/* =============================================================================
 * B08_Quantity_UI_Milestone_State.ts
 * 거리이정표(PLAN 244-1) 데이터 층 — 저장본 · 캐시 · [저장] · 경로 그림 길 + 좌측 패널 카드(공사지 · 기준점).
 *
 *   저장본 = GET …/quantity/milestone(서버 정본 · 표는 서버가 셈) · 조작 = 캐시 `b08-milestone` 즉시 +
 *   표는 TS 짝(`…_Milestone_Calc`)이 바로 셈 · [저장](좌측 패널 한 줄) = PUT → 캐시 비움 · 자동 저장 없음.
 *   그림 = 올리는 즉시 서버(경로 하나 = 그림 하나 · B09 견적서 꼴).
 * ========================================================================== */

import { API_BASE_URL } from "@config/config_frontend";
import { createCheckbox } from "@ui/ui_template_checkbox";
import { createInputField, createSelectField, el } from "@ui/ui_template_elements";
import { clearState, readState, writeState } from "../A00_Common/b_page_state";
import { request } from "./B08_Quantity_UI_Hydro";
import { DIRS, ROADS, type MilestoneData, type Road } from "./B08_Quantity_Milestone_Calc";

export interface SiteInfo {
  length_m: number | null;
  mid_default_m: number | null;
  start_lonlat: [number, number] | null;
  mid_lonlat: [number, number] | null;
}

interface Payload {
  data: MilestoneData;
  site: SiteInfo;
  images: Record<string, string>;
}

/** 8방 이름 */
export const DIR_TEXT: Record<string, string> = {
  N: "북",
  NE: "북동",
  E: "동",
  SE: "남동",
  S: "남",
  SW: "남서",
  W: "서",
  NW: "북서",
};

export const EMPTY: MilestoneData = {
  site: { mid_station_m: null, mid_road: "비포장" },
  base: { enabled: false, name: "", address: "", dir: null, legs: [] },
  routes: [],
};

const changes = new EventTarget();
let saved: Payload | null = null;
let savedFor: string | null = null;

const clone = <T>(value: T): T => JSON.parse(JSON.stringify(value)) as T;

/** 저장본 읽기(프로젝트마다 한 번 · force = 다시) */
export async function loadMilestone(projectId: string, force = false): Promise<Payload> {
  if (!saved || savedFor !== projectId || force) {
    saved = await request<Payload>(`/projects/${projectId}/quantity/milestone`);
    savedFor = projectId;
    changes.dispatchEvent(new Event("change"));
  }
  return saved;
}

export const siteInfo = (): SiteInfo | null => saved?.site ?? null;
export const routeImages = (): Record<string, string> => saved?.images ?? {};

export const hasMilestoneDraft = (projectId: string): boolean =>
  readState<MilestoneData>("b08-milestone", projectId) !== null;

/** 지금 값 — 캐시 → 저장본 → 빈 꼴(늘 복사본) */
export function liveMilestone(projectId: string): MilestoneData {
  return clone(readState<MilestoneData>("b08-milestone", projectId) ?? saved?.data ?? EMPTY);
}

/** 고친 한 벌을 캐시에 · 화면에 알림 */
export function putMilestone(projectId: string, data: MilestoneData): void {
  writeState("b08-milestone", data, projectId);
  changes.dispatchEvent(new Event("change"));
}

/** host 가 붙어 있는 동안 바뀔 때마다 fn — 떨어진 뒤 첫 알림에서 스스로 뗌 */
export function onMilestoneChange(host: HTMLElement, fn: () => void): void {
  const listener = (): void => {
    if (host.isConnected) fn();
    else changes.removeEventListener("change", listener);
  };
  changes.addEventListener("change", listener);
}

/** [저장] — 캐시가 있을 때만 PUT · 서버가 표를 다시 셈 */
export async function saveMilestone(projectId: string): Promise<void> {
  const draft = readState<MilestoneData>("b08-milestone", projectId);
  if (!draft) return;
  saved = await request<Payload>(`/projects/${projectId}/quantity/milestone`, {
    method: "PUT",
    body: JSON.stringify(draft),
  });
  savedFor = projectId;
  clearState("b08-milestone", projectId);
  changes.dispatchEvent(new Event("change"));
}

const imageUrl = (projectId: string, routeId: string): string =>
  `${API_BASE_URL}/projects/${projectId}/quantity/milestone/image?route=${encodeURIComponent(routeId)}`;

async function call(input: string, init: RequestInit = {}): Promise<Response> {
  const response = await fetch(input, { credentials: "include", ...init });
  if (!response.ok) {
    const body = (await response.json().catch(() => null)) as { detail?: unknown } | null;
    throw new Error(typeof body?.detail === "string" ? body.detail : `HTTP ${response.status}`);
  }
  return response;
}

/** 경로 그림 — 올리기(교체) · 지우기는 즉시 서버 · 목록 고쳐 알림 */
export async function uploadImage(projectId: string, routeId: string, file: File): Promise<void> {
  const form = new FormData();
  form.append("file", file);
  const body = (await (
    await call(imageUrl(projectId, routeId), { method: "POST", body: form })
  ).json()) as { name: string };
  if (saved) saved.images = { ...saved.images, [routeId]: body.name };
  changes.dispatchEvent(new Event("change"));
}

export async function deleteImage(projectId: string, routeId: string): Promise<void> {
  await call(imageUrl(projectId, routeId), { method: "DELETE" });
  if (saved) {
    const rest = { ...saved.images };
    delete rest[routeId];
    saved.images = rest;
  }
  changes.dispatchEvent(new Event("change"));
}

/** 그림 → 화면 주소(blob · 쿠키 포함) */
export async function imageBlobUrl(projectId: string, routeId: string): Promise<string> {
  return URL.createObjectURL(await (await call(imageUrl(projectId, routeId))).blob());
}

export const roadOptions = ROADS.map((r) => ({ value: r, text: r }));
export const dirOptions = [
  { value: "", text: "방위 —" },
  ...DIRS.map((d) => ({ value: d, text: DIR_TEXT[d] })),
];

const km = (m: number | null | undefined): string =>
  m == null ? "-" : (m / 1000).toLocaleString(undefined, { maximumFractionDigits: 3 });

/** 좌측 패널 「거리이정표」 카드 몸 — 공사지(시점 · 중점) · 기준점(있음 · 이름 · 주소 · 방위) */
export function milestoneCardBody(projectId: string | null): HTMLElement[] {
  const mid = createInputField({ label: "중점 측점 (m)", type: "number", compact: true, min: 0 });
  const midRoad = createSelectField({
    label: "시점 → 중점 도로",
    options: roadOptions,
    compact: true,
  });
  const siteHint = el("p", { className: "b08-options__hint" });
  const has = createCheckbox("기준점 있음");
  const name = createInputField({ label: "기준점 이름", compact: true });
  const address = createInputField({ label: "기준점 주소", compact: true });
  const dir = createSelectField({
    label: "공사지에서 본 방위",
    options: dirOptions,
    compact: true,
  });
  mid.input.dataset.b08Milestone = "mid_station_m";
  has.input.dataset.b08Milestone = "base_enabled";
  const baseFields = el("div", { children: [name.root, address.root, dir.root] });

  const show = (): void => {
    if (!projectId) return;
    const data = liveMilestone(projectId);
    const site = siteInfo();
    mid.input.placeholder = site?.mid_default_m != null ? String(site.mid_default_m) : "";
    if (document.activeElement !== mid.input)
      mid.input.value = data.site.mid_station_m == null ? "" : String(data.site.mid_station_m);
    midRoad.select.value = data.site.mid_road;
    siteHint.textContent =
      `시점 = 노선 첫 점(측점 0) · 노선 ${km(site?.length_m)} km · ` +
      `중점 기본 = 노선 ÷ 2(${km(site?.mid_default_m)} km) · 빈칸 = 기본`;
    has.input.checked = data.base.enabled;
    baseFields.hidden = !data.base.enabled;
    if (document.activeElement !== name.input) name.input.value = data.base.name;
    if (document.activeElement !== address.input) address.input.value = data.base.address;
    dir.select.value = data.base.dir ?? "";
  };
  const edit = (fn: (data: MilestoneData) => void): void => {
    if (!projectId) return;
    const data = liveMilestone(projectId);
    fn(data);
    putMilestone(projectId, data);
  };
  mid.input.addEventListener("input", () =>
    edit((d) => {
      const value = Number(mid.input.value);
      d.site.mid_station_m = mid.input.value.trim() && value >= 0 ? value : null;
    }),
  );
  midRoad.select.addEventListener("change", () =>
    edit((d) => (d.site.mid_road = midRoad.select.value as Road)),
  );
  has.input.addEventListener("change", () =>
    edit((d) => {
      d.base.enabled = has.input.checked;
      if (d.base.enabled && !d.base.legs.length) d.base.legs = [{ road: "1차포장", km: null }];
    }),
  );
  name.input.addEventListener("input", () => edit((d) => (d.base.name = name.input.value)));
  address.input.addEventListener("input", () =>
    edit((d) => (d.base.address = address.input.value)),
  );
  dir.select.addEventListener("change", () =>
    edit((d) => (d.base.dir = (dir.select.value || null) as MilestoneData["base"]["dir"])),
  );

  const host = el("div", {
    children: [mid.root, midRoad.root, siteHint, has.root, baseFields],
  });
  show();
  onMilestoneChange(host, show); // 첫 알림(읽기 끝)은 패널이 붙은 뒤
  if (projectId) void loadMilestone(projectId).catch(() => undefined);
  return [host];
}