using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEditor;
using System.Linq;


namespace Coffee.UISoftMask
{
    /// <summary>
    /// SoftMask editor.
    /// </summary>
    [CustomEditor(typeof(SoftMask))]
    [CanEditMultipleObjects]
    public class SoftMaskEditor : Editor
    {
        private const int k_PreviewSize = 128;
        private const string k_PrefsPreview = "SoftMaskEditor_Preview";
        private static readonly List<Graphic> s_Graphics = new List<Graphic>();
        private static bool s_Preview;

        private void OnEnable()
        {
            s_Preview = EditorPrefs.GetBool(k_PrefsPreview, false);
        }

        public override void OnInspectorGUI()
        {
            base.OnInspectorGUI();

            var current = target as SoftMask;
            current.GetComponentsInChildren<Graphic>(true, s_Graphics);
            var fixTargets = s_Graphics
                .Where(x => x.gameObject != current.gameObject)
                .Where(x => !x.GetComponent<SoftMaskable>() && (!x.GetComponent<Mask>() || x.GetComponent<Mask>().showMaskGraphic))
                .ToList();
            if (0 < fixTargets.Count)
            {
                GUILayout.BeginHorizontal();
                EditorGUILayout.HelpBox("There are child Graphics that does not have a SoftMaskable component.\nAdd SoftMaskable component to them.", MessageType.Warning);
                GUILayout.BeginVertical();
                if (GUILayout.Button("Fix"))
                {
                    foreach (var p in fixTargets)
                    {
                        p.gameObject.AddComponent<SoftMaskable>();
                    }

                    EditorUtils.MarkPrefabDirty();
                }

                if (GUILayout.Button("Ping"))
                {
                    EditorGUIUtility.PingObject(fixTargets[0]);
                }

                GUILayout.EndVertical();
                GUILayout.EndHorizontal();
            }

            var currentImage = current.graphic as Image;
            if (currentImage && IsMaskUI(currentImage.sprite))
            {
                GUILayout.BeginHorizontal();
                EditorGUILayout.HelpBox("SoftMask does not recommend to use 'UIMask' sprite as a source image.\n(It contains only small alpha pixels.)\nDo you want to use 'UISprite' instead?", MessageType.Warning);
                GUILayout.BeginVertical();

                if (GUILayout.Button("Fix"))
                {
                    currentImage.sprite = AssetDatabase.GetBuiltinExtraResource<Sprite>("UI/Skin/UISprite.psd");
                }

                GUILayout.EndVertical();
                GUILayout.EndHorizontal();
            }

            // Preview buffer.
            GUILayout.BeginVertical(EditorStyles.helpBox);
            if (s_Preview != (s_Preview = EditorGUILayout.ToggleLeft("Preview Soft Mask Buffer", s_Preview)))
            {
                EditorPrefs.SetBool(k_PrefsPreview, s_Preview);
            }

            if (s_Preview)
            {
                var tex = current.softMaskBuffer;
                var width = tex.width * k_PreviewSize / tex.height;
                EditorGUI.DrawPreviewTexture(GUILayoutUtility.GetRect(width, k_PreviewSize), tex, null, ScaleMode.ScaleToFit);
                Repaint();
            }

            GUILayout.EndVertical();
        }

        private static bool IsMaskUI(Object obj)
        {
            return obj
                   && obj.name == "UIMask"
                   && AssetDatabase.GetAssetPath(obj) == "Resources/unity_builtin_extra";
        }


        //%%%% Context menu for editor %%%%
        [MenuItem("CONTEXT/Mask/Convert To SoftMask", true)]
        private static bool _ConvertToSoftMask(MenuCommand command)
        {
            return EditorUtils.CanConvertTo<SoftMask>(command.context);
        }

        [MenuItem("CONTEXT/Mask/Convert To SoftMask", false)]
        private static void ConvertToSoftMask(MenuCommand command)
        {
            EditorUtils.ConvertTo<SoftMask>(command.context);
        }

        [MenuItem("CONTEXT/Mask/Convert To Mask", true)]
        private static bool _ConvertToMask(MenuCommand command)
        {
            return EditorUtils.CanConvertTo<Mask>(command.context);
        }

        [MenuItem("CONTEXT/Mask/Convert To Mask", false)]
        private static void ConvertToMask(MenuCommand command)
        {
            EditorUtils.ConvertTo<Mask>(command.context);
        }
    }
}