let pc;
export let app = null;
let cameraEntity = null;
let modelEntity = null;
let viewerInitialized = false;
let resizeObserver = null;

let chosenCameraX, chosenCameraY, chosenCameraZ;
let minZoom, maxZoom, minAngle, maxAngle, minAzimuth, maxAzimuth, minPivotY, minY;
let modelX, modelY, modelZ, modelScale, modelRotationX, modelRotationY, modelRotationZ;
let sogsUrl, glbUrl, canvasBg;

function hexToRgbaArray(hex) {
  try {
    hex = hex.replace("#", "");
    if (hex.length === 6) hex += "FF";
    if (hex.length !== 8) return [1, 1, 1, 1];
    const num = parseInt(hex, 16);
    return [
      ((num >> 24) & 0xFF) / 255,
      ((num >> 16) & 0xFF) / 255,
      ((num >> 8)  & 0xFF) / 255,
      (num & 0xFF) / 255
    ];
  } catch (e) {
    alert("hexToRgbaArray error: " + e);
    return [1, 1, 1, 1];
  }
}

export async function initializeViewer(config, instanceId) {
  alert("initializeViewer: start");

  if (viewerInitialized) {
    alert("Already initialized!");
    return;
  }

  const isIOS = /iPad|iPhone|iPod/.test(navigator.userAgent) && !window.MSStream;
  const isMobile = isIOS || /Android/i.test(navigator.userAgent);

  try {
    // Parse config
    sogsUrl   = config.sogs_json_url;
    glbUrl    = config.glb_url;
    canvasBg  = config.canvas_background || "#ffffff";
    minZoom   = parseFloat(config.minZoom || "1");
    maxZoom   = parseFloat(config.maxZoom || "20");
    minAngle  = parseFloat(config.minAngle || "-45");
    maxAngle  = parseFloat(config.maxAngle || "90");
    minAzimuth= (config.minAzimuth !== undefined) ? parseFloat(config.minAzimuth) : -360;
    maxAzimuth= (config.maxAzimuth !== undefined) ? parseFloat(config.maxAzimuth) : 360;
    minPivotY = parseFloat(config.minPivotY || "0");
    minY      = (config.minY !== undefined) ? parseFloat(config.minY) : 0;

    modelX          = (config.modelX !== undefined) ? parseFloat(config.modelX) : 0;
    modelY          = (config.modelY !== undefined) ? parseFloat(config.modelY) : 0;
    modelZ          = (config.modelZ !== undefined) ? parseFloat(config.modelZ) : 0;
    modelScale      = (config.modelScale !== undefined) ? parseFloat(config.modelScale) : 1;
    modelRotationX  = (config.modelRotationX !== undefined) ? parseFloat(config.modelRotationX) : 0;
    modelRotationY  = (config.modelRotationY !== undefined) ? parseFloat(config.modelRotationY) : 0;
    modelRotationZ  = (config.modelRotationZ !== undefined) ? parseFloat(config.modelRotationZ) : 0;

    const cameraX      = (config.cameraX !== undefined) ? parseFloat(config.cameraX) : 0;
    const cameraY      = (config.cameraY !== undefined) ? parseFloat(config.cameraY) : 2;
    const cameraZ      = (config.cameraZ !== undefined) ? parseFloat(config.cameraZ) : 5;
    const cameraXPhone = (config.cameraXPhone !== undefined) ? parseFloat(config.cameraXPhone) : cameraX;
    const cameraYPhone = (config.cameraYPhone !== undefined) ? parseFloat(config.cameraYPhone) : cameraY;
    const cameraZPhone = (config.cameraZPhone !== undefined) ? parseFloat(config.cameraZPhone) : (cameraZ * 1.5);

    chosenCameraX = isMobile ? cameraXPhone : cameraX;
    chosenCameraY = isMobile ? cameraYPhone : cameraY;
    chosenCameraZ = isMobile ? cameraZPhone : cameraZ;

    const canvasId         = 'canvas-' + instanceId;
    const progressDialog   = document.getElementById('progress-dialog-' + instanceId);
    const progressIndicator= document.getElementById('progress-indicator-' + instanceId);
    const viewerContainer  = document.getElementById('viewer-container-' + instanceId);

    let oldCanvas = document.getElementById(canvasId);
    if (oldCanvas) oldCanvas.remove();

    const canvas = document.createElement('canvas');
    canvas.id = canvasId;
    canvas.className = 'ply-canvas';
    canvas.style.width = "100%";
    canvas.style.height = "100%";
    canvas.setAttribute('tabindex', '0');
    viewerContainer.insertBefore(canvas, progressDialog);

    // Apply background color from config if present
    canvas.style.background = canvasBg;

    canvas.style.touchAction = "none";
    canvas.style.webkitTouchCallout = "none";
    canvas.addEventListener('gesturestart', e => e.preventDefault());
    canvas.addEventListener('gesturechange', e => e.preventDefault());
    canvas.addEventListener('gestureend', e => e.preventDefault());
    canvas.addEventListener('dblclick', e => e.preventDefault());
    canvas.addEventListener('touchstart', e => { if (e.touches.length > 1) e.preventDefault(); }, { passive: false });

    // --- Mouse wheel suppression
    canvas.addEventListener('wheel', (e) => {
      e.preventDefault(); // Only block page scroll if mouse is over viewer
    }, { passive: false });

    if (progressDialog) progressDialog.style.display = 'block';

    alert("Canvas created. Loading PlayCanvas...");

    if (!pc) {
      pc = await import("https://cdn.jsdelivr.net/npm/playcanvas@latest/+esm");
      window.pc = pc;
      alert("PlayCanvas imported.");
    }

    // Create app and graphics device
    let device;
    try {
      device = await pc.createGraphicsDevice(canvas, {
        deviceTypes: ["webgl2", "webgl1"],
        glslangUrl: "https://mikafil-viewer-sgos.static.hf.space/static/lib/glslang/glslang.js",
        twgslUrl:   "https://mikafil-viewer-sgos.static.hf.space/static/lib/twgsl/twgsl.js",
        antialias: false
      });
      device.maxPixelRatio = Math.min(window.devicePixelRatio, 2);
      alert("Graphics device created.");
    } catch (e) {
      alert("Graphics device error: " + e);
      throw e;
    }

    const opts = new pc.AppOptions();
    opts.graphicsDevice = device;
    opts.mouse = new pc.Mouse(canvas);
    opts.touch = new pc.TouchDevice(canvas);
    opts.componentSystems = [
      pc.RenderComponentSystem,
      pc.CameraComponentSystem,
      pc.LightComponentSystem,
      pc.ScriptComponentSystem,
      pc.GSplatComponentSystem,
      pc.CollisionComponentSystem,
      pc.RigidbodyComponentSystem
    ];
    opts.resourceHandlers = [
      pc.TextureHandler,
      pc.ContainerHandler,
      pc.ScriptHandler,
      pc.GSplatHandler
    ];

    app = new pc.Application(canvas, opts);
    app.setCanvasFillMode(pc.FILLMODE_NONE);
    app.setCanvasResolution(pc.RESOLUTION_AUTO);

    alert("App created.");

    // Resizing
    resizeObserver = new ResizeObserver(entries => {
      entries.forEach(entry => {
        try {
          app.resizeCanvas(entry.contentRect.width, entry.contentRect.height);
        } catch (e) { alert("resizeCanvas error: " + e); }
      });
    });
    resizeObserver.observe(viewerContainer);

    window.addEventListener('resize', () => {
      try {
        app.resizeCanvas(viewerContainer.clientWidth, viewerContainer.clientHeight);
      } catch (e) { alert("resizeCanvas error: " + e); }
    });
    app.on('destroy', () => resizeObserver.disconnect());

    // Prepare asset loading (SOGS as 'gsplat')
    const assets = {
      sogs: new pc.Asset('gsplat', 'gsplat', { url: sogsUrl }),
      orbit: new pc.Asset('script', 'script', { url: "https://mikafil-viewer-sgos.static.hf.space/orbit-camera.js" }),
      glb: new pc.Asset('glb', 'container', { url: glbUrl }),
    };
    for (const key in assets) app.assets.add(assets[key]);

    // Individual asset error listeners
    assets.sogs.on('error', (err) => { alert("SOGS asset error: " + err); });
    assets.orbit.on('error', (err) => { alert("Orbit-camera.js asset error: " + err); });
    if (assets.glb) assets.glb.on('error', (err) => { alert("GLB asset error: " + err); });

    assets.sogs.ready(() => { alert("SOGS asset ready."); });
    assets.orbit.ready(() => { alert("orbit-camera.js asset ready."); });
    if (assets.glb) assets.glb.ready(() => { alert("GLB asset ready."); });

    const loader = new pc.AssetListLoader(Object.values(assets), app.assets);

    loader.on('error', (err) => { alert("Asset loader error: " + err); });

    loader.load(() => {
      alert("All assets loaded. Starting app...");

      try {
        app.start();
      } catch (e) {
        alert("app.start() error: " + e);
        throw e;
      }

      if (progressDialog) progressDialog.style.display = 'none';

      // Add SOGS model
      try {
        modelEntity = new pc.Entity('model');
        modelEntity.addComponent('gsplat', { asset: assets.sogs });
        modelEntity.setLocalPosition(modelX, modelY, modelZ);
        modelEntity.setLocalEulerAngles(modelRotationX, modelRotationY, modelRotationZ);
        modelEntity.setLocalScale(modelScale, modelScale, modelScale);
        app.root.addChild(modelEntity);
        alert("Model entity added!");
      } catch (e) {
        alert("Model entity error: " + e);
        throw e;
      }

      // Add the GLB entity if provided
      try {
        if (assets.glb && assets.glb.resource && assets.glb.resource.instantiateRenderEntity) {
          const glbEntity = assets.glb.resource.instantiateRenderEntity();
          app.root.addChild(glbEntity);
          alert("GLB entity added.");
        }
      } catch (e) {
        alert("GLB entity error: " + e);
      }

      // CAMERA
      try {
        cameraEntity = new pc.Entity('camera');
        // Support background color
        let bg = [1, 1, 1, 1];
        if (canvasBg && /^#?[0-9a-f]{6,8}$/i.test(canvasBg.replace("#", ""))) {
          bg = hexToRgbaArray(canvasBg);
        }
        cameraEntity.addComponent('camera', { clearColor: new pc.Color(bg[0], bg[1], bg[2], bg[3]) });
        cameraEntity.setPosition(chosenCameraX, chosenCameraY, chosenCameraZ);
        cameraEntity.lookAt(modelEntity.getPosition());
        cameraEntity.addComponent('script');

        // Pass all attributes to Orbit Camera script
        cameraEntity.script.create('orbitCamera', {
          attributes: {
            focusEntity: modelEntity,
            inertiaFactor: 0.2,
            distanceMax: maxZoom,
            distanceMin: minZoom,
            pitchAngleMax: maxAngle,
            pitchAngleMin: minAngle,
            yawAngleMax: maxAzimuth,
            yawAngleMin: minAzimuth,
            minY: minY,
            frameOnStart: false
          }
        });
        cameraEntity.script.create('orbitCameraInputMouse');
        cameraEntity.script.create('orbitCameraInputTouch');
        app.root.addChild(cameraEntity);

        alert("Camera added.");
      } catch (e) {
        alert("Camera error: " + e);
      }

      try {
        app.resizeCanvas(viewerContainer.clientWidth, viewerContainer.clientHeight);
        alert("resizeCanvas called.");
      } catch (e) {
        alert("resizeCanvas error: " + e);
      }

      try {
        app.once('update', () => resetViewerCamera());
        alert("resetViewerCamera scheduled.");
      } catch (e) {
        alert("resetViewerCamera schedule error: " + e);
      }

      // Tooltips support (optional)
      try {
        if (config.tooltips_url) {
          import('https://mikafil-viewer-sgos.static.hf.space/tooltips.js').then(tooltipsModule => {
            tooltipsModule.initializeTooltips({
              app,
              cameraEntity,
              modelEntity,
              tooltipsUrl: config.tooltips_url,
              defaultVisible: !!config.showTooltipsDefault,
              moveDuration: config.tooltipMoveDuration || 0.6
            });
            alert("Tooltips loaded.");
          }).catch(e => { alert("Tooltips module error: " + e); });
        }
      } catch (e) {
        alert("Tooltips try-catch error: " + e);
      }

      viewerInitialized = true;
      alert("Viewer initialized success!");
    });

    alert("Asset loader started.");
  } catch (e) {
    alert("Main try-catch error: " + e);
    throw e;
  }
}

// Resets the viewer camera (as in your PLY example)
export function resetViewerCamera() {
  alert("resetViewerCamera called.");
  try {
    if (!cameraEntity || !modelEntity || !app) {
      alert("resetViewerCamera: cameraEntity/modelEntity/app not ready");
      return;
    }
    const orbitCam = cameraEntity.script.orbitCamera;
    if (!orbitCam) {
      alert("resetViewerCamera: orbitCam missing");
      return;
    }

    const modelPos = modelEntity.getPosition();
    const tempEnt = new pc.Entity();
    tempEnt.setPosition(chosenCameraX, chosenCameraY, chosenCameraZ);
    tempEnt.lookAt(modelPos);

    const dist = new pc.Vec3().sub2(
      new pc.Vec3(chosenCameraX, chosenCameraY, chosenCameraZ),
      modelPos
    ).length();

    cameraEntity.setPosition(chosenCameraX, chosenCameraY, chosenCameraZ);
    cameraEntity.lookAt(modelPos);

    orbitCam.pivotPoint = modelPos.clone();
    orbitCam._targetDistance = dist;
    orbitCam._distance       = dist;

    const rot = tempEnt.getRotation();
    const fwd = new pc.Vec3();
    rot.transformVector(pc.Vec3.FORWARD, fwd);

    const yaw = Math.atan2(-fwd.x, -fwd.z) * pc.math.RAD_TO_DEG;
    const yawQuat = new pc.Quat().setFromEulerAngles(0, -yaw, 0);
    const rotNoYaw = new pc.Quat().mul2(yawQuat, rot);
    const fNoYaw = new pc.Vec3();
    rotNoYaw.transformVector(pc.Vec3.FORWARD, fNoYaw);
    const pitch = Math.atan2(fNoYaw.y, -fNoYaw.z) * pc.math.RAD_TO_DEG;

    orbitCam._targetYaw   = yaw;
    orbitCam._yaw         = yaw;
    orbitCam._targetPitch = pitch;
    orbitCam._pitch       = pitch;
    if (orbitCam._updatePosition) orbitCam._updatePosition();

    tempEnt.destroy();
    alert("resetViewerCamera: success");
  } catch (e) {
    alert("resetViewerCamera: error: " + e);
  }
}