import { expandWithIterations } from '../run/iterations';

describe('expandWithIterations', () => {
	type Item = { file: string; scen: string; iter?: number };
	const tag = (item: Item, iter: number): Item => ({ ...item, iter });
	const getFile = (item: Item): string => item.file;

	it('round-robins across files in the first round', () => {
		const items: Item[] = [
			{ file: 'A', scen: '1' },
			{ file: 'A', scen: '2' },
			{ file: 'B', scen: '1' },
			{ file: 'C', scen: '1' },
		];
		const out = [...expandWithIterations(items, getFile, 1, tag)];
		// Round 1 yields one scenario per file in insertion order, then round 2 picks up A's second scenario.
		expect(out.map((x) => `${x.file}.${x.scen}`)).toEqual(['A.1', 'B.1', 'C.1', 'A.2']);
	});

	it('iter-interleaves per scenario before moving on', () => {
		const items: Item[] = [
			{ file: 'A', scen: '1' },
			{ file: 'B', scen: '1' },
		];
		const out = [...expandWithIterations(items, getFile, 3, tag)];
		expect(out.map((x) => `${x.file}.${x.scen}.${String(x.iter)}`)).toEqual([
			'A.1.0',
			'A.1.1',
			'A.1.2',
			'B.1.0',
			'B.1.1',
			'B.1.2',
		]);
	});

	it('skips files that ran out of scenarios in later rounds', () => {
		const items: Item[] = [
			{ file: 'A', scen: '1' },
			{ file: 'A', scen: '2' },
			{ file: 'B', scen: '1' },
		];
		const out = [...expandWithIterations(items, getFile, 1, tag)];
		// Round 1: A.1, B.1. Round 2: A.2 (B has no second scenario, skipped).
		expect(out.map((x) => `${x.file}.${x.scen}`)).toEqual(['A.1', 'B.1', 'A.2']);
	});

	it('yields nothing for empty input', () => {
		expect([...expandWithIterations<Item>([], getFile, 3, tag)]).toEqual([]);
	});

	it('yields nothing when iterations is 0', () => {
		const items: Item[] = [{ file: 'A', scen: '1' }];
		expect([...expandWithIterations(items, getFile, 0, tag)]).toEqual([]);
	});

	it('first wave covers all files after enough items pulled', () => {
		const items: Item[] = [];
		for (const f of ['A', 'B', 'C', 'D', 'E']) {
			for (const s of ['1', '2', '3']) items.push({ file: f, scen: s });
		}
		const out = [...expandWithIterations(items, getFile, 3, tag)];
		// Total: 5 files × 3 scenarios × 3 iters = 45 yielded items.
		expect(out).toHaveLength(45);
		// First 5×3 = 15 items cover one scenario per file × all 3 iterations.
		const firstWave = out.slice(0, 15).map((x) => x.file);
		expect(new Set(firstWave)).toEqual(new Set(['A', 'B', 'C', 'D', 'E']));
	});
});