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

namespace XNodeEditor {
    /// <summary> Contains reflection-related info </summary>
    public partial class NodeEditorWindow {
        /// <summary> Custom node tint colors defined with [NodeColor(r, g, b)] </summary>
        public static Dictionary<Type, Color> nodeTint { get { return _nodeTint != null ? _nodeTint : _nodeTint = GetNodeTint(); } }
            [NonSerialized] private static Dictionary<Type, Color> _nodeTint;
        /// <summary> All available node types </summary>
        public static Type[] nodeTypes { get { return _nodeTypes != null ? _nodeTypes : _nodeTypes = GetNodeTypes(); } }
            [NonSerialized] private static Type[] _nodeTypes = null;

        public static Type[] GetNodeTypes() {
            //Get all classes deriving from Node via reflection
            return GetDerivedTypes(typeof(XNode.Node));
        }

        public static Dictionary<Type, Color> GetNodeTint() {
            Dictionary<Type, Color> tints = new Dictionary<Type, Color>();
            for (int i = 0; i < nodeTypes.Length; i++) {
                var attribs = nodeTypes[i].GetCustomAttributes(typeof(XNode.Node.NodeTint), true);
                if (attribs == null || attribs.Length == 0) continue;
                XNode.Node.NodeTint attrib = attribs[0] as XNode.Node.NodeTint;
                tints.Add(nodeTypes[i], attrib.color);
            }
            return tints;
        }

        public static Type[] GetDerivedTypes(Type baseType) {
            //Get all classes deriving from baseType via reflection
            Assembly assembly = Assembly.GetAssembly(baseType);
            return assembly.GetTypes().Where(t =>
                !t.IsAbstract &&
                baseType.IsAssignableFrom(t)
            ).ToArray();
        }

        public static object ObjectFromType(Type type) {
            return Activator.CreateInstance(type);
        }

        public static object ObjectFromFieldName(object obj, string fieldName) {
            Type type = obj.GetType();
            FieldInfo fieldInfo = type.GetField(fieldName);
            return fieldInfo.GetValue(obj);
        }

        public static KeyValuePair<ContextMenu, MethodInfo>[] GetContextMenuMethods(object obj) {
            Type type = obj.GetType();
            MethodInfo[] methods = type.GetMethods(BindingFlags.Instance | BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic);
            List<KeyValuePair<ContextMenu, MethodInfo>> kvp = new List<KeyValuePair<ContextMenu, MethodInfo>>();
            for (int i = 0; i < methods.Length; i++) {
                ContextMenu[] attribs = methods[i].GetCustomAttributes(typeof(ContextMenu), true).Select(x => x as ContextMenu).ToArray();
                if (attribs == null || attribs.Length == 0) continue;
                if (methods[i].GetParameters().Length != 0) {
                    Debug.LogWarning("Method " + methods[i].DeclaringType.Name + "." + methods[i].Name + " has parameters and cannot be used for context menu commands.");
                    continue;
                }
                if (methods[i].IsStatic) {
                    Debug.LogWarning("Method " + methods[i].DeclaringType.Name + "." + methods[i].Name + " is static and cannot be used for context menu commands.");
                    continue;
                }

                for (int k = 0; k < attribs.Length; k++) {
                    kvp.Add(new KeyValuePair<ContextMenu, MethodInfo>(attribs[k], methods[i]));
                }
            }
            #if UNITY_5_5_OR_NEWER
            //Sort menu items
            kvp.Sort((x, y) => x.Key.priority.CompareTo(y.Key.priority));
            #endif
            return kvp.ToArray();
        }

        /// <summary> Very crude. Uses a lot of reflection. </summary>
        public static void OpenPreferences() {
            try {
                //Open preferences window
                Assembly assembly = Assembly.GetAssembly(typeof(UnityEditor.EditorWindow));
                Type type = assembly.GetType("UnityEditor.PreferencesWindow");
                type.GetMethod("ShowPreferencesWindow", BindingFlags.NonPublic | BindingFlags.Static).Invoke(null, null);

                //Get the window
                EditorWindow window = EditorWindow.GetWindow(type);

                //Make sure custom sections are added (because waiting for it to happen automatically is too slow)
                FieldInfo refreshField = type.GetField("m_RefreshCustomPreferences", BindingFlags.NonPublic | BindingFlags.Instance);
                if ((bool) refreshField.GetValue(window)) {
                    type.GetMethod("AddCustomSections", BindingFlags.NonPublic | BindingFlags.Instance).Invoke(window, null);
                    refreshField.SetValue(window, false);
                }

                //Get sections
                FieldInfo sectionsField = type.GetField("m_Sections", BindingFlags.Instance | BindingFlags.NonPublic);
                IList sections = sectionsField.GetValue(window) as IList;

                //Iterate through sections and check contents
                Type sectionType = sectionsField.FieldType.GetGenericArguments() [0];
                FieldInfo sectionContentField = sectionType.GetField("content", BindingFlags.Instance | BindingFlags.Public);
                for (int i = 0; i < sections.Count; i++) {
                    GUIContent sectionContent = sectionContentField.GetValue(sections[i]) as GUIContent;
                    if (sectionContent.text == "Node Editor") {
                        //Found contents - Set index
                        FieldInfo sectionIndexField = type.GetField("m_SelectedSectionIndex", BindingFlags.Instance | BindingFlags.NonPublic);
                        sectionIndexField.SetValue(window, i);
                        return;
                    }
                }
            } catch (Exception e) {
                Debug.LogError(e);
                Debug.LogWarning("Unity has changed around internally. Can't open properties through reflection. Please contact xNode developer and supply unity version number.");
            }
        }
    }
}