AppExperiments

using Leap.Unity.Attributes;
using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace Leap.Unity.Animation {

  public class ScaleSwitch : TweenSwitch, IPropertySwitch {

    public const float NEAR_ZERO = 0.0002f;

    #region Inspector

    [Header("Scale Control")]

    /// <summary> The target to animate. </summary>
    public Transform localScaleTarget;

    /// <summary>
    /// The desired local scale of the scale target when the switch is on.
    /// </summary>
    public Vector3 onLocalScale = Vector3.one;

    /// <summary>
    /// The desired local scale of the scale target when the switch is off.
    /// </summary>
    public Vector3 offLocalScale = Vector3.zero;

    /// <summary>
    /// Enforces a minimum value of 0.0001f for each localScale axis.
    /// </summary>
    public bool enforceNonzeroScale = true;

    /// <summary>
    /// Deactivates THIS OBJECT when its target localScale or any of the component values
    /// of its non-uniform local scale a very near the minimum value specified on the
    /// scale curve.
    /// </summary>
    public bool deactivateSelfWhenSmallestValue = true;
    
    [Tooltip("Enable this setting to connect a Switch that will receive Off() when the "
           + "scale is effectively zero and On() when the scale is effectively nonzero.")]
    public bool switchWhenNonzero = false;

    [SerializeField, ImplementsInterface(typeof(IPropertySwitch))]
    [DisableIf("switchWhenNonzero", isEqualTo: false)]
    [Tooltip("The switch attached here will receive Off() when this Scale Switch is at an "
           + "effectively 'zero' scale (even if Enforce Nonzero Scale is checked), and "
           + "On() when the Scale Switch is at an effectively nonzero scale.")]
    private MonoBehaviour _nonzeroSwitch = default;
    public IPropertySwitch nonzeroSwitch {
      get {
        return _nonzeroSwitch as IPropertySwitch;
      }
    }

    [Header("Animation Curves")]
    [UnitCurve]
    [DisableIf("nonUniformScale", isEqualTo: true)]
    public AnimationCurve scaleCurve = DefaultCurve.SigmoidUp;

    public bool nonUniformScale = false;

    [UnitCurve]
    [DisableIf("nonUniformScale", isEqualTo: false)]
    public AnimationCurve xScaleCurve = DefaultCurve.SigmoidUp;
    [UnitCurve]
    [DisableIf("nonUniformScale", isEqualTo: false)]
    public AnimationCurve yScaleCurve = DefaultCurve.SigmoidUp;
    [UnitCurve]
    [DisableIf("nonUniformScale", isEqualTo: false)]
    public AnimationCurve zScaleCurve = DefaultCurve.SigmoidUp;

    #endregion

    #region Unity Events

    protected virtual void Reset() {
      if (localScaleTarget == null) localScaleTarget = this.transform;
    }

    #endregion

    #region Switch Implementation

    protected override void updateSwitch(float time, bool immediately = false) {
#if UNITY_EDITOR
      if (!Application.isPlaying) {
        if (localScaleTarget != null) {
          UnityEditor.Undo.RecordObject(localScaleTarget.transform, "Update Scale Switch");
        }
      }
#endif

      Vector3 targetScale = getTargetScale(time);

      if (enforceNonzeroScale) {
        targetScale = Vector3.Max(targetScale, Vector3.one * NEAR_ZERO);
      }

      if (localScaleTarget != null) {
        localScaleTarget.localScale = targetScale;
      }

      float smallestCurveValue;
      if (nonUniformScale) {
        smallestCurveValue = Mathf.Min(getSmallestCurveValue(xScaleCurve),
                             Mathf.Min(getSmallestCurveValue(yScaleCurve),
                                       getSmallestCurveValue(zScaleCurve)));
      }
      else {
        smallestCurveValue = getSmallestCurveValue(scaleCurve);
      }

      bool effectivelyZeroScale = targetScale.CompMin() <= smallestCurveValue + NEAR_ZERO;

      if (deactivateSelfWhenSmallestValue) {
        this.gameObject.SetActive(!effectivelyZeroScale);
      }

      if (switchWhenNonzero && nonzeroSwitch != null) {
        if (effectivelyZeroScale && nonzeroSwitch.GetIsOnOrTurningOn()) {
          if (immediately) nonzeroSwitch.OffNow();
          else nonzeroSwitch.Off();
        }
        if (!effectivelyZeroScale && nonzeroSwitch.GetIsOffOrTurningOff()) {
          if (immediately) nonzeroSwitch.OnNow();
          else nonzeroSwitch.On();
        }
      }
    }

    private Vector3 getTargetScale(float time) {
      if (!nonUniformScale) {
        return Vector3.Lerp(offLocalScale, onLocalScale, scaleCurve.Evaluate(time));
      }
      else {
        return new Vector3(Mathf.Lerp(offLocalScale.x, onLocalScale.x, xScaleCurve.Evaluate(time)),
                           Mathf.Lerp(offLocalScale.y, onLocalScale.y, yScaleCurve.Evaluate(time)),
                           Mathf.Lerp(offLocalScale.z, onLocalScale.z, zScaleCurve.Evaluate(time)));
      }
    }

    private float getSmallestCurveValue(AnimationCurve animCurve) {
      float smallestValueSoFar = 1f; // unit curve constraints prevent anything larger.
      foreach (var keyframe in animCurve.keys) {
        var testValue = keyframe.value;
        if (testValue < smallestValueSoFar) {
          smallestValueSoFar = testValue;
        }
      }
      return smallestValueSoFar;
    }

    #endregion

  }

}