export interface AppSettings {
  theme: 'light' | 'dark' | 'system';
  audioBufferSize: number;
  sampleRate: number;
  autoSave: boolean;
  autoSaveInterval: number; // in seconds
  snapToGrid: boolean;
  gridResolution: number; // in ms
  waveformColor: string;
  showSpectrogram: boolean;
  maxHistorySize: number;
}

const DEFAULT_SETTINGS: AppSettings = {
  theme: 'system',
  audioBufferSize: 4096,
  sampleRate: 44100,
  autoSave: true,
  autoSaveInterval: 60,
  snapToGrid: false,
  gridResolution: 100,
  waveformColor: '#3b82f6',
  showSpectrogram: false,
  maxHistorySize: 50,
};

const SETTINGS_KEY = 'audio-ui-settings';

export function getSettings(): AppSettings {
  if (typeof window === 'undefined') return DEFAULT_SETTINGS;

  try {
    const stored = localStorage.getItem(SETTINGS_KEY);
    if (!stored) return DEFAULT_SETTINGS;

    const parsed = JSON.parse(stored);
    return { ...DEFAULT_SETTINGS, ...parsed };
  } catch (error) {
    console.error('Failed to load settings:', error);
    return DEFAULT_SETTINGS;
  }
}

export function saveSettings(settings: Partial<AppSettings>): void {
  if (typeof window === 'undefined') return;

  try {
    const current = getSettings();
    const updated = { ...current, ...settings };
    localStorage.setItem(SETTINGS_KEY, JSON.stringify(updated));

    // Dispatch custom event for settings updates
    window.dispatchEvent(
      new CustomEvent('settingsUpdated', { detail: updated })
    );
  } catch (error) {
    console.error('Failed to save settings:', error);
  }
}

export function resetSettings(): void {
  if (typeof window === 'undefined') return;

  try {
    localStorage.removeItem(SETTINGS_KEY);
    window.dispatchEvent(
      new CustomEvent('settingsUpdated', { detail: DEFAULT_SETTINGS })
    );
  } catch (error) {
    console.error('Failed to reset settings:', error);
  }
}