// ==============================
// 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 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)
 *
 * - Dynamically imports PlayCanvas (once).
 * - Creates a new <canvas id="canvas-<instanceId>"> inside the viewer container.
 * - Sets up lights, model loading, camera + orbit controls, HDR, etc.
 * - Exposes app, cameraEntity, modelEntity, so that interface.js can resize or reset.
 * - Imports & initializes info-points from points.js.
 */
export async function initializeViewer(config, instanceId) {
  if (viewerInitialized) return;

  // Detect device type again (for camera coordinates & input sensitivity)
  const isIOS    = /iPad|iPhone|iPod/.test(navigator.userAgent) && !window.MSStream;
  const isMobile = isIOS || /Android/i.test(navigator.userAgent);

  // ─── 1. Read all relevant config values ───────────────────────────────────────
  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 elements inside interface.js’s container ─────────────────────
  const canvasId       = 'canvas-' + instanceId;
  const progressDialog = document.getElementById('progress-dialog-' + instanceId);
  const progressIndicator = document.getElementById('progress-indicator-' + instanceId);
  const viewerContainerElem = document.getElementById('viewer-container-' + instanceId);

  // ─── 3. Create a fresh <canvas> (removing any old one) ────────────────────────
  let oldCanvas = document.getElementById(canvasId);
  if (oldCanvas) {
    oldCanvas.remove();
  }
  const newCanvas = document.createElement('canvas');
  newCanvas.id = canvasId;
  newCanvas.className = 'ply-canvas';
  newCanvas.style.zIndex = "1";
  viewerContainerElem.insertBefore(newCanvas, progressDialog);
  const canvas = newCanvas;

  // ─── 4. Add mouse‐wheel listener for zoom adjustments ────────────────────────
  canvas.addEventListener('wheel', function(e) {
    if (cameraEntity && cameraEntity.script && cameraEntity.script.orbitCamera) {
      const orbitCam = cameraEntity.script.orbitCamera;
      const sensitivity = (cameraEntity.script.orbitCameraInputMouse && cameraEntity.script.orbitCameraInputMouse.distanceSensitivity) || 0.4;

      if (cameraEntity.camera.projection === pc.PROJECTION_PERSPECTIVE) {
        orbitCam.distance -= e.deltaY * 0.01 * sensitivity * (orbitCam.distance * 0.1);
      } else {
        orbitCam.orthoHeight -= e.deltaY * 0.01 * sensitivity * (orbitCam.orthoHeight * 0.1);
      }
      e.preventDefault();
      e.stopPropagation();
    }
  }, { passive: false });

  progressDialog.style.display = 'block';

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

  try {
    // ─── 6. Create a GraphicsDevice + AppOptions ────────────────────────────────
    const deviceType = "webgl2";
    const gfxOptions = {
      deviceTypes: [deviceType],
      glslangUrl:  "https://playcanvas.vercel.app/static/lib/glslang/glslang.js",
      twgslUrl:    "https://playcanvas.vercel.app/static/lib/twgsl/twgsl.js",
      antialias:   false
    };
    const device = await pc.createGraphicsDevice(canvas, gfxOptions);
    device.maxPixelRatio = Math.min(window.devicePixelRatio, 2);

    const createOptions = new pc.AppOptions();
    createOptions.graphicsDevice = device;
    createOptions.mouse = new pc.Mouse(canvas);
    createOptions.touch = new pc.TouchDevice(canvas);

    // ─── ADD: include physics systems for collision-based picking ───────────────
    createOptions.componentSystems = [
      pc.RenderComponentSystem,
      pc.CameraComponentSystem,
      pc.LightComponentSystem,
      pc.ScriptComponentSystem,
      pc.GSplatComponentSystem,
      pc.CollisionComponentSystem,
      pc.RigidbodyComponentSystem
    ];
    createOptions.resourceHandlers = [
      pc.TextureHandler,
      pc.ContainerHandler,
      pc.ScriptHandler,
      pc.GSplatHandler
    ];

    // ─── REPLACED: use pc.Application (instead of deprecated / removed AppBase) ──
    app = new pc.Application(canvas, createOptions);

    // ─── LISTEN for fullscreen-exit from interface.js to resize the canvas ───────
    window.addEventListener('viewerFullscreenExit', () => {
      if (app && canvas && viewerContainerElem) {
        const vcw = viewerContainerElem.clientWidth;
        const vch = viewerContainerElem.clientHeight;
        app.resizeCanvas(vcw, vch);
      }
    });

    // Configure application
    app.setCanvasFillMode(pc.FILLMODE_NONE);
    app.setCanvasResolution(pc.RESOLUTION_AUTO);
    app.scene.exposure    = 0.5;
    app.scene.toneMapping = pc.TONEMAP_ACES;

    // ─── NEW: Observe viewerContainer size changes to guarantee we resize at final dims ───
    const ro = new ResizeObserver(entries => {
      for (const entry of entries) {
        const { width, height } = entry.contentRect;
        if (app) {
          app.resizeCanvas(width, height);
        }
      }
    });
    ro.observe(viewerContainerElem);

    // ─── 7. Handle window‐resize for the PlayCanvas canvas ─────────────────────
    const resizeCanvas = () => {
      if (app) {
        if (document.fullscreenElement === viewerContainerElem) {
          app.resizeCanvas(window.innerWidth, window.innerHeight);
        } else {
          const cw = canvas.clientWidth;
          const ch = canvas.clientHeight;
          app.resizeCanvas(cw, ch);
        }
      }
    };
    window.addEventListener('resize', resizeCanvas);
    app.on('destroy', () => {
      window.removeEventListener('resize', resizeCanvas);
      ro.disconnect();
    });

    // ─── 8. Declare assets: PLY + orbit‐camera.js + GLB + HDR ───────────────────
    const assets = {
      model: new pc.Asset('gsplat', 'gsplat', { url: plyUrl }),
      orbit: new pc.Asset('script', 'script', { url: "https://bilca-visionneur-play-canva-2.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 assetListLoader = new pc.AssetListLoader(Object.values(assets), app.assets);
    let lastProgress = 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 checkProgress = () => {
      if (assets.model.resource) {
        progressIndicator.value = 100;
        clearInterval(progressChecker);
        progressDialog.style.display = 'none';
      } else if (assets.model.loading) {
        lastProgress += 2;
        if (lastProgress > 90) lastProgress = 90;
        progressIndicator.value = lastProgress;
      }
    };
    const progressChecker = setInterval(checkProgress, 100);

    // ─── 9. Once assets are loaded, build the scene ────────────────────────────
    assetListLoader.load(async () => {
      app.start();
      app.scene.envAtlas = assets.hdr.resource;

      // 9a. Create & position the model
      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);

      // 9b. Add a directional 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
      });
      app.root.addChild(dirLight);
      dirLight.setLocalEulerAngles(0, 0, 0);

      // 9c. Instantiate the GLB “gallery” if any
      const galleryEntity = assets.galerie.resource.instantiateRenderEntity();
      app.root.addChild(galleryEntity);

      // 9d. Create & configure the camera + orbit‐camera scripts
      cameraEntity = new pc.Entity('camera');
      cameraEntity.addComponent('camera', {
        clearColor: config.canvas_background
          ? parseInt(config.canvas_background.substr(1, 2), 16) / 255
          : 0,
        toneMapping: pc.TONEMAP_ACES
      });
      // *** Set initial position/orientation from config immediately ***
      cameraEntity.setPosition(chosenCameraX, chosenCameraY, chosenCameraZ);
      cameraEntity.lookAt(modelEntity.getPosition());

      // Warn if camera is very far
      const distanceCheck = new pc.Vec3().sub2(
        cameraEntity.getPosition(),
        modelEntity.getPosition()
      ).length();
      if (distanceCheck > 100) {
        console.warn("Warning: Camera is far from model; it might not be visible");
      }

      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
        }
      });
      // Disable default onMouseWheel in orbitCameraInputMouse so we handle it ourselves
      if (cameraEntity.script.orbitCameraInputMouse) {
        cameraEntity.script.orbitCameraInputMouse.onMouseWheel = function() {};
      }
      cameraEntity.script.create('orbitCameraInputTouch', {
        attributes: {
          orbitSensitivity: 0.6,
          distanceSensitivity: 0.5
        }
      });

      app.root.addChild(cameraEntity);

      // ─── NEW: Ensure camera is reset on the first frame ───────────────────────
      app.once('update', function() {
        // Call existing resetViewerCamera() so that pivot, yaw/pitch, and distance get  
        // recalculated correctly before the first render.
        resetViewerCamera();
      });

      // 9e. Constrain camera’s Y so it never dips below minY
      app.on('update', function(dt) {
        if (cameraEntity) {
          const pos = cameraEntity.getPosition();
          if (pos.y < minY) {
            cameraEntity.setPosition(pos.x, minY, pos.z);
          }
        }
      });

      // 9f. Resize canvas one last time to fit container
      const initialW = viewerContainerElem.clientWidth;
      const initialH = viewerContainerElem.clientHeight;
      app.resizeCanvas(initialW, initialH);

      // ─── NEW: Load & initialize the info-points module ──────────────────────
      try {
        const pointsModule = await import('./points.js');
        pointsModule.initializePoints({
          app,
          cameraEntity,
          modelEntity,
          pointsUrl: config.points_url,
          defaultVisible: !!config.showPointsDefault,
          moveDuration: config.pointMoveDuration || 0.6  // optional smooth‐move duration
        });
      } catch (e) {
        console.error("Error loading points.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>`;
  }
}

/**
 * resetViewerCamera()
 *
 * Re‐centers the camera on the model, using the chosenCameraXYZ from config.
 * Exactly the same math as in the old index.js‘s resetCamera().
 */
export function resetViewerCamera() {
  try {
    if (!cameraEntity || !modelEntity || !app) return;
    const orbitCam = cameraEntity.script.orbitCamera;
    if (!orbitCam) return;

    const modelPos = modelEntity.getPosition();
    // Create a temporary entity at chosenCameraX,Y,Z to compute yaw/pitch
    const tempEntity = new pc.Entity();
    tempEntity.setPosition(chosenCameraX, chosenCameraY, chosenCameraZ);
    tempEntity.lookAt(modelPos);

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

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

    orbitCam.pivotPoint = new pc.Vec3(modelPos.x, modelPos.y, modelPos.z);
    orbitCam._targetDistance = distance;
    orbitCam._distance       = distance;

    // Compute yaw & pitch from the “tempEntity”
    const rotation = tempEntity.getRotation();
    const tempForward = new pc.Vec3();
    rotation.transformVector(pc.Vec3.FORWARD, tempForward);

    const yaw = Math.atan2(-tempForward.x, -tempForward.z) * pc.math.RAD_TO_DEG;
    const yawQuat = new pc.Quat().setFromEulerAngles(0, -yaw, 0);
    const rotWithoutYaw = new pc.Quat().mul2(yawQuat, rotation);
    const forwardWithoutYaw = new pc.Vec3();
    rotWithoutYaw.transformVector(pc.Vec3.FORWARD, forwardWithoutYaw);
    const pitch = Math.atan2(forwardWithoutYaw.y, -forwardWithoutYaw.z) * pc.math.RAD_TO_DEG;

    orbitCam._targetYaw   = yaw;
    orbitCam._yaw         = yaw;
    orbitCam._targetPitch = pitch;
    orbitCam._pitch       = pitch;
    if (typeof orbitCam._updatePosition === 'function') {
      orbitCam._updatePosition();
    }

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

/**
 * cleanupViewer()
 *
 * Destroys the PlayCanvas `app` (if it exists) and clears references.  Called when the user clicks “X”.
 */
export function cleanupViewer() {
  if (app) {
    try {
      app.destroy();
    } catch (e) {
      console.error("Error destroying PlayCanvas app:", e);
    }
    app = null;
  }
  cameraEntity   = null;
  modelEntity    = null;
  viewerInitialized = false;
}