import '../../initPathAlias';

import { ApplicantSessionSummary, SessionManifestData } from '@/examtools/actions/applicant';
import { generateManifestPdf } from '@/lib/examForms/ManifestForm';
import { ExamData, Form605Data } from '@/lib/examForms/SharedTypes';
import { remoteMethod, remoteStream } from '@/lib/nats/types';
import { createDocument } from '@/lib/pdf/pdflib';
import { VECList } from '@shared/licenseInfo';
import * as form605 from '@/lib/examForms/form605generator';
import * as csce from '@/lib/examForms/formCSCEgenerator';
import * as examResults from "@/lib/results/generatePdfLib";
import stream from 'stream';
import { WorkerService } from '@/lib/nats/WorkerService';

export interface PDFRenderManifestDoc {
    type: 'manifest';
    data: SessionManifestData;
}
export interface PDFRenderCSCEDoc {
    type: 'csce';
    vec: VECList;
    applicant: ApplicantSessionSummary;
    session: ExamData;
    isDraft: boolean;
}
export interface PDFRender605Doc {
    type: '605';
    vec: VECList;
    data: Form605Data;
}
export interface PDFRenderExamResultsDoc {
    type: 'examResults';
    results: examResults.ResultDocument[];
    passCopies: number;
    failCopies: number;
}

export type PDFRenderDoc = PDFRenderManifestDoc | PDFRenderCSCEDoc | PDFRender605Doc | PDFRenderExamResultsDoc;

// NATS-capable email service
class PDFService {
    @remoteStream({})
    makePDF(pages: PDFRenderDoc[]): stream.Readable {
        const outStream = new stream.Readable({
            read() {}, // There is no way to pause the stream, so we just ignore this
            // readableObjectMode: true,
            // writableObjectMode: true,
            // objectMode: true,
        });

        (async () => {
            const pdfDoc = await createDocument();

            for (const page of pages) {
                switch (page.type) {
                    case 'manifest':
                        await generateManifestPdf(page.data, pdfDoc);
                        break;
                    case 'csce':
                        await csce.renderToPdf(page.vec, page.applicant, page.session, page.isDraft, pdfDoc);
                        break;
                    case '605':
                        await form605.renderToPdf([page.data], page.vec, pdfDoc);
                        break;
                    case 'examResults':
                        await examResults.generateResultsPdf(pdfDoc, page.results, page.passCopies, page.failCopies);
                        break;
                    default:
                        throw new Error(`Unknown PDFRenderDoc type ${(<any>page).type}`);
                }
            }

            const savedBytes = await pdfDoc.save();
            outStream.push(savedBytes);
            outStream.push(null);
        })().catch((err) => {
            outStream.emit('error', err);
        });

        return outStream;
    }
}

const service = new PDFService();
WorkerService.createOnWorkerThread(service);

export default service;