# Program.js

    import GitHubInfo from './GitHubInfo';
    import program from 'commander';
    import { getConfigFromFile } from './_utils.js';

    /** Class creating a Commander program, managing the options passed via bash and config file. */
    class Program {
        constructor(props) {
            const { programOptions, defaults } = this._consumeOptions(props.options);

            this.name = props.name;
            this.description = props.description;
            this.examples = props.examples;
            this.defaults = defaults;
            this.program = this._programWithEvents(this._programWithOptions(program, programOptions), props.events)
                .name(this.name)
                .description(this.description)
                .parse(props.argv);

            this.options = Object.assign({}, getConfigFromFile(props.cwd), this._getOptionsFromObject(this.program, this.defaults));
        }

        /**
         * Initialise the module
         *
         * @since 0.10.0
         * @public
         *
         * @return {Promise}
         */
        init() {
            return this._getEnvOptions()
                .then(options => {
                    this.options = this._filterObject(this._camelCaseObjectKeys(
                        Object.assign(
                            {},
                            this.defaults,
                            Object.assign({}, ...[].concat(options)),
                            this.options
                        )
                    ));

                    return this.options;
                });
        }

        /**
         * Get informations from the local folder
         *
         * @since 0.10.0
         * @private
         *
         * @return {Promise}
         */
        _getEnvOptions() {
            const githubInfo = new GitHubInfo();
            const { username, repo } = this.options;

            if (username && repo) {
                return githubInfo.token;
            }

            return githubInfo.options;
        }

        /**
         * Remove all the properties that have undefined values from an object
         *
         * @since  0.10.0
         * @private
         *
         * @param  {Object} object
         *
         * @return {Object}
         */
        _filterObject(object) {
            return Object.entries(object)
                .filter(([key, value]) => value !== undefined)
                .reduce((carry, [key, value]) => {
                    carry[key] = value;
                    return carry;
                }, {});
        }

        /**
         * Add all the given events to a program
         *
         * @since  0.10.0
         * @private
         *
         * @param  {Commander} program
         * @param  {Object} events
         *
         * @return {Commander}
         */
        _programWithEvents(program, events) {
            if (!events || !events.length) {
                return program;
            }

            Object.entries(events).forEach(([event, action]) => {
                program.on(event, action);
            });

            return program;
        }

        /**
         * Add all the given options to a program
         *
         * @since 0.10.0
         * @private
         *
         * @param  {Commander} program
         * @param  {Array} options
         *
         * @return {Commander}
         */
        _programWithOptions(program, options) {
            options.forEach(({ name, description, action, defaultValue }) => program.option(...[name, description, action, defaultValue].filter(Boolean)));
            return program;
        }

        /**
         * Consume the options from the properties and provide get the defaults and the programOptions
         *
         * @since  0.10.0
         * @private
         *
         * @param  {Array} opts
         *
         * @return {Object}
         */
        _consumeOptions(opts = []) {
            if (!Array.isArray(opts)) {
                return {
                    programOptions: [],
                    defaults: {}
                };
            }

            const programOptions = opts.map(({ short, name, valueType, description, defaultValue, action }) => ({
                name: short && name ? `${short}, --${name} ${valueType || ''}` : ' ',
                description,
                defaultValue,
                action
            }));

            const defaults = this._camelCaseObjectKeys(
                opts.reduce((carry, opt) => {
                    carry[opt.name] = opt.defaultValue;
                    return carry;
                }, {})
            );

            return {
                programOptions,
                defaults
            };
        }

        /**
         * Extrapulate the options from a program
         *
         * @since  0.10.0
         * @private
         *
         * @param  {Object} defaults
         *
         * @return {Object}
         */
        _getOptionsFromObject(object = {}, defaults = {}) {
            if (typeof object !== 'object' || Array.isArray(object)) {
                return {};
            }

            return Object.keys(defaults).reduce((carry, option) => {
                if (object[option]) {
                    carry[option] = object[option];
                }

                return carry;
            }, {});
        }

        /**
         * Converts all Object values to camel case
         *
         * @param  {Object} object
         *
         * @return {Object}
         */
        _camelCaseObjectKeys(object = {}) {
            if (typeof object !== 'object' || Array.isArray(object)) {
                return {};
            }

            return Object.entries(object).reduce((carry, [key, value]) => {
                carry[this._dashToCamelCase(key)] = value;
                return carry;
            }, {});
        }

        /**
        * Transforms a dasherize string into a camel case one.
        *
        * @since 0.3.2
        * @private
        *
        * @param  {string} value The dasherize string
        *
        * @return {string}       The camel case string
        */
        _dashToCamelCase(value = '') {
            if (typeof value !== 'string') {
                return '';
            }

            return value
                .replace(/-([a-z])/g, (match) => match[1].toUpperCase());
        }
    }

    export default Program;