/**
 * Example custom image backend adapter (feature 2026-08-16).
 *
 * Any OpenAI-compatible-ish or arbitrary REST API can be plugged in by writing
 * a file like this and pointing a backend at it:
 *
 *   dsh-multimodal:
 *     image:
 *       backends:
 *         my-api:
 *           kind: custom
 *           adapterFile: D:/path/to/example-custom.mjs
 *           baseURL: https://api.example.com/v1
 *           apiKeyEnv: MY_API_KEY
 *           model: my-image-model
 *           defaultSize: 1024*1024
 *       activeBackend: my-api
 *
 * The adapter receives everything it needs (prompt, size, key, baseURL, model,
 * signal, fetch, log) and must return image URLs or base64 payloads.
 * Loaded with full process privileges — only point it at files you trust.
 */

/**
 * @type {import('../../src/image-gen.ts').CustomImageBackendAdapter}
 */
export default {
  async generate({ prompt, size, n, negative_prompt, reference_image, apiKey, baseURL, model, signal, fetch, log }) {
    log(`calling ${model} size=${size} n=${n}`)

    // Arbitrary protocol: build your own request here.
    const body = {
      model,
      prompt,
      size,
      n: Math.max(1, n),
      ...(negative_prompt !== undefined ? { negative_prompt } : {}),
      ...(reference_image !== undefined ? { reference_image } : {}),
    }

    const response = await fetch(`${baseURL.replace(/\/$/, '')}/images/generate`, {
      method: 'POST',
      headers: {
        'content-type': 'application/json',
        authorization: `Bearer ${apiKey}`,
      },
      body: JSON.stringify(body),
      signal,
    })
    if (!response.ok) {
      const text = await response.text().catch(() => '')
      throw new Error(`my-api HTTP ${response.status}: ${text.slice(0, 200)}`)
    }
    const data = await response.json()

    // Adapt the response shape to the contract: urls[] and/or b64s[].
    const urls = Array.isArray(data.images) ? data.images.map((it) => it.url).filter(Boolean) : []
    const b64s = Array.isArray(data.images) ? data.images.map((it) => it.b64_json).filter(Boolean) : []
    log(`got ${urls.length} urls, ${b64s.length} base64`)
    return { urls, b64s }
  },
}