import React = require('react');
import axios from 'axios';
import { action, computed, IReactionDisposer, reaction } from 'mobx';
import { observer } from 'mobx-react';
import Waveform from 'react-audio-waveform';
import { Doc, NumListCast } from '../../fields/Doc';
import { List } from '../../fields/List';
import { listSpec } from '../../fields/Schema';
import { Cast } from '../../fields/Types';
import { numberRange } from '../../Utils';
import './AudioWaveform.scss';
import { Colors } from './global/globalEnums';

/**
 * AudioWaveform
 *
 * Used in CollectionStackedTimeline to render a canvas with a visual of an audio waveform for AudioBox and VideoBox documents.
 * Uses react-audio-waveform package.
 * Bins the audio data into audioBuckets which are passed to package to render the lines.
 * Calculates new buckets each time a new zoom factor or new set of trim bounds is created and stores it in a field on the layout doc with a title indicating the bounds and zoom for that list (see audioBucketField)
 */

export interface AudioWaveformProps {
    duration: number; // length of media clip
    rawDuration: number; // length of underlying media data
    mediaPath: string;
    layoutDoc: Doc;
    clipStart: number;
    clipEnd: number;
    zoomFactor: number;
    PanelHeight: number;
    PanelWidth: number;
    fieldKey: string;
}

@observer
export class AudioWaveform extends React.Component<AudioWaveformProps> {
    public static NUMBER_OF_BUCKETS = 100; // number of buckets data is divided into to draw waveform lines

    _disposer: IReactionDisposer | undefined;

    @computed get waveHeight() {
        return Math.max(50, this.props.PanelHeight);
    }

    @computed get clipStart() {
        return this.props.clipStart;
    }
    @computed get clipEnd() {
        return this.props.clipEnd;
    }
    @computed get zoomFactor() {
        return this.props.zoomFactor;
    }

    @computed get audioBuckets() {
        return NumListCast(this.props.layoutDoc[this.audioBucketField(this.clipStart, this.clipEnd, this.zoomFactor)]);
    }
    audioBucketField = (start: number, end: number, zoomFactor: number) => this.props.fieldKey + '_audioBuckets/' + '/' + start.toFixed(2).replace('.', '_') + '/' + end.toFixed(2).replace('.', '_') + '/' + zoomFactor * 10;

    componentWillUnmount() {
        this._disposer?.();
    }

    componentDidMount() {
        this._disposer = reaction(
            () => ({ clipStart: this.clipStart, clipEnd: this.clipEnd, fieldKey: this.audioBucketField(this.clipStart, this.clipEnd, this.zoomFactor), zoomFactor: this.props.zoomFactor }),
            ({ clipStart, clipEnd, fieldKey, zoomFactor }) => {
                if (!this.props.layoutDoc[fieldKey]) {
                    // setting these values here serves as a "lock" to prevent multiple attempts to create the waveform at nerly the same time.
                    const waveform = Cast(this.props.layoutDoc[this.audioBucketField(0, this.props.rawDuration, 1)], listSpec('number'));
                    this.props.layoutDoc[fieldKey] = waveform && new List<number>(waveform.slice((clipStart / this.props.rawDuration) * waveform.length, (clipEnd / this.props.rawDuration) * waveform.length));
                    setTimeout(() => this.createWaveformBuckets(fieldKey, clipStart, clipEnd, zoomFactor));
                }
            },
            { fireImmediately: true }
        );
    }

    // decodes the audio file into peaks for generating the waveform
    createWaveformBuckets = async (fieldKey: string, clipStart: number, clipEnd: number, zoomFactor: number) => {
        axios({ url: this.props.mediaPath, responseType: 'arraybuffer' }).then(response => {
            const context = new window.AudioContext();
            context.decodeAudioData(
                response.data,
                action(buffer => {
                    const rawDecodedAudioData = buffer.getChannelData(0);
                    const startInd = clipStart / this.props.rawDuration;
                    const endInd = clipEnd / this.props.rawDuration;
                    const decodedAudioData = rawDecodedAudioData.slice(Math.floor(startInd * rawDecodedAudioData.length), Math.floor(endInd * rawDecodedAudioData.length));
                    const numBuckets = Math.floor(AudioWaveform.NUMBER_OF_BUCKETS * zoomFactor);

                    const bucketDataSize = Math.floor(decodedAudioData.length / numBuckets);
                    const brange = Array.from(Array(bucketDataSize));
                    const bucketList = numberRange(numBuckets).map((i: number) => brange.reduce((p, x, j) => Math.abs(Math.max(p, decodedAudioData[i * bucketDataSize + j])), 0) / 2);
                    this.props.layoutDoc[fieldKey] = new List<number>(bucketList);
                })
            );
        });
    };

    render() {
        return (
            <div className="audioWaveform">
                <Waveform color={Colors.MEDIUM_BLUE_ALT} height={this.waveHeight} barWidth={200 / this.audioBuckets.length} pos={this.props.duration} duration={this.props.duration} peaks={Array.from(this.audioBuckets)} progressColor={Colors.MEDIUM_BLUE_ALT} />
            </div>
        );
    }
}