namespace UnityEngine.Experimental.Rendering
{
    [RequireComponent(typeof(Light))]
    public class AdditionalShadowData : MonoBehaviour
    {
#pragma warning disable 414 // CS0414 The private field '...' is assigned but its value is never used
        // We can't rely on Unity for our additional data, we need to version it ourself.
        [SerializeField]
        float m_Version = 1.0f;
#pragma warning restore 414

        public const int DefaultShadowResolution = 512;

        public int shadowResolution = DefaultShadowResolution;

        public static int GetShadowResolution(AdditionalShadowData shadowData)
        {
            if (shadowData != null)
                return shadowData.shadowResolution;
            else
                return DefaultShadowResolution;
        }

        [Range(0.0f, 1.0f)]
        public float shadowDimmer = 1.0f;
        public float shadowFadeDistance = 10000.0f;
        // Contact shadows
        public bool enableContactShadows = false;
        [Range(0.0f, 1.0f)]
        public float contactShadowLength = 0.0f;
        [Range(0.0f, 1.0f)]
        public float contactShadowDistanceScaleFactor = 0.5f;
        public float contactShadowMaxDistance = 50.0f;
        public float contactShadowFadeDistance = 5.0f;
        [Range(4, 64)]
        public uint contactShadowSampleCount = 8;

        // shadow related parameters
        [System.Serializable]
        public struct ShadowData
        {
            public int format;
            public int[] data;
        };

        [HideInInspector, SerializeField]
        private int shadowCascadeCount = 4;
        [HideInInspector, SerializeField]
        private float[] shadowCascadeRatios = new float[3] { 0.05f, 0.2f, 0.3f };
        [HideInInspector, SerializeField]
        private float[] shadowCascadeBorders = new float[4] { 0.2f, 0.2f, 0.2f, 0.2f };
        [HideInInspector, SerializeField]
        private int shadowAlgorithm;
        [HideInInspector, SerializeField]
        private int shadowVariant;
        [HideInInspector, SerializeField]
        private int shadowPrecision;
        [HideInInspector, SerializeField]
        private ShadowData shadowData;
        [HideInInspector, SerializeField]
        private ShadowData[] shadowDatas = new ShadowData[0];

        public int cascadeCount { get { return shadowCascadeCount; } }
        public void GetShadowCascades(out int cascadeCount, out float[] cascadeRatios, out float[] cascadeBorders) { cascadeCount = shadowCascadeCount; cascadeRatios = shadowCascadeRatios; cascadeBorders = shadowCascadeBorders; }
        public void SetShadowCascades(int cascadeCount, float[] cascadeRatios, float[] cascadeBorders) { shadowCascadeCount = cascadeCount; shadowCascadeRatios = cascadeRatios; shadowCascadeBorders = cascadeBorders; }
        public void GetShadowAlgorithm(out int algorithm, out int variant, out int precision) { algorithm = shadowAlgorithm; variant = shadowVariant; precision = shadowPrecision; }
        public void SetShadowAlgorithm(int algorithm, int variant, int precision, int format, int[] data)
        {
            shadowAlgorithm = algorithm;
            shadowVariant = variant;
            shadowPrecision = precision;
            shadowData.format = format;
            shadowData.data = data;

            int idx = FindShadowData(format);
            if (idx < 0)
            {
                idx = shadowDatas.Length;
                ShadowData[] tmp = new ShadowData[idx + 1];
                for (int i = 0; i < idx; ++i)
                    tmp[i] = shadowDatas[i];
                shadowDatas = tmp;
            }
            shadowDatas[idx].format = format;
            shadowDatas[idx].data = data != null ? data : new int[0];
        }
        // Load a specific shadow data. Returns null if requested data is not present.
        public int[] GetShadowData(int shadowDataFormat)
        {
            if (shadowData.format == shadowDataFormat)
                return shadowData.data;

            int idx = FindShadowData(shadowDataFormat);
            return idx >= 0 ? shadowDatas[idx].data : null;
        }
        // Returns the currently set shadow data and format. Can return null.
        public int[] GetShadowData(out int shadowDataFormat)
        {
            shadowDataFormat = shadowData.format;
            return shadowData.data;
        }
#if UNITY_EDITOR
        public void CompactShadowData()
        {
            shadowDatas = new ShadowData[0];
            UnityEditor.EditorUtility.SetDirty(this);
        }
#endif
        private int FindShadowData(int shadowDataFormat)
        {
            for (int i = 0; i < shadowDatas.Length; ++i)
            {
                if (shadowDatas[i].format == shadowDataFormat)
                    return i;
            }
            return -1;
        }
    }

#if UNITY_EDITOR
    [UnityEditor.CustomEditor(typeof(AdditionalShadowData))]
    [UnityEditor.CanEditMultipleObjects]
    public class AdditionalShadowDataEditor : UnityEditor.Editor
    {
        static ShadowRegistry m_ShadowRegistry;

#pragma warning disable 414 // CS0414 The private field '...' is assigned but its value is never used
        UnityEditor.SerializedProperty m_ShadowAlgorithm;
        UnityEditor.SerializedProperty m_ShadowVariant;
        UnityEditor.SerializedProperty m_ShadowData;
        UnityEditor.SerializedProperty m_ShadowDatas;
#pragma warning restore 414
        UnityEditor.SerializedProperty m_ShadowCascadeCount;
        UnityEditor.SerializedProperty m_ShadowCascadeRatios;
        UnityEditor.SerializedProperty m_ShadowCascadeBorders;

        public static void SetRegistry( ShadowRegistry registry ) { m_ShadowRegistry = registry; }

        void OnEnable()
        {
            m_ShadowAlgorithm = serializedObject.FindProperty( "shadowAlgorithm" );
            m_ShadowVariant   = serializedObject.FindProperty( "shadowVariant" );
            m_ShadowData      = serializedObject.FindProperty( "shadowData" );
            m_ShadowDatas     = serializedObject.FindProperty( "shadowDatas" );
            m_ShadowCascadeCount  = serializedObject.FindProperty( "shadowCascadeCount" );
            m_ShadowCascadeRatios = serializedObject.FindProperty( "shadowCascadeRatios" );
            m_ShadowCascadeBorders = serializedObject.FindProperty( "shadowCascadeBorders" );
        }
        public override void OnInspectorGUI()
        {
            base.OnInspectorGUI();

            if( m_ShadowRegistry == null )
                return;

            AdditionalShadowData asd = (AdditionalShadowData) target;
            if( asd == null )
                return;

            UnityEditor.EditorGUI.BeginChangeCheck();

            m_ShadowRegistry.Draw( asd.gameObject.GetComponent<Light>() );
            serializedObject.Update();

            // cascade code
            if( asd.gameObject.GetComponent<Light>().type == LightType.Directional )
            {
                UnityEditor.EditorGUI.BeginChangeCheck();
                UnityEditor.EditorGUILayout.PropertyField( m_ShadowCascadeCount );
                if( UnityEditor.EditorGUI.EndChangeCheck() )
                {
                    const int kMaxCascades = (int) ShadowAtlas.k_MaxCascadesInShader; // depending on where you look this is either 32 or 4, so we're limiting it to 4 for now
                    int newcnt = m_ShadowCascadeCount.intValue <= 0 ? 1 : (m_ShadowCascadeCount.intValue > kMaxCascades ? kMaxCascades : m_ShadowCascadeCount.intValue);
                    m_ShadowCascadeCount.intValue = newcnt;
                    m_ShadowCascadeRatios.arraySize = newcnt-1;
                    m_ShadowCascadeBorders.arraySize = newcnt;
                }
                UnityEditor.EditorGUI.indentLevel++;
                for( int i = 0; i < m_ShadowCascadeRatios.arraySize; i++ )
                {
                    UnityEditor.EditorGUILayout.Slider( m_ShadowCascadeRatios.GetArrayElementAtIndex( i ), 0.0f, 1.0f, new GUIContent( "Cascade " + i ) );
                }
                for (int i = 0; i < m_ShadowCascadeBorders.arraySize; i++)
                {
                    UnityEditor.EditorGUILayout.Slider( m_ShadowCascadeBorders.GetArrayElementAtIndex( i ), 0.0f, 1.0f, new GUIContent( "Transition " + i ) );
                }
                UnityEditor.EditorGUI.indentLevel--;
            }

            if( UnityEditor.EditorGUI.EndChangeCheck() )
            {
                UnityEditor.EditorUtility.SetDirty( asd );
                UnityEditor.SceneManagement.EditorSceneManager.MarkAllScenesDirty();
                UnityEditor.SceneView.RepaintAll();
            }
            serializedObject.ApplyModifiedProperties();
        }
    }
#endif
}