#!/usr/bin/env node
// Prints the image-edit request for one lifestyle scene. It does not call any API.
// Usage: node scripts/build-input.mjs --product "Ostra coffee bag" --image https://... --scene cafe-counter [--ratio 4:5|1:1|16:9] [--draft] [--props "..."]
// --scene is a recipe id from references/scenes.json, or free text starting with "custom:".
import { readFileSync } from 'node:fs'
import { dirname, join } from 'node:path'
import { fileURLToPath } from 'node:url'

const root = join(dirname(fileURLToPath(import.meta.url)), '..')
const usage = 'Usage: node scripts/build-input.mjs --product "Name" --image https://... --scene <id> [--ratio 4:5|1:1|16:9] [--draft] [--model primary|fallback] [--props "..."]'
const allowed = new Set(['product', 'image', 'scene', 'ratio', 'props', 'draft', 'model'])
const options = {}
const args = process.argv.slice(2)
for (let index = 0; index < args.length; index += 1) {
  const key = args[index]
  if (!key.startsWith('--') || !allowed.has(key.slice(2))) {
    console.error(`Unknown argument: ${key}`)
    console.error(usage)
    process.exit(1)
  }
  if (key === '--draft') {
    options.draft = true
    continue
  }
  const value = args[index + 1]
  if (value === undefined || value.startsWith('--')) {
    console.error(`${key} needs a value.`)
    console.error(usage)
    process.exit(1)
  }
  options[key.slice(2)] = value
  index += 1
}
const scenes = JSON.parse(readFileSync(join(root, 'references/scenes.json'), 'utf8'))
const { product, image, scene } = options
if (!product || !image || !scene) {
  console.error(usage)
  console.error(`Scene ids: ${Object.keys(scenes).join(', ')}`)
  process.exit(1)
}
if (!/^https:\/\//.test(image)) {
  console.error('The product photo must be a public https URL.')
  process.exit(1)
}
let recipe = scenes[scene]
if (!recipe && scene.startsWith('custom:')) {
  recipe = { scene: scene.slice(7).trim(), light: 'soft natural light from one side, consistent colour temperature across the scene.', camera: '50mm lens, shallow depth of field.' }
}
if (!recipe) {
  console.error(`Unknown scene "${scene}". Use one of: ${Object.keys(scenes).join(', ')}, or custom:<description>.`)
  process.exit(1)
}
const settings = JSON.parse(readFileSync(join(root, 'assets/generation-input.json'), 'utf8'))
const ratio = options.ratio ?? '4:5'
const size = settings.ratios[ratio]
if (!size) {
  console.error('Ratio must be 1:1, 4:5 or 16:9.')
  process.exit(1)
}
const template = readFileSync(join(root, 'assets/prompt-template.md'), 'utf8').trim()
const values = {
  product,
  scene: recipe.scene,
  light: recipe.light,
  camera: recipe.camera,
  props: options.props ? `Props and details, kept away from the label: ${options.props}.` : '',
}
// One pass over the template, so text inside a value is never treated as a placeholder.
const prompt = template.replace(/\{\{(\w+)\}\}/g, (match, name) => (name in values ? values[name] : match)).replace(/\s{2,}/g, ' ').trim()

const useFallback = options.model === 'fallback'
if (options.model !== undefined && !['primary', 'fallback'].includes(options.model)) {
  console.error('--model must be primary or fallback.')
  process.exit(1)
}
if (useFallback) {
  // fal-ai/nano-banana-pro/edit: about $0.15 per image. It takes aspect_ratio and resolution, not image_size and quality.
  const input = {
    prompt,
    image_urls: [image],
    aspect_ratio: ratio,
    resolution: options.draft ? '1K' : '2K',
    num_images: 1,
    output_format: 'jpeg',
  }
  console.log(JSON.stringify({ model: settings.fallback_model, input }, null, 2))
} else {
  const input = {
    ...settings.input,
    ...(options.draft ? { quality: settings.draft.quality } : {}),
    image_size: options.draft ? settings.draft.sizes[ratio] : size,
    image_urls: [image],
    prompt,
  }
  console.log(JSON.stringify({ model: settings.model, input }, null, 2))
}