Show time since done or lateness instead of the last-done date

1 files changed, 64 insertions, 0 deletions

diff --git a/src/lib/shared/routine-metrics.test.ts b/src/lib/shared/routine-metrics.test.ts
index 88d0498..7f4d656 100644
--- a/src/lib/shared/routine-metrics.test.ts
+++ b/src/lib/shared/routine-metrics.test.ts
@@ -4,6 +4,7 @@ import {
 	computeHealthScore,
 	computeHealthSeries,
 	computeProjectHealthSeries,
+	formatDoneAge,
 	type HealthPoint,
 } from './routine-metrics';
 const CREATED = '2026-09-01T00:00:00.000Z';
@@ -240,6 +241,69 @@ describe('computeRoutineState (quota)', () => {
 	});
 });
 
+describe('daysSinceDone', () => {
+	it('is null when the routine was never done', () => {
+		const state = computeRoutineState(routine, [], plusDays(created, 3));
+		expect(state.daysSinceDone).toBeNull();
+	});
+
+	it('counts whole UTC calendar days since the last completion', () => {
+		const state = computeRoutineState(
+			routine,
+			[{ routineId: 1, doneAt: '2026-09-07T20:00:00.000Z' }],
+			Temporal.Instant.from('2026-09-10T08:00:00.000Z'),
+		);
+		expect(state.daysSinceDone).toBe(3); // not 2: calendar days, not 24h chunks
+	});
+
+	it('is 0 for a completion earlier the same calendar day', () => {
+		const state = computeRoutineState(
+			routine,
+			[{ routineId: 1, doneAt: '2026-09-10T08:00:00.000Z' }],
+			Temporal.Instant.from('2026-09-10T20:00:00.000Z'),
+		);
+		expect(state.daysSinceDone).toBe(0);
+	});
+
+	it('clamps a future-dated completion to 0', () => {
+		const state = computeRoutineState(
+			routine,
+			[{ routineId: 1, doneAt: '2026-09-12T08:00:00.000Z' }],
+			Temporal.Instant.from('2026-09-10T20:00:00.000Z'),
+		);
+		expect(state.daysSinceDone).toBe(0);
+	});
+});
+
+describe('formatDoneAge', () => {
+	it('shows the lateness once a day past due, even when never done', () => {
+		expect(formatDoneAge({ daysSinceDone: null, overdueDays: 3 })).toBe(
+			'3 jours de retard',
+		);
+		expect(formatDoneAge({ daysSinceDone: 10, overdueDays: 1 })).toBe(
+			'1 jour de retard',
+		);
+		expect(formatDoneAge({ daysSinceDone: 10, overdueDays: 3 })).toBe(
+			'3 jours de retard',
+		);
+	});
+
+	it('shows the time since done while the deadline is still ahead', () => {
+		expect(formatDoneAge({ daysSinceDone: null, overdueDays: 0 })).toBe(
+			'jamais fait',
+		);
+		expect(formatDoneAge({ daysSinceDone: 0, overdueDays: 0 })).toBe(
+			"fait aujourd'hui",
+		);
+		expect(formatDoneAge({ daysSinceDone: 1, overdueDays: 0 })).toBe(
+			'fait hier',
+		);
+		expect(formatDoneAge({ daysSinceDone: 5, overdueDays: 0 })).toBe(
+			'fait il y a 5 jours',
+		);
+	});
+});
+
 describe('computeHealthSeries', () => {
 	it('decays from 100 at creation to 0 two periods overdue when never done', () => {
 		const now = plusDays(created, 22);