using System;

using UnityEngine;

namespace Framework.Cameras {

  /// <summary>Controls a camera in a 2.5D platformer</summary>
  public class PlatformerCameraController : CameraController {

    /// <summary>Height adjustment of the camera</summary>
    public float ExtraHeight = 1.0f;

    /// <summary>Distance from which the camera observes the target</summary>
    public float Distance = 8.0f;

    /// <summary>Called once per physics frame</summary>
    protected void FixedUpdate() {
      if(base.Target != null) {
        this.targetPosition = base.Target.position;
      }

      Vector3 adjustedTargetPosition = this.targetPosition;
      adjustedTargetPosition.y += this.ExtraHeight;
      adjustedTargetPosition.z -= this.Distance;

      Vector3 newPosition = transform.position;
      {
        float elapsedTime = Time.fixedDeltaTime;
        while(elapsedTime > 0.01f) { // Poor man's integration
          newPosition += (adjustedTargetPosition - newPosition) / 8.0f;
          elapsedTime -= 0.01f;
        }

        newPosition += (adjustedTargetPosition - newPosition) / 8.0f * (elapsedTime * 100.0f);
      }

      transform.position = newPosition;
    }

    /// <summary>Position of the camera's current or latest valid target</summary>
    protected Vector3 TargetPosition {
      get { return this.targetPosition; }
    }

    /// <summary>Current position of the camera's target</summary>
    private Vector3 targetPosition;

  }

} // namespace Framework.Cameras