import * as Promise from 'bluebird'

import ChecksumCalculator from '../src/ChecksumCalculator'
import CobaltFilesHandler from '../src/CobaltFilesHandler'
import PresentationFileChecksums from '../src/PresentationFileChecksums'
import PresentationFileDiff from '../src/PresentationFileDiff'

export default class PresentationChecksums {
    constructor(private checksumCalculator: ChecksumCalculator, private cobaltFilesHandler: CobaltFilesHandler) {}

    public findDiff(dir: string): Promise<PresentationFileDiff> {
        return this.getChecksums(dir)
            .then(this.makeDiff);
    }

    public getChecksums(dir: string): Promise<ChecksumsParams> {
        return Promise.all([
            this.calculateFilesChecksums(dir),
            this.readChecksums()
        ]).then(([currentChecksums, previousChecksums]) => ({
            previousChecksums,
            currentChecksums
        }))
    }

    public calculateFilesChecksums(dir: string): Promise<PresentationFileChecksums> {
        return this.checksumCalculator.calculate(dir);
    }

    public saveChecksums(checksums: PresentationFileChecksums): Promise<void> {
        return this.cobaltFilesHandler.saveChecksums(checksums);
    }

    public createChecksums(dir: string) {
        return this.calculateFilesChecksums(dir)
            .then((checksums) => this.saveChecksums(checksums))
    }

    private readChecksums(): Promise<PresentationFileChecksums> {
        return this.cobaltFilesHandler.readChecksums();
    }

    public makeDiff(checksums: ChecksumsParams): PresentationFileDiff {
        const { previousChecksums, currentChecksums } = checksums;

        return previousChecksums.makeDiff(currentChecksums);
    }
}

class ChecksumsParams {
    public previousChecksums: PresentationFileChecksums;
    public currentChecksums: PresentationFileChecksums;
}