// Pure formatters for "copy to clipboard": a single case (Q + answer + evidence) or a whole thread.
// No DOM/clipboard here (that is the caller's side effect) so this stays testable.

import type { AdvisorResponse, EvidenceUnit } from './contract'
import { resolveRegulation } from './regulation-display'

export interface CopyableCase {
  question: string
  response: AdvisorResponse | null
}

function evidenceLine(e: EvidenceUnit): string {
  const { familyLabel } = resolveRegulation({ code: e.regulation_code || e.document, short: e.document })
  const loc = [e.section, e.paragraph].filter(Boolean).join(' ')
  const ref = [familyLabel, loc].filter(Boolean).join(', ')
  return e.url ? `- ${ref} (${e.url})` : `- ${ref}`
}

/** One case as portable Markdown: question, answer (or general definition), and its evidence. */
export function formatCaseForCopy(c: CopyableCase): string {
  const parts: string[] = [`### Frage`, c.question.trim()]
  const r = c.response
  const answer = (r?.answer || r?.general_answer || '').trim()
  parts.push('', '### Antwort', answer || '(keine Antwort)')

  if (r && r.evidence.length > 0) {
    parts.push('', '### Belege', ...r.evidence.map(evidenceLine))
  }
  if (r && r.footnotes.length > 0) {
    parts.push(
      '',
      '### Fußnoten',
      ...r.footnotes.map((f, i) => {
        const head = f.ref || `Fußnote ${i + 1}`
        const src = [f.document, f.section].filter(Boolean).join(' / ')
        return `- ${[head, src].filter(Boolean).join(' — ')}${f.text ? `: ${f.text}` : ''}`
      }),
    )
  }
  return parts.join('\n')
}

/** A whole topic thread: a title heading followed by every case, separated by rules. */
export function formatThreadForCopy(title: string, cases: CopyableCase[]): string {
  const header = `# ${title.trim() || 'Compliance-Advisor-Verlauf'}`
  const body = cases.map(formatCaseForCopy).join('\n\n---\n\n')
  return `${header}\n\n${body}`
}