import { ReadingPreference } from '@/types'

const PRESETS: Record<string, ReadingPreference> = {
  default: {
    fontFamily: 'georgia',
    fontSize: 18,
    lineHeight: 1.8,
    letterSpacing: 0,
    textAlign: 'left',
    backgroundColor: '#faf8f3',
    textColor: '#333333',
    margin: 'normal',
    preset: 'default'
  },
  dyslexia: {
    fontFamily: 'atkinson',
    fontSize: 18,
    lineHeight: 1.9,
    letterSpacing: 0.08,
    textAlign: 'left',
    backgroundColor: '#f5f5dc',
    textColor: '#333333',
    margin: 'normal',
    preset: 'dyslexia'
  },
  highContrast: {
    fontFamily: 'inter',
    fontSize: 16,
    lineHeight: 1.6,
    letterSpacing: 0,
    textAlign: 'left',
    backgroundColor: '#000000',
    textColor: '#ffffff',
    margin: 'wide',
    preset: 'highContrast'
  },
  minimal: {
    fontFamily: 'georgia',
    fontSize: 16,
    lineHeight: 1.6,
    letterSpacing: 0,
    textAlign: 'left',
    backgroundColor: '#ffffff',
    textColor: '#000000',
    margin: 'narrow',
    preset: 'minimal'
  }
}

const STORAGE_KEY = 'bibleReaderPreferences'

export function getPreset(name: keyof typeof PRESETS): ReadingPreference {
  return PRESETS[name]
}

export function loadPreferences(): ReadingPreference {
  if (typeof window === 'undefined') {
    return PRESETS.default
  }

  try {
    const stored = localStorage.getItem(STORAGE_KEY)
    return stored ? JSON.parse(stored) : PRESETS.default
  } catch {
    return PRESETS.default
  }
}

export function savePreferences(prefs: ReadingPreference): void {
  if (typeof window === 'undefined') return

  try {
    localStorage.setItem(STORAGE_KEY, JSON.stringify(prefs))
  } catch (e) {
    console.error('Failed to save preferences:', e)
  }
}

export function getCSSVariables(prefs: ReadingPreference): Record<string, string> {
  return {
    '--font-family': getFontStack(prefs.fontFamily),
    '--font-size': `${prefs.fontSize}px`,
    '--line-height': `${prefs.lineHeight}`,
    '--letter-spacing': `${prefs.letterSpacing}em`,
    '--text-align': prefs.textAlign,
    '--bg-color': prefs.backgroundColor,
    '--text-color': prefs.textColor,
    '--margin-width': getMarginWidth(prefs.margin),
  }
}

function getFontStack(fontFamily: string): string {
  const stacks: Record<string, string> = {
    georgia: 'Georgia, serif',
    inter: 'Inter, -apple-system, BlinkMacSystemFont, sans-serif',
    atkinson: '"Atkinson Hyperlegible", sans-serif',
    merriweather: '"Merriweather", serif',
  }
  return stacks[fontFamily] || stacks.georgia
}

function getMarginWidth(margin: string): string {
  const margins: Record<string, string> = {
    narrow: 'max(1rem, 5%)',
    normal: 'max(2rem, 10%)',
    wide: 'max(4rem, 15%)',
  }
  return margins[margin] || margins.normal
}