/* =============================================================================
 * B03_FileInput_UI_PlanImport.ts
 * 예정노선에서 가져오기(요구서 345 3-5 · PLAN 531-3) — 본보기 `B03_FileInput_UI_TempPicker.ts`.
 *   노선 칸 옆 [예정노선에서 가져오기] = 우리 회사에 지정된 확정 연도 고르기 →
 *     POST /api/dashboard/plan-routes/{assignee}/link {mode: existing, project_id: 이 프로젝트}.
 *   머리 띠 = 이어 받은 예정노선이 바뀌면 「예정노선이 바뀜 — [다시 가져오기]」(같은 길 · 자동 반영 없음).
 *   옛 결과가 지워지면 서버가 409 confirm 으로 묻고 → 확인 창 → confirm_replace 로 다시.
 * ========================================================================== */

import { API_BASE_URL, CURRENT_PROJECT_ID_KEY } from "@config/config_frontend";
import {
  createButton,
  el,
  hideLoadingOverlay,
  showConfirmDialog,
  showLoadingOverlay,
  showToast,
} from "@ui/ui_template_elements";
import { t } from "@ui/ui_template_locale";
import { openModal } from "@ui/ui_template_modal";

interface AssignedRoute {
  assignee_id: number;
  project_name: string;
  year: number;
  linked_project_id: string | null;
  linked_project_name: string | null;
  update_available: boolean;
}

interface PlanSource {
  linked: boolean;
  assignee_id?: number;
  plan_name?: string;
  year?: number;
  update_available?: boolean;
}

async function getJson<T>(path: string): Promise<T> {
  const response = await fetch(`${API_BASE_URL}${path}`, { credentials: "include" });
  if (!response.ok) throw new Error(`HTTP ${response.status}`);
  return (await response.json()) as T;
}

/** 연결 — 지울 결과가 있으면 한 번 묻고 다시 · 성공 = 참 */
async function linkRoute(
  assigneeId: number,
  projectId: string,
  lasFree: boolean,
): Promise<boolean> {
  const send = (confirmReplace: boolean): Promise<Response> =>
    fetch(`${API_BASE_URL}/dashboard/plan-routes/${assigneeId}/link`, {
      method: "POST",
      credentials: "include",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({
        mode: "existing",
        project_id: projectId,
        confirm_replace: confirmReplace,
        las_free: lasFree,
      }),
    });
  showLoadingOverlay();
  try {
    let response = await send(false);
    let data = (await response.json().catch(() => ({}))) as {
      confirm?: string;
      message?: string;
      detail?: unknown;
    };
    if (response.status === 409 && data.confirm === "replace_outputs") {
      hideLoadingOverlay();
      const agreed = await showConfirmDialog(data.message ?? "", t("D04_Import_Btn"));
      showLoadingOverlay();
      if (!agreed) return false;
      response = await send(true);
      data = (await response.json().catch(() => ({}))) as typeof data;
    }
    if (!response.ok) {
      throw new Error(typeof data.detail === "string" ? data.detail : `HTTP ${response.status}`);
    }
    showToast(t("D04_Import_Done"), "success");
    return true;
  } catch (error) {
    showToast(error instanceof Error ? error.message : String(error), "error");
    return false;
  } finally {
    hideLoadingOverlay();
  }
}

/** 노선 칸에 단추 · 본문 위에 바뀜 띠를 끼움 — `onImported` = 카드 현황 다시 읽기.
 *  프로젝트 · 「LAS 없이 설계」는 B03 화면과 같은 기억값(localStorage)을 읽음. */
export function mountPlanImport(
  buttonHost: HTMLElement,
  bannerHost: HTMLElement,
  onImported: () => void,
): void {
  const projectId = localStorage.getItem(CURRENT_PROJECT_ID_KEY) ?? "";
  if (!projectId) return;
  const lasFree = (): boolean => localStorage.getItem(`b03_las_free_${projectId}`) === "1";
  const banner = el("div", { className: "b03-file__overview-pending b03-file__plan-update" });
  banner.hidden = true;
  bannerHost.prepend(banner);

  const done = async (assigneeId: number): Promise<void> => {
    if (!(await linkRoute(assigneeId, projectId, lasFree()))) return;
    onImported();
    void refreshBanner();
  };

  async function refreshBanner(): Promise<void> {
    const source = await getJson<PlanSource>(`/projects/${projectId}/plan-source`).catch(
      () => null,
    );
    banner.hidden = !source?.update_available;
    if (!source?.update_available || source.assignee_id === undefined) return;
    const assigneeId = source.assignee_id;
    banner.replaceChildren(
      el("span", { text: `${t("D04_Update_Banner")} (${source.plan_name} ${source.year}) — ` }),
      createButton({
        label: t("D04_Update_Reimport"),
        variant: "ghost",
        size: "sm",
        onClick: () => void done(assigneeId),
      }),
    );
  }

  const openPicker = async (): Promise<void> => {
    let routes: AssignedRoute[];
    try {
      routes = (await getJson<{ routes: AssignedRoute[] }>("/dashboard/plan-routes/assigned"))
        .routes;
    } catch (error) {
      showToast(error instanceof Error ? error.message : String(error), "error");
      return;
    }
    const { close } = openModal({
      title: t("D04_Import_Title"),
      closeLabel: "×",
      mount: (body) => {
        if (!routes.length) {
          body.append(el("p", { text: t("D04_Import_Empty") }));
          return;
        }
        for (const route of routes) {
          const linked = route.linked_project_name
            ? ` · ${t("D04_Linked")}: ${route.linked_project_name}`
            : "";
          body.append(
            el("div", {
              className: "b03-file__plan-pick",
              children: [
                el("span", { text: `${route.project_name} · ${route.year}${linked}` }),
                createButton({
                  label: t("D04_Import_Btn"),
                  variant: "filled",
                  size: "sm",
                  onClick: () => {
                    close();
                    void done(route.assignee_id);
                  },
                }),
              ],
            }),
          );
        }
      },
    });
  };

  buttonHost.append(
    createButton({
      label: t("D04_Import_Btn"),
      variant: "ghost",
      onClick: () => void openPicker(),
    }),
  );
  void refreshBanner();
}