TheKingsRace/Assets/Scripts/PlayerScripts/PlayerItems/ItemScripts/GrapplingHook.cs

using System.Collections;
using System.Collections.Generic;
using MLAPI;
using UnityEngine;

public class GrapplingHook : NetworkBehaviour
{
    public float maxGrappleDistance = 20;
    public float maxGrabDistance = 30;

    public bool isGrappled;
    private int hookPointIndex;
    private GameObject hookPoint;
    private GameObject[] hookPoints;
    private float distance;

    private CharacterController movementController;
    private PlayerMovement playerMovement;
    private PlayerStats pStats;
    private float ropeLength;
    private Vector3 swingDirection;
    float inclinationAngle;
    float theta = -1;

    private float maxSwingSpeed = 50;
    private float minSwingSpeed = 20;
    private float swingAcc = 3f;
    private float swingSpeed = 10;

    private float swingMom;
    private float maxSwingMom = 60;

    private Vector3 tensionMomDirection;
    private Vector3 hookPointRight;
    private Vector3 momDirection;

    private Vector3 curXZDir;
    private Vector3 oldXZDir;

    private bool swingback = false; //swing the player back
    private float oldSwingMom;

    Vector3 tensionDirection;
    float tensionForce;
    public Vector3 forceDirection;

    private Vector3 tempRelease;
    private Vector3 lerpRelease;
    bool release = false;


    // Start is called before the first frame update
    void Start()
    {
        isGrappled = false; 
        hookPoints = GameObject.FindGameObjectsWithTag("HookPoint");
        movementController = gameObject.GetComponent<CharacterController>();
        playerMovement = gameObject.GetComponent<PlayerMovement>();
        pStats = gameObject.GetComponent<PlayerStats>();
    }

    // Update is called once per frame
    void Update()
    {
        if (!IsLocalPlayer) { return; }

        if ((Input.GetKeyDown(KeyCode.E) || Input.GetKeyDown(KeyCode.JoystickButton2)) && pStats.HasGrapple) //If grapple button is hit
        {
            if (!isGrappled) //If we are not grappling
            {
                hookPointIndex = FindHookPoint(); //Find the nearest hook point within max distance
                if (hookPointIndex != -1) //If there is a hookpoint
                {
                    hookPoint = hookPoints[hookPointIndex]; //The point we are grappling from
                    ropeLength = Vector3.Distance(gameObject.transform.position, hookPoint.transform.position);
                    if(ropeLength > maxGrappleDistance){
                        ropeLength = maxGrappleDistance;
                    }

                    oldXZDir = (new Vector3(hookPoint.transform.position.x,0,hookPoint.transform.position.z) - new Vector3(transform.position.x,0,transform.position.z)).normalized;
                    curXZDir = (new Vector3(hookPoint.transform.position.x,0,hookPoint.transform.position.z) - new Vector3(transform.position.x,0,transform.position.z)).normalized;

                    swingMom = CalculateSwingMom(playerMovement.driftVel.magnitude * 50f);
                    oldSwingMom = swingMom;
                    playerMovement.g = -1;
                    isGrappled = true; //toggle grappling state
                    release = false;
                    lerpRelease = Vector3.zero;
                }
            }
            else //Else we are grappling
            {
                isGrappled = false; //toggle grappling state to release
                release = true;
                playerMovement.g = 0;
            }
        }
    }

    private void FixedUpdate()
    {
        if (!IsLocalPlayer) { return; }
        if (isGrappled)
        {
            Debug.DrawRay(gameObject.transform.position, (hookPoint.transform.position - gameObject.transform.position)); //Visual of line

            //Debug.Log(Vector3.Distance(gameObject.transform.position, hookPoint.transform.position));
            //Calculate tether force direction based on hookpoint
            if (Vector3.Distance(gameObject.transform.position, hookPoint.transform.position) >= ropeLength )
            {
                Debug.Log(ropeLength);
                forceDirection = CalculateForceDirection(1, playerMovement.g, hookPoint.transform.position) + RopeLengthOffset(hookPoint.transform.position, Vector3.Distance(gameObject.transform.position, hookPoint.transform.position));
                

            }
            else{
                forceDirection = Vector3.zero;
            }

            //apply special swing movement when aerial
            if(!playerMovement.isGrounded){
                movementController.Move(SwingMoveController());
                if(swingMom != 0){
                    movementController.Move(CalculateMomentumDirection(playerMovement.g, hookPoint.transform.position));
                    swingMom -= .5f;
                }
            }
            else{
                swingMom = CalculateSwingMom(playerMovement.driftVel.magnitude * 50f);
            }

            if(swingMom<0) swingMom = 0;

            tempRelease = CalculateSwingReleaseForce();
        }
        else if(!isGrappled){
            //Reset force direction after unhook
            forceDirection = Vector3.zero;
            swingback = true;

            if(release){
                lerpRelease = Vector3.Lerp(lerpRelease, tempRelease, 10f * Time.deltaTime);
                tempRelease *= .95f;
                movementController.Move(lerpRelease);
            }

            
        }

        //WILL NEED ADJUSTMENT OR REMOVAL IN THE FUTURE
        //ungrapple on jump
        if(playerMovement.GetJumpPressed() && !playerMovement.isGrounded && isGrappled){
            release = true;
            isGrappled = false; 
        }
        if(playerMovement.isGrounded){
            swingback = true;
            release = false;
        }
    }

    //Finds the nearest hook to the player
    int FindHookPoint()
    {
        float least = maxGrabDistance;
        int index = -1;
        for(int i = 0; i<hookPoints.Length; i++)
        {
            distance = Vector3.Distance(gameObject.transform.position, hookPoints[i].transform.position);
            if (distance <= least)
            {
                index = i;
            }
        }
        return index;
    }

    //Needs to be Overhauled to properly implement energy loss taking into account players current Velocity, height and input
    //------Important Equations--------
    // TensionForce = Cos(theta) * g * m * Vector3(tensionDirection)
    // Potential Energy = m * g * h -- Will need to modify adding current speed
    // Kinetic Energy = 1/2 * m * V^2 -- assuming no energy loss at the bottom KE = PE at peak we will add energy loss ourselves
    // Total Energy = m * ((g*h) + (1/2 * V^2))
    // Velocity = (2 * ((TotalEnergy/m) - (g*h)))^(1/2) -- This hypothetically could be used for our swing momentum calculation
    // Movement Direction right angle of tension force = Sin(theta) * g * m * Vector3(Right angle to tensionDirection)

    //Calculate the tether direction vector and how much force that vector needs
    Vector3 CalculateForceDirection(float mass, float g, Vector3 hPoint){

        //tension direction and angle calculation
        tensionDirection = (hPoint - transform.position).normalized;
        inclinationAngle = Vector3.Angle((transform.position - hPoint).normalized, -transform.up);
        theta = Mathf.Deg2Rad * inclinationAngle;
        if(theta<=.1) theta = 0;

        //How much force the tension needs
        tensionForce = mass * -g * Mathf.Cos(theta);

        //force direction calculation based on tension direction and force
        Vector3 fDirection = tensionDirection * tensionForce;
        return fDirection;
    }

    Vector3 CalculateMomentumDirection(float g, Vector3 hPoint){

        tensionMomDirection = (hPoint - transform.position).normalized;
        hookPointRight = Vector3.Cross(oldXZDir, transform.up).normalized;
        momDirection = -1 * Vector3.Cross(hookPointRight, tensionMomDirection).normalized;
        
        if(oldXZDir != curXZDir){
            //midpointMom = swingMom;
            swingback = false;
            //Debug.Log("flip");
        }

        if(swingback == false && swingMom <= (oldSwingMom*(.75f))){
            swingback = true;
            oldSwingMom = swingMom;
            oldXZDir = (new Vector3(hookPoint.transform.position.x,0,hookPoint.transform.position.z) - new Vector3(transform.position.x,0,transform.position.z)).normalized;
            //Debug.Log("swingback");
        }

        curXZDir = (new Vector3(hPoint.x,0,hPoint.z) - new Vector3(transform.position.x,0,transform.position.z)).normalized;
        Debug.DrawRay(transform.position,  momDirection * Time.deltaTime* 100, Color.green);
        return (momDirection * Time.deltaTime * swingMom);
    }

    //Calculates the players initial swing momentum using their height and their current velocity
    float CalculateSwingMom(float playerSpeed){

        //Calculate the players height compared to the lowest point in the swing
        float swingHeight = transform.position.y - (hookPoint.transform.position.y - ropeLength);
        if(swingHeight <= 1){
            swingHeight = 1;
        }

        float sMom = playerSpeed + (swingHeight*2);
        if(sMom > maxSwingMom){
            sMom = maxSwingMom;
        }
        return sMom;
    }
    
    //Special movement for the player while they swing
    Vector3 SwingMoveController(){

        //WASD input
        float inputVert = Input.GetAxis("Vertical");
        float inputHor = Input.GetAxis("Horizontal");

        //input is zero when nothing is pressed to prevent button easing values
        if((!Input.GetKey(KeyCode.W) && !Input.GetKey(KeyCode.S))) inputVert = 0;
        if((!Input.GetKey(KeyCode.A) && !Input.GetKey(KeyCode.D))) inputHor = 0;

        //Swingspeed build up
        if((inputVert != 0 || inputHor != 0) && swingSpeed < maxSwingSpeed){
            swingSpeed += swingAcc;
        }
        else if((inputVert != 0 || inputHor != 0) && swingSpeed >= maxSwingSpeed){
            swingSpeed = maxSwingSpeed;
        }
        else if((inputVert == 0 && inputHor == 0)){
            swingSpeed = minSwingSpeed;
        }

        //Swing direction based on player input
        swingDirection = Vector3.Cross(tensionDirection, ((transform.right * -inputVert) + (transform.forward * inputHor))).normalized;


        //NEED TO ADD SWINGSPEED EASING
        //this could be just adding a gradual increase in the swing speed instead of using a flat rate
        //Swing movement with swing speed added
        Vector3 swingMovement = (swingDirection * Time.deltaTime * swingSpeed);
        

        return (swingMovement);
    }

    Vector3 RopeLengthOffset(Vector3 hPoint, float curDistance){
        
        //How powerful our offset movement has to be
        float offsetPower = ((curDistance - ropeLength) * 200f);

        //The direction we need to apply force to offset when the rope gets lengthened beyond the necessary point
        Vector3 tenDirOffset = (hPoint - transform.position).normalized;
 

        return tenDirOffset * offsetPower * Time.deltaTime;
    }

    Vector3 CalculateSwingReleaseForce(){

        Vector3 releaseSwingForceDirection = momDirection * ((swingMom) + 10);

        releaseSwingForceDirection = new Vector3(releaseSwingForceDirection.x, 0, releaseSwingForceDirection.z);

        if(swingMom < 5){
            return Vector3.zero;
        }
        
        return releaseSwingForceDirection * Time.deltaTime;
    }
}