// Copyright 2016 Google Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// This script is not available for versions of Unity without the
// GVR native integration.

using UnityEngine;
using System.Collections;

/// This script positions and rotates the transform that it is attached to
/// according to a joint in the arm model. See GvrArmModel.cs for details.
public class GvrArmModelOffsets : MonoBehaviour {
#if UNITY_HAS_GOOGLEVR && (UNITY_ANDROID || UNITY_EDITOR)
  /// Used to draw a line between joints for debugging purposes.
  private LineRenderer lineRenderer;

  public enum Joint {
    Pointer,
    Wrist,
    Shoulder,
    Elbow
  }

  /// Determines which joint to set the position and rotation to.
  public Joint joint;

  /// Determines what object to draw a line to (for debugging purposes).
  public GameObject debugDrawTo;

  void Awake() {
    lineRenderer = gameObject.GetComponent<LineRenderer>();
  }

  void Start() {
    if (GvrArmModel.Instance != null) {
      GvrArmModel.Instance.OnArmModelUpdate += OnArmModelUpdate;
    } else {
      Debug.LogError("Unable to find GvrArmModel.");
    }
  }

  void OnDestroy() {
    if (GvrArmModel.Instance != null) {
      GvrArmModel.Instance.OnArmModelUpdate -= OnArmModelUpdate;
    }
  }

  private void OnArmModelUpdate() {
    Vector3 jointPosition;
    Quaternion jointRotation;

    switch (joint) {
      case Joint.Pointer:
        jointPosition = GvrArmModel.Instance.pointerPosition;
        jointRotation = GvrArmModel.Instance.pointerRotation;
        break;
      case Joint.Wrist:
        jointPosition = GvrArmModel.Instance.wristPosition;
        jointRotation = GvrArmModel.Instance.wristRotation;
        break;
      case Joint.Elbow:
        jointPosition = GvrArmModel.Instance.elbowPosition;
        jointRotation = GvrArmModel.Instance.elbowRotation;
        break;
      case Joint.Shoulder:
        jointPosition = GvrArmModel.Instance.shoulderPosition;
        jointRotation = GvrArmModel.Instance.shoulderRotation;
        break;
      default:
        throw new System.Exception("Invalid FromJoint.");
    }

    transform.localPosition = jointPosition;
    transform.localRotation = jointRotation;

    DrawDebugLine();
  }

  private void DrawDebugLine() {
    if (lineRenderer == null || debugDrawTo == null) {
      return;
    }
    if (lineRenderer.useWorldSpace) {
      lineRenderer.SetPosition(0, transform.position);
      lineRenderer.SetPosition(1, debugDrawTo.transform.position);
    } else {
      lineRenderer.SetPosition(0, Vector3.zero);
      lineRenderer.SetPosition(1, transform.InverseTransformPoint(debugDrawTo.transform.position));
    }
  }

#endif  // UNITY_HAS_GOOGLEVR && (UNITY_ANDROID || UNITY_EDITOR)
}