const EstAttachments = (() => {
  function render() {
    const { state, esc, number, byId } = EstApp;
    const rows = state.project.attachments || [];
    byId("work-content").innerHTML =
      `<div class="business-tools"><b>첨부파일</b><label>파일 추가 <input type="file" data-attachment-add multiple></label><span>${rows.length}개</span></div><p>첨부파일은 이 작업의 JSON 저장에 포함됩니다.</p><table class="sheet"><thead><tr><th>파일명</th><th>크기 (바이트)</th><th>작업</th></tr></thead><tbody>${rows.map((row) => `<tr><td>${esc(row.name)}</td><td>${number(row.size)}</td><td><button data-attachment-download="${esc(row.id)}">내려받기</button><button data-attachment-delete="${esc(row.id)}">삭제</button></td></tr>`).join("")}</tbody></table>`;
  }
  function read(file) {
    return new Promise((resolve, reject) => {
      const reader = new FileReader();
      reader.onerror = () => reject(Error(`파일 읽기 실패: ${file.name}`));
      reader.onload = () =>
        resolve({
          id: EstApp.uid(),
          name: file.name,
          type: file.type || "",
          size: file.size,
          data: String(reader.result).split(",", 2)[1],
        });
      reader.readAsDataURL(file);
    });
  }
  function requiredBytes(project, files) {
    const metadata = files.map((file) => ({
      id: "0".repeat(36),
      name: file.name,
      type: file.type || "",
      size: file.size,
      data: "",
    }));
    const candidate = {
      ...project,
      id: project.id || "0".repeat(24),
      attachments: [...(project.attachments || []), ...metadata],
    };
    return (
      new Blob([JSON.stringify(candidate)]).size +
      files.reduce((sum, file) => sum + 4 * Math.ceil(file.size / 3), 0)
    );
  }
  function install() {
    document.addEventListener("change", async (event) => {
      const input = event.target;
      if (input.dataset.attachmentAdd === undefined || !input.files.length) return;
      const { state } = EstApp,
        key = state.documentKey,
        revision = state.revision;
      try {
        const selected = [...input.files];
        if (requiredBytes(state.project, selected) > 256 * 1024 * 1024)
          throw Error("첨부파일을 포함한 작업이 저장 한도 256MB를 초과합니다.");
        const files = await Promise.all(selected.map(read));
        if (key !== state.documentKey || revision !== state.revision)
          throw Error("작업이 변경되었습니다. 첨부파일을 다시 추가하세요.");
        EstApp.change(() => (state.project.attachments ||= []).push(...files), false);
      } catch (error) {
        state.notice = error.message;
        EstApp.render();
      } finally {
        input.value = "";
      }
    });
    document.addEventListener("click", (event) => {
      const node = event.target.closest("[data-attachment-download],[data-attachment-delete]");
      if (!node) return;
      const { state } = EstApp,
        id = node.dataset.attachmentDownload ?? node.dataset.attachmentDelete;
      const index = (state.project.attachments || []).findIndex((item) => item.id === id);
      if (index < 0) return;
      if (node.dataset.attachmentDelete !== undefined)
        EstApp.change(() => state.project.attachments.splice(index, 1), false);
      else {
        const item = state.project.attachments[index],
          text = atob(item.data),
          bytes = new Uint8Array(text.length);
        for (let i = 0; i < text.length; i++) bytes[i] = text.charCodeAt(i);
        EstApp.download(item.name, bytes, "application/octet-stream");
      }
    });
  }
  return { render, install, requiredBytes };
})();