/* =============================================================================
 * E03_StabSection_UI_Section.ts
 * E03 가운데 횡단(PLAN 532-3) — 지층 색 · 벽(회색 빗금 · 532-5) · 지표 · 지하수선 · 노면 하중 · 등안전율 색 지도(원호 중심 격자
 *   최소 안전율) · 원호 중심 점 · 다른 후보(옅게) · 임계 활동면(굵게 · 중심 · 반경) · 절편(누르면 고름).
 *   도형 좌표 = 결과 좌표 그대로 · 묶음 transform(`viewMatrix`) 하나 — 계산은 logic.
 *   줌 · 팬 = 공용 `attachSvgZoomPan`(휠 = 줌 · 가운데 끌기 = 팬 · 두 번 누름 = 원배율).
 * ========================================================================== */

import "./E03_StabSection_UI_Walls.css";
import { t } from "@ui/ui_template_locale";
import { el } from "@ui/ui_template_elements";
import { attachSvgZoomPan, type ZoomPanState } from "../A00_Common/b_svg_zoom_pan";
import {
  bandIndex,
  bandLegend,
  fitView,
  focusHome,
  pointsText,
  sliceShape,
  toModel,
  toScreen,
  viewMatrix,
  type Analysis,
  type Point,
  type SectionView,
} from "./logic/E03_StabSection_Logic";

const SVG_NS = "http://www.w3.org/2000/svg";
const PAD = 28;
const MAX_SCALE = 30;
/** 벽(옹벽 · 석축) 물성 id — 서버 `WALL_MATERIAL` */
export const WALL_ID = "wall";

export function svgEl<K extends keyof SVGElementTagNameMap>(
  tag: K,
  attrs: Record<string, string | number> = {},
  text?: string,
): SVGElementTagNameMap[K] {
  const node = document.createElementNS(SVG_NS, tag);
  for (const [k, v] of Object.entries(attrs)) node.setAttribute(k, String(v));
  if (text !== undefined) node.textContent = text;
  return node;
}

export interface SectionToggles {
  map: boolean;
  centers: boolean;
  candidates: boolean;
}

export interface SectionDraw {
  view: SectionView;
  analysis: Analysis | null;
  toggles: SectionToggles;
  picked: number | null;
}

const fmt = (v: number | null | undefined, d = 3): string =>
  v === null || v === undefined || !Number.isFinite(v) ? "-" : v.toFixed(d);

/** 지층 색 번호 — 물성 표 차례(정해진 차례 · 순환 없이 8 넘으면 마지막 색) */
export function materialClass(view: SectionView, id: string): string {
  const i = view.materials.findIndex((m) => m.id === id);
  return `e03-mat-${Math.min(Math.max(i, 0), 7)}`;
}

/** 범례 줄 — 등안전율 띠(기준안전율 기준 실제 값) · 지층 */
export function buildLegends(draw: SectionDraw): HTMLElement {
  const box = el("div", { className: "e03-legend" });
  const required = draw.analysis?.required ?? null;
  if (draw.toggles.map && draw.analysis?.grid) {
    box.append(el("span", { className: "e03-muted", text: t("E03_Legend_Map") }));
    for (const band of bandLegend(required)) {
      const text =
        band.from === null
          ? `< ${band.to}`
          : band.to === null
            ? `≥ ${band.from}`
            : `${band.from}–${band.to}`;
      const item = el("span", {
        className: "e03-legend__item",
        attrs: { "data-band": String(band.index) },
      });
      item.append(el("span", { className: `e03-legend__swatch e03-band-${band.index}` }), text);
      box.append(item);
    }
  }
  const used = new Set(draw.view.regions.map((r) => r.material_id));
  box.append(el("span", { className: "e03-muted", text: t("E03_Legend_Layers") }));
  for (const m of draw.view.materials.filter((x) => used.has(x.id))) {
    const item = el("span", { className: "e03-legend__item" });
    item.append(
      el("span", {
        className: `e03-legend__swatch ${m.id === WALL_ID ? "e03-wall-swatch" : materialClass(draw.view, m.id)}`,
      }),
      m.name,
    );
    box.append(item);
  }
  return box;
}

export interface SectionCanvas {
  root: HTMLElement;
  render: (draw: SectionDraw | null) => void;
}

export function createSectionCanvas(onPick: (index: number | null) => void): SectionCanvas {
  const root = el("div", { className: "e03-section" });
  const tip = el("div", { className: "e03-tip" });
  let last: SectionDraw | null = null;
  let zoom: ZoomPanState | undefined;
  let zoomKey = "";

  const paint = (): void => {
    root.replaceChildren(tip);
    const draw = last;
    if (!draw) return;
    const width = Math.max(root.clientWidth, 320);
    const height = Math.max(root.clientHeight, 240);
    const { view, analysis, toggles } = draw;
    const fit = fitView(view, width, height, PAD);
    const svg = svgEl("svg", { viewBox: `0 0 ${width} ${height}`, "data-role": "section" });
    const layer = svgEl("g");
    const world = svgEl("g", { transform: viewMatrix(fit), "data-role": "world" });
    const ns = { "vector-effect": "non-scaling-stroke" };
    const unit = 1 / fit.k; // 1 px 의 결과 좌표 길이

    // 벽 빗금 — 결과 좌표 패턴(화면 6 px 간격)
    const hatch = svgEl("pattern", {
      id: "e03-wall-hatch",
      patternUnits: "userSpaceOnUse",
      width: 6 * unit,
      height: 6 * unit,
      patternTransform: "rotate(45)",
    });
    hatch.append(
      svgEl("rect", { width: 6 * unit, height: 6 * unit, class: "e03-wall-hatch__bg" }),
      svgEl("line", {
        x1: 0,
        y1: 0,
        x2: 0,
        y2: 6 * unit,
        "stroke-width": 1.5 * unit,
        class: "e03-wall-hatch__line",
      }),
    );
    const defs = svgEl("defs");
    defs.append(hatch);
    world.append(defs);
    for (const region of view.regions) {
      const wall = region.material_id === WALL_ID;
      const ring = svgEl("polygon", {
        points: pointsText(region.polygon),
        class: wall ? "e03-wall" : `e03-region ${materialClass(view, region.material_id)}`,
        ...(wall ? { fill: "url(#e03-wall-hatch)", "data-role": "wall" } : {}),
        ...ns,
      });
      world.append(ring);
    }
    // 등안전율 색 지도 — 격자 중심마다 칸(이웃 중심 사이 절반)
    const grid = analysis?.grid;
    if (grid && toggles.map) {
      const half = (arr: number[], i: number): [number, number] => {
        const lo =
          i > 0 ? (arr[i] - arr[i - 1]) / 2 : i + 1 < arr.length ? (arr[i + 1] - arr[i]) / 2 : 0.5;
        const hi = i + 1 < arr.length ? (arr[i + 1] - arr[i]) / 2 : lo;
        return [arr[i] - lo, arr[i] + hi];
      };
      const cells = svgEl("g", { "data-role": "safety-map", opacity: 0.8 });
      grid.z.forEach((_z, iz) => {
        grid.x.forEach((_x, ix) => {
          const band = bandIndex(grid.fs[iz]?.[ix], analysis.required);
          if (band === null) return;
          const [x0, x1] = half(grid.x, ix).sort((a, b) => a - b);
          const [z0, z1] = half(grid.z, iz).sort((a, b) => a - b);
          const cell = svgEl("rect", {
            x: x0,
            y: z0,
            width: x1 - x0,
            height: z1 - z0,
            class: `e03-cell e03-band-${band}`,
            "data-fs": String(grid.fs[iz][ix]),
          });
          cells.append(cell);
        });
      });
      world.append(cells);
    }
    if (grid && toggles.centers) {
      const dots = svgEl("g", { "data-role": "centers" });
      grid.z.forEach((z) =>
        grid.x.forEach((x) =>
          dots.append(svgEl("circle", { cx: x, cy: z, r: 1.6 * unit, class: "e03-gridpt" })),
        ),
      );
      world.append(dots);
    }
    // 노면 하중 — 지표 위 띠 + 아래 화살 눈금
    for (const load of view.surcharge) {
      const zTop = Math.max(
        ...view.surface.filter((p) => p[0] >= load.x0 && p[0] <= load.x1).map((p) => p[1]),
      );
      if (!Number.isFinite(zTop)) continue;
      const up = zTop + 14 * unit;
      const g = svgEl("g", { class: "e03-load", "data-role": "surcharge" });
      g.append(
        svgEl("polyline", {
          points: pointsText([
            [load.x0, up],
            [load.x1, up],
          ]),
          ...ns,
        }),
      );
      const n = Math.max(2, Math.round((load.x1 - load.x0) / (10 * unit)));
      for (let i = 0; i <= n; i += 1) {
        const x = load.x0 + ((load.x1 - load.x0) * i) / n;
        g.append(
          svgEl("polyline", {
            points: pointsText([
              [x, up],
              [x, zTop + 3 * unit],
            ]),
            ...ns,
          }),
        );
      }
      world.append(g);
    }
    world.append(
      svgEl("polyline", { points: pointsText(view.surface), class: "e03-surface", ...ns }),
    );
    const water = analysis ? view.water[analysis.condition] : null;
    if (water) {
      world.append(
        svgEl("polyline", {
          points: pointsText(water),
          class: "e03-water",
          "data-role": "water",
          ...ns,
        }),
      );
    }
    const critical = analysis?.critical ?? null;
    if (analysis && toggles.candidates) {
      for (const c of analysis.candidates) {
        if (critical && c.method === critical.method && c.kind === critical.kind) continue;
        const line = svgEl("polyline", {
          points: pointsText(c.points),
          class: "e03-candidate",
          "data-role": "candidate",
          ...ns,
        });
        line.append(
          svgEl(
            "title",
            {},
            `${t(`E03_Method_${c.method}` as never)} · ${c.kind} · Fs ${fmt(c.fs)}`,
          ),
        );
        world.append(line);
      }
    }
    const labels = svgEl("g", { "data-role": "labels" });
    if (critical && analysis) {
      const slices = svgEl("g", { "data-role": "slices" });
      analysis.slices.forEach((slice, i) => {
        const poly = svgEl("polygon", {
          points: pointsText(sliceShape(slice, view.surface, critical.points)),
          class: `e03-slice${draw.picked === i ? " is-picked" : ""}`,
          "data-i": String(i),
          ...ns,
        });
        poly.addEventListener("click", (ev) => {
          ev.stopPropagation();
          onPick(draw.picked === i ? null : i);
        });
        slices.append(poly);
      });
      world.append(slices);
      if (critical.center && critical.entry && critical.exit) {
        const c = critical.center;
        world.append(
          svgEl("polyline", {
            points: pointsText([critical.entry, c, critical.exit]),
            class: "e03-radius",
            ...ns,
          }),
          svgEl("circle", { cx: c[0], cy: c[1], r: 3 * unit, class: "e03-gridpt" }),
        );
      }
      world.append(
        svgEl("polyline", {
          points: pointsText(critical.points),
          class: "e03-critical",
          "data-role": "critical",
          ...ns,
        }),
      );
      // 글 — 안전율 · 중심 · 반경(화면 좌표 · 뒤집지 않음)
      const anchor: Point =
        critical.center ?? critical.points[Math.floor(critical.points.length / 2)];
      const [ax, ay] = toScreen(fit, anchor);
      labels.append(
        svgEl(
          "text",
          {
            x: ax,
            y: ay,
            dx: "0.6em",
            dy: "-0.7em",
            class: "e03-label e03-label--fs",
            "data-role": "fs-label",
          },
          `Fs = ${fmt(critical.fs)}`,
        ),
      );
      if (critical.center) {
        labels.append(
          svgEl(
            "text",
            { x: ax, y: ay, dx: "0.7em", dy: "0.5em", class: "e03-label" },
            `Xc ${fmt(critical.center[0], 2)} · Zc ${fmt(critical.center[1], 2)} · R ${fmt(critical.radius, 2)} m`,
          ),
        );
      }
    }
    layer.append(world, labels);
    svg.append(layer);
    svg.addEventListener("click", () => draw.picked !== null && onPick(null));
    root.append(svg);

    // 마우스 아래 offset · 표고 (줌 상태 되돌려 셈)
    svg.addEventListener("mousemove", (ev) => {
      const box = svg.getBoundingClientRect();
      const sx = ((ev.clientX - box.left) / box.width) * width;
      const sy = ((ev.clientY - box.top) / box.height) * height;
      const s = zoom ?? { scale: 1, tx: 0, ty: 0 };
      const [x, z] = toModel(fit, [(sx - s.tx) / s.scale, (sy - s.ty) / s.scale]);
      tip.textContent = `${t("E03_Offset")} ${x.toFixed(2)} m · EL ${z.toFixed(2)} m`;
      tip.style.display = "block";
      tip.style.left = `${ev.clientX - box.left + 12}px`;
      tip.style.top = `${ev.clientY - box.top + 12}px`;
    });
    svg.addEventListener("mouseleave", () => (tip.style.display = "none"));

    const key = `${view.key}|${analysis?.condition}|${analysis?.side}|${width}x${height}`;
    if (key !== zoomKey) zoom = undefined;
    zoomKey = key;
    attachSvgZoomPan({
      svg,
      layer,
      widthPx: width,
      heightPx: height,
      pad: { left: 0, right: 0, top: 0, bottom: 0 },
      wheelZoom: true,
      maxScale: MAX_SCALE,
      home: focusHome(fit, view, analysis, width, height, MAX_SCALE),
      initial: zoom,
      onChange: (state) => {
        zoom = state;
        labels.style.setProperty("--e03-label-k", String(1 / state.scale)); // 글자는 확대 안 함
      },
    });
  };

  new ResizeObserver(() => last && paint()).observe(root);
  return {
    root,
    render(draw) {
      last = draw;
      paint();
    },
  };
}