using UnityEngine;

namespace Passer.CreatureControl {

    public class Creature : MonoBehaviour {
        /// <summary>The target bones rig</summary>
        /// The target bones rig contain the target pose of the creature
        /// The creature movements will try to move the creature such that the target pose is reached
        /// as closely as possible
        public Transform model;

        public TargetRig targetRig;

        public Vector3 targetToModelTranslation;
        public Quaternion targetToModelRotation;

        #region Init

        /// <summary>
        /// Ensure a target rig is available
        /// </summary>
        /// <param name="targetRigResourceName">The name of the target rig resource</param>
        /// <returns>True when the creature rig has been updated</returns>
        /// The parameter is used to instantiate a new target rig when none has been found.
        public bool CheckTargetRig(string targetRigResourceName) {
            if (this.targetRig == null) {
                // See if there is a target rig, but we just haven't found it
                this.targetRig = this.GetComponentInChildren<InsectRig>();
                if (this.targetRig == null) {
                    GameObject targetsRigPrefab = Resources.Load<GameObject>(targetRigResourceName);
                    GameObject targetRig = Instantiate(targetsRigPrefab);
                    targetRig.name = "Target Rig";

                    targetRig.transform.SetPositionAndRotation(this.transform.position, this.transform.rotation);
                    targetRig.transform.SetParent(this.transform);
                    this.targetRig = targetRig.GetComponent<InsectRig>();
                }
                return true;
            }
            else
                return false;
        }

        public virtual bool CheckTargetRig() {
            return CheckTargetRig("TargetRig");
        }

        /// <summary>
        /// Ensure that the creature rig is available
        /// </summary>
        /// <returns>True when the creature rig has been updated</returns>
        public bool CheckModel() {
            if (this.model == null) {
                SkinnedMeshRenderer[] skinnedMeshRenderers = this.GetComponentsInChildren<SkinnedMeshRenderer>();
                foreach (SkinnedMeshRenderer skinnedMeshRenderer in skinnedMeshRenderers) {
                    Transform rendererParent = skinnedMeshRenderer.transform.parent;
                    if (this.model == null || this.model == rendererParent)
                        this.model = rendererParent;
                    else
                        Debug.LogWarning("Unclear model root");
                }
                return this.model != null;
            }
            else
                return false;
        }

        #endregion Init

        #region Start

        protected virtual void Start() {
            this.CheckTargetRig();
            this.CheckModel();
            this.targetRig.MatchTo(this);
        }

        #endregion Start

        #region Update

        public virtual void Update() {
            if (this.targetRig == null)
                return;

            UpdatePose();

            // copy animator root motion to the humanoid
            this.transform.SetPositionAndRotation(targetRig.transform.position, targetRig.transform.rotation);
            // As target rig is probably a child of this.transform,
            // We need to restore the position/rotation of the targetsRig.
            targetRig.transform.SetPositionAndRotation(this.transform.position, this.transform.rotation);        
        }

        public void UpdatePose() {
            if (this.targetRig == null)
                return;

            this.targetRig.PoseLimbs();
            UpdateBones();            
        }

        public virtual void UpdateBones() {
            Vector3 newPosition = this.targetRig.transform.position + this.targetToModelTranslation;
            Quaternion newOrientation = this.targetRig.transform.rotation * this.targetToModelRotation;
            this.model.SetPositionAndRotation(newPosition, newOrientation);
        }

        #endregion Update

        void OnDrawGizmos() {
            // This ensures that the model is always following the target rig
            if (Application.isPlaying == false) {
                this.UpdatePose();
            }
        }
    }

}