// Variables used by Scriptable.
// These must be at the very top of the file. Do not edit.
// icon-color: blue; icon-glyph: train;
let param = args.widgetParameter;

if (param == null) {
    console.log('Please set the widget parameter.')
    Script.complete();
    return;
}

const scriptName = 'TrainTracker';
const scriptUrl = 'https://raw.githubusercontent.com/froehr/mvg-train-tracker/main/widget.js';

let modulePath = await downloadModule(scriptName, scriptUrl); // jshint ignore:line
if (modulePath != null) {
    let importedModule = importModule(modulePath); // jshint ignore:line
    await importedModule.main(JSON.parse(param)); // jshint ignore:line
} else {
    console.log('Failed to download new module and could not find any local version.');
}

async function downloadModule(scriptName, scriptUrl) {
    // returns path of latest module version which is accessible
    let fm = FileManager.local();
    let scriptPath = module.filename;
    let moduleDir = scriptPath.replace(fm.fileName(scriptPath, true), scriptName);
    if (fm.fileExists(moduleDir) && !fm.isDirectory(moduleDir)) fm.remove(moduleDir);
    if (!fm.fileExists(moduleDir)) fm.createDirectory(moduleDir);
    let dayNumber = Math.floor(Date.now() / 1000 / 60 / 60 / 24);
    let moduleFilename = dayNumber.toString() + '.js';
    let modulePath = fm.joinPath(moduleDir, moduleFilename);
    if (fm.fileExists(modulePath)) {
        console.log('Module already downloaded ' + moduleFilename); 
        return modulePath;
    } else {
        let [moduleFiles, moduleLatestFile] = getModuleVersions(scriptName);
        console.log('Downloading ' + moduleFilename + ' from URL: ' + scriptUrl);
        let req = new Request(scriptUrl);
        let moduleJs = await req.load().catch(() => {
            return null;
        });
        if (moduleJs) {
            fm.write(modulePath, moduleJs);
            if (moduleFiles != null) {
                moduleFiles.map(x => {
                    fm.remove(fm.joinPath(moduleDir, x));
                });
            }
            return modulePath;
        } else {
            console.log('Failed to download new module. Using latest local version: ' + moduleLatestFile);
            return (moduleLatestFile != null) ? fm.joinPath(moduleDir, moduleLatestFile) : null;
        }
    }
}

function getModuleVersions(scriptName) {
    // returns all saved module versions and latest version of them
    let fm = FileManager.local();
    let scriptPath = module.filename;
    let moduleDir = scriptPath.replace(fm.fileName(scriptPath, true), scriptName);
    let dirContents = fm.listContents(moduleDir);
    if (dirContents.length > 0) {
        let versions = dirContents.map(x => {
            if (x.endsWith('.js')) return parseInt(x.replace('.js', ''));
        });
        versions.sort(function(a, b) {
            return b - a;
        });
        versions = versions.filter(Boolean);
        if (versions.length > 0) {
            let moduleFiles = versions.map(x => {
                return x + '.js';
            });
            moduleLatestFile = versions[0] + '.js';
            return [moduleFiles, moduleLatestFile];
        }
    }
    return [null, null];
}