/* =============================================================================
 * E03_StabSection_UI_Plan.ts
 * E03 위 평면 위험 띠(PLAN 532-3) — 측점 중심을 이은 노선을 그 조건 판정 색으로(이웃 측점 사이
 *   가운데서 끊음 · 북쪽 위 · 같은 축척) · 고른 측점 표시 · 누르면 가장 가까운 측점.
 *   범례 = 판정마다 아이콘 + 글 + 측점 수. 계산은 logic `bandSegments` · `planFit`.
 *   확대 · 이동 = 공용 `attachSvgZoomPan`(휠 · 가운데 끌기 · 두 번 누름 원배율 · 요구 390) · 측점 글 솎음
 *   = logic `labelStride` · `planLabelKeys` · 배율 · 폭은 바깥 `PlanView` 가 쥠(다시 지어도 살아남음).
 * ========================================================================== */

import { createBadge } from "@ui/ui_template_badge";
import { attachSvgZoomPan, type ZoomPanState } from "../A00_Common/b_svg_zoom_pan";
import { stationLabel } from "../common_util/common_util_station";
import { el } from "@ui/ui_template_elements";
import { t, type LocaleKey } from "@ui/ui_template_locale";
import {
  bandSegments,
  labelStride,
  planFit,
  planLabelKeys,
  verdictOf,
  type Condition,
  type Point,
  type StationRow,
} from "./logic/E03_StabSection_Logic";
import { card } from "./E03_StabSection_UI_Parts";
import { svgEl } from "./E03_StabSection_UI_Section";

const H = 96;
const PAD = 10;
const LABEL_GAP = 64; // 측점 글 사이 최소 화면 간격(px)

/** 띠 배율 · 그때 폭 — 폭이 바뀌면 원배율로 */
export interface PlanView {
  zoom?: ZoomPanState;
  width?: number;
}

export function buildPlan(
  rows: StationRow[],
  condition: Condition,
  active: string | null,
  interval: number,
  state: PlanView,
  onSelect: (key: string) => void,
): HTMLElement {
  const box = card("e03-plan");
  const head = el("div", { className: "e03-card__head" });
  head.append(el("h3", { className: "e03-card__title", text: t("E03_Plan") }));
  const legend = el("div", { className: "e03-legend", attrs: { "data-role": "plan-legend" } });
  const counts = { ok: 0, ng: 0, none: 0 };
  rows.forEach((r) => (counts[verdictOf(r, condition)] += 1));
  for (const v of ["ng", "ok", "none"] as const) {
    if (!counts[v]) continue;
    const item = createBadge(
      `${t(`E03_Verdict_${v}` as LocaleKey)} ${counts[v]}`,
      v === "ok" ? "success" : v === "ng" ? "danger" : "neutral",
      { kind: "lamp" },
    );
    item.classList.add("e03-verdict", `e03-verdict--${v}`);
    legend.append(item);
  }
  head.append(legend);
  box.append(head);

  const host = el("div");
  box.append(host);
  const ro = new ResizeObserver(() => draw());
  const draw = (): void => {
    if (!host.isConnected) return void ro.disconnect(); // 다시 지은 띠 — 옛 것은 손 뗌
    const W = Math.max(host.clientWidth, 300);
    const segs = bandSegments(rows, condition);
    const all: Point[] = segs.flatMap((s) => s.points);
    const svg = svgEl("svg", { viewBox: `0 0 ${W} ${H}`, "data-role": "plan" });
    host.replaceChildren(svg);
    if (!all.length) return;
    const fit = planFit(all, W, H, PAD);
    const scr = (p: Point): Point => [fit.k * p[0] + fit.tx, -fit.k * p[1] + fit.ty];
    const layer = svgEl("g", { "data-role": "plan-layer" }) as SVGGElement;
    for (const seg of segs) {
      layer.append(
        svgEl("polyline", {
          points: seg.points.map((p) => scr(p).join(",")).join(" "),
          class: `e03-plan__seg e03-plan__seg--${seg.verdict}`,
          "data-verdict": seg.verdict,
        }),
      );
    }
    const centers = rows
      .filter((r) => r.center && r.center[0] !== null && r.center[1] !== null)
      .sort((a, b) => a.chainage_m - b.chainage_m);
    const at = (r: StationRow): Point => scr([r.center![0]!, r.center![1]!]);
    // 측점 간격 하나의 화면 길이(원배율) — 중심 이은 길이 ÷ 누가 길이 × 간격
    const span =
      centers.length > 1 ? centers[centers.length - 1].chainage_m - centers[0].chainage_m : 0;
    let len = 0;
    for (let i = 1; i < centers.length; i += 1) {
      const [a, b] = [at(centers[i - 1]), at(centers[i])];
      len += Math.hypot(b[0] - a[0], b[1] - a[1]);
    }
    const intervalPx = span > 0 ? (len / span) * interval : 0;
    const maxScale = Math.min(500, Math.max(8, Math.ceil(240 / Math.max(intervalPx, 1e-3))));
    const picked = centers.find((r) => r.key === active);
    const pick = picked
      ? svgEl("circle", {
          cx: at(picked)[0],
          cy: at(picked)[1],
          r: 6,
          class: "e03-plan__pick",
          "data-key": picked.key,
        })
      : null;
    const labels = svgEl("g", { class: "e03-plan__labels" }) as SVGGElement;
    layer.append(labels, ...(pick ? [pick] : []));
    svg.append(layer);
    let stride = 0;
    const apply = (s: ZoomPanState): void => {
      state.zoom = s;
      labels.style.setProperty("--e03-label-k", String(1 / s.scale)); // 글 · 표시는 확대 안 함
      pick?.setAttribute("r", String(6 / s.scale));
      const next = intervalPx > 0 ? labelStride(intervalPx * s.scale, LABEL_GAP) : 100;
      if (next === stride) return;
      stride = next;
      const keep = new Set(planLabelKeys(centers, interval, stride, active));
      labels.replaceChildren(
        ...centers
          .filter((r) => keep.has(r.key))
          .map((r) =>
            svgEl(
              "text",
              {
                x: at(r)[0],
                y: at(r)[1],
                dy: "-0.9em",
                class: "e03-label e03-plan__label",
                "data-key": r.key,
              },
              stationLabel(r.chainage_m, interval, 1),
            ),
          ),
      );
    };
    const initial = state.width === W ? state.zoom : undefined;
    state.width = W;
    attachSvgZoomPan({
      svg,
      layer,
      widthPx: W,
      heightPx: H,
      pad: { left: 0, right: 0, top: 0, bottom: 0 },
      wheelZoom: true,
      maxScale,
      initial,
      onChange: apply,
    });
    apply(initial ?? { scale: 1, tx: 0, ty: 0 });
    svg.addEventListener("click", (ev) => {
      const box2 = svg.getBoundingClientRect();
      const px = ((ev.clientX - box2.left) / box2.width) * W;
      const py = ((ev.clientY - box2.top) / box2.height) * H;
      const s = state.zoom ?? { scale: 1, tx: 0, ty: 0 };
      let best: StationRow | null = null;
      let dist = Infinity;
      for (const r of centers) {
        const [x, y] = at(r);
        const d = Math.hypot(s.scale * x + s.tx - px, s.scale * y + s.ty - py);
        if (d < dist) [best, dist] = [r, d];
      }
      if (best && dist < 30) onSelect(best.key);
    });
  };
  ro.observe(host);
  return box;
}