// packages/core/src/utils/markdown-to-docx.ts
// Phase 14.5: 마크다운 → DOCX 변환 유틸리티.
// 마크다운 해석은 meeting-markdown 의 parseMarkdownBlocks 가 단일 정본이다 —
// 여기서는 블록을 docx 요소로 렌더링만 한다(docx 의존은 이 서브패스에만 격리).

import {
  Document,
  Packer,
  Paragraph,
  Table,
  TableCell,
  TableRow,
  TextRun,
  HeadingLevel,
  WidthType,
} from 'docx'
import {
  CHECKBOX_CHECKED,
  CHECKBOX_UNCHECKED,
  parseMarkdownBlocks,
  type MarkdownBlock,
} from './meeting-markdown'

const HEADING_LEVELS = {
  1: HeadingLevel.HEADING_1,
  2: HeadingLevel.HEADING_2,
  3: HeadingLevel.HEADING_3,
} as const

function tableCell(text: string, bold: boolean): TableCell {
  return new TableCell({
    children: [new Paragraph({ children: [new TextRun({ text, bold })] })],
  })
}

/** 블록을 docx 문서 요소(문단/표)로 바꾼다. 순수 매핑이라 개수·종류로 검증할 수 있다. */
export function blocksToDocxElements(blocks: readonly MarkdownBlock[]): Array<Paragraph | Table> {
  const elements: Array<Paragraph | Table> = []
  for (const block of blocks) {
    switch (block.type) {
      case 'heading':
        elements.push(new Paragraph({ text: block.text, heading: HEADING_LEVELS[block.level] }))
        break
      case 'bullet':
        elements.push(new Paragraph({ text: block.text, bullet: { level: 0 } }))
        break
      case 'checkbox':
        elements.push(
          new Paragraph({
            text: `${block.checked ? CHECKBOX_CHECKED : CHECKBOX_UNCHECKED} ${block.text}`,
            bullet: { level: 0 },
          }),
        )
        break
      case 'paragraph':
        // 줄마다 문단 하나 — 한 줄짜리 항목이 한 문단으로 합쳐지지 않게 한다
        for (const line of block.lines) {
          elements.push(new Paragraph({ children: [new TextRun(line)] }))
        }
        break
      case 'table': {
        const rows: TableRow[] = []
        if (block.header.length > 0) {
          rows.push(new TableRow({ children: block.header.map((c) => tableCell(c, true)), tableHeader: true }))
        }
        for (const row of block.rows) {
          rows.push(new TableRow({ children: row.map((c) => tableCell(c, false)) }))
        }
        if (rows.length > 0) {
          elements.push(new Table({ rows, width: { size: 100, type: WidthType.PERCENTAGE } }))
        }
        break
      }
      case 'rule':
        // 구분선은 문서 흐름상 빈 문단으로 둔다
        elements.push(new Paragraph({ text: '' }))
        break
    }
  }
  return elements
}

export async function markdownToDocx(markdown: string, title: string): Promise<Buffer> {
  const children: Array<Paragraph | Table> = [
    new Paragraph({ text: title, heading: HeadingLevel.TITLE }),
    ...blocksToDocxElements(parseMarkdownBlocks(markdown)),
  ]
  const doc = new Document({ sections: [{ children }] })
  return Buffer.from(await Packer.toBuffer(doc))
}