// viewer.js
// ==============================

let pc;            // will hold the PlayCanvas module once imported
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 plyUrl, glbUrl;

/**
 * initializeViewer(config, instanceId)
 */
export async function initializeViewer(config, instanceId) {
  if (viewerInitialized) return;

  // Detect iOS and Safari
  const isIOS    = /iPad|iPhone|iPod/.test(navigator.userAgent) && !window.MSStream;
  const isSafari = /^((?!chrome|android).)*safari/i.test(navigator.userAgent);
  const isMobile = isIOS || /Android/i.test(navigator.userAgent);

  // 1. Read config
  plyUrl = config.ply_url;
  glbUrl = config.glb_url;
  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;

  // 2. Grab DOM
  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);

  // 3. Create <canvas>
  let oldCanvas = document.getElementById(canvasId);
  if (oldCanvas) oldCanvas.remove();
  const canvas = document.createElement('canvas');
  canvas.id = canvasId;
  canvas.className = 'ply-canvas';
  canvas.style.zIndex = "1";
  viewerContainer.insertBefore(canvas, progressDialog);

  // 4. Wheel listener
  canvas.addEventListener('wheel', e => {
    if (cameraEntity && cameraEntity.script && cameraEntity.script.orbitCamera) {
      const orbitCam = cameraEntity.script.orbitCamera;
      const sens = (cameraEntity.script.orbitCameraInputMouse?.distanceSensitivity) || 0.4;
      if (cameraEntity.camera.projection === pc.PROJECTION_PERSPECTIVE) {
        orbitCam.distance -= e.deltaY * 0.01 * sens * (orbitCam.distance * 0.1);
      } else {
        orbitCam.orthoHeight -= e.deltaY * 0.01 * sens * (orbitCam.orthoHeight * 0.1);
      }
      e.preventDefault();
      e.stopPropagation();
    }
  }, { passive: false });

  progressDialog.style.display = 'block';

  // 5. Import PlayCanvas
  if (!pc) {
    pc = await import("https://esm.run/playcanvas");
    window.pc = pc;
  }

  try {
    // 6. Setup device & app
    const device = await pc.createGraphicsDevice(canvas, {
      deviceTypes: ["webgl2"],
      glslangUrl:  "https://playcanvas.vercel.app/static/lib/glslang/glslang.js",
      twgslUrl:    "https://playcanvas.vercel.app/static/lib/twgsl/twgsl.js",
      antialias:   false,
      // ---- CRUCIAL FOR iOS/Safari BLANK SCREEN BUG: ----
      preserveDrawingBuffer: isIOS || isSafari ? true : false
    });
    device.maxPixelRatio = Math.min(window.devicePixelRatio, 2);

    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);

    // Attach ResizeObserver to keep canvas in sync with container size
    resizeObserver = new ResizeObserver(entries => {
      for (const entry of entries) {
        const { width, height } = entry.contentRect;
        if (app) {
          app.resizeCanvas(width, height);
        }
      }
    });
    resizeObserver.observe(viewerContainer);

    window.addEventListener('resize', () => {
      if (app) app.resizeCanvas(viewerContainer.clientWidth, viewerContainer.clientHeight);
    });
    app.on('destroy', () => {
      window.removeEventListener('resize', resizeCanvas);
    });

    // 7. Assets
    const assets = {
      model: new pc.Asset('gsplat', 'gsplat', { url: plyUrl }),
      orbit: new pc.Asset('script', 'script', { url: "https://mikafil-viewer-gs.static.hf.space/orbit-camera.js" }),
      galerie: new pc.Asset('galerie', 'container', { url: glbUrl }),
      hdr: new pc.Asset('hdr', 'texture', {
        url: `https://huggingface.co/datasets/bilca/ply_files/resolve/main/galeries/blanc.png`
      }, { type: pc.TEXTURETYPE_RGBP, mipmaps: false })
    };

    const loader = new pc.AssetListLoader(Object.values(assets), app.assets);
    let lastProg = 0;
    assets.model.on('load', () => progressDialog.style.display = 'none');
    assets.model.on('error', err => {
      console.error("Error loading PLY file:", err);
      progressDialog.innerHTML = `<p style="color: red">Error loading model: ${err}</p>`;
    });

    const progCheck = setInterval(() => {
      if (assets.model.resource) {
        progressIndicator.value = 100;
        clearInterval(progCheck);
        progressDialog.style.display = 'none';
      } else if (assets.model.loading) {
        lastProg = Math.min(lastProg + 2, 90);
        progressIndicator.value = lastProg;
      }
    }, 100);

    loader.load(async () => {
      app.start();
      app.scene.envAtlas = assets.hdr.resource;

      // Model entity
      modelEntity = new pc.Entity('model');
      modelEntity.addComponent('gsplat', { asset: assets.model });
      modelEntity.setLocalPosition(modelX, modelY, modelZ);
      modelEntity.setLocalEulerAngles(modelRotationX, modelRotationY, modelRotationZ);
      modelEntity.setLocalScale(modelScale, modelScale, modelScale);
      app.root.addChild(modelEntity);

      // Light
      const dirLight = new pc.Entity('Cascaded Light');
      dirLight.addComponent('light', {
        type: 'directional',
        color: pc.Color.WHITE,
        shadowBias: 0.3,
        normalOffsetBias: 0.2,
        intensity: 1.0,
        soft: true,
        shadowResolution: 4096,
        penumbraSize: 7,
        penumbraFalloff: 1.5,
        shadowSamples: 128,
        shadowBlockerSamples: 16,
        castShadows: true,
        shadowType: pc.SHADOW_PCSS_32F,
        shadowDistance: 1000
      });
      dirLight.setLocalEulerAngles(0, 0, 0);
      app.root.addChild(dirLight);

      // Gallery GLB
      const galleryEntity = assets.galerie.resource.instantiateRenderEntity();
      app.root.addChild(galleryEntity);

      // Camera setup
      cameraEntity = new pc.Entity('camera');
      cameraEntity.addComponent('camera', {
        clearColor: config.canvas_background
          ? parseInt(config.canvas_background.substr(1, 2), 16) / 255
          : 0,
      });
      cameraEntity.setPosition(chosenCameraX, chosenCameraY, chosenCameraZ);
      cameraEntity.lookAt(modelEntity.getPosition());

      cameraEntity.addComponent('script');
      cameraEntity.script.create('orbitCamera', {
        attributes: {
          inertiaFactor: 0.2,
          focusEntity: modelEntity,
          distanceMax: maxZoom,
          distanceMin: minZoom,
          pitchAngleMax: maxAngle,
          pitchAngleMin: minAngle,
          yawAngleMax: maxAzimuth,
          yawAngleMin: minAzimuth,
          minPivotY: minPivotY,
          frameOnStart: false
        }
      });
      cameraEntity.script.create('orbitCameraInputMouse', {
        attributes: {
          orbitSensitivity: isMobile ? 0.6 : 0.3,
          distanceSensitivity: isMobile ? 0.5 : 0.4
        }
      });
      if (cameraEntity.script.orbitCameraInputMouse) {
        cameraEntity.script.orbitCameraInputMouse.onMouseWheel = function() {};
      }
      cameraEntity.script.create('orbitCameraInputTouch', {
        attributes: {
          orbitSensitivity: 0.6,
          distanceSensitivity: 0.5
        }
      });
      app.root.addChild(cameraEntity);

      // Reset & constrain updates
      app.once('update', () => resetViewerCamera());
      app.on('update', dt => {
        if (cameraEntity) {
          const pos = cameraEntity.getPosition();
          if (pos.y < minY) {
            cameraEntity.setPosition(pos.x, minY, pos.z);
          }
        }
      });

      // Final resize
      app.resizeCanvas(viewerContainer.clientWidth, viewerContainer.clientHeight);

      // Tooltips
      try {
        const tooltipsModule = await import('./tooltips.js');
        tooltipsModule.initializeTooltips({
          app,
          cameraEntity,
          modelEntity,
          tooltipsUrl: config.tooltips_url,
          defaultVisible: !!config.showTooltipsDefault,
          moveDuration: config.tooltipMoveDuration || 0.6
        });
      } catch (e) {
        console.error("Error loading tooltips.js:", e);
      }

      progressDialog.style.display = 'none';
      viewerInitialized = true;
    });

  } catch (error) {
    console.error("Error initializing PlayCanvas viewer:", error);
    progressDialog.innerHTML = `<p style="color: red">Error loading viewer: ${error.message}</p>`;
  }
}

export function resetViewerCamera() {
  try {
    if (!cameraEntity || !modelEntity || !app) return;
    const orbitCam = cameraEntity.script.orbitCamera;
    if (!orbitCam) 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;
    orbitCam._updatePosition && orbitCam._updatePosition();

    tempEnt.destroy();
  } catch (e) {
    console.error("Error resetting camera:", e);
  }
}

export function cleanupViewer() {
  if (app) {
    try {
      app.destroy();
    } catch {}
    app = null;
  }
  cameraEntity = null;
  modelEntity  = null;
  viewerInitialized = false;

  // Disconnect the ResizeObserver to avoid leaks
  if (resizeObserver) {
    resizeObserver.disconnect();
    resizeObserver = null;
  }
}