const zlib = require("node:zlib");
const quantity = require("./native-quantity.cjs");
const same = (a, b) => JSON.stringify(a) === JSON.stringify(b);

function escapeText(text) {
  return [...text]
    .map((c) => {
      if (c === "&") return "&";
      if (c === "<") return "&lt;";
      if (c === ">") return "&gt;";
      const code = c.codePointAt(0);
      return code > 126 ? `&#${code};` : c;
    })
    .join("");
}

// Change text inside an existing styled run, never WPTools tags or bookmarks.
function editDocument(text, oldSheet, sheet) {
  if (
    !same({ ...oldSheet, rows: [] }, { ...sheet, rows: [] }) ||
    oldSheet.rows.length !== sheet.rows.length
  )
    throw Error("수량산출서 목록·연결·행 구조 변경은 ESTX 저장을 지원하지 않습니다.");
  const declarations = [...text.matchAll(/<(?:cs|begin)\b[^>]*>/gi)].map((m) => m[0]).join("");
  const parse = (div) => quantity.fromWpt("", "", declarations + div, [], {}).rows;
  let rowIndex = 0;
  const result = text.replace(/<div\b[^>]*>[\s\S]*?<\/div>/gi, (div) => {
    const parsed = parse(div);
    if (!parsed.length) return div;
    const before = oldSheet.rows[rowIndex],
      after = sheet.rows[rowIndex++];
    if (!before || !after || !same(parsed[0], before)) throw Error("수량산출서 원본 행 대응 오류");
    if (same(before, after)) return div;
    if (!same(before.markers, after.markers))
      throw Error("수량산출서 표지 변경은 저장할 수 없습니다.");
    for (const match of div.matchAll(/>([^<>]+)(?=<)/g)) {
      const raw = match[1],
        decoded = quantity.entities(raw.replace(/\r?\n/g, ""));
      if (!decoded) continue;
      let position = -1;
      while ((position = before.LineData.indexOf(decoded, position + 1)) >= 0) {
        const prefix = before.LineData.slice(0, position),
          suffix = before.LineData.slice(position + decoded.length);
        if (
          !after.LineData.startsWith(prefix) ||
          !after.LineData.endsWith(suffix) ||
          after.LineData.length < prefix.length + suffix.length
        )
          continue;
        const replacement = after.LineData.slice(
          prefix.length,
          after.LineData.length - suffix.length,
        );
        const at = match.index + 1;
        const candidate = div.slice(0, at) + escapeText(replacement) + div.slice(at + raw.length);
        if (same(parse(candidate)[0], after)) return candidate;
      }
    }
    throw Error(
      `수량산출서 ${rowIndex}행: 기존 서식 구간을 넘는 편집은 ESTX에 저장할 수 없습니다.`,
    );
  });
  if (rowIndex !== oldSheet.rows.length) throw Error("수량산출서 행 수 불일치");
  if (!same(quantity.fromWpt(sheet.Code, sheet.Name, result, sheet.items, sheet.options), sheet))
    throw Error("수량산출서 문서 재읽기 검산 실패");
  return result;
}

function updateQuantities(project, base, cp949) {
  const sheets = project.quantitySheets || [],
    originals = base.quantitySheets || [];
  if (sheets.length !== originals.length) throw Error("수량산출서 추가·삭제는 지원하지 않습니다.");
  const rows = project.tables.MulMainDat.map((r) => ({ ...r }));
  for (let i = 0; i < sheets.length; i++) {
    if (same(sheets[i], originals[i])) continue;
    const row = rows.find((r) => r.Code === originals[i].Code);
    const oldRow = base.tables.MulMainDat.find((r) => r.Code === originals[i].Code);
    if (!row?.Editor?.binary || !same(row.Editor, oldRow.Editor))
      throw Error("수량산출서 원본 편집기 데이터 충돌");
    const packed = Buffer.from(row.Editor.binary, "base64"),
      compressed = packed[0] === 0x78;
    const bytes = compressed
      ? zlib.inflateSync(packed, { maxOutputLength: 256 * 1024 * 1024 })
      : packed;
    const text = new TextDecoder("euc-kr", { fatal: true }).decode(bytes);
    if (!cp949(text).equals(bytes)) throw Error("수량산출서 원본 인코딩 보존 불가");
    const output = cp949(editDocument(text, originals[i], sheets[i]));
    row.Editor = { binary: (compressed ? zlib.deflateSync(output) : output).toString("base64") };
  }
  return { ...project, tables: { ...project.tables, MulMainDat: rows } };
}
module.exports = { editDocument, updateQuantities };