// requirements
const path = require('path');
const async = require('async');
const fse = require('fs-extra');
const recursive = require('recursive-readdir');
const progress = require('progress');

// create path for target file
function getPathByMetadata(source, output, metadata, callback) {
    // define directory
    let filePath = path.normalize(output);
    if (metadata.albumartist && metadata.albumartist.length > 0) {
        let tmp;
        const artistCount = metadata.albumartist.length;
        for (let counter = 0; counter < artistCount; counter++) {
            if (counter > 0) {
                tmp += ' - ' + metadata.albumartist[counter];
            } else {
                tmp = metadata.albumartist[counter];
            }
        }
        filePath = path.join(filePath, tmp);
    } else {
        filePath = path.join(filePath, metadata.artist[0]);
    }
    if (metadata.album) {
        filePath = path.join(filePath, metadata.album);
    }
    // define filename
    let fileName = '';
    if (metadata.disk.no) {
        fileName += frontFill(metadata.disk.no, '0', 2);
    }
    if (metadata.track.no) {
        if (fileName) {
            fileName += '-' + frontFill(metadata.track.no, '0', 2) + ' ';
        } else {
            fileName += frontFill(metadata.track.no, '0', 2) + ' ';
        }
    }
    if (metadata.artist) {
        fileName += metadata.artist[0] + ' - ';
    }
    if (metadata.title) {
        fileName += metadata.title;
    }
    // append extension
    fileName += path.extname(source);
    // join directory and name
    callback(null, path.join(filePath, fileName));
}

// create target directory and move the file
function moveFile(source, target, callback) {
    async.series([
        function (asyncCallback) {
            fse.mkdirs(path.dirname(target), asyncCallback);
        },
        function (asyncCallback) {
            fse.move(source, target, asyncCallback);
        }
    ], function (err, results) {
        if (err) {
            return callback(err);
        }
        callback();
    });
}

// fill a string beginning from the front
function frontFill(string, fill, length) {
    while (string.toString().length < length) {
        string = fill + string;
    }
    return string;
}

// list files in directory
function readDirRecursive(where, extension, callback) {
    if (extension.indexOf('.') !== 0) {
        extension = '.' + extension;
    }
    recursive(where, [ignoreFilter], callback);
    function ignoreFilter(file, stats) {
        return !stats.isDirectory() && extension.indexOf(path.extname(file)) === -1;
    }
}

// api
exports.getPathByMetadata = getPathByMetadata;
exports.moveFile = moveFile;
exports.frontFill = frontFill;
exports.readDirRecursive = readDirRecursive;