using UnityEngine;
using System.Collections;

//Predictor script for client
//with client side prediction

public class C_Predictor : MonoBehaviour {

    public float pingMargin = 0.5f;

    private float clientPing;

    private NetState[] serverStateBuffer = new NetState[20];

    private NetState[] clientStateBuffer = new NetState[20];

    //Keep track of what Slots are used
    private int m_LocalStateCount;

    // Stat variabels for prediction stuff
    private float m_TimeAccuracy = 0;
    private float m_PredictionAccuracy = 0;
    private bool m_FixError = false;
    private Vector3 m_NewPosition;
    private Quaternion m_NewRotation;

    // The position vector distance to start error correction. The higher the latency the higher this
    // value should be or it constantly tries to correct errors in prediction
    public float m_PredictionThreshold = 0.3F;

    // Time difference in milliseconds where we check for error in position. If the server time value
    // of a state is too different from the local state time then the error correction comparison is
    // highly unreliable and might try to correct more errors than there really are.
    public float m_TimeThreshold = 0.05F;



    public void uLink_OnSerializeNetworkView(uLink.BitStream stream, uLink.NetworkMessageInfo info)
    {
        if(!stream.isWriting)
        {
            Vector3 pos = Vector3.zero;
            Quaternion rot = Quaternion.identity;

            stream.Serialize(ref pos, 0.001f);
            stream.Serialize(ref rot, 0.001f);

            //take care of data for interpolating remote objects movements
            //Shift up the buffer
            for(int i = serverStateBuffer.Length - 1; i >= 1; i--)
            {
                serverStateBuffer[i] = serverStateBuffer[i - 1];
            }

            //Override the first element with the latest server info
            serverStateBuffer[0] = new NetState((float)info.timestamp, pos, rot);

            /*int m_TimestampCount;
            for(int i = 0; i < m_TimestampCount-1; i++)
            {
                if(serverStateBuffer[i].timeStamp < serverStateBuffer[i + 1].timeStamp)
                {
                    Debug.Log("State inconsistent");
                }
            }*/

        }

    }

    // Use this for initialization
    void Start ()
    {
        StartCoroutine(StoreLocalMovement());
    }

    IEnumerator StoreLocalMovement()
    {
        while(true)
        {
            yield return new WaitForSeconds(1/10);

            //shift buffer content
            for(int i = clientStateBuffer.Length - 1; i >= 1; i--)
            {
                clientStateBuffer[i] = clientStateBuffer[i - 1];
            }

            clientStateBuffer[0] = new NetState((float)uLink.Network.time, transform.position, transform.rotation);

            m_LocalStateCount = Mathf.Min(m_LocalStateCount + 1, clientStateBuffer.Length);

            //
            //Check if the client side prediction has an error
            //

            //Find the local buffered state which is closest to network state in time
            int j = 0;
            bool match = false;
            for(j = 0; j < m_LocalStateCount - 1; j++)
            {
                if(serverStateBuffer[0] != null)
                {
                    if(serverStateBuffer[0].timeStamp <= clientStateBuffer[j].timeStamp && clientStateBuffer[j].timeStamp - serverStateBuffer[0].timeStamp <= m_TimeThreshold)
                    {
                        if(Debug.isDebugBuild)
                        {
                            Debug.Log("Comparing state " + j + "localtime: " + clientStateBuffer[j].timeStamp  + " networktime: " + serverStateBuffer[0].timeStamp);
                            Debug.Log("Local: " + clientStateBuffer[j].pos + " Network: " + serverStateBuffer[0].pos);
                        }

                        //m_TimeAccuracy = Mathf.Abs(clientStateBuffer[j].timeStamp - serverStateBuffer[0].timeStamp);
                        m_PredictionAccuracy = (Vector3.Distance(clientStateBuffer[j].pos, serverStateBuffer[0].pos));
                        match = true;
                        break;
                    }
                }
            }

            if(!match)
            {
                //Debug.log("Not match");
            }
            else if(m_PredictionAccuracy > m_PredictionThreshold) //if prediction is off, diverge current location by the amount of the offset
            {
                if(Debug.isDebugBuild) Debug.Log("PredictionAccuracy sup to Predictionthreshold");

                //Find how fat we travelled since the prediction failed
                Vector3 localMovement = clientStateBuffer[j].pos - clientStateBuffer[0].pos;

                //"Erase" old value in the local buffer
                m_LocalStateCount = 1;

                //New position which we need to converge to in the update loop
                m_NewPosition = serverStateBuffer[0].pos;

                m_NewRotation = serverStateBuffer[0].rot;

                //Trigger the new position convergence routine
                m_FixError = true;
            }
            else
            {
                m_FixError = false;
            }
        }
    }

    // Update is called once per frame
    void Update ()
    {
        if(m_FixError)
        {
            //transform.position = Vector3.Lerp(m_NewPosition, transform.position, difference.magnitude);
            Vector3 predictPos = (m_NewPosition/2) + (clientStateBuffer[0].pos/2);
            Vector3 difference = predictPos - transform.position;


            transform.position = Vector3.Lerp(transform.position, predictPos, difference.magnitude);
            transform.rotation = Quaternion.Slerp(transform.rotation, m_NewRotation, difference.magnitude);
        }


    }

}