first pass analytics redo

tests/stats-segments.test.ts

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+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
+	});
+});