/* =============================================================================
 * B05_Profile_UI_RouteEdit.ts
 * 계획노선 편집 모달 — 예상노선(점선) 위에 계획노선(실선)을 고쳐 그린다.
 *
 * 왜 모달인가(2026-09-06 사용자 확정) — [확인]을 누르면 배수유역부터 종·횡단·유토곡선까지
 * 전 단계가 다시 도는 무거운 작업이다(용화 67측점 3분대). 신중히 하라는 뜻으로 큰 모달을
 * 쓰고, **편집 중에는 아무 계산도 나가지 않는다**.
 *
 * 노선은 두 벌이다 — 예상노선(원본, 안 바뀜)과 계획노선(수정본, 사용자가 고침).
 * [예상노선으로]는 수정본을 버리고 원본으로 되돌린다(서버가 파일을 지우고 같은 재계산).
 *
 * 그림은 배수유역도와 같은 지도 도구(`B04_PreProcess_UI_MapRender`)를 쓴다 — 등고선 도엽은
 * 위경도, 노선은 사업지 좌표계(m)지만 두 변환기가 같은 정규화 공간을 본다.
 * ========================================================================== */

import {
  computeMapRect,
  computeRouteView,
  drawPreparedLayer,
  createNormalizer,
  metricToScreen,
  prepareLayer,
  type PreparedLayer,
  type ViewState,
} from "../B04_PreProcess/B04_PreProcess_UI_MapRender";
import type { VWorldMeta } from "../B04_PreProcess/B04_PreProcess_Api_Fetch";
import { clearDrafts, clearResults } from "../A00_Common/b_page_state";
import { showToast } from "@ui/ui_template_elements";
import { fetchDrainageLayers } from "./B05_Profile_UI_Drainage_Parts";
import { fetchRoutePlan, replanRoute, resetRoutePlan } from "./B05_Profile_Api_Replan";
import "./B05_Profile_UI_Style_RouteEdit.css";

/** 노드를 잡았다고 볼 거리(px). 손가락·마우스 모두 무리 없는 크기. */
const NODE_HIT_PX = 9;
/** 노드 반지름(px). */
const NODE_R = 4;
/** 끌기로 볼 최소 이동(px) — 이보다 작으면 클릭으로 본다. */
const DRAG_THRESHOLD_PX = 3;

type Vertex = [number, number];

/** 모달을 연다. [확인]·[예상노선으로]가 끝나면 `onApplied`를 부른다(화면 다시 읽기). */
export async function openRouteEditModal(
  projectId: string,
  onApplied: () => void | Promise<void>,
): Promise<void> {
  const overlay = document.createElement("div");
  overlay.className = "b05-routeedit";
  overlay.innerHTML = `
    <div class="b05-routeedit__box" role="dialog" aria-label="계획노선 편집">
      <div class="b05-routeedit__head">
        <strong>계획노선 편집</strong>
        <span class="b05-routeedit__hint">
          노드를 끌어 옮기고, 선을 두 번 누르면 노드가 생깁니다. 노드 오른쪽 클릭은 삭제.
        </span>
        <button type="button" class="b05-routeedit__close" aria-label="닫기">✕</button>
      </div>
      <div class="b05-routeedit__canvas-wrap"><canvas class="b05-routeedit__canvas"></canvas></div>
      <div class="b05-routeedit__foot">
        <span class="b05-routeedit__status">노선을 읽는 중…</span>
        <span class="b05-routeedit__legend">
          <i class="is-expected"></i> 예상노선(원본)
          <i class="is-planned"></i> 계획노선
        </span>
        <button type="button" class="b05-routeedit__btn" data-act="reset">예상노선으로</button>
        <button type="button" class="b05-routeedit__btn" data-act="cancel">취소</button>
        <button type="button" class="b05-routeedit__btn is-primary" data-act="apply">확인</button>
      </div>
      <div class="b05-routeedit__busy" hidden><span></span></div>
    </div>`;
  document.body.append(overlay);

  const canvas = overlay.querySelector<HTMLCanvasElement>(".b05-routeedit__canvas")!;
  const status = overlay.querySelector<HTMLElement>(".b05-routeedit__status")!;
  const busy = overlay.querySelector<HTMLElement>(".b05-routeedit__busy")!;
  const context = canvas.getContext("2d")!;

  let expected: Vertex[] = [];
  let planned: Vertex[] = [];
  let meta: VWorldMeta | null = null;
  let sheets: PreparedLayer[] = [];
  let view: ViewState = {
    width: 0,
    height: 0,
    scale: 1,
    offsetX: 0,
    offsetY: 0,
    mapRect: computeMapRect(null, 0, 0),
  };
  let closed = false;

  const close = (): void => {
    closed = true;
    window.removeEventListener("resize", resize);
    overlay.remove();
  };
  overlay.querySelector(".b05-routeedit__close")!.addEventListener("click", close);
  overlay.querySelector('[data-act="cancel"]')!.addEventListener("click", close);
  // 배경 클릭으로 닫지 않는다 — 고치던 노선을 실수로 날리지 않게.

  function resize(): void {
    if (closed) return;
    const wrap = canvas.parentElement!;
    const ratio = window.devicePixelRatio || 1;
    const width = wrap.clientWidth;
    const height = wrap.clientHeight;
    canvas.width = Math.round(width * ratio);
    canvas.height = Math.round(height * ratio);
    canvas.style.width = `${width}px`;
    canvas.style.height = `${height}px`;
    context.setTransform(ratio, 0, 0, ratio, 0, 0);
    view = { ...view, width, height, mapRect: computeMapRect(meta, width, height) };
    draw();
  }
  window.addEventListener("resize", resize);

  const toScreen = (vertex: Vertex): [number, number] =>
    meta ? metricToScreen(meta, view, vertex[0], vertex[1]) : [0, 0];

  /** 화면 px → 사업지 좌표(m). `metricToScreen`이 선형이므로 두 기준점으로 역산한다. */
  function toMetric(px: number, py: number): Vertex {
    if (!meta) return [0, 0];
    const [x0, y0] = metricToScreen(meta, view, meta.x_min, meta.y_min);
    const [x1, y1] = metricToScreen(
      meta,
      view,
      meta.x_min + meta.width_meters,
      meta.y_min + meta.height_meters,
    );
    const sx = (x1 - x0) / (meta.width_meters || 1);
    const sy = (y1 - y0) / (meta.height_meters || 1);
    return [meta.x_min + (px - x0) / (sx || 1), meta.y_min + (py - y0) / (sy || 1)];
  }

  function strokePolyline(points: Vertex[], dash: number[], color: string, width: number): void {
    if (points.length < 2) return;
    context.save();
    context.setLineDash(dash);
    context.strokeStyle = color;
    context.lineWidth = width;
    context.beginPath();
    points.forEach((vertex, index) => {
      const [x, y] = toScreen(vertex);
      if (index === 0) context.moveTo(x, y);
      else context.lineTo(x, y);
    });
    context.stroke();
    context.restore();
  }

  function draw(): void {
    if (closed) return;
    const style = getComputedStyle(document.documentElement);
    context.clearRect(0, 0, view.width, view.height);
    context.fillStyle = style.getPropertyValue("--color-surface") || "#111";
    context.fillRect(0, 0, view.width, view.height);

    context.save();
    context.strokeStyle = style.getPropertyValue("--map-sheet-contour") || "#a5b4fc";
    context.lineWidth = 0.8;
    for (const layer of sheets) drawPreparedLayer(context, layer, view, "dot");
    context.restore();

    strokePolyline(
      expected,
      [6, 5],
      style.getPropertyValue("--color-text-secondary") || "#9ca3af",
      1.6,
    );
    strokePolyline(planned, [], style.getPropertyValue("--map-route") || "#f97316", 2.4);

    context.save();
    context.fillStyle = style.getPropertyValue("--map-route") || "#f97316";
    context.strokeStyle = style.getPropertyValue("--map-halo") || "rgba(255,255,255,0.9)";
    context.lineWidth = 1;
    for (const vertex of planned) {
      const [x, y] = toScreen(vertex);
      context.beginPath();
      context.arc(x, y, NODE_R, 0, Math.PI * 2);
      context.fill();
      context.stroke();
    }
    context.restore();
  }

  /** 화면 좌표에 가장 가까운 노드. 문턱 밖이면 -1. */
  function nodeAt(px: number, py: number): number {
    let best = -1;
    let bestDistance = NODE_HIT_PX;
    planned.forEach((vertex, index) => {
      const [x, y] = toScreen(vertex);
      const distance = Math.hypot(x - px, y - py);
      if (distance <= bestDistance) {
        bestDistance = distance;
        best = index;
      }
    });
    return best;
  }

  /** 두 노드 사이 선분 중 클릭에 가장 가까운 것 — 새 노드를 끼울 자리. */
  function segmentAt(px: number, py: number): number {
    let best = -1;
    let bestDistance = 12;
    for (let index = 0; index < planned.length - 1; index += 1) {
      const [ax, ay] = toScreen(planned[index]);
      const [bx, by] = toScreen(planned[index + 1]);
      const dx = bx - ax;
      const dy = by - ay;
      const lengthSquared = dx * dx + dy * dy || 1;
      const t = Math.max(0, Math.min(1, ((px - ax) * dx + (py - ay) * dy) / lengthSquared));
      const distance = Math.hypot(ax + t * dx - px, ay + t * dy - py);
      if (distance < bestDistance) {
        bestDistance = distance;
        best = index;
      }
    }
    return best;
  }

  // ── 조작 — 노드 끌기 / 배경 끌기(팬) / 휠 확대 / 두 번 클릭 삽입 / 오른쪽 클릭 삭제 ──
  let dragNode = -1;
  let panFrom: { x: number; y: number; offsetX: number; offsetY: number } | null = null;

  canvas.addEventListener("pointerdown", (event) => {
    if (event.button !== 0) return;
    const rect = canvas.getBoundingClientRect();
    const px = event.clientX - rect.left;
    const py = event.clientY - rect.top;
    dragNode = nodeAt(px, py);
    if (dragNode < 0) panFrom = { x: px, y: py, offsetX: view.offsetX, offsetY: view.offsetY };
    canvas.setPointerCapture(event.pointerId);
  });

  canvas.addEventListener("pointermove", (event) => {
    const rect = canvas.getBoundingClientRect();
    const px = event.clientX - rect.left;
    const py = event.clientY - rect.top;
    if (dragNode >= 0) {
      planned[dragNode] = toMetric(px, py);
      draw();
      return;
    }
    if (panFrom) {
      if (Math.hypot(px - panFrom.x, py - panFrom.y) < DRAG_THRESHOLD_PX) return;
      view = {
        ...view,
        offsetX: panFrom.offsetX + (px - panFrom.x),
        offsetY: panFrom.offsetY + (py - panFrom.y),
      };
      draw();
      return;
    }
    canvas.style.cursor = nodeAt(px, py) >= 0 ? "grab" : "default";
  });

  const endDrag = (event: PointerEvent): void => {
    if (canvas.hasPointerCapture(event.pointerId)) canvas.releasePointerCapture(event.pointerId);
    dragNode = -1;
    panFrom = null;
  };
  canvas.addEventListener("pointerup", endDrag);
  canvas.addEventListener("pointercancel", endDrag);

  canvas.addEventListener("dblclick", (event) => {
    const rect = canvas.getBoundingClientRect();
    const px = event.clientX - rect.left;
    const py = event.clientY - rect.top;
    const segment = segmentAt(px, py);
    if (segment < 0) return;
    planned.splice(segment + 1, 0, toMetric(px, py));
    status.textContent = `노드 ${planned.length}개 — 새 노드를 넣었습니다.`;
    draw();
  });

  canvas.addEventListener("contextmenu", (event) => {
    event.preventDefault();
    const rect = canvas.getBoundingClientRect();
    const index = nodeAt(event.clientX - rect.left, event.clientY - rect.top);
    if (index < 0) return;
    if (planned.length <= 2) {
      showToast("노선은 노드가 2개 이상이어야 합니다.", "error");
      return;
    }
    planned.splice(index, 1);
    status.textContent = `노드 ${planned.length}개 — 노드를 지웠습니다.`;
    draw();
  });

  canvas.addEventListener(
    "wheel",
    (event) => {
      event.preventDefault();
      const rect = canvas.getBoundingClientRect();
      const px = event.clientX - rect.left;
      const py = event.clientY - rect.top;
      const factor = event.deltaY < 0 ? 1.2 : 1 / 1.2;
      const nextScale = Math.max(1, Math.min(2000, view.scale * factor));
      const ratio = nextScale / view.scale;
      // 커서 아래 지점이 제자리에 남도록 이동량을 함께 고친다.
      view = {
        ...view,
        scale: nextScale,
        offsetX: px - (px - view.offsetX) * ratio,
        offsetY: py - (py - view.offsetY) * ratio,
      };
      draw();
    },
    { passive: false },
  );

  async function runHeavy(label: string, task: () => Promise<unknown>): Promise<void> {
    busy.hidden = false;
    busy.querySelector("span")!.textContent =
      `${label} — 배수유역부터 다시 계산 중입니다. 몇 분 걸립니다.`;
    try {
      await task();
      // 노선이 바뀌면 세션 초안·조회 캐시는 옛 노선 것이라 남기지 않는다(PLAN 0-7 확정 5).
      clearDrafts(projectId);
      clearResults(projectId);
      showToast("노선을 다시 계산했습니다.", "success");
      close();
      await onApplied();
    } catch (error) {
      busy.hidden = true;
      showToast(error instanceof Error ? error.message : "노선 재계산에 실패했습니다.", "error");
    }
  }

  overlay.querySelector('[data-act="apply"]')!.addEventListener("click", () => {
    if (planned.length < 2) {
      showToast("노선은 노드가 2개 이상이어야 합니다.", "error");
      return;
    }
    void runHeavy("계획노선 반영", () => replanRoute(projectId, planned));
  });
  overlay.querySelector('[data-act="reset"]')!.addEventListener("click", () => {
    void runHeavy("예상노선으로 되돌리기", () => resetRoutePlan(projectId));
  });

  // ── 자료 읽기 — 노선 두 벌 + 등고선 도엽(배수유역도와 같은 것) ──
  try {
    const [plan, drainage] = await Promise.all([
      fetchRoutePlan(projectId),
      fetchDrainageLayers(projectId, () => {}),
    ]);
    if (closed) return;
    expected = plan.expected as Vertex[];
    planned = (plan.planned as Vertex[]).map((vertex) => [vertex[0], vertex[1]]);
    meta = drainage.meta;
    const normalizer = createNormalizer(drainage.meta);
    sheets = drainage.layers
      .map(([, collection]) => (collection ? prepareLayer(collection, normalizer) : null))
      .filter((layer): layer is PreparedLayer => layer !== null);
    resize();
    const xs = planned.map((vertex) => vertex[0]);
    const ys = planned.map((vertex) => vertex[1]);
    const fitted = computeRouteView(
      meta,
      {
        x_min: Math.min(...xs),
        x_max: Math.max(...xs),
        y_min: Math.min(...ys),
        y_max: Math.max(...ys),
      },
      view.width,
      view.height,
    );
    view = { ...view, ...fitted };
    status.textContent = `노드 ${planned.length}개 · ${plan.edited ? "고친 계획노선" : "예상노선과 같음"}`;
    draw();
  } catch (error) {
    status.textContent = error instanceof Error ? error.message : "노선을 읽지 못했습니다.";
  }
}