import { mkdir, writeFile } from 'fs'
import { spawn } from 'child_process'
import { v1 as uuidv1 } from 'uuid'

import { getDirPath, getDocPath } from './utils';


function copyToTemp(id: string, texDocument: string): Promise<string> {
    return new Promise((resolve, reject) => {
        const dirPath = getDirPath(id);

        mkdir(dirPath, (err) => {
            if (err) {
                reject(err);
                return;
            }

            const docPath = getDocPath(id);
            writeFile(docPath, texDocument, (err) => {
                if (err) {
                    reject(err);
                }
                resolve(id);
            });
        });
    });
}

function generateDoc(id: string) {
    return new Promise((resolve, reject) => {
        const pdflatex = spawn('pdflatex', ['-interaction', 'nonstopmode', getDocPath(id)], { cwd: getDirPath(id) });
        pdflatex.stderr.on('data', (data) => {
            console.error('onData', data);
        });

        pdflatex.on('close', (code) => {
            if (code > 0) {
                reject(`pdflatex returned with code ${code}`);
                return;
            }
            console.log(`PDF ${id} generated`);
            resolve(id);
        });
    });
}

export default function(texDocument: string) {
    const id = uuidv1();
    return copyToTemp(id, texDocument)
        .then(generateDoc);
};