path: root/src/client/util/RecordingApi.ts

import { CollectionFreeFormView } from "../views/collections/collectionFreeForm";
import { IReactionDisposer, observable, reaction } from "mobx";
import { NumCast } from "../../fields/Types";
import { Doc } from "../../fields/Doc";
import { VideoBox } from "../views/nodes/VideoBox";
import { scaleDiverging } from "d3-scale";
import { Transform } from "./Transform";

type Movement = {
    time: number,
    panX: number,
    panY: number,
    scale: number,
}

type Presentation = {
    movements: Array<Movement> | null
    meta: Object,
}

export class RecordingApi {

    private static NULL_PRESENTATION: Presentation = {
        movements: null,
        meta: {},
    }

    // instance variables
    private currentPresentation: Presentation;
    private isRecording: boolean;
    private absoluteStart: number;


    // create static instance and getter for global use
    @observable static _instance: RecordingApi;
    public static get Instance(): RecordingApi { return RecordingApi._instance }
    public constructor() {
        // init the global instance
        RecordingApi._instance = this;

        // init the instance variables
        this.currentPresentation = RecordingApi.NULL_PRESENTATION
        this.isRecording = false;
        this.absoluteStart = -1;

        // used for tracking movements in the view frame
        this.disposeFunc = null;
        this.recordingFFView = null;

        // for now, set playFFView
        this.playFFView = null;
        this.timers = null;
    }

    // little helper :)
    private get isInitPresenation(): boolean {
        return this.currentPresentation.movements === null
    }

    public start = (meta?: Object): Error | undefined => {
        // check if already init a presentation
        if (!this.isInitPresenation) {
            console.error('[recordingApi.ts] start() failed: current presentation data exists. please call clear() first.')
            return new Error('[recordingApi.ts] start()')
        }

        // update the presentation mode
        Doc.UserDoc().presentationMode = 'recording'

        // (1a) get start date for presenation
        const startDate = new Date()
        // (1b) set start timestamp to absolute timestamp
        this.absoluteStart = startDate.getTime()

        // (2) assign meta content if it exists
        this.currentPresentation.meta = meta || {}
        // (3) assign start date to currentPresenation
        this.currentPresentation.movements = []
        // (4) set isRecording true to allow trackMovements
        this.isRecording = true
    }

    public clear = (): Error | Presentation => {
        // TODO: maybe archive the data?
        if (this.isRecording) {
            console.error('[recordingApi.ts] clear() failed: currently recording presentation. call pause() first')
            return new Error('[recordingApi.ts] clear()')
        }

        // update the presentation mode
        Doc.UserDoc().presentationMode = 'none'
        // set the previus recording view to the play view
        this.playFFView = this.recordingFFView

        const presCopy = { ...this.currentPresentation }

        // clear presenation data
        this.currentPresentation = RecordingApi.NULL_PRESENTATION
        // clear isRecording
        this.isRecording = false
        // clear absoluteStart
        this.absoluteStart = -1
        // clear the disposeFunc
        this.removeRecordingFFView()

        return presCopy;
    }

    public pause = (): Error | undefined => {
        if (this.isInitPresenation) {
            console.error('[recordingApi.ts] pause() failed: no presentation started. try calling init() first')
            return new Error('[recordingApi.ts] pause(): no presentation')
        }
        // don't allow track movments
        this.isRecording = false

        // set adjust absoluteStart to add the time difference
        const timestamp = new Date().getTime()
        this.absoluteStart = timestamp - this.absoluteStart
    }

    public resume = () => {
        this.isRecording = true
        // set absoluteStart to the difference in time
        this.absoluteStart = new Date().getTime() - this.absoluteStart
    }

    private trackMovements = (panX: number, panY: number, scale: number = 0): Error | undefined => {
        // ensure we are recording
        if (!this.isRecording) {
            return new Error('[recordingApi.ts] trackMovements()')
        }
        // check to see if the presetation is init
        if (this.isInitPresenation) {
            return new Error('[recordingApi.ts] trackMovements(): no presentation')
        }

        // get the time
        const time = new Date().getTime() - this.absoluteStart
        // make new movement object
        const movement: Movement = { time, panX, panY, scale }
        
        // add that movement to the current presentation data's movement array
        this.currentPresentation.movements && this.currentPresentation.movements.push(movement)
    }

    // instance variable for the FFView
    private disposeFunc: IReactionDisposer | null;
    private recordingFFView: CollectionFreeFormView | null;
    
    // set the FFView that will be used in a reaction to track the movements
    public setRecordingFFView = (view: CollectionFreeFormView): void => {
        // set the view to the current view
        if (view === this.recordingFFView || view == null) return;
        
        // this.recordingFFView = view;
        // set the reaction to track the movements
        this.disposeFunc = reaction(
            () => ({ x: NumCast(view.Document.panX, -1), y: NumCast(view.Document.panY, -1), scale: NumCast(view.Document.viewScale, -1) }),
            (res) => (res.x !== -1 && res.y !== -1 && this.isRecording) && this.trackMovements(res.x, res.y, res.scale)
        )

        // for now, set the most recent recordingFFView to the playFFView
        this.recordingFFView = view;
    }

    // call on dispose function to stop tracking movements
    public removeRecordingFFView = (): void => {
        this.disposeFunc?.();
        this.disposeFunc = null;
    }

    // TODO: extract this into different class with pause and resume recording
    // TODO: store the FFview with the movements
    private playFFView: CollectionFreeFormView | null;
    private timers: NodeJS.Timeout[] | null;

    public setPlayFFView = (view: CollectionFreeFormView): void => {
        this.playFFView = view
    }

    // pausing movements will dispose all timers that are planned to replay the movements
    // play movemvents will recreate them when the user resumes the presentation
    public pauseMovements = (): undefined | Error => {
        if (this.playFFView === null) {
            return new Error('[recordingApi.ts] pauseMovements() failed: no view')
        }

        if (!this._isPlaying) {
            //return new Error('[recordingApi.ts] pauseMovements() failed: not playing')
            return
        }
        this._isPlaying = false
        // TODO: set userdoc presentMode to browsing
        this.timers?.map(timer => clearTimeout(timer))

        // this.videoBox = null;
    }
    
    private videoBox: VideoBox | null = null;

    // by calling pause on the VideoBox, the pauseMovements will be called
    public pauseVideoAndMovements = (): boolean => {
        this.videoBox?.Pause()

        this.pauseMovements()
        return this.videoBox == null
    }

    public _isPlaying = false;

    public playMovements = (presentation: Presentation, timeViewed: number = 0, videoBox?: VideoBox): undefined | Error => {
        if (presentation.movements === null || this.playFFView === null) {
            return new Error('[recordingApi.ts] followMovements() failed: no presentation data or no view')
        }
        if(this._isPlaying) return;

        this._isPlaying = true;
        Doc.UserDoc().presentationMode = 'watching';

        // TODO: consider this bug at the end of the clip on seek
        this.videoBox = videoBox || null;

        // only get the movements that are remaining in the video time left
        const filteredMovements = presentation.movements.filter(movement => movement.time > timeViewed * 1000)

        // helper to replay a movement
        const document = this.playFFView
        let preScale = -1;
        const zoomAndPan = (movement: Movement) => {
            const { panX, panY, scale } = movement;
            (scale !== -1 && preScale !== scale) && document.zoomSmoothlyAboutPt([panX, panY], scale, 0);
            document.Document._panX = panX;
            document.Document._panY = panY;

            preScale = scale;
        }

        // set the first frame to be at the start of the pres
        zoomAndPan(filteredMovements[0]);

        // make timers that will execute each movement at the correct replay time
        this.timers = filteredMovements.map(movement => {
            const timeDiff = movement.time - timeViewed*1000
            return setTimeout(() => {
                // replay the movement
                zoomAndPan(movement)
                // if last movement, presentation is done -> set the instance var
                if (movement === filteredMovements[filteredMovements.length - 1]) RecordingApi.Instance._isPlaying = false;
            }, timeDiff)
        })
    }

    // Unfinished code for tracing multiple free form views
    // export let pres: Map<CollectionFreeFormView, IReactionDisposer> = new Map()

    // export function AddRecordingFFView(ffView: CollectionFreeFormView): void {
    //     pres.set(ffView,
    //          reaction(() => ({ x: ffView.panX, y: ffView.panY }),
    //     (pt) => RecordingApi.trackMovements(ffView, pt.x, pt.y)))
    //     )
    // }

    // export function RemoveRecordingFFView(ffView: CollectionFreeFormView): void {
    //     const disposer = pres.get(ffView);
    //     disposer?.();
    //     pres.delete(ffView)
    // }
}