feat: add multi-user profile support (#3)

* feat: add multi-user profile support

Add profile-based multi-user support so multiple people can track
their workouts independently on the same machine.

- Add profile management module (src/data/profiles.ts) with CRUD operations
- Update Storage class to be profile-aware with per-user data isolation
- Add global --profile flag for explicit profile selection
- Add profile commands: list, create, delete
- Exercises are shared across profiles, templates/workouts/config are per-user
- Auto-migrate existing data to 'default' profile on first use
- Single profile works automatically (backwards compatible)
- Multiple profiles require explicit --profile flag

* refactor: simplify profile implementation

- Replace imperative loop with declarative some() in hasLegacyData()
- Remove redundant fs.existsSync checks in ensureDir() (mkdirSync recursive is idempotent)
- Extract requireProfileDir() helper to consolidate duplicate checks
- Remove redundant null check in updateExercise()
- Remove redundant profileExists check in delete command

Author: gricha

README.md

@@ -34,6 +34,52 @@ workout log overhead-press 95 10,9,8
 workout done
 ```
 
+## Multi-User Profiles
+
+Multiple people can track workouts independently on the same machine using profiles.
+
+### How it Works
+
+- **Single profile**: Commands work automatically (backwards compatible)
+- **Multiple profiles**: Use `--profile <name>` to specify which profile
+- **Shared exercises**: The exercise library is shared across all profiles
+- **Per-user data**: Templates, workouts, config, and current session are per-profile
+
+### Profile Commands
+
+```bash
+# List all profiles
+workout profile list
+
+# Create a new profile
+workout profile create sarah
+
+# Delete a profile (cannot delete the last one)
+workout profile delete old-profile
+```
+
+### Using Profiles
+
+```bash
+# When multiple profiles exist, specify which one to use
+workout --profile mike start push-day
+workout --profile mike log bench-press 185 8,8,7,6
+workout --profile mike done
+
+# Sarah can workout simultaneously
+workout --profile sarah start leg-day
+workout --profile sarah log squat 135 8,8,8
+workout --profile sarah done
+
+# Check each person's status
+workout --profile mike status
+workout --profile sarah status
+```
+
+### Migration
+
+If you have existing data, it will automatically migrate to a `default` profile on first use. The exercise library stays shared at the root level.
+
 ## Commands
 
 ### Workout Sessions
@@ -377,11 +423,18 @@ All data is stored locally in `~/.workout/`:
 
 ```
 ~/.workout/
-  config.json      # User preferences
-  exercises.json   # Custom exercises
-  templates.json   # Workout templates  
-  history/         # Completed workouts
-  current.json     # Active workout (if any)
+├── exercises.json        # Shared exercise library
+├── profiles/
+│   ├── default/          # Default profile (or your profile name)
+│   │   ├── config.json   # User preferences (units, etc.)
+│   │   ├── templates.json
+│   │   ├── current.json  # Active workout (if any)
+│   │   └── workouts/     # Completed workouts
+│   └── sarah/            # Another profile
+│       ├── config.json
+│       ├── templates.json
+│       ├── current.json
+│       └── workouts/
 ```
 
 ## JSON Output

src/commands/analytics.ts

@@ -47,14 +47,14 @@ function findPRs(storage: ReturnType<typeof getStorage>): Map<string, PR> {
   return prs;
 }
 
-export function createPRCommand(): Command {
+export function createPRCommand(getProfile: () => string | undefined): Command {
   return new Command('pr')
     .description('Show personal records')
     .argument('[exercise]', 'Exercise ID (optional, shows all if omitted)')
     .option('-m, --muscle <muscle>', 'Filter by muscle group')
     .option('--json', 'Output as JSON')
     .action((exerciseId: string | undefined, options: { muscle?: string; json?: boolean }) => {
-      const storage = getStorage();
+      const storage = getStorage(getProfile());
       const config = storage.getConfig();
       const unit = config.units;
       const prs = findPRs(storage);
@@ -123,7 +123,7 @@ function formatDateRange(start: Date, end: Date): string {
   return `${startStr} to ${endStr}`;
 }
 
-export function createVolumeCommand(): Command {
+export function createVolumeCommand(getProfile: () => string | undefined): Command {
   return new Command('volume')
     .description('Analyze training volume')
     .option('-w, --week', 'Show current week')
@@ -139,7 +139,7 @@ export function createVolumeCommand(): Command {
         by?: string;
         json?: boolean;
       }) => {
-        const storage = getStorage();
+        const storage = getStorage(getProfile());
         const config = storage.getConfig();
         const unit = config.units;
         const workouts = storage.getAllWorkouts();
@@ -268,14 +268,14 @@ export function createVolumeCommand(): Command {
     );
 }
 
-export function createProgressionCommand(): Command {
+export function createProgressionCommand(getProfile: () => string | undefined): Command {
   return new Command('progression')
     .description('Show progression over time for an exercise')
     .argument('<exercise>', 'Exercise ID')
     .option('-n, --last <count>', 'Show last N sessions', '10')
     .option('--json', 'Output as JSON')
     .action((exerciseId: string, options: { last: string; json?: boolean }) => {
-      const storage = getStorage();
+      const storage = getStorage(getProfile());
       const config = storage.getConfig();
       const unit = config.units;
       const exercise = storage.getExercise(exerciseId);

src/commands/exercises.ts

@@ -1,5 +1,5 @@
 import { Command } from 'commander';
-import { getStorage } from '../data/storage.js';
+import { getSharedStorage } from '../data/storage.js';
 import {
   Exercise,
   slugify,
@@ -8,7 +8,7 @@ import {
   type Equipment,
 } from '../types.js';
 
-export function createExercisesCommand(): Command {
+export function createExercisesCommand(_getProfile: () => string | undefined): Command {
   const exercises = new Command('exercises').description('Manage exercise library');
 
   exercises
@@ -18,7 +18,7 @@ export function createExercisesCommand(): Command {
     .option('-t, --type <type>', 'Filter by exercise type (compound/isolation)')
     .option('--json', 'Output as JSON')
     .action((options: { muscle?: string; type?: string; json?: boolean }) => {
-      const storage = getStorage();
+      const storage = getSharedStorage();
       let exerciseList = storage.getExercises();
 
       if (options.muscle) {
@@ -51,7 +51,7 @@ export function createExercisesCommand(): Command {
     .description('Show exercise details')
     .option('--json', 'Output as JSON')
     .action((id: string, options: { json?: boolean }) => {
-      const storage = getStorage();
+      const storage = getSharedStorage();
       const exercise = storage.getExercise(id);
 
       if (!exercise) {
@@ -98,7 +98,7 @@ export function createExercisesCommand(): Command {
           notes?: string;
         }
       ) => {
-        const storage = getStorage();
+        const storage = getSharedStorage();
         const id = options.id ?? slugify(name);
         const muscles = options.muscles.split(',').map((m) => m.trim()) as MuscleGroup[];
         const aliases = options.aliases ? options.aliases.split(',').map((a) => a.trim()) : [];
@@ -146,7 +146,7 @@ export function createExercisesCommand(): Command {
           notes?: string;
         }
       ) => {
-        const storage = getStorage();
+        const storage = getSharedStorage();
         const exercise = storage.getExercise(id);
 
         if (!exercise) {
@@ -192,7 +192,7 @@ export function createExercisesCommand(): Command {
     .command('delete <id>')
     .description('Delete an exercise')
     .action((id: string) => {
-      const storage = getStorage();
+      const storage = getSharedStorage();
 
       try {
         storage.deleteExercise(id);

src/commands/history.ts

@@ -1,13 +1,13 @@
 import { Command } from 'commander';
 import { getStorage } from '../data/storage.js';
 
-export function createLastCommand(): Command {
+export function createLastCommand(getProfile: () => string | undefined): Command {
   return new Command('last')
     .description('Show last workout')
     .option('--full', 'Show full details')
     .option('--json', 'Output as JSON')
     .action((options: { full?: boolean; json?: boolean }) => {
-      const storage = getStorage();
+      const storage = getStorage(getProfile());
       const workout = storage.getLastWorkout();
 
       if (!workout) {
@@ -82,14 +82,14 @@ export function createLastCommand(): Command {
     });
 }
 
-export function createHistoryCommand(): Command {
+export function createHistoryCommand(getProfile: () => string | undefined): Command {
   return new Command('history')
     .description('Show exercise history')
     .argument('<exercise>', 'Exercise ID')
     .option('-n, --last <count>', 'Show last N sessions', '10')
     .option('--json', 'Output as JSON')
     .action((exerciseId: string, options: { last: string; json?: boolean }) => {
-      const storage = getStorage();
+      const storage = getStorage(getProfile());
       const exercise = storage.getExercise(exerciseId);
 
       if (!exercise) {

src/commands/profile.ts

@@ -0,0 +1,51 @@
+import { Command } from 'commander';
+import { getProfiles, createProfile, deleteProfile } from '../data/profiles.js';
+
+export function createProfileCommand(): Command {
+  const profile = new Command('profile').description('Manage user profiles');
+
+  profile
+    .command('list')
+    .description('List all profiles')
+    .action(() => {
+      const profiles = getProfiles();
+
+      if (profiles.length === 0) {
+        console.log('No profiles found. A default profile will be created on first use.');
+        return;
+      }
+
+      console.log('Profiles:');
+      for (const p of profiles) {
+        console.log(`  ${p}`);
+      }
+    });
+
+  profile
+    .command('create <name>')
+    .description('Create a new profile')
+    .action((name: string) => {
+      try {
+        createProfile(name);
+        console.log(`Created profile: ${name}`);
+      } catch (err) {
+        console.error((err as Error).message);
+        process.exit(1);
+      }
+    });
+
+  profile
+    .command('delete <name>')
+    .description('Delete a profile')
+    .action((name: string) => {
+      try {
+        deleteProfile(name);
+        console.log(`Deleted profile: ${name}`);
+      } catch (err) {
+        console.error((err as Error).message);
+        process.exit(1);
+      }
+    });
+
+  return profile;
+}

src/commands/session.ts

@@ -36,14 +36,14 @@ function calculateStats(workout: Workout, storage: ReturnType<typeof getStorage>
   };
 }
 
-export function createStartCommand(): Command {
+export function createStartCommand(getProfile: () => string | undefined): Command {
   return new Command('start')
     .description('Start a new workout session')
     .argument('[template]', 'Template ID to use')
     .option('--empty', 'Start an empty freestyle session')
     .option('--continue', 'Resume an interrupted session')
     .action((templateId: string | undefined, options: { empty?: boolean; continue?: boolean }) => {
-      const storage = getStorage();
+      const storage = getStorage(getProfile());
 
       if (options.continue) {
         const current = storage.getCurrentWorkout();
@@ -101,15 +101,15 @@ export function createStartCommand(): Command {
     });
 }
 
-export function createLogCommand(): Command {
+export function createLogCommand(getProfile: () => string | undefined): Command {
   return new Command('log')
     .description('Log a set')
     .argument('<exercise>', 'Exercise ID')
     .argument('<weight>', 'Weight (number or +/- for relative)')
     .argument('<reps>', 'Reps (single number or comma-separated for multiple sets)')
     .option('--rir <rir>', 'Reps in reserve (0-10)')
     .action((exerciseId: string, weightStr: string, repsStr: string, options: { rir?: string }) => {
-      const storage = getStorage();
+      const storage = getStorage(getProfile());
       const workout = storage.getCurrentWorkout();
 
       if (!workout) {
@@ -168,9 +168,9 @@ export function createLogCommand(): Command {
     });
 }
 
-export function createStatusCommand(): Command {
+export function createStatusCommand(getProfile: () => string | undefined): Command {
   return new Command('status').description('Show current workout status').action(() => {
-    const storage = getStorage();
+    const storage = getStorage(getProfile());
     const workout = storage.getCurrentWorkout();
 
     if (!workout) {
@@ -218,9 +218,9 @@ export function createStatusCommand(): Command {
   });
 }
 
-export function createDoneCommand(): Command {
+export function createDoneCommand(getProfile: () => string | undefined): Command {
   return new Command('done').description('Finish current workout').action(() => {
-    const storage = getStorage();
+    const storage = getStorage(getProfile());
     const workout = storage.getCurrentWorkout();
 
     if (!workout) {
@@ -247,9 +247,9 @@ export function createDoneCommand(): Command {
   });
 }
 
-export function createCancelCommand(): Command {
+export function createCancelCommand(getProfile: () => string | undefined): Command {
   return new Command('cancel').description('Cancel current workout without saving').action(() => {
-    const storage = getStorage();
+    const storage = getStorage(getProfile());
     const workout = storage.getCurrentWorkout();
 
     if (!workout) {
@@ -262,12 +262,12 @@ export function createCancelCommand(): Command {
   });
 }
 
-export function createNoteCommand(): Command {
+export function createNoteCommand(getProfile: () => string | undefined): Command {
   return new Command('note')
     .description('Add a note to the current workout')
     .argument('<text...>', 'Note text (or exercise ID followed by note text)')
     .action((textParts: string[]) => {
-      const storage = getStorage();
+      const storage = getStorage(getProfile());
       const workout = storage.getCurrentWorkout();
 
       if (!workout) {
@@ -297,13 +297,13 @@ export function createNoteCommand(): Command {
     });
 }
 
-export function createSwapCommand(): Command {
+export function createSwapCommand(getProfile: () => string | undefined): Command {
   return new Command('swap')
     .description('Swap an exercise in the current workout with another')
     .argument('<old-exercise>', 'Exercise ID to replace')
     .argument('<new-exercise>', 'Exercise ID to swap in')
     .action((oldExerciseId: string, newExerciseId: string) => {
-      const storage = getStorage();
+      const storage = getStorage(getProfile());
       const workout = storage.getCurrentWorkout();
 
       if (!workout) {
@@ -347,12 +347,12 @@ export function createSwapCommand(): Command {
     });
 }
 
-export function createAddCommand(): Command {
+export function createAddCommand(getProfile: () => string | undefined): Command {
   return new Command('add')
     .description('Add an exercise to the current workout')
     .argument('<exercise>', 'Exercise ID to add')
     .action((exerciseId: string) => {
-      const storage = getStorage();
+      const storage = getStorage(getProfile());
       const workout = storage.getCurrentWorkout();
 
       if (!workout) {