fitness: add weekly workout goal with streak counter on stats page

Store a per-user weekly workout target (1-14) in a new FitnessGoal model.
Compute consecutive-week streak from WorkoutSession history via a new
/api/fitness/goal endpoint. Display streak as a 4th lifetime card on the
stats page with an inline goal editor modal.

src/lib/js/fitnessI18n.ts

@@ -216,6 +216,15 @@ const translations: Translations = {
 
 	// WorkoutFab
 	active_workout: { en: 'Active Workout', de: 'Aktives Training' },
+
+	// Streak / Goal
+	streak: { en: 'Streak', de: 'Serie' },
+	streak_weeks: { en: 'Weeks', de: 'Wochen' },
+	streak_week: { en: 'Week', de: 'Woche' },
+	weekly_goal: { en: 'Weekly Goal', de: 'Wochenziel' },
+	workouts_per_week_goal: { en: 'workouts / week', de: 'Trainings / Woche' },
+	set_goal: { en: 'Set Goal', de: 'Ziel setzen' },
+	goal_set: { en: 'Goal set', de: 'Ziel gesetzt' },
 };
 
 /** Get a translated string */

src/models/FitnessGoal.ts

@@ -0,0 +1,18 @@
+import mongoose from 'mongoose';
+
+const FitnessGoalSchema = new mongoose.Schema(
+  {
+    username: { type: String, required: true, unique: true },
+    weeklyWorkouts: { type: Number, required: true, default: 4, min: 1, max: 14 }
+  },
+  { timestamps: true }
+);
+
+interface IFitnessGoal {
+  username: string;
+  weeklyWorkouts: number;
+}
+
+let _model: mongoose.Model<IFitnessGoal>;
+try { _model = mongoose.model<IFitnessGoal>("FitnessGoal"); } catch { _model = mongoose.model<IFitnessGoal>("FitnessGoal", FitnessGoalSchema); }
+export const FitnessGoal = _model;

src/routes/api/fitness/goal/+server.ts

@@ -0,0 +1,111 @@
+import { json } from '@sveltejs/kit';
+import type { RequestHandler } from './$types';
+import { requireAuth } from '$lib/server/middleware/auth';
+import { dbConnect } from '$utils/db';
+import { FitnessGoal } from '$models/FitnessGoal';
+import { WorkoutSession } from '$models/WorkoutSession';
+
+export const GET: RequestHandler = async ({ locals }) => {
+	const user = await requireAuth(locals);
+	await dbConnect();
+
+	const goal = await FitnessGoal.findOne({ username: user.nickname }).lean() as any;
+	const weeklyWorkouts = goal?.weeklyWorkouts ?? null;
+
+	// If no goal set, return early
+	if (weeklyWorkouts === null) {
+		return json({ weeklyWorkouts: null, streak: 0 });
+	}
+
+	const streak = await computeStreak(user.nickname, weeklyWorkouts);
+	return json({ weeklyWorkouts, streak });
+};
+
+export const PUT: RequestHandler = async ({ request, locals }) => {
+	const user = await requireAuth(locals);
+	const { weeklyWorkouts } = await request.json();
+
+	if (typeof weeklyWorkouts !== 'number' || weeklyWorkouts < 1 || weeklyWorkouts > 14 || !Number.isInteger(weeklyWorkouts)) {
+		return json({ error: 'weeklyWorkouts must be an integer between 1 and 14' }, { status: 400 });
+	}
+
+	await dbConnect();
+
+	await FitnessGoal.findOneAndUpdate(
+		{ username: user.nickname },
+		{ weeklyWorkouts },
+		{ upsert: true }
+	);
+
+	const streak = await computeStreak(user.nickname, weeklyWorkouts);
+	return json({ weeklyWorkouts, streak });
+};
+
+async function computeStreak(username: string, weeklyGoal: number): Promise<number> {
+	// Get weekly workout counts going back up to 2 years
+	const cutoff = new Date();
+	cutoff.setFullYear(cutoff.getFullYear() - 2);
+
+	const weeklyAgg = await WorkoutSession.aggregate([
+		{
+			$match: {
+				createdBy: username,
+				startTime: { $gte: cutoff }
+			}
+		},
+		{
+			$group: {
+				_id: {
+					year: { $isoWeekYear: '$startTime' },
+					week: { $isoWeek: '$startTime' }
+				},
+				count: { $sum: 1 }
+			}
+		},
+		{
+			$sort: { '_id.year': -1, '_id.week': -1 }
+		}
+	]);
+
+	// Build a set of weeks that met the goal
+	const metGoal = new Set<string>();
+	for (const item of weeklyAgg) {
+		if (item.count >= weeklyGoal) {
+			metGoal.add(`${item._id.year}-${item._id.week}`);
+		}
+	}
+
+	// Walk backwards week-by-week counting consecutive weeks that met the goal.
+	// Current (incomplete) week counts if it already meets the goal, otherwise skip it.
+	const now = new Date();
+	let streak = 0;
+
+	const currentKey = isoWeekKey(now);
+	const currentWeekMet = metGoal.has(currentKey);
+
+	// If current week already met: count it, then check previous weeks.
+	// If not: start checking from last week (current week still in progress).
+	if (currentWeekMet) streak = 1;
+
+	for (let i = 1; i <= 104; i++) {
+		const weekDate = new Date(now);
+		weekDate.setDate(weekDate.getDate() - i * 7);
+		if (metGoal.has(isoWeekKey(weekDate))) {
+			streak++;
+		} else {
+			break;
+		}
+	}
+
+	return streak;
+}
+
+function isoWeekKey(date: Date): string {
+	const d = new Date(date.getTime());
+	d.setHours(0, 0, 0, 0);
+	d.setDate(d.getDate() + 3 - ((d.getDay() + 6) % 7));
+	const year = d.getFullYear();
+	const week1 = new Date(year, 0, 4);
+	const week = 1 + Math.round(((d.getTime() - week1.getTime()) / 86400000 - 3 + ((week1.getDay() + 6) % 7)) / 7);
+	return `${year}-${week}`;
+}

src/routes/fitness/[stats=fitnessStats]/+page.server.ts

@@ -2,7 +2,11 @@ import type { PageServerLoad } from './$types';
 
 export const load: PageServerLoad = async ({ fetch, locals }) => {
 	const session = await locals.auth();
-	const res = await fetch('/api/fitness/stats/overview');
+	const [res, goalRes] = await Promise.all([
+		fetch('/api/fitness/stats/overview'),
+		fetch('/api/fitness/goal')
+	]);
 	const stats = await res.json();
-	return { session, stats };
+	const goal = goalRes.ok ? await goalRes.json() : { weeklyWorkouts: null, streak: 0 };
+	return { session, stats, goal };
 };

src/routes/fitness/[stats=fitnessStats]/+page.svelte

@@ -1,7 +1,7 @@
 <script>
 	import { page } from '$app/stores';
 	import FitnessChart from '$lib/components/fitness/FitnessChart.svelte';
-	import { Dumbbell, Route, Flame } from 'lucide-svelte';
+	import { Dumbbell, Route, Flame, Zap } from 'lucide-svelte';
 	import { onMount } from 'svelte';
 	import { detectFitnessLang, t } from '$lib/js/fitnessI18n';
 
@@ -32,6 +32,36 @@
 
 	const stats = $derived(data.stats ?? {});
 
+	let goalStreak = $state(data.goal?.streak ?? 0);
+	let goalWeekly = $state(data.goal?.weeklyWorkouts ?? null);
+	let goalEditing = $state(false);
+	let goalInput = $state(4);
+	let goalSaving = $state(false);
+
+	function startGoalEdit() {
+		goalInput = goalWeekly ?? 4;
+		goalEditing = true;
+	}
+
+	async function saveGoal() {
+		goalSaving = true;
+		try {
+			const res = await fetch('/api/fitness/goal', {
+				method: 'PUT',
+				headers: { 'Content-Type': 'application/json' },
+				body: JSON.stringify({ weeklyWorkouts: goalInput })
+			});
+			if (res.ok) {
+				const d = await res.json();
+				goalWeekly = d.weeklyWorkouts;
+				goalStreak = d.streak;
+				goalEditing = false;
+			}
+		} finally {
+			goalSaving = false;
+		}
+	}
+
 	const workoutsChartData = $derived({
 		labels: stats.workoutsChart?.labels ?? [],
 		datasets: [{
@@ -113,8 +143,39 @@
 			<div class="card-value">{stats.totalCardioKm ?? 0}<span class="card-unit">km</span></div>
 			<div class="card-label">{t('distance_covered', lang)}</div>
 		</div>
+		<button class="lifetime-card streak" onclick={startGoalEdit}>
+			<div class="card-icon"><Zap size={24} /></div>
+			<div class="card-value">{goalStreak}</div>
+			<div class="card-label">{t('streak', lang)}</div>
+			{#if goalWeekly !== null}
+				<div class="card-goal">{goalWeekly}x / {t('streak_week', lang).toLowerCase()}</div>
+			{:else}
+				<div class="card-goal">{t('set_goal', lang)}</div>
+			{/if}
+		</button>
 	</div>
 
+	{#if goalEditing}
+		<div class="goal-editor-overlay" onkeydown={(e) => { if (e.key === 'Escape') goalEditing = false; }} role="dialog">
+			<div class="goal-editor-backdrop" onclick={() => goalEditing = false}></div>
+			<div class="goal-editor-panel">
+				<h3>{t('weekly_goal', lang)}</h3>
+				<div class="goal-input-row">
+					<button class="adj-btn" onclick={() => { if (goalInput > 1) goalInput--; }} disabled={goalInput <= 1}>-</button>
+					<span class="goal-value">{goalInput}</span>
+					<button class="adj-btn" onclick={() => { if (goalInput < 14) goalInput++; }} disabled={goalInput >= 14}>+</button>
+				</div>
+				<span class="goal-unit">{t('workouts_per_week_goal', lang)}</span>
+				<div class="goal-actions">
+					<button class="goal-save" onclick={saveGoal} disabled={goalSaving}>
+						{goalSaving ? t('saving', lang) : t('save', lang)}
+					</button>
+					<button class="goal-cancel" onclick={() => goalEditing = false}>{t('cancel', lang)}</button>
+				</div>
+			</div>
+		</div>
+	{/if}
+
 	{#if (stats.workoutsChart?.data?.length ?? 0) > 0}
 		<FitnessChart
 			type="bar"
@@ -149,7 +210,7 @@
 
 	.lifetime-cards {
 		display: grid;
-		grid-template-columns: repeat(3, 1fr);
+		grid-template-columns: repeat(4, 1fr);
 		gap: 0.6rem;
 	}
 	.lifetime-card {
@@ -165,6 +226,16 @@
 		position: relative;
 		overflow: hidden;
 	}
+	button.lifetime-card {
+		border: none;
+		cursor: pointer;
+		font-family: inherit;
+		color: inherit;
+		transition: box-shadow 0.15s;
+	}
+	button.lifetime-card:hover {
+		box-shadow: var(--shadow-sm), 0 0 0 2px var(--nord13);
+	}
 	.lifetime-card::before {
 		content: '';
 		position: absolute;
@@ -181,6 +252,9 @@
 	.lifetime-card.cardio::before {
 		background: var(--nord14);
 	}
+	.lifetime-card.streak::before {
+		background: var(--nord13);
+	}
 	.card-icon {
 		display: flex;
 		align-items: center;
@@ -202,6 +276,10 @@
 		color: var(--nord14);
 		background: color-mix(in srgb, var(--nord14) 15%, transparent);
 	}
+	.streak .card-icon {
+		color: var(--nord13);
+		background: color-mix(in srgb, var(--nord13) 15%, transparent);
+	}
 	.card-value {
 		font-size: 1.4rem;
 		font-weight: 800;
@@ -221,7 +299,18 @@
 		text-transform: uppercase;
 		color: var(--color-text-secondary);
 	}
+	.card-goal {
+		font-size: 0.6rem;
+		color: var(--color-text-secondary);
+		opacity: 0.7;
+		margin-top: 0.1rem;
+	}
 
+	@media (max-width: 600px) {
+		.lifetime-cards {
+			grid-template-columns: repeat(2, 1fr);
+		}
+	}
 	@media (max-width: 400px) {
 		.lifetime-cards {
 			grid-template-columns: 1fr;
@@ -238,6 +327,108 @@
 		}
 	}
 
+	/* Goal editor overlay */
+	.goal-editor-overlay {
+		position: fixed;
+		inset: 0;
+		z-index: 100;
+		display: grid;
+		place-items: center;
+	}
+	.goal-editor-backdrop {
+		position: absolute;
+		inset: 0;
+		background: rgba(0, 0, 0, 0.5);
+	}
+	.goal-editor-panel {
+		position: relative;
+		background: var(--color-surface);
+		border-radius: 16px;
+		padding: 1.5rem 2rem;
+		display: flex;
+		flex-direction: column;
+		align-items: center;
+		gap: 0.75rem;
+		box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
+		min-width: 240px;
+	}
+	.goal-editor-panel h3 {
+		margin: 0;
+		font-size: 1.1rem;
+	}
+	.goal-input-row {
+		display: flex;
+		align-items: center;
+		gap: 1rem;
+	}
+	.adj-btn {
+		width: 36px;
+		height: 36px;
+		border-radius: 50%;
+		border: 1.5px solid var(--color-border, var(--nord3));
+		background: transparent;
+		color: inherit;
+		font-size: 1.3rem;
+		font-weight: 600;
+		cursor: pointer;
+		display: grid;
+		place-items: center;
+		font-family: inherit;
+		transition: background 0.15s;
+	}
+	.adj-btn:hover:not(:disabled) {
+		background: var(--nord13);
+		color: var(--nord0);
+		border-color: var(--nord13);
+	}
+	.adj-btn:disabled {
+		opacity: 0.3;
+		cursor: default;
+	}
+	.goal-value {
+		font-size: 2rem;
+		font-weight: 700;
+		min-width: 2ch;
+		text-align: center;
+	}
+	.goal-unit {
+		font-size: 0.8rem;
+		color: var(--color-text-secondary);
+	}
+	.goal-actions {
+		display: flex;
+		gap: 0.5rem;
+		margin-top: 0.25rem;
+	}
+	.goal-save {
+		padding: 0.4rem 1rem;
+		border: none;
+		border-radius: 8px;
+		background: var(--nord13);
+		color: var(--nord0);
+		font-size: 0.85rem;
+		font-weight: 600;
+		cursor: pointer;
+		font-family: inherit;
+	}
+	.goal-save:disabled {
+		opacity: 0.6;
+		cursor: default;
+	}
+	.goal-cancel {
+		padding: 0.4rem 1rem;
+		border: none;
+		border-radius: 8px;
+		background: transparent;
+		color: var(--color-text-secondary);
+		font-size: 0.75rem;
+		font-weight: 600;
+		cursor: pointer;
+		text-transform: uppercase;
+		letter-spacing: 0.04em;
+		font-family: inherit;
+	}
+
 	.empty-chart {
 		text-align: center;
 		color: var(--color-text-secondary);