#!/usr/bin/env node

// requirements
const os = require('os');
const path = require('path');
const async = require('async');
const commander = require('commander');
const recursive = require('recursive-readdir');
const app = require('./package.json');
const audio = require('./lib/audio');
const util = require('./lib/util');

// generate timestamp
const start = process.hrtime();

util.printLogo();

// general options
commander
    .version(app.version)
    .usage('[options] <command>')
    .option('-c, --concurrency <n>', 'specify concurrency level', os.cpus().length);

// conversion mode
commander
    .command('convert <input> <output>')
    .description('convert .flac to .mp3 files')
    .option('-b, --bitrate <n>', 'specify conversion bitrate', 320)
    .action(function (input, output, options) {
        console.log('--- CONVERT MODE ---');
        console.log('input: ' + input);
        console.log('output: ' + output);
        console.log('bitrate: ' + commander.options.bitrate);
        console.log('conc: ' + commander.concurrency);
    });

// sort mode
commander
    .command('sort <input> <output>')
    .description('sort audio files by tags')
    .option('-f, --format <type>', 'specify audio format (\'flac\', \'mp3\')', 'flac')
    .action(sort);

// parse command line arguments
commander.parse(process.argv);

// sort files
function sort(input, output, options) {
    const concurrency = commander.concurrency;
    async.waterfall([
        function (asyncCallback) {
            recursive(input, [ignoreFilter], asyncCallback);
        },
        function (files, asyncCallback) {
            console.log(files.length + ' \'' + options.format + '\' files found');
            // display progressbar
            const bar = util.createProgressBar(files.length);
            // handle each file
            async.eachLimit(files, concurrency, function (file, eachCallback) {
                processFileSort(output, file, function (err) {
                    bar.tick();
                    if (err) {
                        return eachCallback(err);
                    }
                    eachCallback();
                });
            }, function (err) {
                if (err) {
                    return asyncCallback(err);
                }
                asyncCallback();
            });
        }
    ], function (err, result) {
        util.exit(err, start);
    });

    function ignoreFilter(file, stats) {
        return !stats.isDirectory() && path.extname(file).indexOf(options.format) == -1;
    }
}

// move file to location defined by its metadata
function processFileSort(output, sourceFile, callback) {
    async.waterfall([
        function (asyncCallback) {
            audio.extractMetadata(sourceFile, asyncCallback)
        },
        function (sourceFile, metadata, asyncCallback) {
            util.pathFromMetadata(sourceFile, output, metadata, asyncCallback);
        },
        function (targetFile, asyncCallback) {
            util.moveFile(sourceFile, targetFile, asyncCallback);
        }
    ], function (err, results) {
        if (err) {
            return callback(err);
        }
        callback(null, results);
    });
}