export interface TemplateContext {
  chapterNumber: number
  chapterTitle: string
  penName: string
  date: string
  volumeName: string
  previousChapterTitle: string
  outlineItem: string
  characterList: string
}

const VARS = [
  'chapterNumber',
  'chapterTitle',
  'penName',
  'date',
  'volumeName',
  'previousChapterTitle',
  'outlineItem',
  'characterList'
] as const

export function replaceChapterTemplate(body: string, ctx: TemplateContext): string {
  let out = body
  for (const key of VARS) {
    out = out.split(`{${key}}`).join(String(ctx[key]))
  }
  return out
}

export function plainTextToEditorHtml(text: string): string {
  const trimmed = text.trim()
  if (!trimmed) return '<p></p>'
  return trimmed
    .split(/\n{2,}/)
    .map((p) => `<p>${escapeHtml(p).replace(/\n/g, '<br>')}</p>`)
    .join('')
}

function escapeHtml(text: string): string {
  return text
    .replace(/&/g, '&amp;')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
}

export function bodyPlainToChapterHtml(bodyPlain: string): string {
  return plainTextToEditorHtml(bodyPlain)
}