import { strlen, truncate } from './utils.ts';
import { getRuntime, importForRuntime } from './runtime.ts';

class Buffer {
	#b = '';

	constructor() {
	}

	public append(s: string, maxLen?: number): void {
		this.#b += (maxLen === undefined) ? s : truncate(s, maxLen);
	}

	public appendLine(s = ''): void {
		this.#b += s + '\r\n';
	}

	public clear(): void {
		this.#b = '';
	}

	/**
	 * Output the contents of the buffer into stdout
	 */
	public async flush() {
		const term = await importForRuntime('terminal_io');
		await term.writeStdout(this.#b);
		this.clear();
	}

	public strlen(): number {
		return strlen(this.#b);
	}
}

export default Buffer;