/**
 * Compact test reporter: silent on pass, prints failures + final summary.
 * Usage: --test-reporter=./scripts/test-reporter-compact.mjs
 */
import { Transform } from "node:stream";

export default class CompactReporter extends Transform {
	#pass = 0;
	#fail = 0;
	#skip = 0;
	#failures = [];

	constructor() {
		super({ objectMode: true });
	}

	_transform(event, _enc, cb) {
		switch (event.type) {
			case "test:pass":
				if (!event.data.skip) this.#pass++;
				else this.#skip++;
				break;
			case "test:fail": {
				this.#fail++;
				const { name, details } = event.data;
				const err = details?.error;
				const msg = err?.message ?? String(err ?? "unknown");
				const loc = err?.cause?.stack?.split("\n")[1]?.trim() ?? "";
				this.#failures.push(
					`  ✖ ${name}\n    ${msg}${loc ? `\n    ${loc}` : ""}`,
				);
				break;
			}
		}
		cb();
	}

	_flush(cb) {
		if (this.#failures.length) {
			this.push(`\n✖ failing tests:\n${this.#failures.join("\n\n")}\n`);
		}
		const status = this.#fail === 0 ? "✔" : "✖";
		this.push(
			`\n${status} ${this.#pass} passed, ${this.#fail} failed, ${this.#skip} skipped\n`,
		);
		cb();
	}
}