parameters.
     * @see https://doc.babylonjs.com/how_to/video_texture
     * @param name optional name, will detect from video source, if not defined
     * @param src can be used to provide an url, array of urls or an already setup HTML video element.
     * @param scene is obviously the current scene.
     * @param generateMipMaps can be used to turn on mipmaps (Can be expensive for videoTextures because they are often updated).
     * @param invertY is false by default but can be used to invert video on Y axis
     * @param samplingMode controls the sampling method and is set to TRILINEAR_SAMPLINGMODE by default
     * @param settings allows finer control over video usage
     */
    constructor(
        name: Nullable<string>,
        src: string | string[] | HTMLVideoElement,
        scene: Nullable<Scene>,
        generateMipMaps = false,
        invertY = false,
        samplingMode: number = Texture.TRILINEAR_SAMPLINGMODE,
        settings: VideoTextureSettings = {
            autoPlay: true,
            loop: true,
            autoUpdateTexture: true,
        }
    ) {
        super(null, scene, !generateMipMaps, invertY);

        this._engine = this.getScene()!.getEngine();
        this._generateMipMaps = generateMipMaps;
        this._initialSamplingMode = samplingMode;
        this.autoUpdateTexture = settings.autoUpdateTexture;

        this._currentSrc = src;
        this.name = name || this._getName(src);
        this.video = this._getVideo(src);
        this._settings = settings;

        if (settings.poster) {
            this.video.poster = settings.poster;
        }

        if (settings.autoPlay !== undefined) {
            this.video.autoplay = settings.autoPlay;
        }
        if (settings.loop !== undefined) {
            this.video.loop = settings.loop;
        }

        this.video.setAttribute("playsinline", "");

        this.video.addEventListener("paused", this._updateInternalTexture);
        this.video.addEventListener("seeked", this._updateInternalTexture);
        this.video.addEventListener("emptied", this.reset);
        this._createInternalTextureOnEvent = (settings.poster && !settings.autoPlay) ? "play" : "canplay";
        this.video.addEventListener(this._createInternalTextureOnEvent, this._createInternalTexture);

        const videoHasEnoughData = (this.video.readyState >= this.video.HAVE_CURRENT_DATA);
        if (settings.poster &&
            (!settings.autoPlay || !videoHasEnoughData)) {
            this._texture = this._engine.createTexture(settings.poster!, false, !this.invertY, scene);
            this._displayingPosterTexture = true;
        }
        else if (videoHasEnoughData) {
            this._createInternalTexture();
        }
    }

    private _getName(src: string | string[] | HTMLVideoElement): string {
        if (src instanceof HTMLVideoElement) {
            return src.currentSrc;
        }

        if (typeof src === "object") {
            return src.toString();
        }

        return src;
    }

    private _getVideo(src: string | string[] | HTMLVideoElement): HTMLVideoElement {
        if (src instanceof HTMLVideoElement) {
            Tools.SetCorsBehavior(src.currentSrc, src);
            return src;
        }
        const video: HTMLVideoElement = document.createElement("video");
        if (typeof src === "string") {
            Tools.SetCorsBehavior(src, video);
            video.src = src;
        } else {
            Tools.SetCorsBehavior(src[0], video);
            src.forEach((url) => {
                const source = document.createElement("source");
                source.src = url;
                video.appendChild(source);
            });
        }
        return video;
    }

    private _createInternalTexture = (): void => {
        if (this._texture != null) {
            if (this._displayingPosterTexture) {
                this._texture.dispose();
                this._displayingPosterTexture = false;
            }
            else {
                return;
            }
        }

        if (!this._engine.needPOTTextures ||
            (Tools.IsExponentOfTwo(this.video.videoWidth) && Tools.IsExponentOfTwo(this.video.videoHeight))) {
            this.wrapU = Texture.WRAP_ADDRESSMODE;
            this.wrapV = Texture.WRAP_ADDRESSMODE;
        } else {
            this.wrapU = Texture.CLAMP_ADDRESSMODE;
            this.wrapV = Texture.CLAMP_ADDRESSMODE;
            this._generateMipMaps = false;
        }

        this._texture = this._engine.createDynamicTexture(
            this.video.videoWidth,
            this.video.videoHeight,
            this._generateMipMaps,
            this.samplingMode
        );

        if (!this.video.autoplay && !this._settings.poster) {
            let oldHandler = this.video.onplaying;
            let error = false;
            let oldMuted = this.video.muted;
            this.video.muted = true;
            this.video.onplaying = () => {
                this.video.muted = oldMuted;
                this.video.onplaying = oldHandler;
                this._texture!.isReady = true;
                this._updateInternalTexture();
                if (!error) {
                    this.video.pause();
                }
                if (this.onLoadObservable.hasObservers()) {
                    this.onLoadObservable.notifyObservers(this);
                }
            };
            var playing = this.video.play();
            if (playing) {
                playing.then(() => {
                    // Everything is good.
                })
                    .catch(() => {
                        error = true;
                        // On Chrome for instance, new policies might prevent playing without user interaction.
                        if (this._onUserActionRequestedObservable && this._onUserActionRequestedObservable.hasObservers()) {
                            this._onUserActionRequestedObservable.notifyObservers(this);
                        }
                    });
            }
            else {
                this.video.onplaying = oldHandler;
                this._texture.isReady = true;
                this._updateInternalTexture();
                if (this.onLoadObservable.hasObservers()) {
                    this.onLoadObservable.notifyObservers(this);
                }
            }
        }
        else {
            this._texture.isReady = true;
            this._updateInternalTexture();
            if (this.onLoadObservable.hasObservers()) {
                this.onLoadObservable.notifyObservers(this);
            }
        }
    }

    private reset = (): void => {
        if (this._texture == null) {
            return;
        }

        if (!this._displayingPosterTexture) {
            this._texture.dispose();
            this._texture = null;
        }
    }

    /**
     * @hidden Internal method to initiate `update`.
     */
    public _rebuild(): void {
        this.update();
    }

    /**
     * Update Texture in the `auto` mode. Does not do anything if `settings.autoUpdateTexture` is false.
     */
    public update(): void {
        if (!this.autoUpdateTexture) {
            // Expecting user to call `updateTexture` manually
            return;
        }

        this.updateTexture(true);
    }

    /**
     * Update Texture in `manual` mode. Does not do anything if not visible or paused.
     * @param isVisible Visibility state, detected by user using `scene.getActiveMeshes()` or othervise.
     */
    public updateTexture(isVisible: boolean): void {
        if (!isVisible) {
            return;
        }
        if (this.video.paused && this._stillImageCaptured) {
            return;
        }
        this._stillImageCaptured = true;
        this._updateInternalTexture();
    }

    protected _updateInternalTexture = (): void => {
        if (this._texture == null || !this._texture.isReady) {
            return;
        }
        if (this.video.readyState < this.video.HAVE_CURRENT_DATA) {
            return;
        }
        if (this._displayingPosterTexture) {
            return;
        }

        let frameId = this.getScene()!.getFrameId();
        if (this._frameId === frameId) {
            return;
        }

        this._frameId = frameId;

        this._engine.updateVideoTexture(this._texture, this.video, this._invertY);
    }

    /**
     * Change video content. Changing video instance or setting multiple urls (as in constructor) is not supported.
     * @param url New url.
     */
    public updateURL(url: string): void {
        this.video.src = url;
        this._currentSrc = url;
    }

    /**
     * Clones the texture.
     * @returns the cloned texture
     */
    public clone(): VideoTexture {
        return new VideoTexture(this.name,
            this._currentSrc!,
            this.getScene(),
            this._generateMipMaps,
            this.invertY,
            this.samplingMode,
            this._settings);
    }

    /**
     * Dispose the texture and release its associated resources.
     */
    public dispose(): void {
        super.dispose();

        this._currentSrc = null;

        if (this._onUserActionRequestedObservable) {
            this._onUserActionRequestedObservable.clear();
            this._onUserActionRequestedObservable = null;
        }

        this.video.removeEventListener(this._createInternalTextureOnEvent, this._createInternalTexture);
        this.video.removeEventListener("paused", this._updateInternalTexture);
        this.video.removeEventListener("seeked", this._updateInternalTexture);
        this.video.removeEventListener("emptied", this.reset);
        this.video.pause();
    }

    /**
     * Creates a video texture straight from a stream.
     * @param scene Define the scene the texture should be created in
     * @param stream Define the stream the texture should be created from
     * @returns The created video texture as a promise
     */
    public static CreateFromStreamAsync(scene: Scene, stream: MediaStream): Promise<VideoTexture> {
        var video = document.createElement("video");
        video.setAttribute('autoplay', '');
        video.setAttribute('muted', 'true');
        video.setAttribute('playsinline', '');
        video.muted = true;

        if (video.mozSrcObject !== undefined) {
            // hack for Firefox < 19
            video.mozSrcObject = stream;
        } else {
            if (typeof video.srcObject == "object") {
                video.srcObject = stream;
            } else {
                window.URL = window.URL || window.webkitURL || window.mozURL || window.msURL;
                video.src = (window.URL && window.URL.createObjectURL(stream));
            }
        }

        return new Promise<VideoTexture>((resolve) => {
            let onPlaying = () => {
                resolve(new VideoTexture("video", video, scene, true, true));
                video.removeEventListener("playing", onPlaying);
            };

            video.addEventListener("playing", onPlaying);
            video.play();
        });
    }

    /**
     * Creates a video texture straight from your WebCam video feed.
     * @param scene Define the scene the texture should be created in
     * @param constraints Define the constraints to use to create the web cam feed from WebRTC
     * @param audioConstaints Define the audio constraints to use to create the web cam feed from WebRTC
     * @returns The created video texture as a promise
     */
    public static CreateFromWebCamAsync(
        scene: Scene,
        constraints: {
            minWidth: number;
            maxWidth: number;
            minHeight: number;
            maxHeight: number;
            deviceId: string;
        } & MediaTrackConstraints,
        audioConstaints: boolean | MediaTrackConstraints = false
    ): Promise<VideoTexture> {
        var constraintsDeviceId;
        if (constraints && constraints.deviceId) {
            constraintsDeviceId = {
                exact: constraints.deviceId,
            };
        }

        if (navigator.mediaDevices) {
            return navigator.mediaDevices.getUserMedia({
                    video: constraints,
                    audio: audioConstaints
                })
                .then((stream) => {
                    return this.CreateFromStreamAsync(scene, stream);
                });
        }
        else {
            navigator.getUserMedia =
                navigator.getUserMedia ||
                navigator.webkitGetUserMedia ||
                navigator.mozGetUserMedia ||
                navigator.msGetUserMedia;

            if (navigator.getUserMedia) {
                navigator.getUserMedia(
                    {
                        video: {
                            deviceId: constraintsDeviceId,
                            width: {
                                min: (constraints && constraints.minWidth) || 256,
                                max: (constraints && constraints.maxWidth) || 640,
                            },
                            height: {
                                min: (constraints && constraints.minHeight) || 256,
                                max: (constraints && constraints.maxHeight) || 480,
                            },
                        },
                        audio: audioConstaints
                    },
                    (stream: any) => {
                        return this.CreateFromStreamAsync(scene, stream);
                    },
                    function(e: MediaStreamError) {
                        Logger.Error(e.name);
                    }
                );
            }
        }

        return Promise.reject("No support for userMedia on this device");
    }

    /**
     * Creates a video texture straight from your WebCam video feed.
     * @param scene Define the scene the texture should be created in
     * @param onReady Define a callback to triggered once the texture will be ready
     * @param constraints Define the constraints to use to create the web cam feed from WebRTC
     * @param audioConstaints Define the audio constraints to use to create the web cam feed from WebRTC
     */
    public static CreateFromWebCam(
        scene: Scene,
        onReady: (videoTexture: VideoTexture) => void,
        constraints: {
            minWidth: number;
            maxWidth: number;
            minHeight: number;
            maxHeight: number;
            deviceId: string;
        } & MediaTrackConstraints,
        audioConstaints: boolean | MediaTrackConstraints = false
    ): void {
        this.CreateFromWebCamAsync(scene, constraints, audioConstaints)
            .then(function(videoTexture) {
                if (onReady) {
                    onReady(videoTexture);
                }
            })
            .catch(function(err) {
                Logger.Error(err.name);
            });
    }
}