using System;
using System.Collections;
using UnityEngine;
using UnityEngine.Events;

[RequireComponent(typeof(Rigidbody2D))]
[RequireComponent(typeof(CapsuleCollider2D))]

public class CharacterController2D : MonoBehaviour
{
    public enum Direction
    {
        left = -1,
        right = 1
    }

    [SerializeField] Camera mainCamera;
    [SerializeField] float acceleration = 40f;
    [SerializeField][Range(0, .3f)] float smoothing = .05f;
    [SerializeField] float gravityScale = 1.5f;
    [SerializeField] float jumpForce = 50f;
    [SerializeField] int maxJumpCount = 1;
    [SerializeField] bool airControl = true;

    internal UnityEvent OnIdleEvent;
    internal UnityEvent OnFlip;
    internal UnityEvent OnJump;
    internal UnityEvent OnLand;
    internal UnityEvent OnFall;

    public Direction direction = Direction.right;
    public Vector2 velocity = Vector2.zero;
    public int jumpCount = 0;
    public bool isGrounded = false;
    public Vector3 cameraPos;
    public Rigidbody2D _rigidBody;
    public CapsuleCollider2D _collider;
    public Transform _transform;

    void Awake()
    {
        _rigidBody = GetComponent<Rigidbody2D>();
        _collider = GetComponent<CapsuleCollider2D>();
        OnIdleEvent ??= new UnityEvent();
        OnFlip ??= new UnityEvent();
        OnJump ??= new UnityEvent();
        OnFall ??= new UnityEvent();
        OnLand ??= new UnityEvent();
    }

    // Use this for initialization
    void Start()
    {
        _transform = transform;
        _rigidBody.freezeRotation = true;
        _rigidBody.collisionDetectionMode = CollisionDetectionMode2D.Continuous;
        _rigidBody.gravityScale = gravityScale;
        direction = (Direction)(_transform.localScale.x / Mathf.Abs(_transform.localScale.x));

        jumpCount = maxJumpCount;

        if (mainCamera)
            cameraPos = mainCamera.transform.position;

        OnFlip.AddListener(HandleFlip);
        OnJump.AddListener(HandleJump);
        OnFall.AddListener(HandleFall);
        OnLand.AddListener(HandleLand);
    }

    void Update()
    {
        if (isGrounded || airControl)
            HandleHorzInput(Input.GetAxisRaw("Horizontal"));

        // Changing this to `canJump` or `jumpCount > 0` would allow for things like double jumping.
        if (jumpCount > 0 && Input.GetButtonDown("Jump"))
            OnJump.Invoke();


        if (mainCamera)
        {
            var targetPos = new Vector3(_transform.position.x, cameraPos.y, cameraPos.z);
            mainCamera.transform.position = Vector3.Lerp(mainCamera.transform.position, targetPos, 0.25f);
        }
    }

    void FixedUpdate()
    {
        CheckCollision();
    }

    public void Move(float magnitude)
    {
        Vector3 targetVelocity = new Vector2(magnitude, _rigidBody.velocity.y);
        _rigidBody.velocity = Vector2.SmoothDamp(_rigidBody.velocity, targetVelocity, ref velocity, smoothing);
    }

    void CheckCollision()
    {
        var evnt = isGrounded ? OnFall : OnLand;

        float colliderRadius = _collider.size.x * 0.4f * Mathf.Abs(transform.localScale.x);
        Vector3 groundCheckPos = new Vector3(_collider.bounds.size.x * 0.5f, colliderRadius * 0.9f, 0) + _collider.bounds.min;
        Collider2D[] colliders = Physics2D.OverlapCircleAll(groundCheckPos, colliderRadius);

        if (Array.Exists(colliders, c => c != _collider))
        {
            Debug.Log(Array.Find(colliders, c => c != _collider));
            evnt.Invoke();
        }
    }

    void HandleHorzInput(float horzInput)
    {
        Move(horzInput * acceleration);

        if (horzInput * (int)direction < 0)
            OnFlip.Invoke();
    }


    void HandleFlip()
    {
        Debug.Log("Flipping");
        Vector3 theScale = transform.localScale;
        theScale.x *= -1;
        transform.localScale = theScale;

        direction = direction == Direction.left ? Direction.right : Direction.left;
    }

    void HandleJump()
    {
        Debug.Log("Jumping");
        jumpCount--;
        _rigidBody.AddForce(Vector2.up * jumpForce);
        OnFall.Invoke();
    }


    void HandleFall()
    {
        Debug.Log("Falling");
        isGrounded = false;
    }

    void HandleLand()
    {
        Debug.Log("Landing");
        isGrounded = true;
        jumpCount = maxJumpCount;
    }
}