/* =============================================================================
 * B06_wf3_ProfileCross_UI_Cross_View.ts
 * 개별 횡단면 카드 SVG 렌더러와 X:Y 1:1 스케일 지표 계산.
 *
 * 700줄 제한 대응으로 기존 단일 렌더러 파일에서 횡단 카드 렌더링만 분리했다. 공통 상수·유틸은
 * `_UI_Section_Common`, 설계 지정 컨트롤/설계선 오버레이는 `_UI_Cross_Design`을 참조한다.
 * 횡단은 종/횡 공통 Y스케일을 쓰지 않고 카드마다 자체 1:1 ppm으로 스케일한다.
 * ========================================================================== */

import type { CrossSection, SectionSample } from "./B06_wf3_ProfileCross_Api_Fetch";
import {
  appendCrossDesignOverlay,
  appendPavementOverlay,
  appendRockBoundaryOverlay,
  buildAreaReadout,
  buildDesignControls,
  buildRockBoundaryControl,
  sectionModeLabel,
  type RockBoundaryControl,
} from "./B06_wf3_ProfileCross_UI_Cross_Design";
import {
  CROSS_HEIGHT,
  CROSS_PAD,
  CROSS_WIDTH,
  type DesignChangeHandler,
  emptyView,
  L,
  stationLabel,
  svgElement,
  svgText,
  validElevation,
} from "./B06_wf3_ProfileCross_UI_Section_Common";

interface CrossPlotMetrics {
  sourceSamples: SectionSample[];
  minOffset: number;
  maxOffset: number;
  elevationMid: number;
  displaySpan: number;
  displayMax: number;
  pixelsPerMeter: number;
  heightPx: number;
}

/**
 * 횡단 카드의 X:Y 1:1 스케일 지표를 계산한다.
 * X pixels-per-meter는 반폭(offset 범위)이 카드 폭을 채우도록 고정하고, 같은 ppm을 Y에도 써서
 * 형상 왜곡을 없앤다(과장=1 → 정확히 1:1). 카드 높이는 데이터가 요구하는 자연 높이에 최소
 * `CROSS_HEIGHT`(250px) 바닥을 적용하며, `forcedHeightPx`가 오면 그 높이로 강제한다(같은 행 높이 통일).
 * 어느 경우든 displaySpan을 실제 plotHeight에 맞춰 되계산하므로 ppm(=1:1)은 그대로 보존되고,
 * 남는 세로 공간은 elevationMid를 중심으로 대칭 여백이 된다.
 */
function crossPlotMetrics(
  section: CrossSection,
  verticalExaggeration: number,
  widthPx: number,
  crossHalfWidth?: number,
  designElevation?: number,
  forcedHeightPx?: number,
): CrossPlotMetrics | null {
  const sourceSamples = section.samples.filter(
    (sample) =>
      crossHalfWidth === undefined || Math.abs(sample.offset_m ?? 0) <= crossHalfWidth + 1e-6,
  );
  const valid = sourceSamples.filter(validElevation);
  if (!valid.length) return null;
  const offsets = sourceSamples.map((sample) => sample.offset_m ?? 0);
  const minOffset = Math.min(...offsets, -1);
  const maxOffset = Math.max(...offsets, 1);
  const hasDesign = designElevation !== undefined && Number.isFinite(designElevation);
  const elevations = valid.map((sample) => sample.elevation_m);
  if (hasDesign) elevations.push(designElevation as number);
  const rawMin = Math.min(...elevations);
  const rawMax = Math.max(...elevations);
  const elevationMid = (rawMin + rawMax) / 2;
  const padding = rawMax > rawMin ? (rawMax - rawMin) * 0.08 : 0.5;
  const exaggeration = Math.max(verticalExaggeration, 0.1);
  const plotWidth = widthPx - CROSS_PAD.left - CROSS_PAD.right;
  const xSpan = Math.max(maxOffset - minOffset, 1e-6);
  const pixelsPerMeter = plotWidth / xSpan;
  const rawSpan = Math.max((rawMax - rawMin + padding * 2) * exaggeration, 1e-6);
  const naturalHeight = rawSpan * pixelsPerMeter + CROSS_PAD.top + CROSS_PAD.bottom;
  // 강제 높이가 있으면 그것을, 없으면 자연 높이에 250px 바닥 적용.
  const heightPx = forcedHeightPx ?? Math.max(naturalHeight, CROSS_HEIGHT);
  const plotHeight = Math.max(heightPx - CROSS_PAD.top - CROSS_PAD.bottom, 1e-6);
  // 실제 plotHeight에 맞춰 표시 표고폭을 되계산 → ppm(1:1) 보존, 여유분은 상하 대칭 여백.
  const displaySpan = plotHeight / pixelsPerMeter;
  const displayMax = elevationMid + displaySpan / 2;
  return {
    sourceSamples,
    minOffset,
    maxOffset,
    elevationMid,
    displaySpan,
    displayMax,
    pixelsPerMeter,
    heightPx,
  };
}

/** 같은 행 높이 통일을 위해 카드를 만들지 않고 자연(바닥 적용) 높이만 계산한다. */
export function crossCardNaturalHeight(
  section: CrossSection,
  verticalExaggeration: number,
  widthPx: number,
  crossHalfWidth?: number,
  designElevation?: number,
): number {
  return (
    crossPlotMetrics(section, verticalExaggeration, widthPx, crossHalfWidth, designElevation)
      ?.heightPx ?? CROSS_HEIGHT
  );
}

/**
 * 카드 SVG에 마우스 휠 줌(커서 중심) + 드래그 팬 + 더블클릭 원복을 붙인다(E-5).
 * viewBox만 조작하고 선은 `vector-effect: non-scaling-stroke`(CSS)로 굵기를 유지해
 * 확대해도 선·글자가 선명하다. 최대 8배까지, 축소는 원본까지만 허용한다.
 */
function attachZoomPan(svg: SVGSVGElement, widthPx: number, heightPx: number): void {
  const base = { x: 0, y: 0, w: widthPx, h: heightPx };
  const vb = { ...base };
  const applyVB = (): void => svg.setAttribute("viewBox", `${vb.x} ${vb.y} ${vb.w} ${vb.h}`);
  const clampPan = (): void => {
    vb.x = Math.min(Math.max(vb.x, base.x), base.x + base.w - vb.w);
    vb.y = Math.min(Math.max(vb.y, base.y), base.y + base.h - vb.h);
  };

  svg.addEventListener(
    "wheel",
    (event) => {
      event.preventDefault();
      const rect = svg.getBoundingClientRect();
      const mx = vb.x + ((event.clientX - rect.left) / rect.width) * vb.w;
      const my = vb.y + ((event.clientY - rect.top) / rect.height) * vb.h;
      const factor = event.deltaY < 0 ? 0.85 : 1 / 0.85;
      const nw = Math.min(base.w, Math.max(base.w / 8, vb.w * factor));
      const nh = Math.min(base.h, Math.max(base.h / 8, vb.h * factor));
      vb.x = mx - (mx - vb.x) * (nw / vb.w);
      vb.y = my - (my - vb.y) * (nh / vb.h);
      vb.w = nw;
      vb.h = nh;
      clampPan();
      applyVB();
    },
    { passive: false },
  );

  let panning = false;
  let moved = false;
  let lastX = 0;
  let lastY = 0;
  svg.addEventListener("pointerdown", (event) => {
    panning = true;
    moved = false;
    lastX = event.clientX;
    lastY = event.clientY;
    svg.setPointerCapture(event.pointerId);
  });
  svg.addEventListener("pointermove", (event) => {
    if (!panning) return;
    if (Math.abs(event.clientX - lastX) + Math.abs(event.clientY - lastY) > 2) moved = true;
    const rect = svg.getBoundingClientRect();
    vb.x -= ((event.clientX - lastX) / rect.width) * vb.w;
    vb.y -= ((event.clientY - lastY) / rect.height) * vb.h;
    lastX = event.clientX;
    lastY = event.clientY;
    clampPan();
    applyVB();
  });
  const endPan = (event: PointerEvent): void => {
    panning = false;
    try {
      svg.releasePointerCapture(event.pointerId);
    } catch {
      /* 이미 해제됨 */
    }
  };
  svg.addEventListener("pointerup", endPan);
  svg.addEventListener("pointercancel", endPan);
  // 드래그(팬)로 끝난 클릭은 카드 선택으로 전파하지 않는다.
  svg.addEventListener("click", (event) => {
    if (moved) event.stopPropagation();
  });
  // 더블클릭 원복.
  svg.addEventListener("dblclick", (event) => {
    event.stopPropagation();
    vb.x = base.x;
    vb.y = base.y;
    vb.w = base.w;
    vb.h = base.h;
    applyVB();
  });
}

export function createCrossSectionCard(
  section: CrossSection,
  selected: boolean,
  verticalExaggeration: number,
  onSelect: (stationId: string) => void,
  stationInterval: number,
  crossHalfWidth?: number,
  widthPx = CROSS_WIDTH,
  forcedHeightPx?: number,
  designElevation?: number,
  onDesignChange?: DesignChangeHandler,
  rockBoundary?: RockBoundaryControl,
): HTMLElement {
  const card = document.createElement("article");
  card.id = `cross-${section.station_id}`;
  card.className = `b06-cross-card${selected ? " b06-cross-card--selected" : ""}`;
  card.tabIndex = 0;
  card.addEventListener("click", () => onSelect(section.station_id));
  card.addEventListener("keydown", (event) => {
    if (event.key === "Enter" || event.key === " ") onSelect(section.station_id);
  });

  // 제목행 1행 구조(E-2/E-3): 측점 위치표기 → 단면유형 pill → 지반유형 → 구조물 → 측점정보.
  const header = document.createElement("header");
  const title = document.createElement("div");
  title.className = "b06-cross-card__title";
  const label = document.createElement("strong");
  label.textContent = stationLabel(section.chainage_m, stationInterval);
  const chainage = document.createElement("span");
  chainage.textContent = `${section.chainage_m.toFixed(1)}m`;
  title.append(label, chainage);

  // 단면유형 pill(자동 판정, 읽기 전용) — 구조물 pill과 동일 표기, 좌측 배치(E-3).
  const modePill = document.createElement("span");
  modePill.className = "b06-cross-card__mode";
  modePill.textContent = sectionModeLabel(section.design?.section_mode);
  modePill.title = L("B06_Design_Mode_Legend");

  const kind = document.createElement("span");
  kind.textContent =
    section.kind === "ep"
      ? L("B06_Profile_View_Kind_EP")
      : section.kind === "bp"
        ? L("B06_Profile_View_Kind_BP")
        : L("B06_Profile_View_Kind_Station");
  const meta = document.createElement("div");
  meta.className = "b06-cross-card__meta";
  if (section.structure) {
    const structure = document.createElement("span");
    structure.className = "b06-cross-card__structure";
    structure.textContent = section.structure;
    structure.title = `구조물: ${section.structure}`;
    meta.append(structure);
  }
  meta.append(kind);

  // 단면유형 pill은 지반유형 우측·우측 맞춤으로 배치(1번). 좌측 구분선은 지반유형 세그먼트에 준다(3번).
  modePill.classList.add("b06-cross-card__mode--right");
  header.append(title);
  if (onDesignChange) {
    // 제목행: 측점 라벨 → (구분선) 지반유형 → 단면유형 pill(우측) → 구조물·kind (D-6/E-2/1·3번).
    const controls = buildDesignControls(section, onDesignChange);
    controls.groundSegment.classList.add("b06-cross-card__ground");
    header.append(controls.groundSegment, modePill, meta);
    card.append(header);
    card.append(controls.bar);
  } else {
    header.append(modePill, meta);
    card.append(header);
  }

  const metrics = crossPlotMetrics(
    section,
    verticalExaggeration,
    widthPx,
    crossHalfWidth,
    designElevation,
    forcedHeightPx,
  );
  if (!metrics) {
    card.append(emptyView(L("B06_Profile_View_NoCross")));
  } else {
    const {
      sourceSamples,
      minOffset,
      maxOffset,
      elevationMid,
      displaySpan,
      displayMax,
      pixelsPerMeter,
      heightPx,
    } = metrics;
    const hasDesign = designElevation !== undefined && Number.isFinite(designElevation);
    const valid = sourceSamples.filter(validElevation);
    const exaggeration = Math.max(verticalExaggeration, 0.1);
    // 좌표 규약(+offset=좌, -offset=우)을 표준 횡단면도 관례에 맞춘다: 진행방향을 바라보는
    // 시점이라 좌측(+offset)이 화면 왼쪽에 와야 B05 3D 방향 표시와 측구 방향이 일치한다(작업 C-3).
    const x = (offset: number) => CROSS_PAD.left + (maxOffset - offset) * pixelsPerMeter;
    const y = (elevation: number) => CROSS_PAD.top + (displayMax - elevation) * pixelsPerMeter;
    const svg = svgElement("svg", {
      class: "b06-section__chart",
      width: widthPx,
      height: heightPx,
      viewBox: `0 0 ${widthPx} ${heightPx}`,
      role: "img",
      "aria-label": `${section.label} ${L("B06_Profile_View_Cross")}`,
    });
    svg.append(svgElement("rect", { width: widthPx, height: heightPx, class: "b06-chart__bg" }));

    const xTicks = Array.from(
      { length: 7 },
      (_, index) => minOffset + ((maxOffset - minOffset) * index) / 6,
    );
    for (const tick of xTicks) {
      svg.append(
        svgElement("line", {
          x1: x(tick),
          y1: CROSS_PAD.top,
          x2: x(tick),
          y2: heightPx - CROSS_PAD.bottom,
          class: "b06-chart__grid",
        }),
        svgText(Math.abs(tick) < 1e-6 ? "0" : tick.toFixed(0), {
          x: x(tick),
          y: heightPx - CROSS_PAD.bottom + 16,
          "text-anchor": "middle",
          class: "b06-chart__tick",
        }),
      );
    }
    const rawDisplaySpan = displaySpan / exaggeration;
    for (let index = 0; index < 5; index += 1) {
      const tick = elevationMid - rawDisplaySpan / 2 + (rawDisplaySpan * index) / 4;
      const displayTick = elevationMid + (tick - elevationMid) * exaggeration;
      svg.append(
        svgElement("line", {
          x1: CROSS_PAD.left,
          y1: y(displayTick),
          x2: widthPx - CROSS_PAD.right,
          y2: y(displayTick),
          class: "b06-chart__grid",
        }),
        svgText(tick.toFixed(1), {
          x: CROSS_PAD.left - 7,
          y: y(displayTick) + 3,
          "text-anchor": "end",
          class: "b06-chart__tick",
        }),
      );
    }

    const segments: string[] = [];
    let current: string[] = [];
    for (const sample of sourceSamples) {
      if (!validElevation(sample)) {
        if (current.length > 1) segments.push(current.join(" "));
        current = [];
        continue;
      }
      const elevated = elevationMid + (sample.elevation_m - elevationMid) * exaggeration;
      current.push(`${x(sample.offset_m ?? 0)},${y(elevated)}`);
    }
    if (current.length > 1) segments.push(current.join(" "));
    segments.forEach((points) =>
      svg.append(svgElement("polyline", { points, class: "b06-chart__cross-profile" })),
    );

    if (section.design) {
      const toDisplayY = (elevation: number): number =>
        y(elevationMid + (elevation - elevationMid) * exaggeration);
      // 포장층 → 설계선 → 암 경계선 순으로 겹쳐, 설계선이 포장 박스 위에 오게 한다.
      appendPavementOverlay(svg, section.design, x, toDisplayY);
      appendCrossDesignOverlay(svg, section.design, x, toDisplayY);
      // 암 경계선은 지면선(지반선) 복사 + 오프셋 — 계획선 기준이 아님에 유의.
      if (rockBoundary && section.design.geometry_preset === "rock") {
        appendRockBoundaryOverlay(
          svg,
          sourceSamples,
          rockBoundary.offsetFor(section),
          x,
          toDisplayY,
        );
      }
    }

    const centerSample = valid.reduce<(typeof valid)[number] | null>((nearest, sample) => {
      if (!nearest || Math.abs(sample.offset_m ?? 0) < Math.abs(nearest.offset_m ?? 0))
        return sample;
      return nearest;
    }, null);
    const centerX = x(0);
    // 십자선은 계획 노선(계획고) 위치를 가리킨다. 계획선이 없는 구 데이터는 지반고로 폴백한다.
    const centerElevation = hasDesign
      ? (designElevation as number)
      : (centerSample?.elevation_m ?? null);
    const centerY =
      centerElevation !== null
        ? y(elevationMid + (centerElevation - elevationMid) * exaggeration)
        : heightPx / 2;
    const centerMarkerClass = `b06-chart__center-marker${hasDesign ? " b06-chart__center-marker--design" : ""}`;
    svg.append(
      svgElement("line", {
        x1: CROSS_PAD.left,
        y1: heightPx - CROSS_PAD.bottom,
        x2: widthPx - CROSS_PAD.right,
        y2: heightPx - CROSS_PAD.bottom,
        class: "b06-chart__axis",
      }),
      svgElement("line", {
        x1: CROSS_PAD.left,
        y1: CROSS_PAD.top,
        x2: CROSS_PAD.left,
        y2: heightPx - CROSS_PAD.bottom,
        class: "b06-chart__axis",
      }),
      svgElement("line", {
        x1: centerX,
        y1: centerY - 18,
        x2: centerX,
        y2: centerY + 18,
        class: centerMarkerClass,
      }),
      svgElement("line", {
        x1: centerX - 18,
        y1: centerY,
        x2: centerX + 18,
        y2: centerY,
        class: centerMarkerClass,
      }),
      svgText(L("B06_Profile_View_CrossXAxis"), {
        x: widthPx / 2,
        y: heightPx - 8,
        "text-anchor": "middle",
        class: "b06-chart__axis-label",
      }),
      svgText(L("B06_Profile_View_ElevationAxis"), {
        x: 13,
        y: heightPx / 2,
        "text-anchor": "middle",
        transform: `rotate(-90 13 ${heightPx / 2})`,
        class: "b06-chart__axis-label",
      }),
    );
    // 마우스 휠 줌·드래그 팬·더블클릭 원복(E-5). viewBox 조작 + non-scaling-stroke로 선명도 유지.
    const chartWrap = document.createElement("div");
    chartWrap.className = "b06-cross-card__chart-wrap";
    attachZoomPan(svg, widthPx, heightPx);
    // 절·성토 면적값은 그래프 중상단 오버레이로 표시(E-4).
    chartWrap.append(svg, buildAreaReadout(section.design));
    // 암 경계선 제어는 그래프 X축 제목 행 우측에 배치(E-7). 암 지반에서만.
    if (rockBoundary && section.design?.geometry_preset === "rock") {
      const rockControl = buildRockBoundaryControl(section, rockBoundary);
      rockControl.classList.add("b06-cross-card__rockb");
      chartWrap.append(rockControl);
    }
    card.append(chartWrap);
  }

  const footer = document.createElement("footer");
  const center = document.createElement("span");
  center.textContent = `${L("B06_Profile_View_CenterElevation")} ${section.center_z?.toFixed(2) ?? "-"}m`;
  const azimuth = document.createElement("span");
  azimuth.textContent = `${L("B06_Profile_View_Azimuth")} ${section.azimuth_deg?.toFixed(1) ?? "-"}°`;
  footer.append(center, azimuth);
  card.append(footer);
  return card;
}