//points.js 

/**
 * initializePoints(options)
 *
 * - options.app: the PlayCanvas App instance
 * - options.cameraEntity: the PlayCanvas camera Entity
 * - options.modelEntity: the main model entity (for any relative positioning; optional)
 * - options.pointsUrl: URL to fetch JSON array of points
 * - options.defaultVisible: boolean: whether points are visible initially
 * - options.moveDuration: number (seconds) for smooth camera move to selected point
 */
export async function initializePoints(options) {
  const {
    app,
    cameraEntity,
    modelEntity,
    pointsUrl,
    defaultVisible,
    moveDuration = 0.6
  } = options;

  if (!app || !cameraEntity || !pointsUrl) {
    console.error("points.js → missing required initialization options");
    return;
  }

  // Load JSON of points:
  let pointsData;
  try {
    const resp = await fetch(pointsUrl);
    pointsData = await resp.json();
  } catch (e) {
    console.error("points.js → failed fetching points.json:", e);
    return;
  }
  if (!Array.isArray(pointsData)) {
    console.error("points.js → points.json must be an array");
    return;
  }

  const pointEntities = [];

  // Create a material for info-point spheres
  const mat = new pc.StandardMaterial();
  mat.diffuse = new pc.Color(1, 0.8, 0);
  mat.specular = new pc.Color(1, 1, 1);
  mat.shininess = 20;
  mat.update();

  // Build each sphere + attach custom data
  for (let i = 0; i < pointsData.length; i++) {
    const pt = pointsData[i];
    const { x, y, z, text, imageUrl } = pt;

    const sphere = new pc.Entity("point-" + i);
    sphere.addComponent("model", { type: "sphere" });
    sphere.model.material = mat;

    // Scale small (primitive sphere radius = 0.5)
    sphere.setLocalScale(0.05, 0.05, 0.05);
    sphere.setLocalPosition(x, y, z);
    sphere.pointData = { text, imageUrl };
    app.root.addChild(sphere);
    pointEntities.push(sphere);
  }

  // Show/hide all point spheres
  function setPointsVisibility(visible) {
    pointEntities.forEach(ent => {
      ent.enabled = visible;
    });
  }
  setPointsVisibility(!!defaultVisible);

  // Respond to toggle-points event from interface.js
  document.addEventListener("toggle-points", (evt) => {
    const { visible } = evt.detail;
    setPointsVisibility(!!visible);
  });

  // Keep track of any in-flight camera tween so we can cancel it
  let currentTween = null;

  // On mouse down (or touch equivalent), perform manual ray‐sphere intersection
  app.mouse.on(pc.EVENT_MOUSEDOWN, (event) => {
    // If a tween is running, cancel it immediately
    if (currentTween) {
      app.off("update", currentTween);
      currentTween = null;
    }

    const x = event.x;
    const y = event.y;
    const from = new pc.Vec3();
    const to   = new pc.Vec3();
    const camera = cameraEntity.camera;

    cameraEntity.camera.screenToWorld(x, y, camera.nearClip, from);
    cameraEntity.camera.screenToWorld(x, y, camera.farClip, to);

    const dir = new pc.Vec3().sub2(to, from).normalize();

    let closestT = Infinity;
    let pickedEntity = null;

    for (const ent of pointEntities) {
      if (!ent.enabled) continue;

      const center = ent.getPosition();
      const worldRadius = 0.5 * ent.getLocalScale().x;

      const oc = new pc.Vec3().sub2(center, from);
      const tca = oc.dot(dir);
      if (tca < 0) continue;

      const d2 = oc.lengthSq() - (tca * tca);
      if (d2 > worldRadius * worldRadius) continue;

      const thc = Math.sqrt(worldRadius * worldRadius - d2);
      const t0 = tca - thc;
      if (t0 < closestT && t0 >= 0) {
        closestT = t0;
        pickedEntity = ent;
      }
    }

    if (pickedEntity) {
      const { text, imageUrl } = pickedEntity.pointData;
      document.dispatchEvent(new CustomEvent("point-selected", {
        detail: { text, imageUrl }
      }));
      tweenCameraToPoint(pickedEntity, moveDuration);
    }
  });

  // Also close tooltip if user interacts (mouse or touch) on the canvas
  const canvasId = app.graphicsDevice.canvas.id;
  const htmlCanvas = document.getElementById(canvasId);
  if (htmlCanvas) {
    htmlCanvas.addEventListener("mousedown", () => {
      document.dispatchEvent(new CustomEvent("hide-tooltip"));
    });
    htmlCanvas.addEventListener("touchstart", () => {
      document.dispatchEvent(new CustomEvent("hide-tooltip"));
    });
  }

  // Tween helper: smoothly move and reorient camera to focus the chosen point entity
  function tweenCameraToPoint(pointEnt, duration) {
    const orbitCam = cameraEntity.script.orbitCamera;
    if (!orbitCam) return;

    // Compute target pivot exactly at the sphere center
    const targetPos = pointEnt.getPosition().clone();
    // Compute current state
    const startPivot   = orbitCam.pivotPoint.clone();
    const startYaw     = orbitCam._yaw;
    const startPitch   = orbitCam._pitch;
    const startDist    = orbitCam._distance;

    // Compute direction & candidate distance:
    const worldRadius  = 0.5 * pointEnt.getLocalScale().x;
    const minZoom = orbitCam.distanceMin;
    const desiredDistance = Math.max(minZoom * 1.2, worldRadius * 4);

    // Compute target yaw/pitch from camera pointing at targetPos
    // Reuse reset logic: place a temp entity at camera’s current position, have it look at target
    const camWorldPos = cameraEntity.getPosition().clone();
    const tempEnt = new pc.Entity();
    tempEnt.setPosition(camWorldPos);
    tempEnt.lookAt(targetPos);
    const rotation = tempEnt.getRotation();
    const forward = new pc.Vec3();
    rotation.transformVector(pc.Vec3.FORWARD, forward);
    const tgtYaw = Math.atan2(-forward.x, -forward.z) * pc.math.RAD_TO_DEG;
    const yawQuat = new pc.Quat().setFromEulerAngles(0, -tgtYaw, 0);
    const rotNoYaw = new pc.Quat().mul2(yawQuat, rotation);
    const fNoYaw = new pc.Vec3();
    rotNoYaw.transformVector(pc.Vec3.FORWARD, fNoYaw);
    const tgtPitch = Math.atan2(fNoYaw.y, -fNoYaw.z) * pc.math.RAD_TO_DEG;
    tempEnt.destroy();

    // Target state:
    const endPivot   = targetPos.clone();
    const endYaw     = tgtYaw;
    const endPitch   = tgtPitch;
    const endDist    = desiredDistance;

    let elapsed = 0;
    const orgPivot = startPivot.clone();
    const orgYaw   = startYaw;
    const orgPitch = startPitch;
    const orgDist  = startDist;

    // If another tween is running, cancel it
    if (currentTween) {
      app.off("update", currentTween);
      currentTween = null;
    }

    // Per-frame update
    function lerpUpdate(dt) {
      elapsed += dt;
      const t = Math.min(elapsed / duration, 1);

      // Interpolate pivot (vector lerp)
      const newPivot = new pc.Vec3().lerp(orgPivot, endPivot, t);
      orbitCam.pivotPoint.copy(newPivot);

      // Interpolate yaw/pitch/distance (simple lerp)
      const newYaw   = pc.math.lerp(orgYaw,   endYaw,   t);
      const newPitch = pc.math.lerp(orgPitch, endPitch, t);
      const newDist  = pc.math.lerp(orgDist,  endDist,  t);

      orbitCam._targetYaw     = newYaw;
      orbitCam._yaw           = newYaw;
      orbitCam._targetPitch   = newPitch;
      orbitCam._pitch         = newPitch;
      orbitCam._targetDistance = newDist;
      orbitCam._distance = newDist;

      orbitCam._updatePosition();

      if (t >= 1) {
        app.off("update", lerpUpdate);
        currentTween = null;
      }
    }

    currentTween = lerpUpdate;
    app.on("update", lerpUpdate);
  }
}