import { RENDER_OPTIONS } from "@config/config_frontend";
import { currentLanguageIndex, ui_locales } from "@ui/ui_template_locale";
import { createProgressCircle } from "@ui/ui_template_progress";
import * as THREE from "three";
import { OrbitControls } from "three/examples/jsm/controls/OrbitControls.js";
import type { SurfaceBounds, SurfacePointCloudSampleResponse } from "./B04_PreProcess_Api_Fetch";
import {
  bindCursorPivotControls,
  bindSurfaceViewerTheme,
  getReferenceCenter,
  getTopFitDistance,
  TOP_VIEW_TILT,
  niceScaleDistance,
  SURFACE_CAMERA_FOV,
  targetPlaneMetersPerPixel,
  type SurfaceCameraState,
} from "./B04_PreProcess_UI_Camera";

export type { SurfaceCameraState } from "./B04_PreProcess_UI_Camera";

function L(key: keyof typeof ui_locales): string {
  return ui_locales[key][currentLanguageIndex];
}

export interface SurfacePointCloudViewer {
  root: HTMLElement;
  controlsGroup: HTMLElement;
  /** 점 크기·밀도 슬라이더 묶음. 페이지가 "모델 표시 옵션" 컨테이너 맨 아래에 붙인다. */
  optionsContent: HTMLElement;
  statusSpan: HTMLElement;
  /** 로딩 서클 표시. 문구를 주면 켜고, null이면 끈다. `render()` 시 자동으로 꺼진다. */
  setLoading: (label: string | null) => void;
  render: (data: SurfacePointCloudSampleResponse | null) => void;
  setAxesVisible: (visible: boolean) => void;
  applyCameraState: (state: SurfaceCameraState) => void;
  onCameraChange: (listener: (state: SurfaceCameraState) => void) => void;
  resetOptions: () => void;
  dispose: () => void;
}

type CameraView = "iso" | "top" | "front" | "side";

function makeButton(label: string): HTMLButtonElement {
  const button = document.createElement("button");
  button.type = "button";
  button.textContent = label;
  return button;
}

export function createSurfacePointCloudViewer(): SurfacePointCloudViewer {
  const root = document.createElement("div");
  root.className = "point-viewer";

  const statusSpan = document.createElement("span");
  statusSpan.className = "b04-surface__status-info";
  statusSpan.textContent = "포인트 데이터 로딩 중...";

  const controls = document.createElement("div");
  controls.className = "viewer-controls";
  const viewButtons: Array<[CameraView, HTMLButtonElement]> = [
    ["iso", makeButton("사시도")],
    ["top", makeButton("상단")],
    ["front", makeButton("정면")],
    ["side", makeButton("측면")],
  ];
  controls.append(...viewButtons.map(([, button]) => button));

  const controlsGroup = document.createElement("section");
  controlsGroup.className = "b04-surface__group";
  const controlsTitle = document.createElement("h3");
  controlsTitle.className = "b04-surface__panel-title";
  controlsTitle.textContent = L("B04_Surface_Group_ViewControls");
  controlsGroup.append(controlsTitle, controls);

  /** 슬라이더 한 줄 — `이름 [현재값] [게이지]`. 값이 게이지 앞에 온다(2026-08-01 사용자 지시). */
  function buildSlider(
    label: string,
    attributes: { min: string; max: string; step: string; value: string },
  ): { root: HTMLLabelElement; input: HTMLInputElement; value: HTMLSpanElement } {
    const root = document.createElement("label");
    root.className = "viewer-option-row";
    const name = document.createElement("span");
    name.className = "viewer-option-name";
    name.textContent = label;
    const value = document.createElement("span");
    value.className = "viewer-option-val";
    const input = document.createElement("input");
    input.type = "range";
    input.min = attributes.min;
    input.max = attributes.max;
    input.step = attributes.step;
    input.value = attributes.value;
    root.append(name, value, input);
    return { root, input, value };
  }

  const options = document.createElement("div");
  options.className = "viewer-options";
  const size = buildSlider(L("B04_Surface_Opt_PointSize"), {
    min: "0.1",
    max: "2.5",
    step: "0.01",
    value: "0.42",
  });
  const density = buildSlider(L("B04_Surface_Opt_Density"), {
    min: "1",
    max: "10",
    step: "1",
    value: "10",
  });
  const sizeInput = size.input;
  const densityInput = density.input;
  options.append(size.root, density.root);

  /** 게이지 앞 숫자를 현재값으로 맞춘다. */
  function syncOptionValues(): void {
    size.value.textContent = Number(sizeInput.value).toFixed(2);
    density.value.textContent = `${Number(densityInput.value) * 10}%`;
  }
  syncOptionValues();

  const viewerArea = document.createElement("div");
  viewerArea.className = "three-viewer";
  const canvas = document.createElement("canvas");
  canvas.className = "b04-surface-viewer__canvas";
  const scaleBar = document.createElement("div");
  scaleBar.className = "b04-surface__scale";
  const scaleText = document.createElement("span");
  scaleBar.append(scaleText);
  viewerArea.append(canvas, scaleBar, statusSpan);
  root.append(viewerArea);
  // 뷰포트 정중앙 로딩 서클 — 지도·그래프·다른 3D 뷰어와 같은 공통 컴포넌트.
  const progress = createProgressCircle({ overlay: true });
  progress.root.hidden = true;
  viewerArea.append(progress.root);

  function setLoading(label: string | null): void {
    progress.root.hidden = label === null;
    if (label !== null) progress.set(null, label);
  }

  const renderer = new THREE.WebGLRenderer({
    canvas,
    antialias: RENDER_OPTIONS.antialias,
  });
  renderer.setPixelRatio(Math.min(window.devicePixelRatio, RENDER_OPTIONS.maxPixelRatio));
  const scene = new THREE.Scene();
  const releaseTheme = bindSurfaceViewerTheme((color) => {
    scene.background = new THREE.Color(color);
  });
  const camera = new THREE.PerspectiveCamera(SURFACE_CAMERA_FOV, 1, 0.1, 22000);
  const orbit = new OrbitControls(camera, canvas);
  orbit.enableDamping = true;
  orbit.dampingFactor = 0.08;
  orbit.screenSpacePanning = true;
  const axes = new THREE.AxesHelper(45);
  axes.visible = false;
  scene.add(axes);

  let pointsObject: THREE.Points | null = null;
  // 회전·줌 중심을 커서 아래 지점으로 (지형 뷰어·B05와 공용 유틸).
  const releaseCursorPivot = bindCursorPivotControls({
    camera,
    controls: orbit,
    element: canvas,
    pickables: () => (pointsObject ? [pointsObject] : []),
    scene,
  });
  let currentData: SurfacePointCloudSampleResponse | null = null;
  let animationFrame = 0;
  let hasConnected = false;
  let disposed = false;
  let cameraListener: ((state: SurfaceCameraState) => void) | null = null;
  let suppressCameraEvent = false;
  let referenceBounds: SurfaceBounds | null = null;

  function resize(): void {
    const rect = viewerArea.getBoundingClientRect();
    const width = Math.max(1, Math.floor(rect.width));
    const height = Math.max(1, Math.floor(rect.height));
    renderer.setSize(width, height, false);
    camera.aspect = width / height;
    camera.updateProjectionMatrix();
  }

  function clearPoints(): void {
    if (!pointsObject) return;
    pointsObject.geometry.dispose();
    const material = pointsObject.material;
    if (Array.isArray(material)) material.forEach((item) => item.dispose());
    else material.dispose();
    scene.remove(pointsObject);
    pointsObject = null;
  }

  function setCameraView(view: CameraView): void {
    const directions: Record<CameraView, [number, number, number]> = {
      iso: [120, 95, 135],
      // 정확히 수직이면 lookAt이 화면 방향을 못 정해 첫 드래그에 화면이 뒤집힌다.
      top: [0, 1, TOP_VIEW_TILT],
      front: [0, 60, 240],
      side: [240, 60, 0],
    };
    const aspect = viewerArea.clientWidth / Math.max(viewerArea.clientHeight, 1);
    const distance = referenceBounds ? getTopFitDistance(referenceBounds, aspect) : 190;
    orbit.target.set(0, 0, 0);
    camera.position
      .set(...directions[view])
      .normalize()
      .multiplyScalar(distance);
    camera.near = Math.max(distance / 10000, 0.01);
    camera.far = distance * 100;
    camera.updateProjectionMatrix();
    camera.lookAt(orbit.target);
    orbit.update();
  }

  function emitCameraState(): void {
    if (suppressCameraEvent || !cameraListener) return;
    const offset = camera.position.clone().sub(orbit.target);
    const distance = Math.max(offset.length(), 0.001);
    offset.normalize();
    cameraListener({
      direction: [offset.x, offset.y, offset.z],
      distanceMeters: distance,
      targetMeters: [orbit.target.x, orbit.target.y, orbit.target.z],
    });
  }

  function applyCameraState(state: SurfaceCameraState): void {
    suppressCameraEvent = true;
    orbit.target.set(...state.targetMeters);
    camera.position
      .set(...state.direction)
      .multiplyScalar(Math.max(state.distanceMeters, 0.001))
      .add(orbit.target);
    camera.lookAt(orbit.target);
    orbit.update();
    suppressCameraEvent = false;
  }

  function renderPointCloud(data: SurfacePointCloudSampleResponse): void {
    clearPoints();
    const bounds = data.bounds;
    const zMin = bounds.z_min ?? 0;
    const zMax = bounds.z_max ?? 0;
    const [xMid, yMid, zMid] = getReferenceCenter(bounds);
    const zSpan = Math.max(zMax - zMin, 1e-9);
    referenceBounds = bounds;
    const density = Number(densityInput.value);
    const step = Math.max(1, Math.ceil(10 / density));
    const count = Math.ceil(data.points.length / step);
    const positions = new Float32Array(count * 3);
    const colors = new Float32Array(count * 3);
    const hasRgb = Boolean(data.rgb && data.rgb.length === data.points.length);
    let outputIndex = 0;
    for (let index = 0; index < data.points.length; index += step) {
      const [x, y, z] = data.points[index];
      positions[outputIndex * 3] = x - xMid;
      positions[outputIndex * 3 + 1] = z - zMid;
      positions[outputIndex * 3 + 2] = -(y - yMid);
      const rgb = hasRgb ? data.rgb?.[index] : undefined;
      if (rgb) {
        const divisor = Math.max(...rgb) > 255 ? 65535 : 255;
        colors[outputIndex * 3] = rgb[0] / divisor;
        colors[outputIndex * 3 + 1] = rgb[1] / divisor;
        colors[outputIndex * 3 + 2] = rgb[2] / divisor;
      } else {
        const ratio = Math.max(0, Math.min(1, (z - zMin) / zSpan));
        colors[outputIndex * 3] = (36 + ratio * 190) / 255;
        colors[outputIndex * 3 + 1] = (86 + Math.sin(ratio * Math.PI) * 95) / 255;
        colors[outputIndex * 3 + 2] = (128 - ratio * 80) / 255;
      }
      outputIndex += 1;
    }
    const geometry = new THREE.BufferGeometry();
    geometry.setAttribute("position", new THREE.BufferAttribute(positions, 3));
    geometry.setAttribute("color", new THREE.BufferAttribute(colors, 3));
    geometry.computeBoundingSphere();
    const material = new THREE.PointsMaterial({
      size: Number(sizeInput.value),
      vertexColors: true,
      sizeAttenuation: true,
    });
    pointsObject = new THREE.Points(geometry, material);
    scene.add(pointsObject);
    statusSpan.textContent = `${count.toLocaleString()}개 점 표시 중`;
  }

  function updateScaleBar(): void {
    if (!currentData) {
      scaleBar.hidden = true;
      return;
    }
    const distance = camera.position.distanceTo(orbit.target);
    const metersPerPixel = targetPlaneMetersPerPixel(distance, viewerArea.clientHeight);
    const meters = niceScaleDistance(100 * metersPerPixel);
    scaleBar.hidden = false;
    scaleBar.style.width = `${meters / metersPerPixel}px`;
    scaleText.textContent = meters >= 1000 ? `${meters / 1000} km` : `${meters} m`;
  }

  function animate(): void {
    if (!root.isConnected) {
      if (!hasConnected) animationFrame = requestAnimationFrame(animate);
      else disposeViewer();
      return;
    }
    hasConnected = true;
    resize();
    orbit.update();
    updateScaleBar();
    renderer.render(scene, camera);
    animationFrame = requestAnimationFrame(animate);
  }

  function disposeViewer(): void {
    if (disposed) return;
    disposed = true;
    cancelAnimationFrame(animationFrame);
    releaseTheme();
    releaseCursorPivot();
    clearPoints();
    orbit.dispose();
    renderer.dispose();
  }

  viewButtons.forEach(([view, button]) => {
    button.addEventListener("click", () => setCameraView(view));
  });
  sizeInput.addEventListener("input", () => {
    syncOptionValues();
    if (pointsObject)
      (pointsObject.material as THREE.PointsMaterial).size = Number(sizeInput.value);
  });
  densityInput.addEventListener("input", () => {
    syncOptionValues();
    if (currentData) renderPointCloud(currentData);
  });
  orbit.addEventListener("change", emitCameraState);
  animationFrame = requestAnimationFrame(animate);

  return {
    root,
    controlsGroup,
    optionsContent: options,
    statusSpan,
    setLoading,
    render(data) {
      setLoading(null);
      currentData = data;
      clearPoints();
      if (!data) {
        statusSpan.textContent = "데이터가 존재하지 않습니다.";
        return;
      }
      renderPointCloud(data);
      setCameraView("top");
    },
    applyCameraState,
    onCameraChange(listener) {
      cameraListener = listener;
    },
    setAxesVisible(visible) {
      axes.visible = visible;
    },
    resetOptions() {
      axes.visible = false;
      sizeInput.value = "0.42";
      densityInput.value = "10";
      syncOptionValues();
      if (currentData) renderPointCloud(currentData);
      setCameraView("iso");
    },
    dispose: disposeViewer,
  };
}