using UnityEngine;

using System;

using System.Collections;



public enum MovementState

{

    Grounded,

    InAir,

    OnWall

}



[RequireComponent(typeof(Rigidbody))]

public class CharacterMotor : MonoBehaviour {



    public float maxVelocityChange = 1.0f;

    public float jumpHeight = 1.0f;

    public bool canJump = true;

	public bool canWallJump = true;

	public float airSpeed = 0.1f;

	public float wallSpeedAdjustment = 0.1f;

    public bool canMoveOnY = false;

	

    [HideInInspector]

    public Vector3 targetVelocity = Vector3.zero;



    [HideInInspector]

    public MovementState State { get; private set; }

	

    public bool OnGround

    {

        get

        {

            return State == MovementState.Grounded;

        }

    }



    public bool AbleToJump

    {

        get

        {

            return (State == MovementState.Grounded && canJump) || (State == MovementState.OnWall && canWallJump);

        }

    }



    public bool InAir

    {

        get

        {

            return State == MovementState.InAir || (!canWallJump && State == MovementState.OnWall);

        }

    }

	

	private const float OnGroundValue = .9f;

	private const float OnWallValue = 0.005f;

	

    private bool jumpQueued = false;

	private Vector3 lastContactNormal;



    void FixedUpdate()

    {

        Vector3 velocity = rigidbody.velocity;

        velocity = (targetVelocity - velocity);

        velocity = velocity.normalized * Mathf.Clamp(velocity.magnitude, 0, maxVelocityChange);

        if (!canMoveOnY)

            velocity.y = 0;

		

		if (State != MovementState.Grounded)

			velocity = velocity * airSpeed;

		

		if (State == MovementState.OnWall)

			velocity.x *= wallSpeedAdjustment;

		

		if (jumpQueued && AbleToJump)

        {

            ExecuteJump();

            jumpQueued = false;

        }



        rigidbody.AddForce(velocity, ForceMode.VelocityChange);

		

		//print(string.Format("Current State: {0}", Enum.GetName(typeof(MovementState), State)));

        State = MovementState.InAir;

    }



    void OnCollisionStay(Collision collision)

    {

		if (State == MovementState.Grounded)

			return;

		

		lastContactNormal = collision.contacts[0].normal;

		

		float totalDot = 0f;

		foreach (ContactPoint point in collision.contacts)

		{

			totalDot += Vector3.Dot(point.normal, Vector3.up);

		}

		

		float avgDot = totalDot / collision.contacts.Length;

		//print(string.Format("Average DOT: {0}", avgDot));

		

		if (Approximately(avgDot, OnGroundValue))

			State = MovementState.Grounded;

		else if (avgDot >= 0)

			State = MovementState.OnWall;

    }



    #region helper functions



    void ExecuteJump()

    {

        float jumpSpeed = Mathf.Sqrt(2 * jumpHeight * -Physics.gravity.y);

        rigidbody.velocity = new Vector3(rigidbody.velocity.x, jumpSpeed, rigidbody.velocity.z);

		if (State == MovementState.OnWall)

		{

			float xVel = rigidbody.velocity.x;

			xVel = lastContactNormal.x * 5f;

			rigidbody.AddForce(new Vector3(xVel, 0, 0), ForceMode.VelocityChange);

		}

    }

	

	// HACK: Mathf.Approximately didn't suit my needs

	bool Approximately(float a, float b) {

		float rangeMax, rangeMin;

		if (a >= 0.1)

		{

			rangeMax = a + 0.1f;

			rangeMin = a - 0.1f;

		}

		else if (a > 0.01) 

		{

			rangeMax = a + 0.01f;

			rangeMin = a - 0.01f;

		}

		else // a > 0.001f 

		{

			rangeMax = a + 0.001f;

			rangeMin = a - 0.001f;

		}

		

		return b > rangeMin && b < rangeMax;

	}

	

    #endregion helper functions



    #region public functions



    public void Impulse(Vector3 direction)

    {

        rigidbody.AddForce(direction, ForceMode.VelocityChange);

    }



    public void Jump()

    {

        jumpQueued = true;

    }



    public void CancelJump()

    {

        jumpQueued = false;

    }



    #endregion public functions

}