var fs = require('fs');
var chalk = require('chalk');

/**
 * File IO, error reporting.
 */
module.exports = {
    /**
     *
     */
    read: function(file) {
        return new Promise(function(resolve) {
            fs.readFile(file, 'utf8', function(err, str) {
                console.log('Read ' + file);
                module.exports.error(err);
                resolve(str || '');
            });
        });
    },

    /**
     *
     */
    write: function(file, str) {
        return new Promise(function(resolve) {
            if (str) {
                fs.writeFile(file, str, module.exports.error, resolve);
                console.log('Write ' + file);
            }
            else {
                resolve();
            }
        });
    },

    /**
     *
     */
    error: function(e) {
        if (e !== null) {
            // Gotcha: Promise.all() will not execute unless all promises are resolved.
            // http://stackoverflow.com/questions/28250680/
            console.log(chalk.yellow(e));
        }
    }
};