/* Copyright IBM Corp. 2017 */
import { Options } from './../options';
import { Command } from './command';
import { CreateLayoutCommand } from './create.layout.command';
import { EmptyCommand } from './empty';
import { CreateReactCommand } from './create.react.command';
import { CreateVueCommand } from './create.vue.command';

interface CommandConstructor {
    new(opts: Options): Command;
}

interface CommandByType {
    [type: string]: CommandConstructor;
}

interface Commands {
    [cmd: string]: CommandByType;
}

function _register(aCommand: string, aType: string, aConstructor: CommandConstructor, aMap: Commands): void {
    // types
    const byType = aMap[aCommand] || (aMap[aCommand] = {});
    byType[aType] = aConstructor;
}

export class CommandFactory {

    private commands: Commands = {};

    constructor() {
        const cmd = this.commands;
        _register(CreateReactCommand.COMMAND, CreateReactCommand.TYPE, CreateReactCommand, cmd);
        _register(CreateVueCommand.COMMAND, CreateVueCommand.TYPE, CreateVueCommand, cmd);
        // for eric's testing workflow
        _register(CreateLayoutCommand.COMMAND, CreateLayoutCommand.TYPE, CreateLayoutCommand, cmd);
    }

    create(options: Options): Command {
        // get the type
        const cmd = options.command || 'help';
        const type = options.commandType || 'help';
        // lookup
        const byType = this.commands[cmd] || {};
        const creator: CommandConstructor = byType[type] || EmptyCommand;
        // construct the command
        return new creator(options);
    }
}