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

[RequireComponent(typeof(LineRenderer))]
public class Grappler : MonoBehaviour, IGadget
{
    public enum eMode { gIdle, gOut, gRetract, gPull}
    [Header("Inscribed")]
    [Tooltip("Speed at which Grappler extends (doubled in gRetract mode)")]
    public float grappleSpd = 10;
    [Tooltip("Maximum length that Grappler will reach")]
    public float maxLength = 7.25f;
    [Tooltip("Minimum distance of Grappler from Dray")]
    public float minLength = 0.5f;
    [Tooltip("Health deducted when Dray ends a grapple on an unsafe tile")]
    public int unsafeTileHealthPenalty = 2;

    [Header("Dynamic")]
    [SerializeField]
    private eMode _mode = eMode.gIdle;
    public eMode mode
    {
        get { return _mode; }
        private set { _mode = value; }
    }

    private LineRenderer line;
    private Rigidbody2D rigid;
    private Collider2D colld;

    private Vector3 p0, p1;
    private int facing;
    private Dray dray;
    private System.Func<IGadget, bool> gadgetDoneCallback;

    private Vector2[] directions = new Vector2[]
    {
        Vector2.right, Vector2.up, Vector2.left, Vector2.down
    };
    private Vector3[] dirV3s = new Vector3[]
    {
        Vector3.right, Vector3.up, Vector3.left, Vector3.down
    };

    private void Awake()
    {
        //Get component references to use throughout the script
        line = GetComponent<LineRenderer>();
        rigid = GetComponent<Rigidbody2D>();
        colld = GetComponent<Collider2D>();
    }

    void Start()
    {
        gameObject.SetActive(false); //Initially disable this GameObject
    }

    void SetGrappleMode(eMode newMode)
    {
        switch (newMode)
        {
            case eMode.gIdle:
                transform.DetachChildren(); //Release any child Transforms
                gameObject.SetActive(false);
                if (dray != null && dray.controlledBy == this as IGadget)
                {
                    dray.controlledBy = null;
                    dray.physicsEnabled = true;
                }
                break;

            case eMode.gOut:
                gameObject.SetActive(true);
                rigid.velocity = directions[facing] * grappleSpd;
                break;

            case eMode.gRetract:
                rigid.velocity = -directions[facing] * (grappleSpd * 2);
                break;

            case eMode.gPull:
                p1 = transform.position;
                rigid.velocity = Vector2.zero;
                dray.controlledBy = this;
                dray.physicsEnabled = false;
                break;
        }

        mode = newMode;
    }

    private void FixedUpdate()
    {
        p1 = transform.position;
        line.SetPosition(1, p1);

        switch (mode)
        {
            case eMode.gOut: //Grappler shooting out
                //See if the Grappler reached its limit without hitting anything
                if ((p1 - p0).magnitude >= maxLength)
                {
                    SetGrappleMode(eMode.gRetract);
                }
                break;

            case eMode.gRetract: //Grappler missed; return at double speed
                //Check to see if the Grappler is no longer in front of Dray
                if (Vector3.Dot((p1 - p0), dirV3s[facing]) < 0) GrappleDone();
                break;

            case eMode.gPull:
                if ((p1-p0).magnitude > minLength)
                {
                    //Move Dray toward the Grappler hit point
                    p0 += dirV3s[facing] * grappleSpd * Time.fixedDeltaTime;
                    dray.transform.position = p0;
                    line.SetPosition(0, p0);
                    //Stop Grappler from moving with Dray
                    transform.position = p1;
                }
                else
                {
                    //Dray is close enough to stop grappling
                    p0 = p1 - (dirV3s[facing] * minLength);
                    dray.transform.position = p0;
                    //Check whether Dray landed on an unsafe tile
                    Vector2 checkPos = (Vector2)p0 + new Vector2(0, -0.25f);
                    if (MapInfo.UNSAFE_TILE_AT_VECTOR2(checkPos))
                    {
                        //Dray landed on an unsafe tile
                        dray.ResetInRoom(unsafeTileHealthPenalty);
                    }
                    GrappleDone();
                }
                break;
        }
    }

    //Ensures that p1 is aligned with the Grappler head
    private void LateUpdate()
    {
        p1 = transform.position;
        line.SetPosition(1, p1);
    }

    ///<summary>
    ///Called when the Grappler hits a Trigger or Collider in the GrapTiles, Items, or Enemies Physics Layers (Grappler's Collider is a Trigger)
    /// </summary>
    /// <param name="coll"></param>
    void OnTriggerEnter2D(Collider2D colld)
    {
        //The Grappler has collided with something, but what?
        string otherLayer = LayerMask.LayerToName(colld.gameObject.layer);

        switch (otherLayer)
        {
            case "Items": //We've possibly hit a PickUp
                PickUp pup = colld.GetComponent<PickUp>();
                if (pup == null) return;
                //If this IS a PickUp, make it a child of this Transform so it moves with the Grappler head
                pup.transform.SetParent(transform);
                pup.transform.localPosition = Vector3.zero;
                SetGrappleMode(eMode.gRetract);
                break;

            case "Enemies": //We've hit an Enemy
                //The Grappler should return when it hits an Enemy
                Enemy e = colld.GetComponent<Enemy>();
                if (e != null)
                {
                    SetGrappleMode(eMode.gRetract);
                    StunEnemy();
                }
                //Damaging the Enemy is handled by the DamageEffect & Enemy scripts
                break;

            case "GrapTiles": //We've hit a GrapTile
                //SetGrappleMode(eMode.gRetract);
                SetGrappleMode(eMode.gPull);
                break;

            default:
                SetGrappleMode(eMode.gRetract);
                break;
        }
    }

    void StunEnemy()
    {

    }

    void GrappleDone()
    {
        SetGrappleMode(eMode.gIdle);

        //Callback to Dray so he returns to normal controls
        gadgetDoneCallback(this);
    }

    #region IGadget_Implementation
    //Implementation of IGadget

    //Called by Dray to use this IGadget
    public bool GadgetUse(Dray tDray, System.Func<IGadget,bool> tCallback)
    {
        if (mode != eMode.gIdle) return false;

        dray = tDray;
        gadgetDoneCallback = tCallback;
        transform.localPosition = Vector3.zero;

        facing = dray.GetFacing();
        p0 = dray.transform.position;
        p1 = p0 + (dirV3s[facing] * minLength);
        gameObject.transform.position = p1;
        gameObject.transform.rotation = Quaternion.Euler(0, 0, 90 * facing);

        line.positionCount = 2;
        line.SetPosition(0, p0);
        line.SetPosition(1, p1);

        SetGrappleMode(eMode.gOut);

        return true;
    }

    //Called by Dray if he is hit while grappling and mode != eMode.inHit
    public bool GadgetCancel()
    {
        //If pulling Dray to a wall, ignore GadgetCancel
        if (mode == eMode.gPull) return false;
        SetGrappleMode(eMode.gIdle);
        gameObject.SetActive(false);
        return true;
    }

    //string name is already part of Grappler (inherited from Object)
    #endregion

}
Fill in the StunEnemy() method for this script so that the enemy is temporarily stunned for 1 second