import { readFile } from 'node:fs/promises'
import { extname } from 'node:path'

/**
 * Resolve repeatable `--reference-image` values into what the Market API takes: an http(s) URL
 * passes through untouched (the provider fetches it), a local file becomes a data URI.
 */
export function loadReferenceImages(refs: string[]): Promise<string[]> {
  return Promise.all(refs.map(loadReferenceImage))
}

async function loadReferenceImage(ref: string): Promise<string> {
  if (ref.startsWith('http://') || ref.startsWith('https://')) return ref
  const data = await readFile(ref)
  return `data:${mimeFor(ref)};base64,${data.toString('base64')}`
}

function mimeFor(path: string): string {
  const ext = extname(path).toLowerCase()
  if (ext === '.png') return 'image/png'
  if (ext === '.jpg' || ext === '.jpeg') return 'image/jpeg'
  if (ext === '.webp') return 'image/webp'
  if (ext === '.gif') return 'image/gif'
  throw new Error(`Unsupported reference image type "${ext}": ${path}`)
}