using System.IO;
using UnityEditor;
using UnityEditor.AssetImporters;
using UnityEngine;

namespace zz.water.editor
{

    [ScriptedImporter(1, FILE_EXTENSION)]
    public class WaterMeshImporter : ScriptedImporter
    {
        private const string FILE_EXTENSION = "zwatermesh";
        
        [SerializeField] public WaterMesh waterMesh = new WaterMesh();

        public override void OnImportAsset(AssetImportContext context)
        {
            waterMesh.Rebuild();
            context.AddObjectToAsset("mesh", waterMesh.mesh);
            context.SetMainObject(waterMesh.mesh);
        }

        //Handles correct behaviour when double-clicking a .watermesh asset assigned to a field
        //Otherwise the OS prompts to open it
        [UnityEditor.Callbacks.OnOpenAsset]
        public static bool OnOpenAsset(int instanceID, int line)
        {
            Object target = EditorUtility.InstanceIDToObject(instanceID);

            if (target is Mesh)
            {
                var path = AssetDatabase.GetAssetPath(instanceID);
                
                if (Path.GetExtension(path) != "." + FILE_EXTENSION) return false;

                Selection.activeObject = target;
                return true;
            }
            
            return false;
        }
    }

	[CustomEditor(typeof(WaterMeshImporter))]
    public class WaterMeshImporterEditor: ScriptedImporterEditor
    {
        private SerializedProperty waterMesh;
        
        private SerializedProperty shape;
        
        private SerializedProperty scale;
        private SerializedProperty UVTiling;
        
        private SerializedProperty vertexDistance;
        
        private SerializedProperty noise;
        private SerializedProperty boundsPadding;
        
        private WaterMeshImporter importer;
        
		private bool autoApplyChanges;

        public override void OnEnable()
        {
			base.OnEnable();
			
            importer = (WaterMeshImporter)target;
            
            waterMesh = serializedObject.FindProperty("waterMesh");
            
            shape = waterMesh.FindPropertyRelative("shape");
            scale = waterMesh.FindPropertyRelative("scale");
            UVTiling = waterMesh.FindPropertyRelative("UVTiling");
            vertexDistance = waterMesh.FindPropertyRelative("vertexDistance");
            noise = waterMesh.FindPropertyRelative("noise");
            boundsPadding = waterMesh.FindPropertyRelative("boundsPadding");
        }

        public override void OnInspectorGUI()
        {
            serializedObject.Update();
            EditorGUI.BeginChangeCheck();
            
            EditorGUILayout.PropertyField(shape);
            
            EditorGUILayout.Space();
            
            EditorGUILayout.PropertyField(scale);
            EditorGUILayout.PropertyField(vertexDistance);
            
            int subdivisions = Mathf.FloorToInt(scale.floatValue / vertexDistance.floatValue);
            int vertexCount = Mathf.FloorToInt(subdivisions * subdivisions);

            using (new EditorGUILayout.HorizontalScope())
            {
                GUILayout.Space(EditorGUIUtility.labelWidth);
                
                Rect rect = EditorGUILayout.GetControlRect();
                EditorGUI.ProgressBar(rect, (float)vertexCount/65535f, $"Vertex count: {vertexCount:N1}/{65535f:N1}");
            }
            if(vertexCount > 65535)
            {
                EditorGUILayout.HelpBox("Vertex count (" + vertexCount + ") is too high. Decrease the scale, or increase the vertex distance.", MessageType.Error);
            }
            
            EditorGUILayout.Space();

            EditorGUILayout.PropertyField(UVTiling);
            EditorGUILayout.PropertyField(noise);
            EditorGUILayout.PropertyField(boundsPadding);
            
            EditorGUILayout.Space();

            autoApplyChanges = EditorGUILayout.Toggle("Auto-apply changes", autoApplyChanges);
            
            if (EditorGUI.EndChangeCheck())
            {
                serializedObject.ApplyModifiedProperties();
                
                if (autoApplyChanges && HasModified())
                {
                    #if UNITY_2022_2_OR_NEWER
                    this.SaveChanges();
                    #else
                    this.ApplyAndImport();
                    #endif
                    
                    importer = (WaterMeshImporter)target;
                }
            }
            
            this.ApplyRevertGUI();
        }
    }
}