KGStudio/src/util/scaleUtil.test.ts

import { describe, it, expect, beforeEach, vi } from 'vitest';
import {
  getRootNoteFromKeySignature,
  noteNameToPitchClass,
  getScalePitchClasses,
  getModeSteps,
  getSuitableChords,
  getChordNotesInKey,
  getMatchingChordsForPitch,
  generatePianoGridBackground,
  validateFunctionalChordsJSON
} from './scaleUtil';
import { KGCore } from '../core/KGCore';
import type { KeySignature } from '../core/KGProject';
import functionalChordsData from '../../public/resources/modes/functional_chords.json';

describe('scaleUtil', () => {
  // Setup: Mock KGCore with real chord data
  beforeEach(() => {
    // Use real functional chords data from JSON file (includes name, steps, and chord data)
    KGCore.FUNCTIONAL_CHORDS_DATA = functionalChordsData;
  });

  describe('getRootNoteFromKeySignature', () => {
    it('should extract root note from C major', () => {
      expect(getRootNoteFromKeySignature('C major')).toBe('C');
    });

    it('should extract root note from F# minor', () => {
      expect(getRootNoteFromKeySignature('F# minor')).toBe('F#');
    });

    it('should extract root note from Bb major', () => {
      expect(getRootNoteFromKeySignature('Bb major')).toBe('Bb');
    });

    it('should handle Db major', () => {
      expect(getRootNoteFromKeySignature('Db major')).toBe('Db');
    });

    it('should default to C for invalid format', () => {
      const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {});
      expect(getRootNoteFromKeySignature('Invalid' as KeySignature)).toBe('C');
      expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining('Invalid key signature format'));
      warnSpy.mockRestore();
    });
  });

  describe('noteNameToPitchClass', () => {
    it('should convert C to 0', () => {
      expect(noteNameToPitchClass('C')).toBe(0);
    });

    it('should convert C# to 1', () => {
      expect(noteNameToPitchClass('C#')).toBe(1);
    });

    it('should convert Db to 1', () => {
      expect(noteNameToPitchClass('Db')).toBe(1);
    });

    it('should convert D to 2', () => {
      expect(noteNameToPitchClass('D')).toBe(2);
    });

    it('should convert E to 4', () => {
      expect(noteNameToPitchClass('E')).toBe(4);
    });

    it('should convert F to 5', () => {
      expect(noteNameToPitchClass('F')).toBe(5);
    });

    it('should convert F# to 6', () => {
      expect(noteNameToPitchClass('F#')).toBe(6);
    });

    it('should convert G to 7', () => {
      expect(noteNameToPitchClass('G')).toBe(7);
    });

    it('should convert A to 9', () => {
      expect(noteNameToPitchClass('A')).toBe(9);
    });

    it('should convert Bb to 10', () => {
      expect(noteNameToPitchClass('Bb')).toBe(10);
    });

    it('should convert B to 11', () => {
      expect(noteNameToPitchClass('B')).toBe(11);
    });

    it('should default to 0 for invalid note', () => {
      const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {});
      expect(noteNameToPitchClass('X')).toBe(0);
      expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining('Invalid note name'));
      warnSpy.mockRestore();
    });
  });

  describe('getModeSteps', () => {
    it('should return ionian steps', () => {
      expect(getModeSteps('ionian')).toEqual([2, 2, 1, 2, 2, 2, 1]);
    });

    it('should return dorian steps', () => {
      expect(getModeSteps('dorian')).toEqual([2, 1, 2, 2, 2, 1, 2]);
    });

    it('should default to ionian for invalid mode', () => {
      const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {});
      expect(getModeSteps('invalid')).toEqual([2, 2, 1, 2, 2, 2, 1]);
      expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining('Mode not found'));
      warnSpy.mockRestore();
    });
  });

  describe('getScalePitchClasses', () => {
    it('should return C major scale pitch classes', () => {
      const steps = [2, 2, 1, 2, 2, 2, 1];
      const result = getScalePitchClasses('C', steps);
      expect(result).toEqual([0, 2, 4, 5, 7, 9, 11]); // C D E F G A B
    });

    it('should return D major scale pitch classes', () => {
      const steps = [2, 2, 1, 2, 2, 2, 1];
      const result = getScalePitchClasses('D', steps);
      expect(result).toEqual([2, 4, 6, 7, 9, 11, 1]); // D E F# G A B C#
    });

    it('should return F# dorian scale pitch classes', () => {
      const steps = [2, 1, 2, 2, 2, 1, 2];
      const result = getScalePitchClasses('F#', steps);
      expect(result).toEqual([6, 8, 9, 11, 1, 3, 4]); // F# G# A B C# D# E
    });
  });

  describe('getSuitableChords', () => {
    it('should return tonic chords for C major ionian', () => {
      const result = getSuitableChords('C major', 'ionian', 'T');
      expect(result).toHaveProperty('I');
      expect(result).toHaveProperty('vi');
      expect(result).toHaveProperty('iii');
      expect(result['I']).toEqual(['C', 'E', 'G']);
      expect(result['vi']).toEqual(['A', 'C', 'E']);
    });

    it('should return subdominant chords for C major ionian', () => {
      const result = getSuitableChords('C major', 'ionian', 'S');
      expect(result).toHaveProperty('IV');
      expect(result).toHaveProperty('ii');
      expect(result['IV']).toEqual(['F', 'A', 'C']);
      expect(result['ii']).toEqual(['D', 'F', 'A']);
    });

    it('should return dominant chords for C major ionian', () => {
      const result = getSuitableChords('C major', 'ionian', 'D');
      expect(result).toHaveProperty('V');
      expect(result).toHaveProperty('V7');
      expect(result['V']).toEqual(['G', 'B', 'D']);
      expect(result['V7']).toEqual(['G', 'B', 'D', 'F']);
    });

    it('should transpose chords for D major ionian', () => {
      const result = getSuitableChords('D major', 'ionian', 'T');
      expect(result['I']).toEqual(['D', 'F#', 'A']);
      expect(result['vi']).toEqual(['B', 'D', 'F#']);
    });

    it('should transpose chords for F# major ionian', () => {
      const result = getSuitableChords('F# major', 'ionian', 'T');
      expect(result['I']).toEqual(['F#', 'A#', 'C#']);
    });

    it('should return empty object for invalid mode', () => {
      const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {});
      const result = getSuitableChords('C major', 'invalid', 'T');
      expect(result).toEqual({});
      expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining('No functional chords found'));
      warnSpy.mockRestore();
    });
  });

  describe('getChordNotesInKey', () => {
    it('should return I chord notes in C major ionian', () => {
      const result = getChordNotesInKey('I', 'C major', 'ionian');
      expect(result).toEqual(['C', 'E', 'G']);
    });

    it('should return V7 chord notes in C major ionian', () => {
      const result = getChordNotesInKey('V7', 'C major', 'ionian');
      expect(result).toEqual(['G', 'B', 'D', 'F']);
    });

    it('should transpose to D major', () => {
      const result = getChordNotesInKey('I', 'D major', 'ionian');
      expect(result).toEqual(['D', 'F#', 'A']);
    });

    it('should return empty array for invalid chord symbol', () => {
      const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {});
      const result = getChordNotesInKey('invalid', 'C major', 'ionian');
      expect(result).toEqual([]);
      expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining('Chord symbol not found'));
      warnSpy.mockRestore();
    });
  });

  describe('getMatchingChordsForPitch', () => {
    describe('valid inputs', () => {
      it('should return matching chords for C (pitch 60) in C major ionian tonic', () => {
        const result = getMatchingChordsForPitch(60, 'C major', 'ionian', 'T');

        // C major ionian T chords from JSON: I ["C","E","G"], vi ["A","C","E"], iii ["E","G","B"], I⁶ ["E","G","C"]
        // Pitch 60 = C (pitch class 0)
        // Expected matches prioritized by position:
        // 1. I chord: C is root (position 0) → [0, 4, 7] (no offset)
        // 2. vi chord: C is 2nd note (position 1) → [9, 12, 16] offset by -12 → [-3, 0, 4]
        // 3. I⁶ chord: C is 3rd note (position 2) → [4, 7, 12] offset by -12 → [-8, -5, 0]
        expect(result).toEqual([
          [0, 4, 7],      // I chord (C-E-G): C is root
          [-3, 0, 4],     // vi chord (A-C-E): C is 2nd, offset applied
          [-8, -5, 0]     // I⁶ chord (E-G-C): C is 3rd, offset applied
        ]);
      });

      it('should return matching chords for E (pitch 64) in C major ionian tonic', () => {
        const result = getMatchingChordsForPitch(64, 'C major', 'ionian', 'T');

        // Pitch 64 = E (pitch class 4)
        // Expected matches prioritized by position:
        // 1. iii chord: E is root (position 0) → [4, 7, 11] (no offset)
        // 2. I⁶ chord: E is root (position 0) → [4, 7, 12] (no offset)
        // 3. I chord: E is 2nd note (position 1) → [0, 4, 7] (no offset, 4 < 12)
        // 4. vi chord: E is 3rd note (position 2) → [9, 12, 16] offset by -12 → [-3, 0, 4]
        expect(result).toEqual([
          [4, 7, 11],     // iii chord (E-G-B): E is root
          [4, 7, 12],     // I⁶ chord (E-G-C): E is root
          [0, 4, 7],      // I chord (C-E-G): E is 2nd
          [-3, 0, 4]      // vi chord (A-C-E): E is 3rd, offset applied
        ]);
      });

      it('should prioritize root matches over other positions', () => {
        const result = getMatchingChordsForPitch(60, 'C major', 'ionian', 'T'); // C
        // First chord should have C as root (position 0)
        if (result.length > 0) {
          expect(result[0][0] % 12).toBe(0); // First note of first chord should be C
        }
      });

      it('should return matching chords for F (pitch 65) in C major ionian subdominant', () => {
        const result = getMatchingChordsForPitch(65, 'C major', 'ionian', 'S'); // F

        // Pitch 65 = F (pitch class 5)
        // C major ionian S chords from JSON: IV ["F","A","C"], ii ["D","F","A"], vi ["A","C","E"], IV⁶ ["A","C","F"]
        // Expected matches prioritized by position:
        // 1. IV chord: F is root → [5, 9, 12] offset by -12 → [-7, -3, 0]
        // 2. ii chord: F is 2nd → [2, 5, 9] (no offset)
        // 3. IV⁶ chord: F is 3rd → [9, 12, 17] offset by -12 → [-3, 0, 5]
        expect(result).toEqual([
          [5, 9, 12],    // IV chord (F-A-C): F is root, offset applied
          [2, 5, 9],      // ii chord (D-F-A): F is 2nd
          [-3, 0, 5]      // IV⁶ chord (A-C-F): F is 3rd, offset applied
        ]);
      });

      it('should return matching chords for G (pitch 67) in C major ionian dominant', () => {
        const result = getMatchingChordsForPitch(67, 'C major', 'ionian', 'D'); // G

        // Pitch 67 = G (pitch class 7)
        // C major ionian D chords from JSON: V ["G","B","D"], V7 ["G","B","D","F"], vii° ["B","D","F"], ♭II ["Db","F","Ab"]
        // Expected matches prioritized by position:
        // 1. V chord: G is root → [7, 11, 14] offset by -12 → [-5, -1, 2]
        // 2. V7 chord: G is root → [7, 11, 14, 17] offset by -12 → [-5, -1, 2, 5]
        expect(result).toEqual([
          [7, 11, 14],       // V chord (G-B-D): G is root, offset applied
          [7, 11, 14, 17]     // V7 chord (G-B-D-F): G is root, offset applied
        ]);
      });

      it('should work with different modes (dorian)', () => {
        const result = getMatchingChordsForPitch(60, 'C major', 'dorian', 'T');
        expect(result.length).toBeGreaterThan(0);
      });

      it('should transpose correctly for D major', () => {
        const result = getMatchingChordsForPitch(62, 'D major', 'ionian', 'T'); // D
        expect(result.length).toBeGreaterThan(0);
        expect(result.some(chord => chord.includes(2))).toBe(true); // Contains D (pitch class 2)
      });

      it('should handle all MIDI pitch ranges (low)', () => {
        const result = getMatchingChordsForPitch(24, 'C major', 'ionian', 'T'); // C1
        expect(Array.isArray(result)).toBe(true);
      });

      it('should handle all MIDI pitch ranges (high)', () => {
        const result = getMatchingChordsForPitch(108, 'C major', 'ionian', 'T'); // C8
        expect(Array.isArray(result)).toBe(true);
      });
    });

    describe('edge cases', () => {
      it('should return empty array for invalid mode', () => {
        const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {});
        const result = getMatchingChordsForPitch(60, 'C major', 'invalid', 'T');
        expect(result).toEqual([]);
        warnSpy.mockRestore();
      });

      it('should handle pitch class calculations correctly', () => {
        // Test that pitch 60 (C4) and pitch 72 (C5) both match C chords
        const result1 = getMatchingChordsForPitch(60, 'C major', 'ionian', 'T');
        const result2 = getMatchingChordsForPitch(72, 'C major', 'ionian', 'T');
        expect(result1.length).toBe(result2.length); // Same chords match
      });

      it('should return pitch classes in ascending order', () => {
        const result = getMatchingChordsForPitch(60, 'C major', 'ionian', 'T');
        result.forEach(chord => {
          for (let i = 1; i < chord.length; i++) {
            expect(chord[i]).toBeGreaterThan(chord[i - 1]);
          }
        });
      });

      it('should apply octave offset correctly for pitch classes >= 12', () => {
        const result = getMatchingChordsForPitch(60, 'C major', 'ionian', 'T');
        // All pitch classes should be < 12 after offset
        result.forEach(chord => {
          chord.forEach(pitchClass => {
            expect(pitchClass).toBeLessThan(24); // Allowing for extended range
          });
        });
      });
    });

    describe('pitch class calculations', () => {
      it('should correctly convert hover pitch to pitch class', () => {
        // C4 (60) should match same chords as C5 (72)
        const result1 = getMatchingChordsForPitch(60, 'C major', 'ionian', 'T');
        const result2 = getMatchingChordsForPitch(72, 'C major', 'ionian', 'T');
        expect(result1).toEqual(result2);
      });

      it('should maintain ascending pitch order in results', () => {
        const result = getMatchingChordsForPitch(64, 'C major', 'ionian', 'T');
        result.forEach(chord => {
          for (let i = 1; i < chord.length; i++) {
            expect(chord[i]).toBeGreaterThan(chord[i - 1]);
          }
        });
      });
    });

    describe('integration with helper functions', () => {
      it('should work with getSuitableChords', () => {
        const suitableChords = getSuitableChords('C major', 'ionian', 'T');
        expect(Object.keys(suitableChords).length).toBeGreaterThan(0);

        const matchingChords = getMatchingChordsForPitch(60, 'C major', 'ionian', 'T');
        expect(matchingChords.length).toBeGreaterThan(0);
      });

      it('should work with noteNameToPitchClass', () => {
        const cPitch = noteNameToPitchClass('C');
        const result = getMatchingChordsForPitch(60, 'C major', 'ionian', 'T');
        expect(result.some(chord => chord.some(pc => pc % 12 === cPitch))).toBe(true);
      });

      it('should respect KGCore.FUNCTIONAL_CHORDS_DATA structure', () => {
        // Verify the data has the expected structure
        const data = KGCore.FUNCTIONAL_CHORDS_DATA;
        expect(data).toHaveProperty('ionian');
        expect(data['ionian']).toHaveProperty('T');
        expect(data['ionian']).toHaveProperty('chords');
      });
    });
  });

  describe('generatePianoGridBackground', () => {
    it('should generate CSS background for C major ionian', () => {
      const result = generatePianoGridBackground('ionian', 'C major');
      expect(result).toContain('linear-gradient');
      expect(typeof result).toBe('string');
      expect(result).toContain('#282828');
      expect(result).toContain('#303030');
      expect(result).toContain('#404040 calc(var(--region-grid-bar-width) - 1px)');
      expect(result).toContain('#343434 calc(var(--region-grid-beat-width) - 1px)');
      expect(result).toContain('#303030 calc(var(--region-piano-key-height) * 0)');
      expect(result).toContain('#404040 calc(var(--region-piano-key-height) * 12 - 1px)');
      expect(result).toContain('#282828 calc(var(--region-piano-key-height) * 1)');
      expect(result).toContain('#343434 calc(var(--region-piano-key-height) * 2 - 1px)');
    });

    it('should generate different backgrounds for different modes', () => {
      const ionian = generatePianoGridBackground('ionian', 'C major');
      const dorian = generatePianoGridBackground('dorian', 'C major');
      expect(ionian).not.toBe(dorian);
    });
  });

  describe('validateFunctionalChordsJSON', () => {
    const validJSON = `{
      "ionian": {
        "name": "Ionian",
        "steps": [2, 2, 1, 2, 2, 2, 1],
        "T": ["I", "vi", "iii", "I⁶"],
        "S": ["IV", "ii", "vi", "IV⁶"],
        "D": ["V", "V7", "vii°", "♭II"],
        "chords": {
          "I": ["C", "E", "G"],
          "vi": ["A", "C", "E"],
          "iii": ["E", "G", "B"],
          "I⁶": ["E", "G", "C"],
          "IV": ["F", "A", "C"],
          "ii": ["D", "F", "A"],
          "IV⁶": ["A", "C", "F"],
          "V": ["G", "B", "D"],
          "V7": ["G", "B", "D", "F"],
          "vii°": ["B", "D", "F"],
          "♭II": ["Db", "F", "Ab"]
        }
      },
      "aeolian": {
        "name": "Aeolian",
        "steps": [2, 1, 2, 2, 1, 2, 2],
        "T": ["i", "VI", "III", "i⁶"],
        "S": ["iv", "ii°", "VI", "iv⁶"],
        "D": ["v", "♭VII"],
        "chords": {
          "i": ["C", "Eb", "G"],
          "VI": ["Ab", "C", "Eb"],
          "III": ["Eb", "G", "Bb"],
          "i⁶": ["Eb", "G", "C"],
          "iv": ["F", "Ab", "C"],
          "ii°": ["D", "F", "Ab"],
          "iv⁶": ["Ab", "C", "F"],
          "v": ["G", "Bb", "D"],
          "♭VII": ["Bb", "D", "F"]
        }
      }
    }`;

    describe('valid JSON', () => {
      it('should validate correct JSON with ionian and aeolian', () => {
        const result = validateFunctionalChordsJSON(validJSON);
        expect(result.valid).toBe(true);
        expect(result.errors).toEqual([]);
      });

      it('should accept empty T/S/D arrays', () => {
        const json = `{
          "ionian": {
            "name": "Test Mode",
            "steps": [2, 2, 1, 2, 2, 2, 1],
            "T": [],
            "S": [],
            "D": [],
            "chords": {}
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(true);
      });

      it('should accept mode names with underscores, dashes, and spaces', () => {
        const json = `{
          "ionian": {
            "name": "Test_Mode-123 Name",
            "steps": [2, 2, 1, 2, 2, 2, 1],
            "T": [],
            "S": [],
            "D": [],
            "chords": {}
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(true);
      });

      it('should accept notes with sharp and flat', () => {
        const json = `{
          "ionian": {
            "name": "Test",
            "steps": [2, 2, 1, 2, 2, 2, 1],
            "T": ["I"],
            "S": [],
            "D": [],
            "chords": {
              "I": ["C#", "Eb", "F#"]
            }
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(true);
      });

      it('should accept chord symbols with special characters', () => {
        const json = `{
          "ionian": {
            "name": "Test",
            "steps": [2, 2, 1, 2, 2, 2, 1],
            "T": ["I⁶", "vii°", "III+", "♭II"],
            "S": [],
            "D": [],
            "chords": {
              "I⁶": ["C", "E", "G"],
              "vii°": ["B", "D", "F"],
              "III+": ["E", "G#", "B"],
              "♭II": ["Db", "F", "Ab"]
            }
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(true);
      });
    });

    describe('invalid JSON', () => {
      it('should reject malformed JSON', () => {
        const result = validateFunctionalChordsJSON('{ invalid json }');
        expect(result.valid).toBe(false);
        expect(result.errors).toContain('Invalid JSON format');
      });

      it('should reject JSON array as root', () => {
        const result = validateFunctionalChordsJSON('[]');
        expect(result.valid).toBe(false);
        expect(result.errors).toContain('Root must be an object');
      });

      it('should reject missing ionian mode', () => {
        const json = `{
          "dorian": {
            "name": "Dorian",
            "steps": [2, 1, 2, 2, 2, 1, 2],
            "T": [],
            "S": [],
            "D": [],
            "chords": {}
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(false);
        expect(result.errors).toContain('Missing required mode: "ionian"');
      });

      it('should reject invalid mode name', () => {
        const json = `{
          "ionian": {
            "name": "Test@Mode!",
            "steps": [2, 2, 1, 2, 2, 2, 1],
            "T": [],
            "S": [],
            "D": [],
            "chords": {}
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(false);
        expect(result.errors.some(e => e.includes('"name" must be a string'))).toBe(true);
      });

      it('should reject steps with wrong number of elements', () => {
        const json = `{
          "ionian": {
            "name": "Test",
            "steps": [2, 2, 1, 2],
            "T": [],
            "S": [],
            "D": [],
            "chords": {}
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(false);
        expect(result.errors.some(e => e.includes('must contain exactly 7 integers'))).toBe(true);
      });

      it('should reject steps that do not sum to 12', () => {
        const json = `{
          "ionian": {
            "name": "Test",
            "steps": [2, 2, 2, 2, 2, 2, 2],
            "T": [],
            "S": [],
            "D": [],
            "chords": {}
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(false);
        expect(result.errors.some(e => e.includes('must sum to 12'))).toBe(true);
      });

      it('should reject non-integer steps', () => {
        const json = `{
          "ionian": {
            "name": "Test",
            "steps": [2.5, 2, 1, 2, 2, 2, 0.5],
            "T": [],
            "S": [],
            "D": [],
            "chords": {}
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(false);
        expect(result.errors.some(e => e.includes('must contain only integers'))).toBe(true);
      });

      it('should reject invalid chord symbol in T/S/D', () => {
        const json = `{
          "ionian": {
            "name": "Test",
            "steps": [2, 2, 1, 2, 2, 2, 1],
            "T": ["invalid123"],
            "S": [],
            "D": [],
            "chords": {
              "invalid123": ["C", "E", "G"]
            }
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(false);
        expect(result.errors.some(e => e.includes('Invalid chord symbol'))).toBe(true);
      });

      it('should reject chord referenced but not defined', () => {
        const json = `{
          "ionian": {
            "name": "Test",
            "steps": [2, 2, 1, 2, 2, 2, 1],
            "T": ["I"],
            "S": [],
            "D": [],
            "chords": {}
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(false);
        expect(result.errors.some(e => e.includes('referenced in T/S/D but not defined'))).toBe(true);
      });

      it('should reject invalid note name', () => {
        const json = `{
          "ionian": {
            "name": "Test",
            "steps": [2, 2, 1, 2, 2, 2, 1],
            "T": ["I"],
            "S": [],
            "D": [],
            "chords": {
              "I": ["C", "X", "G"]
            }
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(false);
        expect(result.errors.some(e => e.includes('Invalid note'))).toBe(true);
      });

      it('should reject note with invalid accidental', () => {
        const json = `{
          "ionian": {
            "name": "Test",
            "steps": [2, 2, 1, 2, 2, 2, 1],
            "T": ["I"],
            "S": [],
            "D": [],
            "chords": {
              "I": ["C##", "E", "G"]
            }
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(false);
        expect(result.errors.some(e => e.includes('Invalid note'))).toBe(true);
      });

      it('should reject lowercase note names', () => {
        const json = `{
          "ionian": {
            "name": "Test",
            "steps": [2, 2, 1, 2, 2, 2, 1],
            "T": ["I"],
            "S": [],
            "D": [],
            "chords": {
              "I": ["c", "e", "g"]
            }
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(false);
        expect(result.errors.some(e => e.includes('Invalid note'))).toBe(true);
      });
    });

    describe('error messages', () => {
      it('should provide descriptive error messages for multiple errors', () => {
        const json = `{
          "dorian": {
            "name": "Test@",
            "steps": [2, 2, 1],
            "T": "not-array",
            "S": [],
            "D": [],
            "chords": {}
          }
        }`;
        const result = validateFunctionalChordsJSON(json);
        expect(result.valid).toBe(false);
        expect(result.errors.length).toBeGreaterThan(1);
      });
    });
  });
});