type Component = {
  name: string,
  type: string,
  animated: boolean,
  sizeBefore: number,
  sizeAfter: number
}

/**
 * Generates the main index file
 */
export function generateIndexFile(components: Component[]) {
  // Import all the actual assets
  const assetImports = components
    .map(({ name }) => `import { type ${name}Asset } from './${name}'`)
    .join('\n')

  const typeExports = components
    .map(({ name }) => `export type { ${name}Asset } from './${name}'`)
    .join('\n')

  const nameUnion = components
    .map(({ name }) => `'${name}'`)
    .join(' | ')

  const assetTypeUnion = components
    .map(({ name }) => `${name}Asset`)
    .join(' | ')

  const illustrationNamesArray = components
    .map(({ name }) => `'${name}'`)
    .join(', ')

  // Create the components map for lazy loading
  const componentsMap = `{
    ${components.map(({ name }) => `'${name}': () => import('./${name}')`).join(',\n    ')}
  }`

  // Generate statistics comment
  const stats = generateStatsComment(components)

  return `// AUTO-GENERATED FILE. DO NOT EDIT.
${stats}

// Re-export shared types
export type {
  IllustrationAsset,
  IllustrationAssetBrand,
  BaseSvgAsset,
  BaseImageAsset,
  BaseAnimatedImageAsset
} from './types'

// Import all assets for union type
${assetImports}

/**
 * Map of all illustrations with lazy loading
 * Use this for dynamic imports of illustrations
 */
export const lazyIllustrationsMap = ${componentsMap}

// Type exports
${typeExports}

/**
 * Union of all available illustration names
 */
export type UnityIllustrationName = ${nameUnion}

/**
 * Union of all branded illustration asset types
 * This prevents creation of fake illustration objects
 */
export type UnityIllustrationAsset = ${assetTypeUnion}

/**
 * Array of all available illustration names
 * Useful for iteration or validation
 */
export const illustrationNames: readonly UnityIllustrationName[] = [${illustrationNamesArray}] as const
`
}

/**
 * Generates statistics comment for the index file
 */
function generateStatsComment(components: Component[]) {
  const totalCount = components.length
  const svgCount = components.filter(c => c.type === 'svg').length
  const imageCount = components.filter(c => c.type === 'image').length
  const animatedCount = components.filter(c => c.animated).length

  const totalSizeBefore = components.reduce((sum, c) => sum + (c.sizeBefore || 0), 0)
  const totalSizeAfter = components.reduce((sum, c) => sum + (c.sizeAfter || 0), 0)
  const totalReduction = totalSizeBefore > 0
    ? ((totalSizeBefore - totalSizeAfter) / totalSizeBefore * 100).toFixed(1)
    : '0'

  return `//
// 📊 Generation Statistics:
// - Total illustrations: ${totalCount}
// - SVGs: ${svgCount}
// - Images: ${imageCount}
// - Animated: ${animatedCount}
// - Size optimization: ${(totalSizeBefore / 1024).toFixed(1)}KB → ${(totalSizeAfter / 1024).toFixed(1)}KB (-${totalReduction}%)
// - Generated: ${new Date().toISOString()}
//`
}