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

public class RotationController : MonoBehaviour
{

    #region Read-Only Fields
    public float RotationPeriod => m_RotationPeriod;
    public Vector3 Position => transform.position;
    public Vector3 RotationAxis => m_RotationAxis;
    public float CoriolisStrength => m_coriolisStrength;
    public float EnvironmentRotationPeriod => m_RotationPeriod / m_SkyboxRotationMultiplier;
    #endregion Read-Only Fields

    [SerializeField]
    private float m_RotationPeriod;

    [SerializeField]
    private Vector3 m_RotationAxis = Vector3.forward;

    [SerializeField]
    private float m_coriolisStrength = 100;

    [SerializeField]
    private Material m_Skybox;

    [SerializeField]
    private float m_SkyboxRotationMultiplier = 1;


    public Vector3 getDownDirection(Vector3 objectPosition, bool normalized = true)
    {
        if (normalized)
            return Vector3.ProjectOnPlane((objectPosition - transform.position), m_RotationAxis).normalized;
        else
            return Vector3.ProjectOnPlane((objectPosition - transform.position), m_RotationAxis);

    }

    public Vector3 getPerpendicularDirection(Vector3 objectPosition)
    {
        return Vector3.Cross(RotationAxis, getDownDirection(objectPosition)).normalized;
    }

    public Quaternion getUpRotation(Vector3 objectPosition)
    {
        return Quaternion.FromToRotation(Vector3.up, -getDownDirection(objectPosition));
    }

    public float GetGravityAtRadius(float radius)
    {
        return radius * Mathf.Pow(2 * Mathf.PI / RotationPeriod, 2);
    }

    public Vector3 GetGravityAtPoint(Vector3 point)
    {
        Vector3 direction = getDownDirection(point,false);
        return direction.normalized * GetGravityAtRadius(direction.magnitude);
    }

    public Vector3 GetCoriolisAtPoint(Vector3 point)
    {
        return getPerpendicularDirection(point) * Vector3.Distance(point, Position) * CoriolisStrength;
    }

    public void SetGravityAtRadius(float Strength, float radius)
    {
        m_RotationPeriod = 2 * Mathf.PI * Mathf.Sqrt(radius / Strength);
    }

    private void Start()
    {
        if (m_Skybox == null)
            m_Skybox = RenderSettings.skybox;
    }

    private void Update()
    {
        if (m_Skybox != null)
        {
            m_Skybox.SetVector("_RotationAxis", m_RotationAxis);
            m_Skybox.SetFloat("_Rotation", (Time.time * 360/EnvironmentRotationPeriod) % 360);
        }
    }


}