/* =============================================================================
 * B08_Quantity_UI_Hydro.ts
 * 4탭 수리집수면적표 — 배수지점 측점마다 보조 탭 · 한 장 = 홍수량 계산서(PLAN 62-2 · 69-4~6).
 *
 *   측점 목록만 저장된 관 지점(pipe_points)에서 · 입력은 이 탭 자기 값(B05/B06 값과 안 이음)
 *   박스암거 = 사각 단면 장(73-11) · 세월교 · 물넘이포장 = 월류 높이 장(73-12) · 그 밖 = 관 장
 *   처음 값 = 표준 값 · 측점 고유 값은 빈칸 · 지역 · R24 = 공사지 자료(서버)
 *   조작 = 캐시(sessionStorage) · [저장] = B08 자기 파일(PUT …/quantity/hydro) · 뒤 캐시 비움
 *   계산 = 서버 단독(POST …/quantity/hydro/calc · 최신 응답만 채택)
 * ========================================================================== */

import "./B08_Quantity_UI_Hydro.css";
import { API_BASE_URL } from "@config/config_frontend";
import {
  createButton,
  hideLoadingOverlay,
  showLoadingOverlay,
  showToast,
} from "@ui/ui_template_elements";
import { clearState, readState, writeState } from "../A00_Common/b_page_state";
import { stationLabel } from "../common_util/common_util_station";
import { stationInterval } from "./B08_Quantity_UI_Summary";
import {
  buildHydroSheet,
  type HydroInputs,
  type HydroOptions,
  type HydroResult,
} from "./B08_Quantity_UI_Hydro_Sheet";

interface HydroStation {
  chainage_m: number;
  facility: string;
  /** 박스암거 · 세월교 · 물넘이포장(관이면 "") */
  kind: string;
  /** 계산서 장 — 시설이 정함(서버 station_rows) */
  sheet: HydroInputs["sheet"];
}

type Drafts = Record<string, Partial<HydroInputs>>;
type HydroPayload = { stations: HydroStation[]; saved: Drafts } & HydroOptions;

async function request<T>(path: string, init: RequestInit = {}): Promise<T> {
  const response = await fetch(`${API_BASE_URL}${path}`, {
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    ...init,
  });
  const body = (await response.json().catch(() => null)) as { detail?: unknown } | null;
  if (!response.ok) {
    const detail = body?.detail;
    throw new Error(typeof detail === "string" ? detail : `HTTP ${response.status}`);
  }
  return body as T;
}

function note(text: string): HTMLElement {
  const p = document.createElement("p");
  p.className = "ui-general-block__empty";
  p.textContent = text;
  return p;
}

const keyOf = (station: HydroStation): string => station.chainage_m.toFixed(3);

export async function renderHydro(host: HTMLElement, projectId: string): Promise<void> {
  host.replaceChildren(note("홍수량 계산서를 불러오는 중…"));
  let sheet: HydroPayload;
  let interval = 20;
  try {
    [sheet, interval] = await Promise.all([
      request<HydroPayload>(`/projects/${projectId}/quantity/hydro`),
      stationInterval(projectId).catch(() => 20),
    ]);
  } catch (error) {
    host.replaceChildren(note(`홍수량 계산서를 불러오지 못했습니다 — ${String(error)}`));
    return;
  }
  if (!sheet.stations.length) {
    host.replaceChildren(
      note("저장된 배수지점(관 지점)이 없습니다 — 배수유역 · 종단에서 관을 저장하세요."),
    );
    return;
  }

  let drafts: Drafts = readState<Drafts>("b08-hydro", projectId) ?? {};
  const inputsOf = (station: HydroStation): HydroInputs =>
    ({
      ...sheet.defaults,
      ...(station.sheet === "pipe" ? {} : sheet.sheet_defaults[station.sheet]),
      ...sheet.saved[keyOf(station)],
      ...drafts[keyOf(station)],
      sheet: station.sheet,
    }) as HydroInputs;

  const tabs = document.createElement("div");
  tabs.className = "b08-quantity__tabs b08-hydro__tabs";
  tabs.setAttribute("role", "tablist");
  const save = createButton({
    label: "저장",
    variant: "filled",
    onClick: () => void saveAll(),
  });
  save.dataset.b08HydroSave = "";
  const toolbar = document.createElement("div");
  toolbar.className = "b08-hydro__toolbar";
  toolbar.append(tabs, save);
  const page = document.createElement("div");
  host.replaceChildren(toolbar, page);
  let seq = 0;
  let openIndex = 0;

  const open = (index: number): void => {
    openIndex = index;
    const station = sheet.stations[index];
    tabs.replaceChildren(
      ...sheet.stations.map((s, i) => {
        const label = stationLabel(s.chainage_m, interval);
        const button = createButton({
          label: s.kind ? `${label} ${s.kind}` : label,
          variant: i === index ? "filled" : "ghost",
          size: "sm",
          onClick: () => i !== index && open(i),
        });
        button.setAttribute("role", "tab");
        button.setAttribute("aria-selected", String(i === index));
        button.dataset.b08HydroStation = String(s.chainage_m);
        button.title = s.kind || s.facility;
        return button;
      }),
    );
    const draw = (inputs: HydroInputs): void => {
      const view = buildHydroSheet(
        stationLabel(station.chainage_m, interval),
        inputs,
        sheet,
        (next) => {
          drafts[keyOf(station)] = next;
          writeState("b08-hydro", drafts, projectId);
          // 단면 가정 · 관 종류는 그림 · 식이 바뀜 — 장을 다시 그림 · 그 밖은 값만
          if (next.section !== inputs.section || next.pipe_kind !== inputs.pipe_kind) draw(next);
          else void calc(next, view.show);
        },
        station.kind,
      );
      page.replaceChildren(view.root);
      void calc(inputs, view.show);
    };
    draw(inputsOf(station));
  };

  const calc = async (
    inputs: HydroInputs,
    show: (r: HydroResult | null, message?: string) => void,
  ): Promise<void> => {
    const mine = ++seq;
    try {
      const result = await request<HydroResult>(`/projects/${projectId}/quantity/hydro/calc`, {
        method: "POST",
        body: JSON.stringify(inputs),
      });
      if (mine === seq) show(result);
    } catch (error) {
      if (mine === seq) show(null, `계산하지 못했습니다 — ${String(error)}`);
    }
  };

  /** [저장] — 측점 전부의 지금 입력을 B08 자기 파일로 · 성공하면 캐시를 비우고 저장본으로 다시 엶 */
  const saveAll = async (): Promise<void> => {
    const stations = Object.fromEntries(sheet.stations.map((s) => [keyOf(s), inputsOf(s)]));
    showLoadingOverlay();
    try {
      const body = await request<{ saved: Drafts }>(`/projects/${projectId}/quantity/hydro`, {
        method: "PUT",
        body: JSON.stringify({ stations }),
      });
      sheet.saved = body.saved;
      drafts = {};
      clearState("b08-hydro", projectId);
      showToast("수리집수면적표를 저장했습니다.", "success");
      open(openIndex);
    } catch (error) {
      showToast(`저장하지 못했습니다 — ${String(error)}`, "error");
    } finally {
      hideLoadingOverlay();
    }
  };

  open(0);
}