import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
import { AudioService } from '../src/services/audioService';

// Mock WaveSurfer
function createMockWaveSurfer() {
  return {
    backend: {
      getAudioContext: vi.fn(() => ({
        state: 'running',
        sampleRate: 44100,
        destination: { channelCount: 2 },
        resume: vi.fn().mockResolvedValue(undefined),
        onstatechange: null
      })),
      ac: null,
      audioContext: null
    },
    getAudioContext: vi.fn(),
    on: vi.fn(),
    load: vi.fn(),
    play: vi.fn(),
    pause: vi.fn(),
    getCurrentTime: vi.fn(() => 0),
    getDuration: vi.fn(() => 120),
    isPlaying: vi.fn(() => false),
    unAll: vi.fn(),
    destroy: vi.fn(),
    setTime: vi.fn()
  };
}

function createMockAudioContext(state: 'suspended' | 'running' | 'closed' = 'running') {
  return {
    state,
    sampleRate: 44100,
    destination: { channelCount: 2 },
    resume: vi.fn().mockResolvedValue(undefined),
    onstatechange: null
  };
}

describe('AudioService', () => {
  let audioService: AudioService;
  let mockWaveSurfer: any;
  let mockAudioContext: any;

  beforeEach(() => {
    // Reset the singleton instance
    AudioService.resetInstance();
    audioService = AudioService.getInstance();
    
    mockWaveSurfer = createMockWaveSurfer();
    mockAudioContext = createMockAudioContext();
    
    // Mock window.AudioContext
    (globalThis as any).window = {
      AudioContext: vi.fn(() => mockAudioContext) as any
    };
  });

  afterEach(() => {
    vi.restoreAllMocks();
  });

describe('setupAudioContext', () => {
  it('should successfully access audio context via backend.getAudioContext()', () => {
    audioService['setupAudioContext'](mockWaveSurfer);
    
    expect(mockWaveSurfer.backend.getAudioContext).toHaveBeenCalled();
    expect(audioService['audioContext']).toBeDefined();
    expect(audioService['audioContext'].state).toBe('running');
  });

  it('should fall back to ws.getAudioContext() if backend method fails', () => {
    const mockWaveSurferNoBackend = {
      ...mockWaveSurfer,
      backend: null,
      getAudioContext: vi.fn(() => mockAudioContext)
    };
    
    audioService['setupAudioContext'](mockWaveSurferNoBackend);
    
    expect(mockWaveSurferNoBackend.getAudioContext).toHaveBeenCalled();
    expect(audioService['audioContext']).toBeDefined();
  });

  it('should handle case when no audio context methods work but not throw error', () => {
    const mockWaveSurferNoMethods = {
      ...mockWaveSurfer,
      backend: {
        getAudioContext: null,
        ac: null,
        audioContext: null
      },
      getAudioContext: null
    };
    
    // Should not throw error - just continue without audio context
    audioService['setupAudioContext'](mockWaveSurferNoMethods);
    
    // Audio context should remain null in this case
    expect(audioService['audioContext']).toBeNull();
  });

  it('should handle suspended audio context by resuming it', () => {
    const suspendedContext = createMockAudioContext('suspended');
    mockWaveSurfer.backend.getAudioContext.mockReturnValue(suspendedContext);
    
    audioService['setupAudioContext'](mockWaveSurfer);
    
    expect(suspendedContext.resume).toHaveBeenCalled();
  });

  it('should not throw error if audio context cannot be created - just continue', () => {
    global.window.AudioContext = vi.fn(() => {
      throw new Error('AudioContext creation failed');
    }) as any;
    
    const mockWaveSurferNoMethods = {
      ...mockWaveSurfer,
      backend: {
        getAudioContext: null,
        ac: null,
        audioContext: null
      },
      getAudioContext: null
    };
    
    // Should not throw error - just continue without audio context
    expect(() => audioService['setupAudioContext'](mockWaveSurferNoMethods))
      .not.toThrow();
    expect(audioService['audioContext']).toBeNull();
  });
});

describe('ensureAudioContext', () => {
  it('should return existing audio context if available', async () => {
    audioService['audioContext'] = mockAudioContext;
    
    const result = await audioService['ensureAudioContext']();
    
    expect(result).toBe(mockAudioContext);
  });

  it('should resume suspended audio context', async () => {
    const suspendedContext = createMockAudioContext('suspended');
    audioService['audioContext'] = suspendedContext;
    
    const result = await audioService['ensureAudioContext']();
    
    expect(suspendedContext.resume).toHaveBeenCalled();
    expect(result).toBe(suspendedContext);
  });

  it('should create new audio context if none exists', async () => {
    const result = await audioService['ensureAudioContext']();
    
    expect(global.window.AudioContext).toHaveBeenCalled();
    expect(result).toBeDefined();
    expect(result.state).toBe('running');
  });

  it('should throw error if audio context creation fails', async () => {
    global.window.AudioContext = vi.fn(() => {
      throw new Error('Creation failed');
    }) as any;
    
    await expect(audioService['ensureAudioContext']())
      .rejects
      .toThrow('Audio context creation failed: Creation failed');
  });
});

describe('getWaveSurferVersion', () => {
  it('should return WaveSurfer version if available', () => {
    audioService['wavesurfer'] = {
      version: '7.12.5'
    } as any;
    
    expect(audioService.getWaveSurferVersion()).toBe('7.12.5');
  });

  it('should return unknown if version not available', () => {
    audioService['wavesurfer'] = {} as any;
    
    expect(audioService.getWaveSurferVersion()).toBe('unknown');
  });

  it('should return null if no wavesurfer instance', () => {
    audioService['wavesurfer'] = null;
    
    expect(audioService.getWaveSurferVersion()).toBeNull();
  });
});

describe('initializeAudioContext', () => {
  it('should initialize audio context successfully', async () => {
    const result = await audioService.initializeAudioContext();
    
    expect(result).toBeDefined();
    expect(result.state).toBe('running');
    expect(audioService['audioContext']).toBe(result);
  });

  it('should resume suspended audio context', async () => {
    const suspendedContext = createMockAudioContext('suspended');
    global.window.AudioContext = vi.fn(() => suspendedContext) as any;
    
    const result = await audioService.initializeAudioContext();
    
    expect(suspendedContext.resume).toHaveBeenCalled();
    expect(result).toBe(suspendedContext);
  });

  it('should handle audio context creation errors', async () => {
    global.window.AudioContext = vi.fn(() => {
      throw new Error('AudioContext creation failed');
    }) as any;
    
    await expect(audioService.initializeAudioContext())
      .rejects
      .toThrow('Failed to initialize audio context: AudioContext creation failed');
  });
});

});