import { describe, test, expect } from 'bun:test';
import { deriveSegments, countSegments } from '$lib/server/stats/segments';
import { SETTINGS_DEFAULTS, type PlayerState, type StatsSettings } from '$lib/types/stats';
import { addDays } from '$lib/server/stats/dates';

const AS_OF = '2026-09-15';

function settings(overrides: Partial<StatsSettings> = {}): StatsSettings {
	return { ...SETTINGS_DEFAULTS, ...overrides };
}

function player(id: string, overrides: Partial<PlayerState>): PlayerState {
	return {
		id,
		firstDate: addDays(AS_OF, -100),
		lastDate: AS_OF,
		totalPlays: 10,
		plays7: 2,
		plays30: 10,
		streak: 2,
		...overrides
	};
}

const players: PlayerState[] = [
	player('new', { firstDate: addDays(AS_OF, -1), lastDate: AS_OF, plays7: 1 }),
	player('core', { lastDate: AS_OF, plays7: 5 }),
	player('resurrected', { lastDate: AS_OF, plays7: 2, plays30: 2 }),
	player('returning', { lastDate: AS_OF, plays7: 2, plays30: 10 }),
	player('atRisk', { lastDate: addDays(AS_OF, -10) }),
	player('churned', { lastDate: addDays(AS_OF, -40) })
];

describe('deriveSegments', () => {
	test('classifies each lifecycle segment', () => {
		const sets = deriveSegments(players, AS_OF, settings());
		expect(sets.new).toEqual(['new']);
		expect(sets.core).toEqual(['core']);
		expect(sets.resurrected).toEqual(['resurrected']);
		expect(sets.returning).toEqual(['returning']);
		expect(sets.atRisk).toEqual(['atRisk']);
		expect(sets.churned).toEqual(['churned']);
		expect(sets.active).toEqual(['new', 'core', 'resurrected', 'returning']);
	});

	test('changing the core threshold re-segments without new data', () => {
		const strict = deriveSegments(players, AS_OF, settings({ core_plays_per_week: 6 }));
		expect(strict.core).toEqual([]);
		expect(strict.returning).toContain('core');

		const lenient = deriveSegments(players, AS_OF, settings({ core_plays_per_week: 2 }));
		expect(lenient.core).toContain('core');
		expect(lenient.core).toContain('returning');
	});

	test('counts include every player exactly once across mutually exclusive sets', () => {
		const counts = countSegments(deriveSegments(players, AS_OF, settings()));
		const activeTotal = counts.new + counts.core + counts.returning + counts.resurrected;
		expect(activeTotal).toBe(counts.active);
		expect(counts.total).toBe(players.length);
	});

	test('at-risk and churned boundaries follow settings', () => {
		const sets = deriveSegments(players, AS_OF, settings({ at_risk_days: 5, churn_days: 20 }));
		expect(sets.atRisk).toContain('atRisk'); // inactive 10 >= 5, < 20
		expect(sets.churned).toContain('churned'); // inactive 40 >= 20
	});
});