/* =============================================================================
 * B09_Draft_Print_Drawings.ts
 * 인쇄 미리보기 도면 영역(PLAN 302-2) — 서버가 만든 목록 · PDF 를 그대로 받음(보는 것 = 받는 것).
 *   차례 = B07 도면번호 → 구조물 조합 도면(도번마다 한 번) · 서버 `B09_Draft_Print_Drawings_Router.py`
 *   PDF 머리 X-Aislo-Skipped-Images = 못 넣은 그림 {id: 수} → `skippedImagesOf(blob)`
 * ========================================================================== */

import { API_BASE_URL } from "@config/config_frontend";
import type { DrawingItem, FetchDrawingList, FetchDrawingsPdf } from "./B09_Draft_Print_Types";

/** 도면 한 장 — 약속 꼴(id · name = label) + 서버가 주는 칸 */
export interface PrintDrawingItem extends DrawingItem {
  source: "b07" | "structure";
  kind: string;
  label: string;
  number: string;
  confirmed: boolean;
  paper: string | null;
  /** PDF 를 만들어야 셈 — 목록에서는 null */
  images_skipped: number | null;
}

async function failure(response: Response): Promise<Error> {
  const body = (await response.json().catch(() => null)) as { message?: string } | null;
  return new Error(body?.message ?? `HTTP ${response.status}`);
}

export const fetchDrawingList: FetchDrawingList = async (projectId) => {
  const response = await fetch(`${API_BASE_URL}/projects/${projectId}/print/drawings`, {
    credentials: "include",
  });
  if (!response.ok) throw await failure(response);
  const items = (await response.json()) as Omit<PrintDrawingItem, "name">[];
  return items.map((item): PrintDrawingItem => ({ ...item, name: item.label }));
};

const skipped = new WeakMap<Blob, Record<string, number>>();

export const fetchDrawingsPdf: FetchDrawingsPdf = async (projectId, ids) => {
  const response = await fetch(`${API_BASE_URL}/projects/${projectId}/print/drawings-pdf`, {
    method: "POST",
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(ids ? { ids } : {}),
  });
  if (!response.ok) throw await failure(response);
  const blob = await response.blob();
  try {
    skipped.set(blob, JSON.parse(response.headers.get("X-Aislo-Skipped-Images") ?? "{}"));
  } catch {
    /* 머리가 깨졌으면 빠진 그림 없음으로 */
  }
  return blob;
};

/** 그 PDF 에서 못 넣은 그림 {도면 id: 수} — 없으면 빈 꼴 */
export function skippedImagesOf(blob: Blob): Record<string, number> {
  return skipped.get(blob) ?? {};
}