// Copyright (c) 2026 Dominic Masters
//
// This software is released under the MIT License.
// https://opensource.org/licenses/MIT

// Radius must stay well outside the floor's footprint (a 20x20 plane has a
// corner-to-center distance of 10*sqrt(2) =~ 14.1) -- orbiting inside that
// puts parts of the floor's own geometry near/behind the camera's view
// direction, which the PSP's legacy GU pipeline can't clip properly and
// drops the whole triangle instead of clipping it.
var CAMERA_ORBIT_RADIUS = 18.0;
var CAMERA_ORBIT_HEIGHT = 10.0;
var CAMERA_ORBIT_SPEED = 0.5;

var cameraOrbitAngle = 0.0;
var cameraPosition = null;

// Orbits the camera around the world origin at a fixed radius/height/
// speed, always looking back at the origin. Called once up front (so the
// very first rendered frame is already positioned correctly) and then
// once per frame via update() below.
function updateCameraOrbit() {
  cameraOrbitAngle += Time.delta * CAMERA_ORBIT_SPEED;

  var eyeX = Math.cos(cameraOrbitAngle) * CAMERA_ORBIT_RADIUS;
  var eyeY = CAMERA_ORBIT_HEIGHT;
  var eyeZ = Math.sin(cameraOrbitAngle) * CAMERA_ORBIT_RADIUS;

  cameraPosition.lookAt(eyeX, eyeY, eyeZ, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
}

module.exports = {
  // Called once by Scene.set(), right after it creates and activates the
  // scene this module owns.
  init: function() {
    // Camera, orbiting the origin (see updateCameraOrbit above).
    var camera = new Entity();
    cameraPosition = camera.add(POSITION);
    camera.add(CAMERA);
    updateCameraOrbit();

    // Static ground plane. Physics ignores the entity's position
    // component -- the shape's own normal/distance fully define the
    // plane in world space.
    var plane = new Entity();
    var planePosition = plane.add(POSITION);
    planePosition.setLocalPosition(-10.0, 0.0, -10.0);
    planePosition.setLocalScale(20.0, 1.0, 20.0);

    var planePhysics = plane.add(PHYSICS);
    planePhysics.setBodyType(PHYSICS_BODY_STATIC);
    planePhysics.setShape(PHYSICS_SHAPE_PLANE, 0.0, 1.0, 0.0, 0.0);

    var planeRenderable = plane.add(RENDERABLE);
    planeRenderable.setMesh(0, MESH_PLANE);
    planeRenderable.setColor(128, 128, 128, 255);

    // Player: dynamic capsule body, moved relative to the camera by
    // PLAYER's own update callback (see entityplayer.c).
    var player = new Entity();
    var playerPosition = player.add(POSITION);
    playerPosition.setLocalPosition(0.0, 2.0, 0.0);

    var playerPhysics = player.add(PHYSICS);
    playerPhysics.setShape(PHYSICS_SHAPE_CAPSULE, 0.5, 0.5);

    var playerRenderable = player.add(RENDERABLE);
    playerRenderable.setMesh(0, MESH_CAPSULE);
    playerRenderable.setColor(0, 0, 255, 255);

    player.add(PLAYER);
  },

  // Called once per engine frame while this module is the active scene
  // (see Scene.set(), engineUpdate() -> moduleSceneUpdateCurrent()).
  update: function() {
    if(cameraPosition) updateCameraOrbit();
  },

  // Called once by Scene.set() when this module is replaced by another,
  // right before the scene it owns is destroyed.
  dispose: function() {
    cameraPosition = null;
  }
};