index.js

'use strict';

// Module dependencies
var _ = require('lodash'),
    fs = require('fs'),
    gm = require('gm'),
    path = require('path');

// Global variables
var EXECUTION_PATH = process.cwd() + path.sep,
    MODULE_PATH = __dirname + path.sep;

// File and directory names
var CONTENTS_JSON = 'Contents.json',
    SUCCESS_BANNER = 'banner.txt',
    HELP_BANNER = 'help.txt',
    ICON_PREFIX = 'Icon-',
    THUMBS_OUTPUT_DIR = 'AppIcon.appiconset';

// File paths
var OUTPUT_DIR_PATH = EXECUTION_PATH + THUMBS_OUTPUT_DIR + path.sep,
    CONTENTS_JSON_OUTPUT_PATH = OUTPUT_DIR_PATH + CONTENTS_JSON,
    CONTENTS_JSON_PATH = MODULE_PATH + CONTENTS_JSON,
    HELP_BANNER_PATH = MODULE_PATH + HELP_BANNER,
    SUCCESS_BANNER_PATH = MODULE_PATH + SUCCESS_BANNER,
    THUMBS_PATH = OUTPUT_DIR_PATH + ICON_PREFIX;

/**
 * Generates all thumbnails.
 */
var generateThumbs = function (baseIconPath) {
    var totalReady = 0,
        sizes = {
            20: [1, 2, 3],
            29: [1, 2, 3],
            40: [1, 2, 3],
            60: [2, 3],
            76: [1, 2],
            '83.5': [2],
            1024: [1]
        };

    var totalImages = _.reduce(sizes, function (memo, num) {
        return memo + num.length;
    }, 0);

    console.log('Creating icons.');
    _.forEach(sizes, function (multipliers, dimension) {
        dimension = parseFloat(dimension);

        _.forEach(multipliers, function (multiplier) {
            var fileName = THUMBS_PATH + dimension,
                size = dimension * multiplier,
                quality = 100;

            fileName += (multiplier > 1 ? ('@' + multiplier + 'x') : '') + '.png';

            gm(baseIconPath).thumb(size, size, fileName, quality, function (err) {
                if (err) {
                    console.error(err);
                    return
                }

                totalReady++;
                (totalImages === totalReady) && success();
            });
        });
    });
};

/**
 * Displays the help banner
 */
var showHelpBanner = function () {
    fs.readFile(HELP_BANNER_PATH, 'utf8', function (err, helpBanner) {
        console.log(err || helpBanner);
    });
};

/**
 * The path to the icon is incorrect.
 */
var baseIconPathDoesNotExist = function () {
    console.error('Please provide a base icon using the --base-icon option.');
};

/**
 * Creates the directory to house all icons.
 * @param baseIconPath
 */
var outputPathDoesNotExist = function (baseIconPath) {
    console.log('Creating output directory.');

    fs.mkdir(OUTPUT_DIR_PATH, function (err) {
        if (err) {
            console.error(err);
            return;
        }

        fs.readdir(OUTPUT_DIR_PATH, function (error) {
            if (error) {
                console.error(error);
                return;
            }

            generateThumbs(baseIconPath);
        });
    });
};

/**
 * Called upon successfully creating all thumbnails.
 */
var success = function () {
    fs.readFile(SUCCESS_BANNER_PATH, 'utf8', function (err, successBanner) {
        if (!err) {
            console.log(successBanner);
            fs.createReadStream(CONTENTS_JSON_PATH)
                .pipe(fs.createWriteStream(CONTENTS_JSON_OUTPUT_PATH));
        } else {
            console.log(err);
        }
    });
};

/**
 * Script entry point.
 * Verifies base icon path and output dir paths exist and
 * shows either the help banner or calls generateThumbs.
 */
var init = function (args) {
    var baseIconPath = args.iconPath,
        helpFlag = args.helpFlag;

    if (helpFlag || !baseIconPath) {
        showHelpBanner();
        return;
    }

    fs.exists(baseIconPath, function (exists) {
        if (!exists) {
            baseIconPathDoesNotExist();
            return;
        }

        fs.readdir(OUTPUT_DIR_PATH, function (err) {
            if (!err) {
                generateThumbs(baseIconPath);
                return;
            }

            var directoryDoesNotExist = _.includes([-2, 34], err.errno);
            if (directoryDoesNotExist) {
                outputPathDoesNotExist(baseIconPath);
                return;
            }

            console.error('Unable to compute', err);
        });
    });
};

module.exports = init;