/** Pure prompt-sequence helpers (shared by page + tests). */

export function newId() {
  if (typeof crypto !== 'undefined' && typeof crypto.randomUUID === 'function') {
    return crypto.randomUUID()
  }
  return `ps-${Date.now().toString(36)}-${Math.random().toString(36).slice(2, 10)}`
}

export function emptyCharacter() {
  return { id: newId(), name: '', description: '' }
}

export function emptyScene(index = 1) {
  return {
    id: newId(),
    title: `Scene ${Math.max(1, index)}`,
    style: '',
    settings: '',
    characters: [emptyCharacter()],
    prompt: ''
  }
}

export function cloneSceneForNext(previous, nextIndex) {
  return {
    id: newId(),
    title: `Scene ${nextIndex}`,
    style: previous.style,
    settings: previous.settings,
    characters: (previous.characters || []).map(character => ({
      id: newId(),
      name: character.name,
      description: character.description
    })),
    prompt: previous.prompt
  }
}

export function formatCharacterLine(character) {
  const name = String(character?.name || '').trim()
  const description = String(character?.description || '').trim()
  if (!name && !description) return ''
  if (name && description) return `${name}: ${description}`
  return name || description
}

export function assembleSceneText(scene) {
  const characterBlock = (scene?.characters || [])
    .map(formatCharacterLine)
    .filter(Boolean)
    .join('\n')
  const parts = [
    String(scene?.style || '').trim(),
    String(scene?.settings || '').trim(),
    characterBlock,
    String(scene?.prompt || '').trim()
  ].filter(Boolean)
  return parts.join('\n\n')
}

/** Scenes join with \\n\\n\\n (desktop Batch double blank). Name is never included. */
export function assembleSequenceText(sequence) {
  return (sequence?.scenes || [])
    .map(assembleSceneText)
    .filter(Boolean)
    .join('\n\n\n')
}