/* =============================================================================
 * M01_MasterData_Api_Fetch.ts
 * 마스터 요소 화면 서버 호출 — 계약 `resources/master_data/_화면_계약.md` · 시스템 관리자만
 * ========================================================================== */

import { API_BASE_URL } from "@config/config_frontend";

/** 줄·표 한 개 — 파일 그대로(한글 칸). */
export type Row = Record<string, unknown>;

export interface GroupInfo {
  group: string;
  files: number;
  rows: number;
}

export interface FileInfo {
  file: string;
  book: string | null;
  chapter: string;
  edition: string | null;
  rows: number;
  version: string;
}

export interface RowsPage {
  file: string;
  version: string;
  total: number;
  page: number;
  size: number;
  rows: Row[];
}

export interface TableHead {
  열쇠: string;
  이름: string;
  기준: string;
  출처: string;
  조건: Record<string, string>;
  값칸: Record<string, string>;
  count: number;
}

export interface Change {
  op: "edit" | "add" | "delete";
  key?: string;
  row?: Row;
}

export interface FileChanges {
  file: string;
  version: string;
  changes: Change[];
}

/** 저장 결과 — 200 은 새 판본 · 나머지는 화면이 그대로 안내할 상태. */
export type SaveResult =
  | { status: 200; files: { file: string; version: string }[] }
  | { status: 409; stale: string[] }
  | { status: 422; errors: string[] }
  | { status: number; detail: string };

async function call<T>(path: string, init: RequestInit = {}): Promise<{ status: number; body: T }> {
  const response = await fetch(`${API_BASE_URL}/m01${path}`, {
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    ...init,
  });
  return { status: response.status, body: (await response.json()) as T };
}

async function get<T>(path: string, params: Record<string, string | number>): Promise<T> {
  const query = new URLSearchParams(Object.entries(params).map(([k, v]) => [k, String(v)]));
  const { status, body } = await call<T & { detail?: unknown }>(`${path}?${query}`);
  if (status !== 200) throw new Error(String(body.detail ?? `HTTP ${status}`));
  return body;
}

export const fetchGroups = async (): Promise<GroupInfo[]> =>
  (await get<{ groups: GroupInfo[] }>("/groups", {})).groups;

export const fetchFiles = async (group: string): Promise<FileInfo[]> =>
  (await get<{ files: FileInfo[] }>(`/groups/${encodeURIComponent(group)}/files`, {})).files;

export const fetchRows = (file: string, page: number, size: number, q: string): Promise<RowsPage> =>
  get<RowsPage>("/rows", { file, page, size, q });

export const fetchTables = (
  file: string,
  q: string,
): Promise<{ version: string; tables: TableHead[] }> => get("/tables", { file, q });

export const fetchTable = (
  file: string,
  key: string,
): Promise<{ version: string; table: Row & { 줄: Row[] } }> => get("/table", { file, key });

export async function saveFiles(files: FileChanges[]): Promise<SaveResult> {
  const { status, body } = await call<Record<string, unknown>>("/save", {
    method: "POST",
    body: JSON.stringify({ files }),
  });
  const detail = body.detail as { stale?: string[]; errors?: string[] } | string | undefined;
  if (status === 200) return { status, files: body.files as { file: string; version: string }[] };
  if (status === 409 && typeof detail === "object") return { status, stale: detail.stale ?? [] };
  if (status === 422 && typeof detail === "object") return { status, errors: detail.errors ?? [] };
  return { status, detail: typeof detail === "string" ? detail : JSON.stringify(detail) };
}