import { Command } from 'commander';

let _definitions;

let _reverseDefinitions;

let _defaults;

Command.prototype.loadDefinitions = function(definitions) {

_definitions = definitions;

Object.keys(definitions).reduce((program, opt) => {

if (typeof definitions[opt] == "object") {

const additionalOptions = definitions[opt];

if (additionalOptions.required === true) {

return program.option(`--${opt} <${opt}>`, additionalOptions.help, additionalOptions.action);

} else {

return program.option(`--${opt} [${opt}]`, additionalOptions.help, additionalOptions.action);

}

}

return program.option(`--${opt} [${opt}]`);

}, this);

_defaults = Object.keys(definitions).reduce((defs, opt) => {

if(_definitions[opt].default) {

defs[opt] = _definitions[opt].default;

}

return defs;

}, {});

_reverseDefinitions = Object.keys(definitions).reduce((object, key) => {

let value = definitions[key];

if (typeof value == "object") {

value = value.env;

}

if (value) {

object[value] = key;

}

return object;

}, {});

/* istanbul ignore next */

this.on('--help', function(){

console.log(' Configure From Environment:');

console.log('');

Object.keys(_reverseDefinitions).forEach((key) => {

console.log(` $ ${key}='${_reverseDefinitions[key]}'`);

});

console.log('');

});

}

function parseEnvironment(env = {}) {

return Object.keys(_reverseDefinitions).reduce((options, key) => {

if (env[key]) {

const originalKey = _reverseDefinitions[key];

let action = (option) => (option);

if (typeof _definitions[originalKey] === "object") {

action = _definitions[originalKey].action || action;

}

options[_reverseDefinitions[key]] = action(env[key]);

}

return options;

}, {});

}

Command.prototype.setValuesIfNeeded = function(options) {

Object.keys(options).forEach((key) => {

if (!this[key]) {

this[key] = options[key];

}

});

}

Command.prototype._parse = Command.prototype.parse;

Command.prototype.parse = function(args, env) {

this._parse(args);

// Parse the environment first

const envOptions = parseEnvironment(env);

// Load the env if not passed from command line

this.setValuesIfNeeded(envOptions);

this.setValuesIfNeeded(_defaults);

}

export default new Command();