import { createFFmpeg, FFmpeg } from '@ffmpeg/ffmpeg';
import { CustomError } from 'utils/common/errorUtil';
import { logError } from 'utils/sentry';
import QueueProcessor from './upload/queueProcessor';
import { getUint8ArrayView } from './upload/readFileService';

class FFmpegService {
    private ffmpeg: FFmpeg = null;
    private isLoading = null;

    private generateThumbnailProcessor = new QueueProcessor<Uint8Array>(1);
    async init() {
        try {
            this.ffmpeg = createFFmpeg({
                ...(!process.env.NEXT_PUBLIC_SENTRY_ENV && {
                    corePath: '/js/ffmpeg/ffmpeg-core.js',
                }),
            });
            this.isLoading = this.ffmpeg.load();
            await this.isLoading;
            this.isLoading = null;
        } catch (e) {
            logError(e, 'ffmpeg load failed');
            throw e;
        }
    }

    async generateThumbnail(file: File) {
        if (!this.ffmpeg) {
            await this.init();
        }
        if (this.isLoading) {
            await this.isLoading;
        }
        const response = this.generateThumbnailProcessor.queueUpRequest(
            generateThumbnailHelper.bind(null, this.ffmpeg, file)
        );

        const thumbnail = await response.promise;
        if (!thumbnail) {
            throw Error(CustomError.THUMBNAIL_GENERATION_FAILED);
        }
        return thumbnail;
    }
}

async function generateThumbnailHelper(ffmpeg: FFmpeg, file: File) {
    try {
        ffmpeg.FS(
            'writeFile',
            file.name,
            await getUint8ArrayView(new FileReader(), file)
        );

        await ffmpeg.run(
            '-i',
            file.name,
            '-ss',
            '00:00:01.000',
            '-vframes',
            '1',
            'thumb.png'
        );
        const thumb = ffmpeg.FS('readFile', 'thumb.png');
        ffmpeg.FS('unlink', 'thumb.png');
        ffmpeg.FS('unlink', file.name);
        return thumb;
    } catch (e) {
        logError(e, 'ffmpeg thumbnail generation failed');
        throw e;
    }
}

export default new FFmpegService();