using System;
using UnityEngine;

[Serializable]
public class Joystick : MonoBehaviour
{
    [NonSerialized]
    private static Joystick[] joysticks;

    [NonSerialized]
    private static bool enumeratedJoysticks;

    [NonSerialized]
    private static float tapTimeDelta = 0.3f;

    public bool touchPad;

    public Rect touchZone;

    public Vector2 deadZone = Vector2.zero;

    public bool normalize;

    public Vector2 position;

    public int tapCount;

    private int lastFingerId = -1;

    private float tapTimeWindow;

    private Vector2 fingerDownPos;

    private float fingerDownTime;

    private float firstDeltaTime = 0.5f;

    private Rect defaultRect;

    private Boundary guiBoundary = new Boundary();

    private Vector2 guiTouchOffset;

    private Vector2 guiCenter;

    void Start()
    {
        defaultRect = new Rect(
            Screen.width * 0.1f,
            Screen.height * 0.1f,
            128,
            128
        );

        if (touchPad)
        {
            touchZone = defaultRect;
            return;
        }

        guiTouchOffset.x = defaultRect.width * 0.5f;
        guiTouchOffset.y = defaultRect.height * 0.5f;

        guiCenter.x = defaultRect.x + guiTouchOffset.x;
        guiCenter.y = defaultRect.y + guiTouchOffset.y;

        guiBoundary.min.x = defaultRect.x - guiTouchOffset.x;
        guiBoundary.max.x = defaultRect.x + guiTouchOffset.x;

        guiBoundary.min.y = defaultRect.y - guiTouchOffset.y;
        guiBoundary.max.y = defaultRect.y + guiTouchOffset.y;
    }

    public void Disable()
    {
        gameObject.SetActive(false);
        enumeratedJoysticks = false;
    }

    public void ResetJoystick()
    {
        lastFingerId = -1;
        position = Vector2.zero;

        defaultRect.x = guiCenter.x - guiTouchOffset.x;
        defaultRect.y = guiCenter.y - guiTouchOffset.y;
    }

    public bool IsFingerDown()
    {
        return lastFingerId != -1;
    }

    public void LatchedFinger(int fingerId)
    {
        if (lastFingerId == fingerId)
        {
            ResetJoystick();
        }
    }

    void Update()
    {
        if (!enumeratedJoysticks)
        {
            joysticks = FindObjectsOfType<Joystick>();
            enumeratedJoysticks = true;
        }

        int count = Input.touchCount;

        if (tapTimeWindow > 0)
        {
            tapTimeWindow -= Time.deltaTime;
        }
        else
        {
            tapCount = 0;
        }

        if (count == 0)
        {
            ResetJoystick();
        }
        else
        {
            for (int i = 0; i < count; i++)
            {
                Touch touch = Input.GetTouch(i);

                Vector2 guiTouchPos = touch.position - guiTouchOffset;

                bool shouldLatchFinger = false;

                if (touchPad)
                {
                    if (touchZone.Contains(touch.position))
                    {
                        shouldLatchFinger = true;
                    }
                }
                else
                {
                    Rect touchRect = new Rect(
                        guiCenter.x - guiTouchOffset.x,
                        guiCenter.y - guiTouchOffset.y,
                        guiTouchOffset.x * 2,
                        guiTouchOffset.y * 2
                    );

                    if (touchRect.Contains(touch.position))
                    {
                        shouldLatchFinger = true;
                    }
                }

                if (
                    shouldLatchFinger &&
                    (lastFingerId == -1 || lastFingerId != touch.fingerId)
                )
                {
                    if (touchPad)
                    {
                        fingerDownPos = touch.position;
                        fingerDownTime = Time.time;
                    }

                    lastFingerId = touch.fingerId;

                    if (tapTimeWindow > 0)
                    {
                        tapCount++;
                    }
                    else
                    {
                        tapCount = 1;
                        tapTimeWindow = tapTimeDelta;
                    }

                    foreach (Joystick j in joysticks)
                    {
                        if (j != this)
                        {
                            j.LatchedFinger(touch.fingerId);
                        }
                    }
                }

                if (lastFingerId == touch.fingerId)
                {
                    if (touch.tapCount > tapCount)
                    {
                        tapCount = touch.tapCount;
                    }

                    if (touchPad)
                    {
                        position.x = Mathf.Clamp(
                            (touch.position.x - fingerDownPos.x) /
                            (touchZone.width / 2),
                            -1,
                            1
                        );

                        position.y = Mathf.Clamp(
                            (touch.position.y - fingerDownPos.y) /
                            (touchZone.height / 2),
                            -1,
                            1
                        );
                    }
                    else
                    {
                        defaultRect.x = Mathf.Clamp(
                            guiTouchPos.x,
                            guiBoundary.min.x,
                            guiBoundary.max.x
                        );

                        defaultRect.y = Mathf.Clamp(
                            guiTouchPos.y,
                            guiBoundary.min.y,
                            guiBoundary.max.y
                        );
                    }

                    if (
                        touch.phase == TouchPhase.Ended ||
                        touch.phase == TouchPhase.Canceled
                    )
                    {
                        ResetJoystick();
                    }
                }
            }
        }

        if (!touchPad)
        {
            position.x =
                (defaultRect.x + guiTouchOffset.x - guiCenter.x) /
                guiTouchOffset.x;

            position.y =
                (defaultRect.y + guiTouchOffset.y - guiCenter.y) /
                guiTouchOffset.y;
        }

        float absoluteX = Mathf.Abs(position.x);
        float absoluteY = Mathf.Abs(position.y);

        if (absoluteX < deadZone.x)
        {
            position.x = 0;
        }
        else if (normalize)
        {
            position.x =
                Mathf.Sign(position.x) *
                (absoluteX - deadZone.x) /
                (1 - deadZone.x);
        }

        if (absoluteY < deadZone.y)
        {
            position.y = 0;
        }
        else if (normalize)
        {
            position.y =
                Mathf.Sign(position.y) *
                (absoluteY - deadZone.y) /
                (1 - deadZone.y);
        }
    }
}