optimize key filter

.dev/project-map.md

@@ -0,0 +1,23 @@
+# Project Map
+_Generated: 2026-05-14 17:20 | Git-backed | Custom location requested by user_
+
+## Directory Structure
+src/app/modules/songs/ - song list, editing, display, key and transpose services.
+src/app/modules/shows/ - show list and show-song workflow.
+src/app/services/ - shared app services including filter state and search helpers.
+src/app/widget-modules/ - shared UI components and pipes.
+
+## Key Files
+src/app/modules/songs/song-list/filter/filter.component.* - sidebar filters for the song list.
+src/app/modules/songs/song-list/song-list.component.* - song list view model and filter application.
+src/app/modules/songs/services/key.helper.ts - canonical key lists, display mapping, and scale selection.
+src/app/services/filter-store.service.ts - in-memory filter state for songs and shows.
+src/app/services/filter.helper.ts - text search scoring and filtering helpers.
+
+## Critical Constraints
+- Memory markdown files are kept in `.dev/` by user request, not project root.
+- Song key data stores major keys uppercase and minor keys lowercase.
+- German notation uses `H`; `B` represents B-flat in flat spellings.
+
+## Hot Files
+src/app/modules/songs/song-list/filter/filter.component.ts, src/app/modules/songs/song-list/filter/filter.component.html, src/app/modules/songs/services/key.helper.ts

.dev/session-log.md

@@ -0,0 +1,12 @@
+# Session Log
+
+## 2026-05-14 17:20 [saved]
+Goal: Improve song key filter readability.
+Decisions:
+- Use root-key controls with refinement because grouped enharmonic dropdowns were still awkward to change.
+- Keep memory markdown files in `.dev/` because the user requested that location.
+Rejected:
+- Keep all sharp and flat variants as separate primary options.
+- Use a grouped enharmonic dropdown that forces users through reset-like interaction.
+Open:
+- User will review the visual result.

.gitignore

@@ -315,3 +315,6 @@ testem.log
 # System Files
 Thumbs.db
 firebase.ts
+
+# AI assistant artifacts
+context-snapshot.json

src/app/modules/songs/services/key-filter.helper.ts

@@ -0,0 +1,130 @@
+export interface KeyFilterSelection {
+  root: string;
+  mode: string;
+  accidental: string;
+  includeRelativeMinor: boolean;
+}
+
+export const KEY_FILTER_ROOTS = [
+  {value: '', label: 'Alle'},
+  {value: 'C', label: 'C'},
+  {value: 'D', label: 'D'},
+  {value: 'E', label: 'E'},
+  {value: 'F', label: 'F'},
+  {value: 'G', label: 'G'},
+  {value: 'A', label: 'A'},
+  {value: 'H', label: 'H'},
+];
+
+export const KEY_FILTER_MODES = [
+  {value: 'major', label: 'Dur'},
+  {value: 'minor', label: 'Moll'},
+];
+
+export const KEY_FILTER_ACCIDENTALS = [
+  {value: '', label: 'keins'},
+  {value: 'sharp', label: '#'},
+  {value: 'flat', label: 'b'},
+];
+
+const rootSemitones: {[root: string]: number} = {
+  C: 0,
+  D: 2,
+  E: 4,
+  F: 5,
+  G: 7,
+  A: 9,
+  H: 11,
+};
+
+const sharpKeysBySemitone = ['C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#', 'A', 'A#', 'H'];
+const flatKeysBySemitone = ['C', 'Db', 'D', 'Eb', 'E', 'F', 'Gb', 'G', 'Ab', 'A', 'B', 'H'];
+
+const relativeMinorByMajorKey: {[key: string]: string} = {
+  C: 'a',
+  'C#': 'a#',
+  Db: 'b',
+  D: 'h',
+  'D#': 'c',
+  Eb: 'c',
+  E: 'c#',
+  F: 'd',
+  'F#': 'd#',
+  Gb: 'eb',
+  G: 'e',
+  'G#': 'f',
+  Ab: 'f',
+  A: 'f#',
+  'A#': 'g',
+  B: 'g',
+  H: 'g#',
+};
+
+const relativeMajorByMinorKey: {[key: string]: string} = Object.fromEntries(Object.entries(relativeMinorByMajorKey).map(([majorKey, minorKey]) => [minorKey, majorKey]));
+
+export const matchesKeyFilter = (songKey: string, filter: KeyFilterSelection): boolean => {
+  if (!filter.root) {
+    return true;
+  }
+
+  return getKeysForFilter(filter).includes(songKey);
+};
+
+export const getKeysForFilter = (filter: KeyFilterSelection): string[] => {
+  const keys = new Set<string>();
+  const majorKey = getKeyForRoot(filter.root, 'major', filter.accidental);
+  const minorKey = getKeyForRoot(filter.root, 'minor', filter.accidental);
+
+  if (filter.mode !== 'minor' && majorKey) {
+    keys.add(majorKey);
+  }
+
+  if (filter.mode !== 'major' && minorKey) {
+    keys.add(minorKey);
+  }
+
+  if (filter.includeRelativeMinor && filter.mode !== 'minor' && majorKey && relativeMinorByMajorKey[majorKey]) {
+    keys.add(relativeMinorByMajorKey[majorKey]);
+  }
+
+  if (filter.includeRelativeMinor && filter.mode !== 'major' && minorKey && relativeMajorByMinorKey[minorKey]) {
+    keys.add(relativeMajorByMinorKey[minorKey]);
+  }
+
+  return [...keys];
+};
+
+export const supportsKeyAccidental = (root: string, accidental: string): boolean => {
+  return !root || rootSemitones[root] !== undefined || !accidental;
+};
+
+export const hasAvailableKeyForRoot = (root: string, availableKeys: string[]): boolean => {
+  if (!root) {
+    return true;
+  }
+
+  const available = new Set(availableKeys.filter(key => !!key));
+  return KEY_FILTER_MODES.some(mode =>
+    KEY_FILTER_ACCIDENTALS.some(accidental =>
+      getKeysForFilter({
+        root,
+        mode: mode.value,
+        accidental: accidental.value,
+        includeRelativeMinor: false,
+      }).some(key => available.has(key)),
+    ),
+  );
+};
+
+const getKeyForRoot = (root: string, mode: 'major' | 'minor', accidental: string): string => {
+  const semitone = rootSemitones[root];
+  if (semitone === undefined) {
+    return '';
+  }
+
+  const offset = accidental === 'sharp' ? 1 : accidental === 'flat' ? -1 : 0;
+  const normalizedSemitone = (semitone + offset + 12) % 12;
+  const key = accidental === 'flat' ? flatKeysBySemitone[normalizedSemitone] : sharpKeysBySemitone[normalizedSemitone];
+
+  return mode === 'minor' ? key.toLowerCase() : key;
+};

src/app/modules/songs/services/key.helper.spec.ts

@@ -1,4 +1,4 @@
-import {getScale, scaleMapping} from './key.helper';
+import {getScale, hasAvailableKeyForRoot, matchesKeyFilter, scaleMapping, supportsKeyAccidental} from './key.helper';
 
 describe('key.helper', () => {
   it('should render Gb correctly', () => {
@@ -12,4 +12,58 @@ describe('key.helper', () => {
   it('should keep flat-based spelling for Db', () => {
     void expect(getScale('Db')).toEqual(['C', 'Db', 'D', 'Eb', 'E', 'F', 'Gb', 'G', 'Ab', 'A', 'B', 'H']);
   });
+
+  it('should match songs by root, mode and accidental', () => {
+    void expect(matchesKeyFilter('Db', {root: 'D', mode: 'major', accidental: 'flat', includeRelativeMinor: false})).toBe(true);
+    void expect(matchesKeyFilter('d#', {root: 'D', mode: 'minor', accidental: 'sharp', includeRelativeMinor: false})).toBe(true);
+    void expect(matchesKeyFilter('D', {root: 'D', mode: 'minor', accidental: '', includeRelativeMinor: false})).toBe(false);
+  });
+
+  it('should include both major and minor when no mode is selected', () => {
+    void expect(matchesKeyFilter('G', {root: 'G', mode: '', accidental: '', includeRelativeMinor: false})).toBe(true);
+    void expect(matchesKeyFilter('g', {root: 'G', mode: '', accidental: '', includeRelativeMinor: false})).toBe(true);
+  });
+
+  it('should include the relative minor for major keys when requested', () => {
+    void expect(matchesKeyFilter('a', {root: 'C', mode: 'major', accidental: '', includeRelativeMinor: true})).toBe(true);
+    void expect(matchesKeyFilter('h', {root: 'D', mode: 'major', accidental: '', includeRelativeMinor: true})).toBe(true);
+    void expect(matchesKeyFilter('e', {root: 'G', mode: 'major', accidental: '', includeRelativeMinor: true})).toBe(true);
+  });
+
+  it('should include the relative minor when all modes are selected', () => {
+    void expect(matchesKeyFilter('a', {root: 'C', mode: '', accidental: '', includeRelativeMinor: true})).toBe(true);
+  });
+
+  it('should include the relative major for minor keys when requested', () => {
+    void expect(matchesKeyFilter('C', {root: 'A', mode: 'minor', accidental: '', includeRelativeMinor: true})).toBe(true);
+    void expect(matchesKeyFilter('G', {root: 'E', mode: 'minor', accidental: '', includeRelativeMinor: true})).toBe(true);
+  });
+
+  it('should normalize enharmonic edge spellings to stored keys', () => {
+    void expect(matchesKeyFilter('F', {root: 'E', mode: 'major', accidental: 'sharp', includeRelativeMinor: false})).toBe(true);
+    void expect(matchesKeyFilter('e', {root: 'F', mode: 'minor', accidental: 'flat', includeRelativeMinor: false})).toBe(true);
+    void expect(matchesKeyFilter('H', {root: 'C', mode: 'major', accidental: 'flat', includeRelativeMinor: false})).toBe(true);
+    void expect(matchesKeyFilter('C', {root: 'H', mode: 'major', accidental: 'sharp', includeRelativeMinor: false})).toBe(true);
+  });
+
+  it('should allow every accidental for every root', () => {
+    void expect(supportsKeyAccidental('E', 'sharp')).toBe(true);
+    void expect(supportsKeyAccidental('F', 'flat')).toBe(true);
+  });
+
+  it('should detect whether a root has any available stored key', () => {
+    void expect(hasAvailableKeyForRoot('C', ['a'])).toBe(true);
+    void expect(hasAvailableKeyForRoot('E', ['F'])).toBe(true);
+    void expect(hasAvailableKeyForRoot('H', ['C'])).toBe(true);
+    void expect(hasAvailableKeyForRoot('D', ['F', 'a'])).toBe(false);
+  });
+
+  it('should not enable a root only because its relative counterpart exists', () => {
+    void expect(hasAvailableKeyForRoot('A', ['C'])).toBe(false);
+    void expect(hasAvailableKeyForRoot('C', ['a'])).toBe(false);
+  });
+
+  it('should not apply a key filter before a root is selected', () => {
+    void expect(matchesKeyFilter('Db', {root: '', mode: 'major', accidental: 'flat', includeRelativeMinor: true})).toBe(true);
+  });
 });

src/app/modules/songs/services/key.helper.ts

@@ -154,3 +154,6 @@ export const scaleMapping: {[key: string]: string} = {
 
 export const getScale = (key: string): string[] => scaleAssignment[key];
 export const getScaleType = (key: string): string[][] => scaleTypeAssignment[key];
+
+export {KEY_FILTER_ACCIDENTALS, KEY_FILTER_MODES, KEY_FILTER_ROOTS, getKeysForFilter, hasAvailableKeyForRoot, matchesKeyFilter, supportsKeyAccidental} from './key-filter.helper';
+export type {KeyFilterSelection} from './key-filter.helper';

src/app/modules/songs/song-list/filter/filter-values.ts

@@ -1,7 +1,10 @@
 export interface FilterValues {
   q: string;
   type: string;
-  key: string;
+  keyRoot: string;
+  keyMode: string;
+  keyAccidental: string;
+  includeRelativeMinor: boolean;
   legalType: string;
   flag: string;
 }

src/app/modules/songs/song-list/filter/filter.component.html

@@ -15,15 +15,38 @@
       </mat-select>
     </mat-form-field>
 
-    <mat-form-field appearance="outline">
-      <mat-label>Tonart</mat-label>
-      <mat-select formControlName="key">
-        <mat-option [value]="null">- kein Filter -</mat-option>
-        @for (key of keys; track key) {
-        <mat-option [value]="key">{{ key | key }} </mat-option>
+    <div class="key-filter">
+      <div class="key-filter-label">Grundtonart</div>
+      <mat-button-toggle-group aria-label="Grundtonart" class="key-root-toggle-group" formControlName="keyRoot">
+        @for (root of keyRoots; track root.value) {
+          <mat-button-toggle [class.key-root-all]="!root.value" [disabled]="isKeyRootDisabled(root.value)" [value]="root.value">{{ root.label }}</mat-button-toggle>
         }
-      </mat-select>
-    </mat-form-field>
+      </mat-button-toggle-group>
+
+      @if (filterFormGroup.controls.keyRoot.value) {
+        <div class="key-filter-details">
+          <div>
+            <div class="key-filter-label">Vorzeichen</div>
+            <mat-button-toggle-group aria-label="Vorzeichen" class="key-accidental-toggle-group" formControlName="keyAccidental">
+              @for (accidental of keyAccidentals; track accidental.value) {
+                <mat-button-toggle [disabled]="isAccidentalDisabled(accidental.value)" [value]="accidental.value">{{ accidental.label }}</mat-button-toggle>
+              }
+            </mat-button-toggle-group>
+          </div>
+
+          <div>
+            <div class="key-filter-label">Dur/Moll</div>
+            <mat-button-toggle-group aria-label="Dur oder Moll" class="key-mode-toggle-group" formControlName="keyMode">
+              @for (mode of keyModes; track mode.value) {
+                <mat-button-toggle [value]="mode.value">{{ mode.label }}</mat-button-toggle>
+              }
+            </mat-button-toggle-group>
+          </div>
+
+          <mat-checkbox formControlName="includeRelativeMinor">Parallele Tonart einschließen</mat-checkbox>
+        </div>
+      }
+    </div>
 
     <mat-form-field appearance="outline">
       <mat-label>Rechtlicher Status</mat-label>

src/app/modules/songs/song-list/filter/filter.component.less

@@ -13,3 +13,85 @@ div[formGroup] {
 :host ::ng-deep .mat-mdc-form-field {
   width: 100%;
 }
+
+.key-filter {
+  display: flex;
+  flex-direction: column;
+  gap: 10px;
+  padding: 2px 0 14px;
+}
+
+.key-filter-label {
+  color: var(--mat-sys-on-surface-variant);
+  font-size: 12px;
+  font-weight: 500;
+  line-height: 18px;
+}
+
+.key-filter-details {
+  display: flex;
+  flex-direction: column;
+  gap: 12px;
+}
+
+mat-button-toggle-group {
+  display: grid;
+  grid-template-columns: repeat(4, minmax(0, 1fr));
+  width: 100%;
+}
+
+.key-mode-toggle-group {
+  grid-template-columns: repeat(2, minmax(0, 1fr));
+}
+
+.key-accidental-toggle-group {
+  grid-template-columns: repeat(3, minmax(0, 1fr));
+}
+
+mat-button-toggle {
+  min-width: 0;
+}
+
+.key-filter mat-button-toggle {
+  --mat-standard-button-toggle-selected-state-background-color: transparent;
+  --mat-standard-button-toggle-selected-state-text-color: var(--mat-sys-primary);
+}
+
+.key-root-toggle-group {
+  grid-template-columns: repeat(7, minmax(0, 1fr));
+}
+
+.key-root-all {
+  grid-column: 1 / -1;
+}
+
+:host ::ng-deep .mat-button-toggle-label-content {
+  line-height: 36px;
+  padding: 0 8px;
+}
+
+:host ::ng-deep .key-filter .mat-button-toggle-checked .mat-button-toggle-label-content {
+  color: var(--mat-sys-primary);
+  font-weight: 700;
+}
+
+:host ::ng-deep .key-filter .mat-button-toggle-checked {
+  background-color: transparent;
+}
+
+:host ::ng-deep .key-filter .mat-button-toggle-checked .mat-button-toggle-button {
+  background-color: transparent;
+}
+
+:host ::ng-deep .key-filter .mat-button-toggle-checkbox-wrapper {
+  display: none;
+}
+
+:host ::ng-deep .key-filter .mat-button-toggle-checked .mat-button-toggle-button {
+  padding-left: 0;
+  padding-right: 0;
+}
+
+:host ::ng-deep .key-filter .mat-button-toggle-checked .mat-pseudo-checkbox {
+  display: none;
+}

src/app/modules/songs/song-list/filter/filter.component.ts

@@ -6,7 +6,7 @@ import {faFilterCircleXmark} from '@fortawesome/free-solid-svg-icons';
 import {SongService} from '../../services/song.service';
 import {FilterValues} from './filter-values';
 import {Song} from '../../services/song';
-import {KEYS} from '../../services/key.helper';
+import {hasAvailableKeyForRoot, KEY_FILTER_ACCIDENTALS, KEY_FILTER_MODES, KEY_FILTER_ROOTS, supportsKeyAccidental} from '../../services/key.helper';
 import {FilterStoreService} from '../../../../services/filter-store.service';
 import {MatFormField, MatLabel} from '@angular/material/form-field';
 import {MatInput} from '@angular/material/input';
@@ -14,15 +14,16 @@ import {MatSelect} from '@angular/material/select';
 import {MatOption} from '@angular/material/core';
 
 import {LegalTypePipe} from '../../../../widget-modules/pipes/legal-type-translator/legal-type.pipe';
-import {KeyPipe} from '../../../../widget-modules/pipes/key-translator/key.pipe';
 import {SongTypePipe} from '../../../../widget-modules/pipes/song-type-translater/song-type.pipe';
 import {ButtonComponent} from '../../../../widget-modules/components/button/button.component';
+import {MatButtonToggle, MatButtonToggleGroup} from '@angular/material/button-toggle';
+import {MatCheckbox} from '@angular/material/checkbox';
 
 @Component({
   selector: 'app-filter',
   templateUrl: './filter.component.html',
   styleUrls: ['./filter.component.less'],
-  imports: [ReactiveFormsModule, MatFormField, MatLabel, MatInput, MatSelect, MatOption, LegalTypePipe, KeyPipe, SongTypePipe, ButtonComponent],
+  imports: [ReactiveFormsModule, MatFormField, MatLabel, MatInput, MatSelect, MatOption, LegalTypePipe, SongTypePipe, ButtonComponent, MatButtonToggleGroup, MatButtonToggle, MatCheckbox],
 })
 export class FilterComponent {
   private filterStore = inject(FilterStoreService);
@@ -32,14 +33,19 @@ export class FilterComponent {
   public filterFormGroup: FormGroup<{
     q: FormControl<string>;
     type: FormControl<string>;
-    key: FormControl<string>;
+    keyRoot: FormControl<string>;
+    keyMode: FormControl<string>;
+    keyAccidental: FormControl<string>;
+    includeRelativeMinor: FormControl<boolean>;
     legalType: FormControl<string>;
     flag: FormControl<string>;
   }>;
   @Input() public songs: Song[] = [];
   public types = SongService.TYPES;
   public legalType = SongService.LEGAL_TYPE;
-  public keys = KEYS;
+  public keyRoots = KEY_FILTER_ROOTS;
+  public keyModes = KEY_FILTER_MODES;
+  public keyAccidentals = KEY_FILTER_ACCIDENTALS;
 
   public constructor() {
     const fb = inject(FormBuilder);
@@ -47,7 +53,10 @@ export class FilterComponent {
     this.filterFormGroup = fb.nonNullable.group({
       q: '',
       type: '',
-      key: '',
+      keyRoot: '',
+      keyMode: 'major',
+      keyAccidental: '',
+      includeRelativeMinor: false as boolean,
       legalType: '',
       flag: '',
     });
@@ -59,7 +68,12 @@ export class FilterComponent {
     this.filterFormGroup.controls.q.valueChanges
       .pipe(debounceTime(100), distinctUntilChanged(), takeUntilDestroyed(this.destroyRef))
       .subscribe(value => this.filterValueChanged('q', value));
-    this.filterFormGroup.controls.key.valueChanges.pipe(takeUntilDestroyed(this.destroyRef)).subscribe(value => this.filterValueChanged('key', value));
+    this.filterFormGroup.controls.keyRoot.valueChanges.pipe(takeUntilDestroyed(this.destroyRef)).subscribe(value => this.updateKeyRoot(value));
+    this.filterFormGroup.controls.keyMode.valueChanges.pipe(takeUntilDestroyed(this.destroyRef)).subscribe(value => this.updateKeyMode(value));
+    this.filterFormGroup.controls.keyAccidental.valueChanges.pipe(takeUntilDestroyed(this.destroyRef)).subscribe(value => this.filterValueChanged('keyAccidental', value));
+    this.filterFormGroup.controls.includeRelativeMinor.valueChanges
+      .pipe(takeUntilDestroyed(this.destroyRef))
+      .subscribe(value => this.filterValueChanged('includeRelativeMinor', value));
     this.filterFormGroup.controls.type.valueChanges.pipe(takeUntilDestroyed(this.destroyRef)).subscribe(value => this.filterValueChanged('type', value));
     this.filterFormGroup.controls.legalType.valueChanges.pipe(takeUntilDestroyed(this.destroyRef)).subscribe(value => this.filterValueChanged('legalType', value));
     this.filterFormGroup.controls.flag.valueChanges.pipe(takeUntilDestroyed(this.destroyRef)).subscribe(value => this.filterValueChanged('flag', value));
@@ -78,14 +92,31 @@ export class FilterComponent {
 
   public get filterActive(): boolean {
     const filter = this.filterFormGroup.getRawValue();
-    return !!(filter.q || filter.type || filter.key || filter.legalType || filter.flag);
+    return !!(filter.q || filter.type || filter.keyRoot || filter.legalType || filter.flag);
   }
 
   public resetFilter(): void {
     this.filterStore.resetSongFilter();
   }
 
-  private filterValueChanged(key: keyof FilterValues, value: string): void {
+  public isAccidentalDisabled(accidental: string): boolean {
+    const root = this.filterFormGroup.controls.keyRoot.value;
+    return !!root && !supportsKeyAccidental(root, accidental);
+  }
+
+  public isKeyRootDisabled(root: string): boolean {
+    return !hasAvailableKeyForRoot(root, this.songs.map(song => song.key));
+  }
+
+  private updateKeyRoot(value: string): void {
+    this.filterValueChanged('keyRoot', value);
+  }
+
+  private updateKeyMode(value: string): void {
+    this.filterValueChanged('keyMode', value);
+  }
+
+  private filterValueChanged(key: keyof FilterValues, value: string | boolean): void {
     this.filterStore.updateSongFilter({[key]: value} as Partial<FilterValues>);
   }
 }

src/app/modules/songs/song-list/song-list.component.html

@@ -1,7 +1,7 @@
 @if (viewModel$ | async; as viewModel) {
   <app-page-frame title="Lieder" [menuBadge]="viewModel.filterActive">
     <div class="sidebar-content" sidebar>
-      <app-filter [songs]="viewModel.songs"></app-filter>
+      <app-filter [songs]="viewModel.availableSongs"></app-filter>
     </div>
     <div content>
       <app-card [padding]="false">

src/app/modules/songs/song-list/song-list.component.spec.ts

@@ -1,16 +1,22 @@
 import {ComponentFixture, TestBed} from '@angular/core/testing';
 import {SongListComponent} from './song-list.component';
-import {of} from 'rxjs';
+import {firstValueFrom, of} from 'rxjs';
 import {ActivatedRoute} from '@angular/router';
 import {TextRenderingService} from '../services/text-rendering.service';
 import {UserService} from '../../../services/user/user.service';
 import {NO_ERRORS_SCHEMA} from '@angular/core';
+import {FilterStoreService} from '../../../services/filter-store.service';
+import {Song} from '../services/song';
 
 describe('SongListComponent', () => {
   let component: SongListComponent;
   let fixture: ComponentFixture<SongListComponent>;
+  let filterStore: FilterStoreService;
 
-  const songs = [{id: 'song-1', title: 'title1', number: 1, text: '', flags: ''}];
+  const songs = [
+    {id: 'song-1', title: 'title1', number: 1, text: '', flags: '', key: 'C'},
+    {id: 'song-2', title: 'title2', number: 2, text: '', flags: '', key: 'D'},
+  ] as Song[];
 
   beforeEach(async () => {
     await TestBed.configureTestingModule({
@@ -27,10 +33,20 @@ describe('SongListComponent', () => {
   beforeEach(() => {
     fixture = TestBed.createComponent(SongListComponent);
     component = fixture.componentInstance;
+    filterStore = TestBed.inject(FilterStoreService);
     fixture.detectChanges();
   });
 
   it('should create', () => {
     void expect(component).toBeTruthy();
   });
+
+  it('should expose unfiltered songs for filter option availability', async () => {
+    filterStore.updateSongFilter({keyRoot: 'C'});
+
+    const viewModel = await firstValueFrom(component.viewModel$);
+
+    void expect(viewModel.songs.map(song => song.key)).toEqual(['C']);
+    void expect(viewModel.availableSongs.map(song => song.key)).toEqual(['C', 'D']);
+  });
 });

src/app/modules/songs/song-list/song-list.component.ts

@@ -16,6 +16,7 @@ import {RoleDirective} from '../../../services/user/role.directive';
 import {FaIconComponent} from '@fortawesome/angular-fontawesome';
 import {PageFrameComponent} from '../../../widget-modules/components/sidebar/page-frame.component';
 import {ButtonComponent} from '../../../widget-modules/components/button/button.component';
+import {matchesKeyFilter} from '../services/key.helper';
 
 interface SongListItem extends Song {
   hasChordValidationIssues: boolean;
@@ -23,6 +24,7 @@ interface SongListItem extends Song {
 
 interface SongListViewModel {
   songs: SongListItem[];
+  availableSongs: Song[];
   filterActive: boolean;
 }
 
@@ -56,6 +58,7 @@ export class SongListComponent {
 
       return {
         songs: filteredSongs,
+        availableSongs: songs,
         filterActive: this.isFilterActive(filter),
       };
     }),
@@ -69,7 +72,14 @@ export class SongListComponent {
 
   private filter(song: Song, filter: FilterValues): boolean {
     let baseFilter = !filter.type || filter.type === song.type;
-    baseFilter = baseFilter && (!filter.key || filter.key === song.key);
+    baseFilter =
+      baseFilter &&
+      matchesKeyFilter(song.key, {
+        root: filter.keyRoot,
+        mode: filter.keyMode,
+        accidental: filter.keyAccidental,
+        includeRelativeMinor: filter.includeRelativeMinor,
+      });
     baseFilter = baseFilter && (!filter.legalType || filter.legalType === song.legalType);
     baseFilter = baseFilter && (!filter.flag || this.checkFlag(filter.flag, song.flags));
 
@@ -77,7 +87,7 @@ export class SongListComponent {
   }
 
   private isFilterActive(filter: FilterValues): boolean {
-    return !!(filter.q || filter.type || filter.key || filter.legalType || filter.flag);
+    return !!(filter.q || filter.type || filter.keyRoot || filter.legalType || filter.flag);
   }
 
   private checkFlag(flag: string, flags: string) {

src/app/services/filter-store.service.ts

@@ -6,7 +6,10 @@ import {FilterValues as ShowFilterValues} from '../modules/shows/list/filter/fil
 const DEFAULT_SONG_FILTER: SongFilterValues = {
   q: '',
   type: '',
-  key: '',
+  keyRoot: '',
+  keyMode: 'major',
+  keyAccidental: '',
+  includeRelativeMinor: false,
   legalType: '',
   flag: '',
 };