"use client";
import { useEffect, useRef, useState } from "react";
import { Plus, Minus, RotateCcw } from "lucide-react";
import * as THREE from "three";
const textureCache = new Map<string, Promise<THREE.Texture>>();
export function preloadFaces(urls: string[]) {
  return Promise.all(
    urls.map((url) => {
      if (!textureCache.has(url))
        textureCache.set(
          url,
          new THREE.TextureLoader()
            .loadAsync(url)
            .then((t) => {
              t.colorSpace = THREE.SRGBColorSpace;
              return t;
            })
            .catch((e) => {
              textureCache.delete(url);
              throw e;
            }),
        );
      return textureCache.get(url)!;
    }),
  );
}
// Explicit projection matches the six positive-FOV camera images emitted by
// both exporters; it avoids CubeTexture's renderer-dependent orientation.
const fragment = `uniform sampler2D px;uniform sampler2D nx;uniform sampler2D py;uniform sampler2D ny;uniform sampler2D pz;uniform sampler2D nz;varying vec3 vDirection;
void main(){vec3 d=normalize(vDirection);vec3 a=abs(d);vec2 uv;vec4 color;if(a.x>=a.y&&a.x>=a.z){if(d.x>0.0){uv=vec2(d.z,d.y)/a.x*.5+.5;color=texture2D(px,uv);}else{uv=vec2(-d.z,d.y)/a.x*.5+.5;color=texture2D(nx,uv);}}else if(a.y>=a.z){if(d.y>0.0){uv=vec2(-d.x,-d.z)/a.y*.5+.5;color=texture2D(py,uv);}else{uv=vec2(-d.x,d.z)/a.y*.5+.5;color=texture2D(ny,uv);}}else{if(d.z>0.0){uv=vec2(-d.x,d.y)/a.z*.5+.5;color=texture2D(pz,uv);}else{uv=vec2(d.x,d.y)/a.z*.5+.5;color=texture2D(nz,uv);}}gl_FragColor=color;
#include <tonemapping_fragment>
#include <colorspace_fragment>
}`;
export function Panorama({
  urls,
  zoom,
  onReady,
  onError,
}: {
  urls: string[];
  zoom: boolean;
  onReady: () => void;
  onError: (message: string) => void;
}) {
  const mount = useRef<HTMLDivElement>(null),
    view = useRef({ yaw: 0, pitch: 0, fov: 80 }),
    [fov, setFov] = useState(80);
  const callbacks = useRef({ onReady, onError });
  callbacks.current = { onReady, onError };
  useEffect(() => {
    let disposed = false,
      renderer: THREE.WebGLRenderer | undefined,
      frame = 0,
      observer: ResizeObserver | undefined;
    let material: THREE.ShaderMaterial | undefined,
      geometry: THREE.SphereGeometry | undefined;
    const element = mount.current!;
    view.current = { yaw: 0, pitch: 0, fov: 80 };
    const down = (e: PointerEvent) => {
        if (e.button !== 0) return;
        element.setPointerCapture(e.pointerId);
        drag = { x: e.clientX, y: e.clientY };
      },
      move = (e: PointerEvent) => {
        if (!drag) return;
        view.current.yaw -= (e.clientX - drag.x) * 0.003;
        view.current.pitch = Math.max(
          -1.5,
          Math.min(1.5, view.current.pitch + (e.clientY - drag.y) * 0.003),
        );
        drag = { x: e.clientX, y: e.clientY };
      },
      up = () => {
        drag = null;
      },
      wheel = (e: WheelEvent) => {
        if (!zoom) return;
        e.preventDefault();
        view.current.fov = Math.max(
          35,
          Math.min(100, view.current.fov + e.deltaY * 0.04),
        );
      };
    let drag: { x: number; y: number } | null = null;
    preloadFaces(urls)
      .then((textures) => {
        if (disposed) return;
        renderer = new THREE.WebGLRenderer({ antialias: true });
        renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));
        renderer.outputColorSpace = THREE.SRGBColorSpace;
        element.appendChild(renderer.domElement);
        const scene = new THREE.Scene(),
          camera = new THREE.PerspectiveCamera(80, 1, 0.1, 10);
        geometry = new THREE.SphereGeometry(5, 32, 16);
        material = new THREE.ShaderMaterial({
          side: THREE.BackSide,
          uniforms: Object.fromEntries(
            ["px", "nx", "py", "ny", "pz", "nz"].map((f, i) => [
              f,
              { value: textures[i] },
            ]),
          ),
          vertexShader:
            "varying vec3 vDirection;void main(){vDirection=position;gl_Position=projectionMatrix*modelViewMatrix*vec4(position,1.0);}",
          fragmentShader: fragment,
        });
        scene.add(new THREE.Mesh(geometry, material));
        const resize = () => {
          camera.aspect = element.clientWidth / element.clientHeight;
          camera.updateProjectionMatrix();
          renderer!.setSize(element.clientWidth, element.clientHeight);
        };
        observer = new ResizeObserver(resize);
        observer.observe(element);
        resize();
        function draw() {
          if (disposed) return;
          const v = view.current;
          camera.fov = zoom ? v.fov : 80;
          camera.updateProjectionMatrix();
          camera.lookAt(
            Math.sin(v.yaw) * Math.cos(v.pitch),
            Math.sin(v.pitch),
            -Math.cos(v.yaw) * Math.cos(v.pitch),
          );
          renderer!.render(scene, camera);
          frame = requestAnimationFrame(draw);
        }
        draw();
        element.addEventListener("pointerdown", down);
        element.addEventListener("pointermove", move);
        element.addEventListener("pointerup", up);
        element.addEventListener("pointercancel", up);
        element.addEventListener("wheel", wheel, { passive: false });
        callbacks.current.onReady();
      })
      .catch((e) =>
        callbacks.current.onError(
          "Panorama could not load. " + (e instanceof Error ? e.message : ""),
        ),
      );
    return () => {
      disposed = true;
      cancelAnimationFrame(frame);
      observer?.disconnect();
      element.removeEventListener("pointerdown", down);
      element.removeEventListener("pointermove", move);
      element.removeEventListener("pointerup", up);
      element.removeEventListener("pointercancel", up);
      element.removeEventListener("wheel", wheel);
      geometry?.dispose();
      material?.dispose();
      renderer?.dispose();
      renderer?.domElement.remove();
    };
  }, [urls, zoom]);
  useEffect(() => {
    view.current.fov = fov;
  }, [fov]);
  return (
    <>
      <div
        className="panorama"
        ref={mount}
        aria-label="360 degree panorama: drag to look around"
      />
      {
        <div className="panorama-controls">
          {zoom && (
            <>
              <button
                aria-label="Zoom in"
                onClick={() => setFov((v) => Math.max(35, v - 10))}
              >
                <Plus size={17} />
              </button>
              <button
                aria-label="Zoom out"
                onClick={() => setFov((v) => Math.min(100, v + 10))}
              >
                <Minus size={17} />
              </button>
            </>
          )}
          <button
            aria-label="Reset view"
            onClick={() => {
              view.current = { yaw: 0, pitch: 0, fov: 80 };
              setFov(80);
            }}
          >
            <RotateCcw size={17} />
          </button>
        </div>
      }
    </>
  );
}