/* =============================================================================
 * D02_PlanBase_UI_Page.ts
 * D02 1단계 기준 지정(요구서 345 3-2 · PLAN 529-3) — 메인 = 카카오맵 · 좌 = 연도 지점 표.
 *   지점 = 경계점 목록 P0..Pn(연도 i = P(i) → P(i+1)) · 직전 종점 = 다음 시점이 모양 그대로.
 *   조작(끌기 · 지도 누름 · 경위도 입력) = sessionStorage 캐시 · [저장] · [>] = PUT 정본(서버가 TM 셈)
 *   · [>] = 저장 성공 뒤 D03 · 자동저장 없음(CLAUDE.md 5장).
 *   산림청이 아니면(지정 회사 = 보기만) 끌기 · 누름 · 입력 · [저장] 없음 · [>] = 그냥 D03.
 * ========================================================================== */

import "./D02_PlanBase_UI_Style.css";
import { API_BASE_URL, CURRENT_PROJECT_ID_KEY, ROUTES } from "@config/config_frontend";
import {
  createButton,
  el,
  hideLoadingOverlay,
  showLoadingOverlay,
  showToast,
} from "@ui/ui_template_elements";
import { createPanelCard } from "@ui/ui_template_collapsible";
import { editMap, type MapPin } from "@ui/ui_template_kakao_map";
import { t } from "@ui/ui_template_locale";
import { mountGroupStep } from "../A00_Common/group_workflow";
import { fetchSessionUser } from "../A06_Login/A06_Login_Api_Fetch";
import { navigateTo } from "../A00_Common/router";

interface LonLat {
  lon: number;
  lat: number;
}
interface ServerPoint extends LonLat {
  x: number;
  y: number;
}
interface PointsView {
  year_start: number;
  year_end: number;
  epsg: number | null;
  years: Array<{ year: number; start: ServerPoint | null; end: ServerPoint | null }>;
}

const YEAR_COLORS = ["#E60046", "#1F6FEB", "#1A9E55", "#D97706", "#8B5CF6", "#0891B2"];
const KOREA_CENTER: [number, number] = [127.8, 36.3];
const DIGITS = 7; // 경위도 소수 7 자리 ≈ 1 cm

const cacheKey = (projectId: string): string => `d02_points_${projectId}`;

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 data = (await response.json().catch(() => ({}))) as { detail?: unknown };
  if (!response.ok)
    throw new Error(typeof data.detail === "string" ? data.detail : `HTTP ${response.status}`);
  return data as T;
}

/** 서버 연도 행 → 경계점 목록(연도 수 + 1) */
function boundaryPoints(view: PointsView): Array<LonLat | null> {
  const pick = (p: ServerPoint | null): LonLat | null => (p ? { lon: p.lon, lat: p.lat } : null);
  return [pick(view.years[0]?.start ?? null), ...view.years.map((y) => pick(y.end))];
}

export async function renderD02PlanBase(root: HTMLElement): Promise<void> {
  const projectId = localStorage.getItem(CURRENT_PROJECT_ID_KEY) ?? "";
  const mapHost = el("div", { className: "d02-map" });
  const table = el("div", { className: "d02-points" });
  const info = el("p", { className: "d02-info" });
  const card = createPanelCard(t("D02_Points_Title"), false);
  const pointsHint = el("p", { className: "d02-info", text: t("D02_Points_Hint") });
  card.append(pointsHint, table, info);
  const save = createButton({
    label: t("D02_Save"),
    variant: "filled",
    onClick: () => void store(),
  });
  const actions = el("div", { className: "ui-sidebar-actions", children: [save] });
  const left = el("div", { className: "ui-sidebar-panel d02-panel", children: [card, actions] });
  mountGroupStep(root, ROUTES.D02_PLAN_BASE, { mainContent: mapHost, leftPanel: left });

  let view: PointsView | null = null;
  let points: Array<LonLat | null> = [];
  let active: number | null = null; // 지도 누름이 놓을 지점
  let editable = false; // 산림청만 고침

  const years = (): number[] => (view ? view.years.map((y) => y.year) : []);
  const pointName = (i: number): string => {
    const ys = years();
    if (i === 0) return `${ys[0]} ${t("D02_Start")}`;
    if (i === ys.length) return `${ys[i - 1]} ${t("D02_End")}`;
    return `${ys[i - 1]} ${t("D02_End")} · ${ys[i]} ${t("D02_Start")}`;
  };
  const firstEmpty = (): number | null => {
    const i = points.findIndex((p) => !p);
    return i < 0 ? null : i;
  };
  const remember = (): void =>
    sessionStorage.setItem(cacheKey(projectId), JSON.stringify({ points }));

  const map = editMap({
    hint: t("D02_Map_Hint"),
    center: () => KOREA_CENTER,
    onMove: (key, lon, lat) => place(Number(key), { lon, lat }),
    onClick: (lon, lat) => {
      if (!editable) return;
      if (active === null) return showToast(t("D02_Pick_Point"), "info");
      place(active, { lon, lat });
    },
  });
  mapHost.append(map.root);

  function place(index: number, at: LonLat): void {
    points[index] = { lon: +at.lon.toFixed(DIGITS), lat: +at.lat.toFixed(DIGITS) };
    if (index === active) active = firstEmpty(); // 놓은 지점 = 다음 빈 지점으로
    remember();
    paint(String(index));
  }

  /** focus = 고친 지점(보기 밖이면 그리로) · 빈 값 = 보기 그대로 */
  function drawMap(focus = ""): void {
    const pins: MapPin[] = points.flatMap((p, i) =>
      p ? [{ key: String(i), name: pointName(i), lon: p.lon, lat: p.lat, movable: editable }] : [],
    );
    const lines: Array<Array<[number, number]>> = [];
    const colors: string[] = [];
    years().forEach((_, i) => {
      const a = points[i];
      const b = points[i + 1];
      if (!a || !b) return;
      lines.push([
        [a.lat, a.lon],
        [b.lat, b.lon],
      ]);
      colors.push(YEAR_COLORS[i % YEAR_COLORS.length]);
    });
    map.set(pins, lines, colors, focus);
  }

  function drawTable(): void {
    const rows = points.map((p, i) => {
      const lon = el("input", { className: "d02-points__input" }) as HTMLInputElement;
      const lat = el("input", { className: "d02-points__input" }) as HTMLInputElement;
      lon.type = lat.type = "number";
      lon.step = lat.step = "any";
      lon.placeholder = t("D02_Lon");
      lat.placeholder = t("D02_Lat");
      lon.value = p ? String(p.lon) : "";
      lat.value = p ? String(p.lat) : "";
      lon.disabled = lat.disabled = !editable;
      lon.dataset.point = lat.dataset.point = String(i);
      lon.dataset.axis = "lon";
      lat.dataset.axis = "lat";
      const typed = (): void => {
        const at = { lon: Number.parseFloat(lon.value), lat: Number.parseFloat(lat.value) };
        const ok = at.lon >= 120 && at.lon <= 135 && at.lat >= 30 && at.lat <= 45;
        lon.classList.toggle("is-invalid", !ok);
        lat.classList.toggle("is-invalid", !ok);
        if (ok) place(i, at);
      };
      lon.addEventListener("change", typed);
      lat.addEventListener("change", typed);
      const pick = createButton({
        label: "📍",
        variant: "ghost",
        size: "sm",
        onClick: () => {
          active = i;
          drawTable();
        },
      });
      pick.title = pick.ariaLabel = t("D02_Pick_Point");
      pick.hidden = !editable;
      const row = el("div", {
        className: `d02-points__row${active === i ? " is-active" : ""}`,
        children: [
          el("span", { className: "d02-points__name", text: pointName(i) }),
          pick,
          lon,
          lat,
        ],
      });
      const color = YEAR_COLORS[Math.min(i, years().length - 1) % YEAR_COLORS.length];
      row.style.setProperty("--d02-year-color", color);
      return row;
    });
    table.replaceChildren(...rows);
    const saved = view?.years.find((y) => y.start);
    info.textContent = view?.epsg
      ? `${t("D02_Saved_Crs")} EPSG:${view.epsg}` +
        (saved?.start
          ? ` · ${saved.year} X ${saved.start.x.toFixed(3)} Y ${saved.start.y.toFixed(3)}`
          : "")
      : t("D02_Not_Saved");
  }

  function paint(focus = ""): void {
    drawTable();
    drawMap(focus);
  }

  function adopt(next: PointsView): void {
    view = next;
    points = boundaryPoints(next);
  }

  async function store(): Promise<boolean> {
    if (!view) return false;
    showLoadingOverlay();
    try {
      const body = {
        years: years().map((year, i) => ({ year, start: points[i], end: points[i + 1] })),
      };
      adopt(
        await request<PointsView>(`/projects/${projectId}/plan/points`, {
          method: "PUT",
          body: JSON.stringify(body),
        }),
      );
      sessionStorage.removeItem(cacheKey(projectId));
      active = firstEmpty();
      paint();
      showToast(t("D02_Saved"), "success");
      return true;
    } catch (error) {
      showToast(error instanceof Error ? error.message : String(error), "error");
      return false;
    } finally {
      hideLoadingOverlay();
    }
  }

  // [>] = 저장 성공 뒤 D03(지형 받기 시작은 D03 몫) · 실패면 머묾
  left.addEventListener("ui-step-nav", (event) => {
    if ((event as CustomEvent<number>).detail !== 1) return;
    event.stopPropagation();
    if (!editable) return navigateTo(ROUTES.D03_PLAN_ANALYSIS);
    void store().then((ok) => ok && navigateTo(ROUTES.D03_PLAN_ANALYSIS));
  });

  try {
    editable = !!(await fetchSessionUser())?.is_forest_service;
    save.hidden = !editable;
    if (!editable) {
      const mapHint = map.root.querySelector<HTMLElement>("[data-kakao-map-hint]");
      pointsHint.textContent = t("D02_View_Only");
      if (mapHint) mapHint.textContent = t("D02_View_Only");
    }
    adopt(await request<PointsView>(`/projects/${projectId}/plan/points`));
    const cached = JSON.parse(sessionStorage.getItem(cacheKey(projectId)) ?? "null") as {
      points?: Array<LonLat | null>;
    } | null;
    if (editable && cached?.points?.length === points.length) points = cached.points;
    active = firstEmpty();
    paint();
  } catch (error) {
    table.replaceChildren(
      el("p", { className: "d02-info", text: error instanceof Error ? error.message : "" }),
    );
  }
}