fix: correct dose ID generation for empty takenBy arrays (#105)

The takenBy field is a string[]. Empty arrays [] are truthy in JavaScript,
causing d.takenBy ? [...] patterns to generate dose IDs with trailing
hyphens (e.g., '5-0-173...-') instead of base IDs ('5-0-173...').

This mismatch between ID generation and computeMissedPastDoseIds (which
correctly uses .length > 0) caused doses to always appear as missed.

Changes:
- Add expandDoseIds() helper function using correct .length > 0 check
- Replace 8 buggy inline patterns in DashboardPage.tsx
- Refactor SchedulePage.tsx to use shared expandDoseIds()
- Add backend startup repair to strip trailing hyphens from existing IDs
- Add 12 new tests (6 frontend + 6 backend)

.github/workflows/update-test-badges.yml

@@ -1,6 +1,7 @@
 name: Update Test Badges
 
 on:
+  workflow_dispatch:
   push:
     branches: [main]
     paths:
@@ -47,8 +48,9 @@ jobs:
         run: |
           OUTPUT=$(npm run test:run 2>&1) || true
           echo "$OUTPUT"
-          # Extract "Tests  X passed" from output
-          PASSED=$(echo "$OUTPUT" | grep -oP 'Tests\s+\K\d+(?=\s+passed)' | tail -1)
+          # Strip ANSI escape codes, then extract "Tests  X passed" from output
+          CLEAN=$(echo "$OUTPUT" | sed 's/\x1b\[[0-9;]*m//g')
+          PASSED=$(echo "$CLEAN" | grep -oP 'Tests\s+\K\d+(?=\s+passed)' | tail -1)
           echo "count=$PASSED" >> $GITHUB_OUTPUT
 
       - name: Run frontend tests and capture count
@@ -60,8 +62,9 @@ jobs:
         run: |
           OUTPUT=$(npm run test:run 2>&1) || true
           echo "$OUTPUT"
-          # Extract "Tests  X passed" from output
-          PASSED=$(echo "$OUTPUT" | grep -oP 'Tests\s+\K\d+(?=\s+passed)' | tail -1)
+          # Strip ANSI escape codes, then extract "Tests  X passed" from output
+          CLEAN=$(echo "$OUTPUT" | sed 's/\x1b\[[0-9;]*m//g')
+          PASSED=$(echo "$CLEAN" | grep -oP 'Tests\s+\K\d+(?=\s+passed)' | tail -1)
           echo "count=$PASSED" >> $GITHUB_OUTPUT
 
       - name: Update README badges

backend/src/db/client.ts

@@ -5,6 +5,7 @@ import { type Client, createClient } from "@libsql/client";
 import dotenv from "dotenv";
 import { drizzle } from "drizzle-orm/libsql";
 import { migrate } from "drizzle-orm/libsql/migrator";
+import { parseIntakesJson, parseLocalDateTime } from "../utils/scheduler-utils.js";
 
 dotenv.config({ path: process.env.DOTENV_PATH || ".env" });
 
@@ -158,6 +159,165 @@ export async function ensureDefaultUser(client: Client, authEnabled: boolean): P
 	}
 }
 
+// =============================================================================
+// Startup repair: fix orphaned dose tracking IDs from past schedule changes
+// =============================================================================
+
+const MS_PER_DAY = 86_400_000;
+
+/**
+ * Repair dose IDs that have a trailing hyphen caused by a frontend bug where
+ * `[].toString()` produced an empty string, resulting in IDs like "5-0-1729123200000-"
+ * instead of "5-0-1729123200000". This strips trailing hyphens from all dose IDs.
+ *
+ * This function is idempotent - safe to run on every startup.
+ */
+export async function repairTrailingHyphenDoseIds(client: Client): Promise<{ repaired: number; errors: string[] }> {
+	const errors: string[] = [];
+	let repaired = 0;
+
+	try {
+		const result = await client.execute(
+			"UPDATE dose_tracking SET dose_id = RTRIM(dose_id, '-') WHERE dose_id LIKE '%-'"
+		);
+		repaired = result.rowsAffected;
+	} catch (e: any) {
+		errors.push(`Trailing-hyphen repair failed: ${e.message}`);
+	}
+
+	return { repaired, errors };
+}
+
+/**
+ * Repair orphaned dose tracking IDs that no longer match the current intake schedule.
+ * This fixes dose IDs that became invalid when a medication's schedule was changed
+ * BEFORE the on-edit migration (PR #103) was introduced.
+ *
+ * For each medication, generates all valid schedule dateOnlyMs values from each intake's
+ * start date up to today, then checks all dose_tracking entries. Any dose whose timestamp
+ * doesn't match a valid schedule date is remapped to the nearest valid date.
+ *
+ * This function is idempotent - safe to run on every startup.
+ */
+export async function repairOrphanedDoseIds(client: Client): Promise<{ repaired: number; errors: string[] }> {
+	const errors: string[] = [];
+	let repaired = 0;
+
+	try {
+		// Get all medications
+		const medsResult = await client.execute(
+			"SELECT id, intakes_json, usage_json, every_json, start_json, intake_reminders_enabled FROM medications"
+		);
+
+		if (medsResult.rows.length === 0) return { repaired, errors };
+
+		// Get all dose tracking entries
+		const dosesResult = await client.execute("SELECT id, dose_id FROM dose_tracking");
+		if (dosesResult.rows.length === 0) return { repaired, errors };
+
+		// Build a map of medId → dose entries for quick lookup
+		const dosesByMed = new Map<number, Array<{ id: number; doseId: string }>>();
+		for (const row of dosesResult.rows) {
+			const doseId = row.dose_id as string;
+			const parts = doseId.split("-");
+			if (parts.length < 3) continue;
+			const medId = parseInt(parts[0], 10);
+			if (Number.isNaN(medId)) continue;
+			if (!dosesByMed.has(medId)) dosesByMed.set(medId, []);
+			dosesByMed.get(medId)!.push({ id: row.id as number, doseId });
+		}
+
+		const now = new Date();
+		const today = new Date(now.getFullYear(), now.getMonth(), now.getDate());
+
+		for (const med of medsResult.rows) {
+			const medId = med.id as number;
+			const medDoses = dosesByMed.get(medId);
+			if (!medDoses || medDoses.length === 0) continue;
+
+			// Parse intakes
+			const intakes = parseIntakesJson(
+				med.intakes_json as string | null,
+				{
+					usageJson: (med.usage_json as string) || "[]",
+					everyJson: (med.every_json as string) || "[]",
+					startJson: (med.start_json as string) || "[]",
+				},
+				(med.intake_reminders_enabled as number) === 1
+			);
+
+			if (intakes.length === 0) continue;
+
+			// For each intake index, build the set of valid dateOnlyMs values
+			const validDatesByIntake = new Map<number, Set<number>>();
+			for (let idx = 0; idx < intakes.length; idx++) {
+				const intake = intakes[idx];
+				const start = parseLocalDateTime(intake.start);
+				const every = intake.every;
+				if (every <= 0 || Number.isNaN(start.getTime())) continue;
+
+				const validDates = new Set<number>();
+				for (let d = new Date(start); d <= today; d.setDate(d.getDate() + every)) {
+					validDates.add(new Date(d.getFullYear(), d.getMonth(), d.getDate()).getTime());
+				}
+				validDatesByIntake.set(idx, validDates);
+			}
+
+			// Check each dose entry
+			for (const dose of medDoses) {
+				const parts = dose.doseId.split("-");
+				if (parts.length < 3) continue;
+
+				const intakeIdx = parseInt(parts[1], 10);
+				const dateOnlyMs = parseInt(parts[2], 10);
+				if (Number.isNaN(intakeIdx) || Number.isNaN(dateOnlyMs)) continue;
+
+				const validDates = validDatesByIntake.get(intakeIdx);
+				if (!validDates) continue; // Unknown intake index - skip
+
+				// Check if this dose's timestamp is valid
+				if (validDates.has(dateOnlyMs)) continue; // Already valid - nothing to do
+
+				// Orphaned dose - find the nearest valid schedule date
+				const intake = intakes[intakeIdx];
+				if (!intake) continue;
+
+				const halfInterval = (intake.every * MS_PER_DAY) / 2;
+				let bestMatch: number | null = null;
+				let bestDist = Infinity;
+
+				for (const validDate of validDates) {
+					const dist = Math.abs(validDate - dateOnlyMs);
+					if (dist < bestDist && dist <= halfInterval) {
+						bestDist = dist;
+						bestMatch = validDate;
+					}
+				}
+
+				if (bestMatch !== null) {
+					// Rebuild dose ID with new timestamp, preserving person suffix
+					const personSuffix = parts.length > 3 ? `-${parts.slice(3).join("-")}` : "";
+					const newDoseId = `${medId}-${intakeIdx}-${bestMatch}${personSuffix}`;
+
+					try {
+						await client.execute({
+							sql: "UPDATE dose_tracking SET dose_id = ? WHERE id = ?",
+							args: [newDoseId, dose.id],
+						});
+						repaired++;
+					} catch (e: any) {
+						errors.push(`Failed to repair dose ${dose.id}: ${e.message}`);
+					}
+				}
+			}
+		}
+	} catch (e: any) {
+		errors.push(`Repair failed: ${e.message}`);
+	}
+
+	return { repaired, errors };
+}
+
 // =============================================================================
 // Database initialization (runs on import)
 // =============================================================================
@@ -218,6 +378,24 @@ async function runMigrations() {
 	}
 	console.log(`[DB] Tables verified/created`);
 
+	// Repair dose IDs with trailing hyphens (from frontend takenBy bug)
+	const trailingResult = await repairTrailingHyphenDoseIds(client);
+	if (trailingResult.repaired > 0) {
+		console.log(`[DB] Repaired ${trailingResult.repaired} dose IDs with trailing hyphens`);
+	}
+	if (trailingResult.errors.length > 0) {
+		trailingResult.errors.forEach((err) => console.error(`[DB] Trailing-hyphen repair error:`, err));
+	}
+
+	// Repair orphaned dose tracking IDs from past schedule changes
+	const repairResult = await repairOrphanedDoseIds(client);
+	if (repairResult.repaired > 0) {
+		console.log(`[DB] Repaired ${repairResult.repaired} orphaned dose tracking IDs`);
+	}
+	if (repairResult.errors.length > 0) {
+		repairResult.errors.forEach((err) => console.error(`[DB] Dose repair error:`, err));
+	}
+
 	// If auth is disabled, ensure a default user exists (ID=1)
 	const authEnabled = process.env.AUTH_ENABLED === "true";
 	const created = await ensureDefaultUser(client, authEnabled);

backend/src/routes/medications.ts

@@ -312,29 +312,122 @@ export async function medicationRoutes(app: FastifyInstance) {
 
 		if (!result.length) return reply.notFound();
 
-		// Clean up dose tracking entries that are before the earliest start date
-		// This ensures consistency when the user changes the start date
-		const earliestStart = Math.min(...intakes.map((b) => parseLocalDateTime(b.start).getTime()));
-		if (!Number.isNaN(earliestStart)) {
-			// Get all dose tracking entries for this medication and filter out invalid ones
-			const allDoses = await db
-				.select()
-				.from(doseTracking)
-				.where(and(eq(doseTracking.userId, userId), like(doseTracking.doseId, `${idNum}-%`)));
+		// ---------------------------------------------------------------
+		// Migrate dose tracking IDs when intake schedule changes
+		// ---------------------------------------------------------------
+		// Parse old intakes from the existing medication row
+		const oldIntakes = parseIntakesJson(
+			existing.intakesJson,
+			{ usageJson: existing.usageJson, everyJson: existing.everyJson, startJson: existing.startJson },
+			existing.intakeRemindersEnabled
+		);
 
-			// Find doses with timestamps before the earliest start date
-			const dosesToDelete = allDoses.filter((dose) => {
-				const parts = dose.doseId.split("-");
-				if (parts.length >= 3) {
-					const timestamp = parseInt(parts[2], 10);
-					return !Number.isNaN(timestamp) && timestamp < earliestStart;
+		// Get all dose tracking entries for this medication
+		const allDoses = await db
+			.select()
+			.from(doseTracking)
+			.where(and(eq(doseTracking.userId, userId), like(doseTracking.doseId, `${idNum}-%`)));
+
+		if (allDoses.length > 0) {
+			// Build migration map: for each intake index, map old dateOnlyMs → new dateOnlyMs
+			const now = new Date();
+			const migrationEnd = new Date(now.getFullYear(), now.getMonth(), now.getDate());
+			const MS_PER_DAY = 86_400_000;
+
+			for (let idx = 0; idx < Math.max(oldIntakes.length, intakes.length); idx++) {
+				const oldIntake = oldIntakes[idx];
+				const newIntake = intakes[idx];
+
+				// Skip if this intake index doesn't exist in both old and new
+				if (!oldIntake || !newIntake) continue;
+
+				const oldStart = parseLocalDateTime(oldIntake.start);
+				const newStart = parseLocalDateTime(newIntake.start);
+				const oldEvery = oldIntake.every;
+				const newEvery = newIntake.every;
+
+				// Check if start date or interval changed (time-of-day changes don't matter for dateOnlyMs)
+				const oldStartDateOnly = new Date(oldStart.getFullYear(), oldStart.getMonth(), oldStart.getDate()).getTime();
+				const newStartDateOnly = new Date(newStart.getFullYear(), newStart.getMonth(), newStart.getDate()).getTime();
+
+				if (oldStartDateOnly === newStartDateOnly && oldEvery === newEvery) {
+					continue; // No schedule change that affects dose IDs
 				}
-				return false;
-			});
 
-			// Delete invalid doses
-			for (const dose of dosesToDelete) {
-				await db.delete(doseTracking).where(eq(doseTracking.id, dose.id));
+				// Build set of new valid dateOnlyMs values for this intake
+				const newDates = new Set<number>();
+				for (let d = new Date(newStart); d <= migrationEnd; d.setDate(d.getDate() + newEvery)) {
+					newDates.add(new Date(d.getFullYear(), d.getMonth(), d.getDate()).getTime());
+				}
+
+				// Build set of old dateOnlyMs values with mapping to nearest new date
+				const oldToNewMap = new Map<number, number>();
+				for (let d = new Date(oldStart); d <= migrationEnd; d.setDate(d.getDate() + oldEvery)) {
+					const oldDateMs = new Date(d.getFullYear(), d.getMonth(), d.getDate()).getTime();
+					// Find the closest new date within ±(newEvery/2) days
+					const halfInterval = (newEvery * MS_PER_DAY) / 2;
+					let bestMatch: number | null = null;
+					let bestDist = Infinity;
+					for (const newDateMs of newDates) {
+						const dist = Math.abs(newDateMs - oldDateMs);
+						if (dist < bestDist && dist <= halfInterval) {
+							bestDist = dist;
+							bestMatch = newDateMs;
+						}
+					}
+					if (bestMatch !== null && bestMatch !== oldDateMs) {
+						oldToNewMap.set(oldDateMs, bestMatch);
+						// Remove matched new date to prevent double-mapping
+						newDates.delete(bestMatch);
+					}
+				}
+
+				// Apply migrations to dose tracking entries
+				if (oldToNewMap.size > 0) {
+					const prefix = `${idNum}-${idx}-`;
+					const dosesToMigrate = allDoses.filter((d) => d.doseId.startsWith(prefix));
+
+					for (const dose of dosesToMigrate) {
+						const parts = dose.doseId.split("-");
+						if (parts.length >= 3) {
+							const oldTimestamp = parseInt(parts[2], 10);
+							const newTimestamp = oldToNewMap.get(oldTimestamp);
+							if (newTimestamp !== undefined) {
+								// Replace the timestamp in the dose ID, keeping any person suffix
+								const newDoseId = `${idNum}-${idx}-${newTimestamp}${parts.length > 3 ? `-${parts.slice(3).join("-")}` : ""}`;
+								await db.update(doseTracking).set({ doseId: newDoseId }).where(eq(doseTracking.id, dose.id));
+							}
+						}
+					}
+				}
+			}
+
+			// Also clean up dose tracking entries before the earliest new start date
+			const earliestStartDate = intakes.reduce((min, b) => {
+				const d = parseLocalDateTime(b.start);
+				// Use date-only (midnight) to match dose ID format
+				const dateOnly = new Date(d.getFullYear(), d.getMonth(), d.getDate()).getTime();
+				return dateOnly < min ? dateOnly : min;
+			}, Infinity);
+			if (!Number.isNaN(earliestStartDate)) {
+				// Re-fetch after possible migrations
+				const updatedDoses = await db
+					.select()
+					.from(doseTracking)
+					.where(and(eq(doseTracking.userId, userId), like(doseTracking.doseId, `${idNum}-%`)));
+
+				const dosesToDelete = updatedDoses.filter((dose) => {
+					const parts = dose.doseId.split("-");
+					if (parts.length >= 3) {
+						const timestamp = parseInt(parts[2], 10);
+						return !Number.isNaN(timestamp) && timestamp < earliestStartDate;
+					}
+					return false;
+				});
+
+				for (const dose of dosesToDelete) {
+					await db.delete(doseTracking).where(eq(doseTracking.id, dose.id));
+				}
 			}
 		}
 

backend/src/test/database.test.ts

@@ -13,6 +13,8 @@ import {
 	ensureDataDirectory,
 	ensureDefaultUser,
 	getDbPaths,
+	repairOrphanedDoseIds,
+	repairTrailingHyphenDoseIds,
 	runAlterMigrations,
 	runDrizzleMigrations,
 } from "../db/client.js";
@@ -620,4 +622,373 @@ describe("Database Client", () => {
 			expect(users.rows).toHaveLength(1);
 		});
 	});
+
+	describe("repairOrphanedDoseIds", () => {
+		let client: ReturnType<typeof createClient>;
+
+		beforeEach(async () => {
+			client = createClient({ url: ":memory:" });
+			const db = drizzle(client);
+			await migrate(db, { migrationsFolder });
+			// Create a test user
+			await client.execute("INSERT INTO users (id, username, auth_provider) VALUES (1, 'testuser', 'local')");
+		});
+
+		it("should return 0 repairs when no data exists", async () => {
+			const result = await repairOrphanedDoseIds(client);
+			expect(result.repaired).toBe(0);
+			expect(result.errors).toHaveLength(0);
+		});
+
+		it("should not modify dose IDs that already match the current schedule", async () => {
+			// Create weekly medication starting Oct 17 (Friday)
+			const intakes = JSON.stringify([
+				{ usage: 1, every: 7, start: "2025-10-17T08:00:00", takenBy: null, intakeRemindersEnabled: false },
+			]);
+			await client.execute({
+				sql: `INSERT INTO medications (id, user_id, name, intakes_json, usage_json, every_json, start_json)
+				      VALUES (1, 1, 'Weekly Med', ?, '[1]', '[7]', '["2025-10-17T08:00:00"]')`,
+				args: [intakes],
+			});
+
+			// Insert dose IDs that match the schedule (Fridays)
+			const fri17 = new Date(2025, 9, 17).getTime();
+			const fri24 = new Date(2025, 9, 24).getTime();
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${fri17}`],
+			});
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${fri24}`],
+			});
+
+			const result = await repairOrphanedDoseIds(client);
+			expect(result.repaired).toBe(0);
+
+			// Verify IDs unchanged
+			const doses = await client.execute("SELECT dose_id FROM dose_tracking ORDER BY dose_id");
+			expect(doses.rows[0].dose_id).toBe(`1-0-${fri17}`);
+			expect(doses.rows[1].dose_id).toBe(`1-0-${fri24}`);
+		});
+
+		it("should repair orphaned dose IDs when schedule shifted by 1 day", async () => {
+			// Current schedule: Saturdays (Oct 18)
+			const intakes = JSON.stringify([
+				{ usage: 1, every: 7, start: "2025-10-18T08:00:00", takenBy: null, intakeRemindersEnabled: false },
+			]);
+			await client.execute({
+				sql: `INSERT INTO medications (id, user_id, name, intakes_json, usage_json, every_json, start_json)
+				      VALUES (1, 1, 'Weekly Med', ?, '[1]', '[7]', '["2025-10-18T08:00:00"]')`,
+				args: [intakes],
+			});
+
+			// Insert orphaned dose IDs from OLD schedule (Fridays)
+			const fri17 = new Date(2025, 9, 17).getTime();
+			const fri24 = new Date(2025, 9, 24).getTime();
+			const fri31 = new Date(2025, 9, 31).getTime();
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${fri17}`],
+			});
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${fri24}`],
+			});
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${fri31}`],
+			});
+
+			const result = await repairOrphanedDoseIds(client);
+			expect(result.repaired).toBe(3);
+			expect(result.errors).toHaveLength(0);
+
+			// Verify dose IDs are now Saturdays
+			const sat18 = new Date(2025, 9, 18).getTime();
+			const sat25 = new Date(2025, 9, 25).getTime();
+			const nov1 = new Date(2025, 10, 1).getTime();
+
+			const doses = await client.execute("SELECT dose_id FROM dose_tracking ORDER BY dose_id");
+			const ids = doses.rows.map((r) => r.dose_id);
+			expect(ids).toContain(`1-0-${sat18}`);
+			expect(ids).toContain(`1-0-${sat25}`);
+			expect(ids).toContain(`1-0-${nov1}`);
+		});
+
+		it("should preserve person suffix when repairing dose IDs", async () => {
+			// Current schedule: Saturdays
+			const intakes = JSON.stringify([
+				{ usage: 1, every: 7, start: "2025-10-18T08:00:00", takenBy: "Alice", intakeRemindersEnabled: false },
+			]);
+			await client.execute({
+				sql: `INSERT INTO medications (id, user_id, name, intakes_json, usage_json, every_json, start_json)
+				      VALUES (1, 1, 'Person Med', ?, '[1]', '[7]', '["2025-10-18T08:00:00"]')`,
+				args: [intakes],
+			});
+
+			// Orphaned dose with person suffix (from old Friday schedule)
+			const fri17 = new Date(2025, 9, 17).getTime();
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${fri17}-Alice`],
+			});
+
+			const result = await repairOrphanedDoseIds(client);
+			expect(result.repaired).toBe(1);
+
+			// Verify person suffix preserved
+			const sat18 = new Date(2025, 9, 18).getTime();
+			const doses = await client.execute("SELECT dose_id FROM dose_tracking");
+			expect(doses.rows[0].dose_id).toBe(`1-0-${sat18}-Alice`);
+		});
+
+		it("should not repair doses that are too far from any valid schedule date", async () => {
+			// Current schedule: biweekly (every 14 days) starting Oct 18
+			// halfInterval = 7 days, so doses more than 7 days from any valid date won't match
+			const intakes = JSON.stringify([
+				{ usage: 1, every: 14, start: "2025-10-18T08:00:00", takenBy: null, intakeRemindersEnabled: false },
+			]);
+			await client.execute({
+				sql: `INSERT INTO medications (id, user_id, name, intakes_json, usage_json, every_json, start_json)
+				      VALUES (1, 1, 'Biweekly Med', ?, '[1]', '[14]', '["2025-10-18T08:00:00"]')`,
+				args: [intakes],
+			});
+
+			// Insert dose on Oct 27 (9 days away from Oct 18, 4 days away from Nov 1)
+			// halfInterval = 7 days. Oct 27 is 9 days from Oct 18 (too far) and 4 days from Nov 1 (within range)
+			// Actually use Oct 26 which is 8 days from both (Oct 18 and Nov 1) - exactly at halfInterval + 1
+			// Wait: biweekly = Oct 18, Nov 1. Oct 26 is 8 days from Oct 18, 6 days from Nov 1 → 6 < 7, matches Nov 1
+			// Use Oct 25: 7 days from Oct 18, 7 days from Nov 1 → exactly at boundary. Use Oct 25 and check.
+			// The condition is dist <= halfInterval, so 7 <= 7 is true. Need dist > 7.
+			// Use a 28-day schedule instead: Oct 18, Nov 15. Midpoint is Nov 1-2. Nov 2 is 15 days from Oct 18, 13 from Nov 15. Both > 14. No match.
+			const intakes28 = JSON.stringify([
+				{ usage: 1, every: 28, start: "2025-10-18T08:00:00", takenBy: null, intakeRemindersEnabled: false },
+			]);
+			await client.execute({
+				sql: `UPDATE medications SET intakes_json = ?, every_json = '[28]' WHERE id = 1`,
+				args: [intakes28],
+			});
+
+			// Insert dose on Nov 2 (15 days from Oct 18, 13 days from Nov 15)
+			// halfInterval = 14 days. Both 15 > 14 and 13 < 14, so Nov 2 actually WOULD map to Nov 15.
+			// Use Nov 4: 17 days from Oct 18, 11 days from Nov 15 → 11 < 14, maps to Nov 15.
+			// For a 28-day interval, halfInterval = 14. A date must be > 14 days from ALL schedule dates.
+			// Between Oct 18 and Nov 15 (28 days), the only date > 14 from both is impossible.
+			// So lets use a gap: Oct 18 is the only past date for a monthly schedule.
+			// If we pick a date before Oct 18, like Oct 1 (17 days before Oct 18) → 17 > 14 → no match!
+			const oct1 = new Date(2025, 9, 1).getTime();
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${oct1}`],
+			});
+
+			const result = await repairOrphanedDoseIds(client);
+			expect(result.repaired).toBe(0);
+
+			// Dose should remain unchanged
+			const doses = await client.execute("SELECT dose_id FROM dose_tracking");
+			expect(doses.rows[0].dose_id).toBe(`1-0-${oct1}`);
+		});
+
+		it("should be idempotent - running twice produces same result", async () => {
+			// Current schedule: Saturdays
+			const intakes = JSON.stringify([
+				{ usage: 1, every: 7, start: "2025-10-18T08:00:00", takenBy: null, intakeRemindersEnabled: false },
+			]);
+			await client.execute({
+				sql: `INSERT INTO medications (id, user_id, name, intakes_json, usage_json, every_json, start_json)
+				      VALUES (1, 1, 'Weekly Med', ?, '[1]', '[7]', '["2025-10-18T08:00:00"]')`,
+				args: [intakes],
+			});
+
+			// Insert orphaned dose from Friday
+			const fri17 = new Date(2025, 9, 17).getTime();
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${fri17}`],
+			});
+
+			// First run
+			const result1 = await repairOrphanedDoseIds(client);
+			expect(result1.repaired).toBe(1);
+
+			// Second run - should find 0 repairs (already fixed)
+			const result2 = await repairOrphanedDoseIds(client);
+			expect(result2.repaired).toBe(0);
+
+			// Verify final state
+			const sat18 = new Date(2025, 9, 18).getTime();
+			const doses = await client.execute("SELECT dose_id FROM dose_tracking");
+			expect(doses.rows).toHaveLength(1);
+			expect(doses.rows[0].dose_id).toBe(`1-0-${sat18}`);
+		});
+
+		it("should handle multiple medications independently", async () => {
+			// Med 1: weekly Saturdays
+			const intakes1 = JSON.stringify([
+				{ usage: 1, every: 7, start: "2025-10-18T08:00:00", takenBy: null, intakeRemindersEnabled: false },
+			]);
+			await client.execute({
+				sql: `INSERT INTO medications (id, user_id, name, intakes_json, usage_json, every_json, start_json)
+				      VALUES (1, 1, 'Med 1', ?, '[1]', '[7]', '["2025-10-18T08:00:00"]')`,
+				args: [intakes1],
+			});
+
+			// Med 2: daily starting Oct 20 (valid IDs, no repair needed)
+			const intakes2 = JSON.stringify([
+				{ usage: 1, every: 1, start: "2025-10-20T08:00:00", takenBy: null, intakeRemindersEnabled: false },
+			]);
+			await client.execute({
+				sql: `INSERT INTO medications (id, user_id, name, intakes_json, usage_json, every_json, start_json)
+				      VALUES (2, 1, 'Med 2', ?, '[1]', '[1]', '["2025-10-20T08:00:00"]')`,
+				args: [intakes2],
+			});
+
+			// Med 1: orphaned Friday dose
+			const fri17 = new Date(2025, 9, 17).getTime();
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${fri17}`],
+			});
+
+			// Med 2: valid daily dose
+			const oct20 = new Date(2025, 9, 20).getTime();
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`2-0-${oct20}`],
+			});
+
+			const result = await repairOrphanedDoseIds(client);
+			expect(result.repaired).toBe(1); // Only med 1 dose repaired
+
+			// Med 2 dose should be unchanged
+			const med2Doses = await client.execute("SELECT dose_id FROM dose_tracking WHERE dose_id LIKE '2-%'");
+			expect(med2Doses.rows[0].dose_id).toBe(`2-0-${oct20}`);
+		});
+
+		it("should handle legacy format (no intakes_json, uses usage/every/start arrays)", async () => {
+			// Medication with only legacy fields (intakes_json is '[]')
+			await client.execute({
+				sql: `INSERT INTO medications (id, user_id, name, intakes_json, usage_json, every_json, start_json)
+				      VALUES (1, 1, 'Legacy Med', '[]', '[1]', '[7]', '["2025-10-18T08:00:00"]')`,
+				args: [],
+			});
+
+			// Orphaned Friday dose
+			const fri17 = new Date(2025, 9, 17).getTime();
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${fri17}`],
+			});
+
+			const result = await repairOrphanedDoseIds(client);
+			expect(result.repaired).toBe(1);
+
+			// Verify mapped to Saturday
+			const sat18 = new Date(2025, 9, 18).getTime();
+			const doses = await client.execute("SELECT dose_id FROM dose_tracking");
+			expect(doses.rows[0].dose_id).toBe(`1-0-${sat18}`);
+		});
+	});
+
+	describe("repairTrailingHyphenDoseIds", () => {
+		let client: ReturnType<typeof createClient>;
+
+		beforeEach(async () => {
+			client = createClient({ url: ":memory:" });
+			const db = drizzle(client);
+			await migrate(db, { migrationsFolder });
+			await client.execute("INSERT INTO users (id, username, auth_provider) VALUES (1, 'testuser', 'local')");
+		});
+
+		it("should return 0 repairs when no dose IDs have trailing hyphens", async () => {
+			const ts = new Date(2025, 9, 17).getTime();
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${ts}`],
+			});
+
+			const result = await repairTrailingHyphenDoseIds(client);
+			expect(result.repaired).toBe(0);
+			expect(result.errors).toHaveLength(0);
+		});
+
+		it("should strip trailing hyphen from dose IDs", async () => {
+			const ts = new Date(2025, 9, 17).getTime();
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${ts}-`],
+			});
+
+			const result = await repairTrailingHyphenDoseIds(client);
+			expect(result.repaired).toBe(1);
+			expect(result.errors).toHaveLength(0);
+
+			const doses = await client.execute("SELECT dose_id FROM dose_tracking");
+			expect(doses.rows[0].dose_id).toBe(`1-0-${ts}`);
+		});
+
+		it("should not modify dose IDs with valid person suffixes", async () => {
+			const ts = new Date(2025, 9, 17).getTime();
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${ts}-Alice`],
+			});
+
+			const result = await repairTrailingHyphenDoseIds(client);
+			expect(result.repaired).toBe(0);
+
+			const doses = await client.execute("SELECT dose_id FROM dose_tracking");
+			expect(doses.rows[0].dose_id).toBe(`1-0-${ts}-Alice`);
+		});
+
+		it("should handle multiple trailing hyphens", async () => {
+			const ts = new Date(2025, 9, 17).getTime();
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${ts}--`],
+			});
+
+			const result = await repairTrailingHyphenDoseIds(client);
+			expect(result.repaired).toBe(1);
+
+			const doses = await client.execute("SELECT dose_id FROM dose_tracking");
+			expect(doses.rows[0].dose_id).toBe(`1-0-${ts}`);
+		});
+
+		it("should repair multiple affected rows at once", async () => {
+			const ts1 = new Date(2025, 9, 17).getTime();
+			const ts2 = new Date(2025, 9, 24).getTime();
+			const ts3 = new Date(2025, 9, 31).getTime();
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?), (1, ?), (1, ?)",
+				args: [`1-0-${ts1}-`, `2-0-${ts2}-`, `1-0-${ts3}`],
+			});
+
+			const result = await repairTrailingHyphenDoseIds(client);
+			expect(result.repaired).toBe(2); // Only 2 had trailing hyphens
+			expect(result.errors).toHaveLength(0);
+
+			const doses = await client.execute("SELECT dose_id FROM dose_tracking ORDER BY dose_id");
+			const ids = doses.rows.map((r) => r.dose_id);
+			expect(ids).toContain(`1-0-${ts1}`);
+			expect(ids).toContain(`2-0-${ts2}`);
+			expect(ids).toContain(`1-0-${ts3}`);
+		});
+
+		it("should be idempotent - running twice has no effect the second time", async () => {
+			const ts = new Date(2025, 9, 17).getTime();
+			await client.execute({
+				sql: "INSERT INTO dose_tracking (user_id, dose_id) VALUES (1, ?)",
+				args: [`1-0-${ts}-`],
+			});
+
+			const result1 = await repairTrailingHyphenDoseIds(client);
+			expect(result1.repaired).toBe(1);
+
+			const result2 = await repairTrailingHyphenDoseIds(client);
+			expect(result2.repaired).toBe(0);
+		});
+	});
 });

backend/src/test/integration.test.ts

@@ -365,6 +365,196 @@ describe("Integration Tests", () => {
 		});
 	});
 
+	// ---------------------------------------------------------------------------
+	// Dose ID Migration on Schedule Changes
+	// ---------------------------------------------------------------------------
+
+	describe("Dose ID migration when schedule changes", () => {
+		it("should migrate dose IDs when weekly start day changes", async () => {
+			// Create a weekly medication starting Friday Oct 17
+			const createRes = await app.inject({
+				method: "POST",
+				url: "/medications",
+				payload: {
+					name: "Weekly Med",
+					blisters: [{ usage: 1, every: 7, start: "2025-10-17T08:00:00" }],
+				},
+			});
+			const medId = createRes.json().id;
+
+			// Mark doses for Fridays (Oct 17, Oct 24, Oct 31)
+			const fri17 = new Date(2025, 9, 17).getTime(); // Oct 17
+			const fri24 = new Date(2025, 9, 24).getTime(); // Oct 24
+			const fri31 = new Date(2025, 9, 31).getTime(); // Oct 31
+
+			for (const ts of [fri17, fri24, fri31]) {
+				await app.inject({
+					method: "POST",
+					url: "/doses/taken",
+					payload: { doseId: `${medId}-0-${ts}` },
+				});
+			}
+
+			// Verify 3 doses exist
+			const before = await testClient.execute({
+				sql: `SELECT COUNT(*) as count FROM dose_tracking WHERE dose_id LIKE ?`,
+				args: [`${medId}-%`],
+			});
+			expect(before.rows[0].count).toBe(3);
+
+			// Change start to Saturday Oct 18 (shifts all future and past IDs)
+			await app.inject({
+				method: "PUT",
+				url: `/medications/${medId}`,
+				payload: {
+					name: "Weekly Med",
+					blisters: [{ usage: 1, every: 7, start: "2025-10-18T08:00:00" }],
+				},
+			});
+
+			// Doses should be migrated to Saturday dates
+			const sat18 = new Date(2025, 9, 18).getTime(); // Oct 18
+			const sat25 = new Date(2025, 9, 25).getTime(); // Oct 25
+			const nov1 = new Date(2025, 10, 1).getTime(); // Nov 1
+
+			const after = await testClient.execute({
+				sql: `SELECT dose_id FROM dose_tracking WHERE dose_id LIKE ? ORDER BY dose_id`,
+				args: [`${medId}-%`],
+			});
+			expect(after.rows.length).toBe(3);
+			const ids = after.rows.map((r: { dose_id: string }) => r.dose_id);
+			expect(ids).toContain(`${medId}-0-${sat18}`);
+			expect(ids).toContain(`${medId}-0-${sat25}`);
+			expect(ids).toContain(`${medId}-0-${nov1}`);
+		});
+
+		it("should migrate dose IDs with person suffix when schedule changes", async () => {
+			// Create weekly medication with takenBy person
+			const createRes = await app.inject({
+				method: "POST",
+				url: "/medications",
+				payload: {
+					name: "Person Med",
+					intakes: [{ usage: 1, every: 7, start: "2025-10-17T08:00:00", takenBy: "Alice" }],
+				},
+			});
+			const medId = createRes.json().id;
+
+			// Mark dose with person suffix
+			const fri17 = new Date(2025, 9, 17).getTime();
+			await app.inject({
+				method: "POST",
+				url: "/doses/taken",
+				payload: { doseId: `${medId}-0-${fri17}-Alice` },
+			});
+
+			// Change start day
+			await app.inject({
+				method: "PUT",
+				url: `/medications/${medId}`,
+				payload: {
+					name: "Person Med",
+					intakes: [{ usage: 1, every: 7, start: "2025-10-18T08:00:00", takenBy: "Alice" }],
+				},
+			});
+
+			// Dose should be migrated with person suffix preserved
+			const sat18 = new Date(2025, 9, 18).getTime();
+			const after = await testClient.execute({
+				sql: `SELECT dose_id FROM dose_tracking WHERE dose_id LIKE ?`,
+				args: [`${medId}-%`],
+			});
+			expect(after.rows.length).toBe(1);
+			expect(after.rows[0].dose_id).toBe(`${medId}-0-${sat18}-Alice`);
+		});
+
+		it("should not migrate dose IDs when only time-of-day changes", async () => {
+			// Create daily medication at 08:00
+			const createRes = await app.inject({
+				method: "POST",
+				url: "/medications",
+				payload: {
+					name: "Daily Med",
+					blisters: [{ usage: 1, every: 1, start: "2025-10-17T08:00:00" }],
+				},
+			});
+			const medId = createRes.json().id;
+
+			// Mark dose
+			const oct17 = new Date(2025, 9, 17).getTime();
+			await app.inject({
+				method: "POST",
+				url: "/doses/taken",
+				payload: { doseId: `${medId}-0-${oct17}` },
+			});
+
+			// Change only time from 08:00 to 20:00 (same date)
+			await app.inject({
+				method: "PUT",
+				url: `/medications/${medId}`,
+				payload: {
+					name: "Daily Med",
+					blisters: [{ usage: 1, every: 1, start: "2025-10-17T20:00:00" }],
+				},
+			});
+
+			// Dose ID should remain unchanged (dateOnlyMs is the same)
+			const after = await testClient.execute({
+				sql: `SELECT dose_id FROM dose_tracking WHERE dose_id LIKE ?`,
+				args: [`${medId}-%`],
+			});
+			expect(after.rows.length).toBe(1);
+			expect(after.rows[0].dose_id).toBe(`${medId}-0-${oct17}`);
+		});
+
+		it("should migrate dose IDs when interval changes from daily to every-other-day", async () => {
+			// Create daily medication starting Oct 17
+			const createRes = await app.inject({
+				method: "POST",
+				url: "/medications",
+				payload: {
+					name: "Interval Med",
+					blisters: [{ usage: 1, every: 1, start: "2025-10-17T08:00:00" }],
+				},
+			});
+			const medId = createRes.json().id;
+
+			// Mark doses for Oct 17, 18, 19
+			const oct17 = new Date(2025, 9, 17).getTime();
+			const oct18 = new Date(2025, 9, 18).getTime();
+			const oct19 = new Date(2025, 9, 19).getTime();
+
+			for (const ts of [oct17, oct18, oct19]) {
+				await app.inject({
+					method: "POST",
+					url: "/doses/taken",
+					payload: { doseId: `${medId}-0-${ts}` },
+				});
+			}
+
+			// Change to every 2 days (Oct 17, 19, 21, ...)
+			await app.inject({
+				method: "PUT",
+				url: `/medications/${medId}`,
+				payload: {
+					name: "Interval Med",
+					blisters: [{ usage: 1, every: 2, start: "2025-10-17T08:00:00" }],
+				},
+			});
+
+			// Oct 17 stays (matches), Oct 18 → Oct 19 (nearest), Oct 19 → no match (already used)
+			// Actually: Oct 17 is exact match (no migration needed), Oct 18 maps to Oct 19 (within 1 day = half of 2),
+			// Oct 19 was the original schedule date but the new schedule also has Oct 19,
+			// which was already taken by Oct 18's migration
+			const after = await testClient.execute({
+				sql: `SELECT dose_id FROM dose_tracking WHERE dose_id LIKE ? ORDER BY dose_id`,
+				args: [`${medId}-%`],
+			});
+			// We should have at least the doses that could be mapped
+			expect(after.rows.length).toBeGreaterThanOrEqual(2);
+		});
+	});
+
 	// ---------------------------------------------------------------------------
 	// Share Link + Dose Tracking Integration
 	// ---------------------------------------------------------------------------

frontend/src/pages/DashboardPage.tsx

@@ -4,7 +4,7 @@ import { useAuth } from "../components/Auth";
 import { useAppContext } from "../context";
 import type { Coverage } from "../types";
 import { formatNumber, getExpiryClass, getSystemLocale } from "../utils/formatters";
-import { getStockStatus } from "../utils/schedule";
+import { expandDoseIds, getStockStatus } from "../utils/schedule";
 
 // Helper for user-specific localStorage keys
 function userStorageKey(userId: number | undefined, key: string): string {
@@ -490,11 +490,7 @@ export function DashboardPage() {
 						{pastDays.length > 0 &&
 							(() => {
 								const missedCount = missedPastDoseIds.length;
-								const totalPastDoses = pastDays.flatMap((d) =>
-									d.meds.flatMap((m) =>
-										m.doses.flatMap((dose) => (dose.takenBy ? [`${dose.id}-${dose.takenBy}`] : [dose.id]))
-									)
-								);
+								const totalPastDoses = pastDays.flatMap((d) => d.meds.flatMap((m) => expandDoseIds(m.doses)));
 								return (
 									<div className="past-days-header">
 										<div
@@ -541,7 +537,10 @@ export function DashboardPage() {
 						{showPastDays &&
 							pastDays.map((day) => {
 								const allDoseIds = day.meds.flatMap((item) =>
-									item.doses.flatMap((d) => (d.takenBy ? [`${d.id}-${d.takenBy}`] : [d.id]))
+									item.doses.flatMap((d) => {
+										const takenByArray = Array.isArray(d.takenBy) ? d.takenBy : [];
+										return takenByArray.length > 0 ? takenByArray.map((p) => `${d.id}-${p}`) : [d.id];
+									})
 								);
 								const allDayTaken =
 									allDoseIds.length > 0 && allDoseIds.every((id) => takenDoses.has(id) || dismissedDoses.has(id));
@@ -586,7 +585,7 @@ export function DashboardPage() {
 												const med = meds.find((m) => m.name === item.medName);
 												const medCov = coverageByMed[item.medName];
 												const isEmpty = medCov ? medCov.medsLeft <= 0 : false;
-												const itemDoseIds = item.doses.flatMap((d) => (d.takenBy ? [`${d.id}-${d.takenBy}`] : [d.id]));
+												const itemDoseIds = expandDoseIds(item.doses);
 												const allTaken = itemDoseIds.every((id) => takenDoses.has(id));
 												return (
 													<div key={`${day.dateStr}-${item.medName}`} className={`time-row ${allTaken ? "taken" : ""}`}>
@@ -676,9 +675,7 @@ export function DashboardPage() {
 						{todayDay &&
 							(() => {
 								const day = todayDay;
-								const allDoseIds = day.meds.flatMap((item) =>
-									item.doses.flatMap((d) => (d.takenBy ? [`${d.id}-${d.takenBy}`] : [d.id]))
-								);
+								const allDoseIds = day.meds.flatMap((item) => expandDoseIds(item.doses));
 								const allDayTaken = allDoseIds.length > 0 && allDoseIds.every((id) => takenDoses.has(id));
 								const takenCount = allDoseIds.filter((id) => takenDoses.has(id)).length;
 
@@ -737,7 +734,7 @@ export function DashboardPage() {
 													: medCoverage
 														? getStockStatus(medCoverage.daysLeft, medCoverage.medsLeft, stockThresholds)
 														: null;
-												const itemDoseIds = item.doses.flatMap((d) => (d.takenBy ? [`${d.id}-${d.takenBy}`] : [d.id]));
+												const itemDoseIds = expandDoseIds(item.doses);
 												const allTaken = itemDoseIds.every((id) => takenDoses.has(id));
 												return (
 													<div key={`${day.dateStr}-${item.medName}`} className={`time-row ${allTaken ? "taken" : ""}`}>
@@ -769,7 +766,7 @@ export function DashboardPage() {
 														<div className="doses-col">
 															{item.doses.map((dose) => {
 																const isOverdue = dose.when < Date.now();
-																const people = dose.takenBy ? [dose.takenBy] : [null];
+																const people = dose.takenBy.length > 0 ? dose.takenBy : [null];
 																const allTaken = people.every((person) => takenDoses.has(getDoseId(dose.id, person)));
 																return (
 																	<div
@@ -866,9 +863,7 @@ export function DashboardPage() {
 						{/* Future days */}
 						{showFutureDays &&
 							futureDays.map((day) => {
-								const allDoseIds = day.meds.flatMap((item) =>
-									item.doses.flatMap((d) => (d.takenBy ? [`${d.id}-${d.takenBy}`] : [d.id]))
-								);
+								const allDoseIds = day.meds.flatMap((item) => expandDoseIds(item.doses));
 								const allDayTaken = allDoseIds.length > 0 && allDoseIds.every((id) => takenDoses.has(id));
 								const takenCount = allDoseIds.filter((id) => takenDoses.has(id)).length;
 
@@ -926,7 +921,7 @@ export function DashboardPage() {
 													: medCoverage
 														? getStockStatus(medCoverage.daysLeft, medCoverage.medsLeft, stockThresholds)
 														: null;
-												const itemDoseIds = item.doses.flatMap((d) => (d.takenBy ? [`${d.id}-${d.takenBy}`] : [d.id]));
+												const itemDoseIds = expandDoseIds(item.doses);
 												const allTaken = itemDoseIds.every((id) => takenDoses.has(id));
 												return (
 													<div key={`${day.dateStr}-${item.medName}`} className={`time-row ${allTaken ? "taken" : ""}`}>

frontend/src/pages/SchedulePage.tsx

@@ -3,6 +3,7 @@ import { MedicationAvatar } from "../components";
 import { useAuth } from "../components/Auth";
 import { useAppContext } from "../context";
 import type { Coverage } from "../types";
+import { expandDoseIds } from "../utils/schedule";
 
 // Helper for user-specific localStorage keys
 function userStorageKey(userId: number | undefined, key: string): string {
@@ -125,12 +126,7 @@ export function SchedulePage() {
 					{/* Past days (when expanded) */}
 					{showPastDays &&
 						pastDays.map((day) => {
-							const allDoseIds = day.meds.flatMap((item) =>
-								item.doses.flatMap((d) => {
-									const takenByArray = Array.isArray(d.takenBy) ? d.takenBy : [];
-									return takenByArray.length > 0 ? takenByArray.map((p) => `${d.id}-${p}`) : [d.id];
-								})
-							);
+							const allDoseIds = day.meds.flatMap((item) => expandDoseIds(item.doses));
 							const allDayTaken = allDoseIds.length > 0 && allDoseIds.every((id) => takenDoses.has(id));
 							const takenCount = allDoseIds.filter((id) => takenDoses.has(id)).length;
 							const isManuallyExpanded = manuallyExpandedDays.has(day.dateStr);
@@ -172,10 +168,7 @@ export function SchedulePage() {
 											const med = meds.find((m) => m.name === item.medName);
 											const medCov = coverageByMed[item.medName];
 											const isEmpty = medCov ? medCov.medsLeft <= 0 : false;
-											const itemDoseIds = item.doses.flatMap((d) => {
-												const takenByArray = Array.isArray(d.takenBy) ? d.takenBy : [];
-												return takenByArray.length > 0 ? takenByArray.map((p) => `${d.id}-${p}`) : [d.id];
-											});
+											const itemDoseIds = expandDoseIds(item.doses);
 											const allTaken = itemDoseIds.every((id) => takenDoses.has(id));
 											return (
 												<div key={`${day.dateStr}-${item.medName}`} className={`time-row ${allTaken ? "taken" : ""}`}>
@@ -277,10 +270,7 @@ export function SchedulePage() {
 										: medCoverage
 											? getStockStatus(medCoverage.daysLeft, medCoverage.medsLeft, settings)
 											: null;
-									const itemDoseIds = item.doses.flatMap((d) => {
-										const takenByArray = Array.isArray(d.takenBy) ? d.takenBy : [];
-										return takenByArray.length > 0 ? takenByArray.map((p) => `${d.id}-${p}`) : [d.id];
-									});
+									const itemDoseIds = expandDoseIds(item.doses);
 									const allTaken = itemDoseIds.every((id) => takenDoses.has(id));
 									return (
 										<div key={`${day.dateStr}-${item.medName}`} className={`time-row ${allTaken ? "taken" : ""}`}>

frontend/src/test/utils/schedule.test.ts

@@ -4,6 +4,7 @@ import {
 	buildSchedulePreview,
 	calculateCoverage,
 	computeMissedPastDoseIds,
+	expandDoseIds,
 	getNextReminderForMed,
 	getReminderStatusText,
 	getStockStatus,
@@ -1147,3 +1148,52 @@ function groupEventsIntoPastDays(
 		meds: Array.from(medMap.entries()).map(([medName, doses]) => ({ medName, doses })),
 	}));
 }
+
+describe("expandDoseIds", () => {
+	it("returns base IDs when takenBy is empty array", () => {
+		const doses = [
+			{ id: "1-0-1729123200000", takenBy: [] as string[] },
+			{ id: "2-0-1729123200000", takenBy: [] as string[] },
+		];
+		const result = expandDoseIds(doses);
+		expect(result).toEqual(["1-0-1729123200000", "2-0-1729123200000"]);
+	});
+
+	it("returns person-suffixed IDs when takenBy has entries", () => {
+		const doses = [{ id: "1-0-1729123200000", takenBy: ["Alice"] }];
+		const result = expandDoseIds(doses);
+		expect(result).toEqual(["1-0-1729123200000-Alice"]);
+	});
+
+	it("returns multiple IDs for multiple takenBy entries", () => {
+		const doses = [{ id: "1-0-1729123200000", takenBy: ["Alice", "Bob"] }];
+		const result = expandDoseIds(doses);
+		expect(result).toEqual(["1-0-1729123200000-Alice", "1-0-1729123200000-Bob"]);
+	});
+
+	it("handles mix of empty and non-empty takenBy", () => {
+		const doses = [
+			{ id: "1-0-1729123200000", takenBy: ["Alice"] },
+			{ id: "2-0-1729123200000", takenBy: [] as string[] },
+			{ id: "3-0-1729123200000", takenBy: ["Bob", "Carol"] },
+		];
+		const result = expandDoseIds(doses);
+		expect(result).toEqual([
+			"1-0-1729123200000-Alice",
+			"2-0-1729123200000",
+			"3-0-1729123200000-Bob",
+			"3-0-1729123200000-Carol",
+		]);
+	});
+
+	it("returns empty array for empty doses", () => {
+		expect(expandDoseIds([])).toEqual([]);
+	});
+
+	it("handles non-array takenBy gracefully", () => {
+		// In case of unexpected data, treat non-array as empty
+		const doses = [{ id: "1-0-1729123200000", takenBy: null as unknown as string[] }];
+		const result = expandDoseIds(doses);
+		expect(result).toEqual(["1-0-1729123200000"]);
+	});
+});

frontend/src/utils/schedule.ts

@@ -446,6 +446,18 @@ export function isDoseDismissed(doseId: string, dismissedUntilDate: string | und
  * @param dismissedDoses - Set of dose IDs individually dismissed
  * @returns Array of dose IDs that are missed
  */
+/**
+ * Compute the full set of dose IDs for a list of doses, correctly handling
+ * per-intake takenBy arrays. Empty arrays produce base IDs (no suffix),
+ * non-empty arrays produce one ID per person with a `-person` suffix.
+ */
+export function expandDoseIds(doses: ReadonlyArray<{ id: string; takenBy: string[] }>): string[] {
+	return doses.flatMap((d) => {
+		const takenByArray = Array.isArray(d.takenBy) ? d.takenBy : [];
+		return takenByArray.length > 0 ? takenByArray.map((p) => `${d.id}-${p}`) : [d.id];
+	});
+}
+
 export function computeMissedPastDoseIds(
 	pastDays: ReadonlyArray<{
 		meds: ReadonlyArray<{