using UnityEngine;

using UnityEngine.Events;



public class CharacterController2D : MonoBehaviour

{

    [SerializeField] private float m_JumpForce = 400f;                          // Amount of force added when the player jumps.

    [Range(0, 1)] [SerializeField] private float m_CrouchSpeed = .36f;          // Amount of maxSpeed applied to crouching movement. 1 = 100%

    [Range(0, .3f)] [SerializeField] private float m_MovementSmoothing = .05f;  // How much to smooth out the movement

    [SerializeField] private bool m_AirControl = false;                         // Whether or not a player can steer while jumping;

    [SerializeField] private LayerMask m_WhatIsGround;                          // A mask determining what is ground to the character

    [SerializeField] private Transform m_GroundCheck;                           // A position marking where to check if the player is grounded.

    [SerializeField] private Transform m_CeilingCheck;                          // A position marking where to check for ceilings

    [SerializeField] private Collider2D m_CrouchDisableCollider;                // A collider that will be disabled when crouching



    const float k_GroundedRadius = .2f; // Radius of the overlap circle to determine if grounded

    private bool m_Grounded;            // Whether or not the player is grounded.

    const float k_CeilingRadius = .2f; // Radius of the overlap circle to determine if the player can stand up

    private Rigidbody2D m_Rigidbody2D;

    private bool m_FacingRight = true;  // For determining which way the player is currently facing.

    private Vector3 m_Velocity = Vector3.zero;



    [Header("Events")]

    [Space]



    public UnityEvent OnLandEvent;



    [System.Serializable]

    public class BoolEvent : UnityEvent<bool> { }



    public BoolEvent OnCrouchEvent;

    private bool m_wasCrouching = false;



    private void Awake()

    {

        m_Rigidbody2D = GetComponent<Rigidbody2D>();



        if (OnLandEvent == null)

            OnLandEvent = new UnityEvent();



        if (OnCrouchEvent == null)

            OnCrouchEvent = new BoolEvent();

    }



    private void FixedUpdate()

    {

        bool wasGrounded = m_Grounded;

        m_Grounded = false;



        // The player is grounded if a circlecast to the groundcheck position hits anything designated as ground

        // This can be done using layers instead but Sample Assets will not overwrite your project settings.

        Collider2D[] colliders = Physics2D.OverlapCircleAll(m_GroundCheck.position, k_GroundedRadius, m_WhatIsGround);

        for (int i = 0; i < colliders.Length; i++)

        {

            if (colliders[i].gameObject != gameObject)

            {

                m_Grounded = true;

                if (!wasGrounded && m_Rigidbody2D.velocity.y < 0)

                    OnLandEvent.Invoke();

            }

        }

    }





    public void Move(float move, bool crouch, bool jump)

    {

        // If crouching, check to see if the character can stand up

        if (!crouch)

        {

            // If the character has a ceiling preventing them from standing up, keep them crouching

            if (Physics2D.OverlapCircle(m_CeilingCheck.position, k_CeilingRadius, m_WhatIsGround))

            {

                crouch = true;

            }

        }



        //only control the player if grounded or airControl is turned on

        if (m_Grounded || m_AirControl)

        {



            // If crouching

            if (crouch)

            {

                if (!m_wasCrouching)

                {

                    m_wasCrouching = true;

                    OnCrouchEvent.Invoke(true);

                }



                // Reduce the speed by the crouchSpeed multiplier

                move *= m_CrouchSpeed;



                // Disable one of the colliders when crouching

                if (m_CrouchDisableCollider != null)

                    m_CrouchDisableCollider.enabled = false;

            }
            else

            {

                // Enable the collider when not crouching

                if (m_CrouchDisableCollider != null)

                    m_CrouchDisableCollider.enabled = true;



                if (m_wasCrouching)

                {

                    m_wasCrouching = false;

                    OnCrouchEvent.Invoke(false);

                }

            }



            // Move the character by finding the target velocity

            Vector3 targetVelocity = new Vector2(move * 10f, m_Rigidbody2D.velocity.y);

            // And then smoothing it out and applying it to the character

            m_Rigidbody2D.velocity = Vector3.SmoothDamp(m_Rigidbody2D.velocity, targetVelocity, ref m_Velocity, m_MovementSmoothing);



            // If the input is moving the player right and the player is facing left...

            if (move > 0 && !m_FacingRight)

            {

                // ... flip the player.

                Flip();

            }

            // Otherwise if the input is moving the player left and the player is facing right...

            else if (move < 0 && m_FacingRight)

            {

                // ... flip the player.

                Flip();

            }

        }

        // If the player should jump...

        if (m_Grounded && jump)

        {

            // Add a vertical force to the player.

            m_Grounded = false;

            if (m_Rigidbody2D.gravityScale >= 0)
            {
                m_Rigidbody2D.AddForce(new Vector2(0f, m_JumpForce));
            }
            else
            {
                m_Rigidbody2D.AddForce(new Vector2(0f, -m_JumpForce));
            }
        }
    }





    private void Flip()

    {

        // Switch the way the player is labelled as facing.

        m_FacingRight = !m_FacingRight;



        // Multiply the player's x local scale by -1.

        Vector3 theScale = transform.localScale;

        theScale.x *= -1;

        transform.localScale = theScale;

    }

}