using UnityEngine;

namespace UnityEditor.TerrainTools
{
    internal class BrushJitterHandler
    {
        private readonly float m_MinValue;
        private readonly float m_MaxValue;

        private bool m_UseNewRandomValue;
        private float m_RandomValue;

        public float jitter { get; set; }

        public bool smoothJitter { get; set; } = false;
        public float frequency { get; set; } = 1.0f;

        public BrushJitterHandler(float jitter, float minValue, float maxValue, bool smoothJitter = false)
        {
            this.jitter = jitter;
            this.smoothJitter = smoothJitter;
            m_MinValue = minValue;
            m_MaxValue = maxValue;
        }

        public float CalculateValue(float initialValue)
        {
            return Mathf.Lerp(initialValue, initialValue + m_RandomValue, jitter);
        }

        public void RequestRandomization()
        {
            m_UseNewRandomValue = true;
        }

        public void Update()
        {
            if (m_UseNewRandomValue)
            {
                if (smoothJitter)
                {
                    m_RandomValue = Mathf.Lerp(m_MinValue, m_MaxValue, Mathf.PerlinNoise(Time.time * frequency, 0.0f));
                }
                else
                {
                    m_RandomValue = Random.Range(m_MinValue, m_MaxValue);
                }
                m_UseNewRandomValue = false;
            }
        }

        public void OnGuiLayout(string toolTip)
        {
            GUIContent content = EditorGUIUtility.TrTextContent("Jitter", toolTip);

            jitter = EditorGUILayout.Slider(content, jitter, 0.0f, 1.0f);
        }
    }
}