import {CLIOption} from './CLIOption'

/**
 * Non-positional, flag-based CLI option.
 */
export class FlagOption<T> extends CLIOption<T> {

    constructor(
        /**
         * The long-form flag for this option.
         * @example --path, --create
         */
        public readonly longFlag?: string,
        /**
         * The short-form flag for this option.
         * @example -p, -c
         */
        public readonly shortFlag?: string,
        /**
         * Usage message describing this flag.
         */
        public readonly message?: string,
        /**
         * Description of the argument required by this flag.
         * If this is set, the flag will expect a positional argument to follow as a param.
         */
        public readonly argumentDescription?: string,
    ) {
        super()
    }

    /**
     * Get the referential name for this option.
     * Defaults to the long flag (without the '--'). If this cannot
     * be found, the short flag (without the '-') is used.
     * @returns {string}
     */
    getArgumentName(): string {
        if ( this.longFlag ) {
            return this.longFlag.replace('--', '')
        } else if ( this.shortFlag ) {
            return this.shortFlag.replace('-', '')
        }

        throw new Error('Missing either a long- or short-flag for FlagOption.')
    }
}