import { IReactionDisposer, observable, observe, reaction } from "mobx";
import { NumCast } from "../../fields/Types";
import { Doc, DocListCast } from "../../fields/Doc";
import { CollectionDockingView } from "../views/collections/CollectionDockingView";
import { Id } from "../../fields/FieldSymbols";

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

export type Presentation = {
    movements: Movement[] | null,
    totalTime: number,
    meta: Object | Object[],
}

export class TrackMovements {

    private static get NULL_PRESENTATION(): Presentation {
        return { movements: null, meta: {}, totalTime: -1, }
    }

    // instance variables
    private currentPresentation: Presentation;
    private tracking: boolean;
    private absoluteStart: number;
    // instance variable for holding the FFViews and their disposers
    private recordingFFViews: Map<string, IReactionDisposer> | null;
    private tabChangeDisposeFunc: IReactionDisposer | null;


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

        // init the instance variables
        this.currentPresentation = TrackMovements.NULL_PRESENTATION
        this.tracking = false;
        this.absoluteStart = -1;

        // used for tracking movements in the view frame
        this.recordingFFViews = null;
        this.tabChangeDisposeFunc = null;
    }

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

    private addRecordingFFView(doc: Doc, key: string = doc[Id]): void {
        // console.info('adding dispose func : docId', key, 'doc', doc);

        if (this.recordingFFViews === null) { console.warn('addFFView on null RecordingApi'); return; }
        if (this.recordingFFViews.has(key)) { console.warn('addFFView : key already in map'); return; }

        const disposeFunc = reaction(
            () => ({ x: NumCast(doc.panX, -1), y: NumCast(doc.panY, -1), scale: NumCast(doc.viewScale, 0)}),
            (res) => (res.x !== -1 && res.y !== -1 && this.tracking) && this.trackMovement(res.x, res.y, key, res.scale),
        );
        this.recordingFFViews?.set(key, disposeFunc);
    }

    private removeRecordingFFView = (key: string) => {
        // console.info('removing dispose func : docId', key);
        if (this.recordingFFViews === null) { console.warn('removeFFView on null RecordingApi'); return; }
        this.recordingFFViews.get(key)?.();
        this.recordingFFViews.delete(key);
    }

    // in the case where only one tab was changed (updates not across dashboards), set only one to true
    private updateRecordingFFViewsFromTabs = (tabbedDocs: Doc[], onlyOne = false) => {
        if (this.recordingFFViews === null) return;

        // so that the size comparisons are correct, we must filter to only the FFViews
        const isFFView = (doc: Doc) => doc && 'viewType' in doc && doc.viewType === 'freeform';
        const tabbedFFViews = new Set<string>();
        for (const DashDoc of tabbedDocs) {
            if (isFFView(DashDoc)) tabbedFFViews.add(DashDoc[Id]);
        }


        // new tab was added - need to add it
        if (tabbedFFViews.size > this.recordingFFViews.size) {
            for (const DashDoc of tabbedDocs) {
                if (!this.recordingFFViews.has(DashDoc[Id])) {
                    if (isFFView(DashDoc)) {
                        this.addRecordingFFView(DashDoc);

                        // only one max change, so return
                        if (onlyOne) return;
                    }
                }
            }
        }
        // tab was removed - need to remove it from recordingFFViews
        else if (tabbedFFViews.size < this.recordingFFViews.size) {
            for (const [key] of this.recordingFFViews) {
                if (!tabbedFFViews.has(key)) { 
                    this.removeRecordingFFView(key);
                    if (onlyOne) return;
                } 
            }
        }
    }

    private initTabTracker = () => {
        if (this.recordingFFViews === null) {
            this.recordingFFViews = new Map();
        }

        // init the dispose funcs on the page
        const docList = DocListCast(CollectionDockingView.Instance.props.Document.data);
        this.updateRecordingFFViewsFromTabs(docList);

        // create a reaction to monitor changes in tabs
        this.tabChangeDisposeFunc =
            reaction(() => CollectionDockingView.Instance.props.Document.data,
                (change) => {
                    // TODO: consider changing between dashboards
                    // console.info('change in tabs', change);
                    this.updateRecordingFFViewsFromTabs(DocListCast(change), true);
                });
    }

    start = (meta?: Object) => {
        this.initTabTracker();

        // 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 tracking true to allow trackMovements
        this.tracking = true
    }

    /* stops the video and returns the presentatation; if no presentation, returns undefined */
    yieldPresentation(clearData: boolean = true): Presentation | null {
        // if no presentation or done tracking, return null
        if (this.nullPresentation || !this.tracking) return null;

        // set the previus recording view to the play view
        // this.playFFView = this.recordingFFView;

        // ensure we add the endTime now that they are done recording    
        const cpy = { ...this.currentPresentation, totalTime: new Date().getTime() - this.absoluteStart };

        // reset the current presentation
        clearData && this.clear();

        // console.info('yieldPresentation', cpy);
        return cpy;
    }

    finish = (): void => {
        // make is tracking false
        this.tracking = false
        // reset the RecordingApi instance
        this.clear();
    }

    private clear = (): void => {
        // clear the disposeFunc if we are done (not tracking)
        if (!this.tracking) {
            this.removeAllRecordingFFViews();
            this.tabChangeDisposeFunc?.();
            // update the presentation mode now that we are done tracking
            Doc.UserDoc().presentationMode = 'none';

            this.recordingFFViews = null;
            this.tabChangeDisposeFunc = null;
        }

        // clear presenation data
        this.currentPresentation = TrackMovements.NULL_PRESENTATION
        // clear absoluteStart
        this.absoluteStart = -1
    }

    removeAllRecordingFFViews = () => {
        if (this.recordingFFViews === null) { console.warn('removeAllFFViews on null RecordingApi'); return; }

        for (const [id, disposeFunc] of this.recordingFFViews) {
            // console.info('calling dispose func : docId', id);
            disposeFunc();
            this.recordingFFViews.delete(id);
        }
    }

    private trackMovement = (panX: number, panY: number, docId: string, scale: number = 0) => {
        // ensure we are recording to track
        if (!this.tracking) {
            console.error('[recordingApi.ts] trackMovements(): tracking is false')
            return;
        }
        // check to see if the presetation is init - if not, we are between segments
        // TODO: make this more clear - tracking should be "live tracking", not always true when the recording api being used (between start and yieldPres)
        // bacuse tracking should be false inbetween segments high key 
        if (this.nullPresentation) {
            console.warn('[recordingApi.ts] trackMovements(): trying to store movemetns between segments')
            return;
        }

        // get the time
        const time = new Date().getTime() - this.absoluteStart
        // make new movement object
        const movement: Movement = { time, panX, panY, scale, docId }

        // add that movement to the current presentation data's movement array
        this.currentPresentation.movements && this.currentPresentation.movements.push(movement)
    }


    // method that concatenates an array of presentatations into one
    public concatPresentations = (presentations: Presentation[]): Presentation => {
        // these three will lead to the combined presentation
        let combinedMovements: Movement[] = [];
        let sumTime = 0;
        let combinedMetas: any[] = [];

        presentations.forEach((presentation) => {
            const { movements, totalTime, meta } = presentation;

            // update movements if they had one
            if (movements) {
                // add the summed time to the movements
                const addedTimeMovements = movements.map(move => { return { ...move, time: move.time + sumTime } });
                // concat the movements already in the combined presentation with these new ones
                combinedMovements.push(...addedTimeMovements);
            }

            // update the totalTime
            sumTime += totalTime;

            // concatenate the metas
            combinedMetas.push(meta);
        });

        // return the combined presentation with the updated total summed time
		return { movements: combinedMovements, totalTime: sumTime, meta: combinedMetas };
    }
}