export interface ArgEvaluatable {
	enabled(): boolean;
	envs(): EnvVar[];
	binary(): string;
	prefix(): string;
	suffix(): string;
	priority(): number;
	arguments(): Arguments[];
}

export type EnvVar = {
	var: string;
	val: string;
};

export type Arguments = {
	arg: string;
	val: string;
	prio: number;
	/** Fixed value set — renders a dropdown in the UI instead of a text input. */
	values?: string[];
	/** JS regex source the value input must match (HTML pattern attr); empty/cleared always valid. */
	pattern?: string;
};

function compareArgPrio(a: Arguments, b: Arguments) {
	return a.prio - b.prio;
}

export class ArgEval {
	Components: ArgEvaluatable[];

	constructor(components: ArgEvaluatable[]) {
		this.Components = components;
	}

	public eval(): string {
		const active = this.Components.filter((c) => c.enabled());

		const env = active.flatMap((c) => c.envs().map((e) => e.var + '=' + e.val)).join(' ');

		const progs = [...active]
			.sort((a, b) => a.priority() - b.priority())
			.map((c) =>
				[
					c.prefix(),
					c.binary(),
					...c
						.arguments()
						.sort(compareArgPrio)
						.flatMap((a) => (a.val ? `${a.arg} ${a.val}` : a.arg)),
					c.suffix()
				]
					.filter((s) => s !== '')
					.join(' ')
			)
			.filter((s) => s !== '')
			.join(' ');

		return [env, progs, '%command%'].filter((s) => s !== '').join(' ');
	}
}