using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Runtime.CompilerServices;

namespace DCFApixels.DragonECS
{
    public static class EcsDebugUtility
    {
        private const BindingFlags RFL_FLAGS = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic;

        #region GetGenericTypeName
        public static string GetGenericTypeFullName<T>(int maxDepth = 2) => GetGenericTypeFullName(typeof(T), maxDepth);
        public static string GetGenericTypeFullName(Type type, int maxDepth = 2) => GetGenericTypeNameInternal(type, maxDepth, true);
        public static string GetGenericTypeName<T>(int maxDepth = 2) => GetGenericTypeName(typeof(T), maxDepth);
        public static string GetGenericTypeName(Type type, int maxDepth = 2) => GetGenericTypeNameInternal(type, maxDepth, false);
        private static string GetGenericTypeNameInternal(Type type, int maxDepth, bool isFull)
        {
#if (DEBUG && !DISABLE_DEBUG)
            string result = isFull ? type.FullName : type.Name;
            if (!type.IsGenericType || maxDepth == 0)
                return result;

            int iBacktick = result.IndexOf('`');
            if (iBacktick > 0)
                result = result.Remove(iBacktick);

            result += "<";
            Type[] typeParameters = type.GetGenericArguments();
            for (int i = 0; i < typeParameters.Length; ++i)
            {
                string typeParamName = GetGenericTypeNameInternal(typeParameters[i], maxDepth - 1, false);//чтобы строка не была слишком длинной, используются сокращенные имена для типов аргументов
                result += (i == 0 ? typeParamName : "," + typeParamName);
            }
            result += ">";
            return result;
#else //optimization for release build
            return type.Name;
#endif
        }
        #endregion

        #region AutoToString
        /// <summary> slow but automatic conversion of ValueType to string in the format "name(field1, field2... fieldn)" </summary>
        public static string AutoToString<T>(this T self, bool isWriteName = true) where T : struct
        {
            return AutoToString(self, typeof(T), isWriteName);
        }
        private static string AutoToString(object target, Type type, bool isWriteName)
        {
#if !REFLECTION_DISABLED
            //TODO сделать специальный вывод в виде названий констант для Enum-ов
#pragma warning disable IL2070 // 'this' argument does not satisfy 'DynamicallyAccessedMembersAttribute' in call to target method. The parameter of method does not have matching annotations.
            var fields = type.GetFields(RFL_FLAGS);
#pragma warning restore IL2070
            string[] values = new string[fields.Length];
            for (int i = 0; i < fields.Length; i++)
            {
                values[i] = (fields[i].GetValue(target) ?? "NULL").ToString();
            }
            if (isWriteName)
            {
                return $"{type.Name}({string.Join(", ", values)})";
            }
            else
            {
                return $"({string.Join(", ", values)})";
            }
#else
            EcsDebug.PrintWarning($"Reflection is not available, the {nameof(AutoToString)} method does not work.");
            return string.Empty;
#endif
        }
        #endregion

        #region GetName
        public static string GetName(object obj, int maxGenericDepth = 2)
        {
            return obj is IEcsMetaProvider intr ?
                GetName(intr.MetaSource, maxGenericDepth) :
                GetName(type: obj.GetType(), maxGenericDepth);
        }
        public static string GetName<T>(int maxGenericDepth = 2) => GetName(typeof(T), maxGenericDepth);
        public static string GetName(Type type, int maxGenericDepth = 2) => type.TryGetCustomAttribute(out MetaNameAttribute atr) ? atr.name : GetGenericTypeName(type, maxGenericDepth);
        public static bool TryGetCustomName(object obj, out string name)
        {
            return obj is IEcsMetaProvider intr ?
                TryGetCustomName(intr.MetaSource, out name) :
                TryGetCustomName(type: obj.GetType(), out name);
        }
        public static bool TryGetCustomName<T>(out string name) => TryGetCustomName(type: typeof(T), out name);
        public static bool TryGetCustomName(Type type, out string name)
        {
            if (type.TryGetCustomAttribute(out MetaNameAttribute atr))
            {
                name = atr.name;
                return true;
            }
            name = string.Empty;
            return false;
        }
        #endregion

        #region GetGroup
        public static MetaGroup GetGroup(object obj)
        {
            return obj is IEcsMetaProvider intr ?
                GetGroup(intr.MetaSource) :
                GetGroup(type: obj.GetType());
        }
        public static MetaGroup GetGroup<T>() => GetGroup(typeof(T));
        public static MetaGroup GetGroup(Type type) => type.TryGetCustomAttribute(out MetaGroupAttribute atr) ? atr.GetData() : MetaGroup.Empty;
        public static bool TryGetGroup(object obj, out MetaGroup group)
        {
            return obj is IEcsMetaProvider intr ?
                TryGetGroup(intr.MetaSource, out group) :
                TryGetGroup(type: obj.GetType(), out group);
        }
        public static bool TryGetGroup<T>(out MetaGroup text) => TryGetGroup(typeof(T), out text);
        public static bool TryGetGroup(Type type, out MetaGroup group)
        {
            if (type.TryGetCustomAttribute(out MetaGroupAttribute atr))
            {
                group = atr.GetData();
                return true;
            }
            group = MetaGroup.Empty;
            return false;
        }
        #endregion

        #region GetDescription
        public static string GetDescription(object obj)
        {
            return obj is IEcsMetaProvider intr ?
                GetDescription(intr.MetaSource) :
                GetDescription(type: obj.GetType());
        }
        public static string GetDescription<T>() => GetDescription(typeof(T));
        public static string GetDescription(Type type) => type.TryGetCustomAttribute(out MetaDescriptionAttribute atr) ? atr.description : string.Empty;
        public static bool TryGetDescription(object obj, out string text)
        {
            return obj is IEcsMetaProvider intr ?
                TryGetDescription(intr.MetaSource, out text) :
                TryGetDescription(type: obj.GetType(), out text);
        }
        public static bool TryGetDescription<T>(out string text) => TryGetDescription(typeof(T), out text);
        public static bool TryGetDescription(Type type, out string text)
        {
            if (type.TryGetCustomAttribute(out MetaDescriptionAttribute atr))
            {
                text = atr.description;
                return true;
            }
            text = string.Empty;
            return false;
        }
        #endregion

        #region GetColor
        public static MetaColor GetColor(object obj)
        {
            return obj is IEcsMetaProvider intr ?
                GetColor(intr.MetaSource) :
                GetColor(type: obj.GetType());
        }
        public static MetaColor GetColor<T>()
        {
            return GetColor(typeof(T));
        }
        public static MetaColor GetColor(Type type)
        {
            var atr = type.GetCustomAttribute<MetaColorAttribute>();
            return atr != null ? atr.color
#if DEBUG //optimization for release build
                : new MetaColor(type.Name);
#else
                : MetaColor.BlackColor;
#endif
        }
        public static bool TryGetColor(object obj, out MetaColor color)
        {
            return obj is IEcsMetaProvider intr ?
                TryGetColor(intr.MetaSource, out color) :
                TryGetColor(type: obj.GetType(), out color);
        }
        public static bool TryGetColor<T>(out MetaColor color)
        {
            return TryGetColor(typeof(T), out color);
        }
        public static bool TryGetColor(Type type, out MetaColor color)
        {
            var atr = type.GetCustomAttribute<MetaColorAttribute>();
            if (atr != null)
            {
                color = atr.color;
                return true;
            }
            color = MetaColor.BlackColor;
            return false;
        }
        #endregion

        #region GetTags
        public static IReadOnlyCollection<string> GetTags(object obj)
        {
            return obj is IEcsMetaProvider intr ?
                GetTags(intr.MetaSource) :
                GetTags(type: obj.GetType());
        }
        public static IReadOnlyCollection<string> GetTags<T>()
        {
            return GetTags(typeof(T));
        }
        public static IReadOnlyCollection<string> GetTags(Type type)
        {
            var atr = type.GetCustomAttribute<MetaTagsAttribute>();
            return atr != null ? atr.Tags : Array.Empty<string>();
        }

        public static bool TryGetTags(object obj, out IReadOnlyCollection<string> tags)
        {
            return obj is IEcsMetaProvider intr ?
                TryGetTags(intr.MetaSource, out tags) :
                TryGetTags(type: obj.GetType(), out tags);
        }
        public static bool TryGetTags<T>(out IReadOnlyCollection<string> tags)
        {
            return TryGetTags(typeof(T), out tags);
        }
        public static bool TryGetTags(Type type, out IReadOnlyCollection<string> tags)
        {
            var atr = type.GetCustomAttribute<MetaTagsAttribute>();
            if (atr != null)
            {
                tags = atr.Tags;
                return true;
            }
            tags = Array.Empty<string>();
            return false;
        }
        #endregion

        #region IsHidden
        public static bool IsHidden(object obj)
        {
            return obj is IEcsMetaProvider intr ?
                IsHidden(intr.MetaSource) :
                IsHidden(type: obj.GetType());
        }
        public static bool IsHidden<T>()
        {
            return IsHidden(typeof(T));
        }
        public static bool IsHidden(Type type)
        {
            return type.TryGetCustomAttribute(out MetaTagsAttribute atr) && atr.Tags.Contains(MetaTags.HIDDEN);
        }
        #endregion

        #region MetaSource
        public static bool IsMetaSourceProvided(object obj)
        {
            return obj is IEcsMetaProvider;
        }
        public static object GetMetaSource(object obj)
        {
            return obj is IEcsMetaProvider intr ? intr.MetaSource : obj;
        }
        #endregion

        #region GenerateTypeMeta
        public static TypeMetaData GenerateTypeMeta(object obj)
        {
            return obj is IEcsMetaProvider intr ?
                GenerateTypeMeta(intr.MetaSource) :
                GenerateTypeMeta(type: obj.GetType());
        }
        public static TypeMetaData GenerateTypeMeta<T>()
        {
            return GenerateTypeMeta(typeof(T));
        }
        public static TypeMetaData GenerateTypeMeta(Type type)
        {
            return new TypeMetaData(
                type,
                GetName(type),
                GetGroup(type),
                GetColor(type),
                GetDescription(type),
                GetTags(type));
        }
        #endregion

        #region GetCachedTypeMeta
        private static readonly Dictionary<Type, TypeMetaDataCached> _metaCache = new Dictionary<Type, TypeMetaDataCached>();
        public static TypeMetaDataCached GetCachedTypeMeta(object obj)
        {
            return obj is IEcsMetaProvider intr ?
                GetCachedTypeMeta(intr.MetaSource) :
                GetCachedTypeMeta(type: obj.GetType());
        }
        public static TypeMetaDataCached GetCachedTypeMeta<T>()
        {
            return GetCachedTypeMeta(typeof(T));
        }
        public static TypeMetaDataCached GetCachedTypeMeta(Type type)
        {
            if (_metaCache.TryGetValue(type, out TypeMetaDataCached result) == false)
            {
                result = new TypeMetaDataCached(type);
                _metaCache.Add(type, result);
            }
            return result;
        }
        #endregion

        #region ReflectionExtensions
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static bool TryGetCustomAttribute<T>(this Type self, out T attribute) where T : Attribute
        {
            attribute = self.GetCustomAttribute<T>();
            return attribute != null;
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static bool TryGetCustomAttribute<T>(this MemberInfo self, out T attribute) where T : Attribute
        {
            attribute = self.GetCustomAttribute<T>();
            return attribute != null;
        }
        #endregion
    }

    [Serializable]
    public sealed class TypeMetaData
    {
        public readonly Type type;
        public readonly string name;
        public readonly MetaGroup group;
        public readonly MetaColor color;
        public readonly string description;
        public readonly IReadOnlyCollection<string> tags;
        public TypeMetaData(Type type, string name, MetaGroup group, MetaColor color, string description, IReadOnlyCollection<string> tags)
        {
            this.type = type;
            this.name = name;
            this.group = group;
            this.color = color;
            this.description = description;
            this.tags = tags;
        }
    }

    public static class TypeMetaDataCachedExtensions
    {
        public static TypeMetaDataCached GetMeta(this object self)
        {
            return EcsDebugUtility.GetCachedTypeMeta(self);
        }
    }
    public class TypeMetaDataCached
    {
        internal readonly Type _type;

        internal string _name;
        internal MetaGroup _group;
        internal MetaColor _color;
        internal string _description;
        internal IReadOnlyCollection<string> _tags;

        private TypeMetaData _typeMetaData = null;
        private InitFlag _initFlags = InitFlag.None;

        public TypeMetaDataCached(Type type)
        {
            _type = type;
        }

        public Type Type
        {
            get { return _type; }
        }
        public string Name
        {
            get
            {
                if (_initFlags.HasFlag(InitFlag.Name) == false)
                {
                    _name = EcsDebugUtility.GetName(_type);
                    _initFlags |= InitFlag.Name;
                }
                return _name;
            }
        }
        public MetaGroup Group
        {
            get
            {
                if (_initFlags.HasFlag(InitFlag.Group) == false)
                {
                    _group = EcsDebugUtility.GetGroup(_type);
                    _initFlags |= InitFlag.Group;
                }
                return _group;
            }
        }
        public MetaColor Color
        {
            get
            {
                if (_initFlags.HasFlag(InitFlag.Color) == false)
                {
                    _color = EcsDebugUtility.GetColor(_type);
                    _initFlags |= InitFlag.Color;
                }
                return _color;
            }
        }
        public string Description
        {
            get
            {
                if (_initFlags.HasFlag(InitFlag.Description) == false)
                {
                    _description = EcsDebugUtility.GetDescription(_type);
                    _initFlags |= InitFlag.Description;
                }
                return _description;
            }
        }
        public IReadOnlyCollection<string> Tags
        {
            get
            {
                if (_initFlags.HasFlag(InitFlag.Tags) == false)
                {
                    _tags = EcsDebugUtility.GetTags(_type);
                    _initFlags |= InitFlag.Tags;
                }
                return _tags;
            }
        }
        public TypeMetaData AllData
        {
            get
            {
                if (_typeMetaData == null)
                {
                    _typeMetaData = new TypeMetaData(
                        Type,
                        Name,
                        Group,
                        Color,
                        Description,
                        Tags);
                }
                return _typeMetaData;
            }
        }

        public void InitializeAll()
        {
            if (_initFlags == InitFlag.All)
            {
                return;
            }
            _ = Name;
            _ = Group;
            _ = Color;
            _ = Description;
            _ = Tags;
        }

        private enum InitFlag : byte
        {
            None = 0,
            Name = 1 << 0,
            Group = 1 << 1,
            Color = 1 << 2,
            Description = 1 << 3,
            Tags = 1 << 4,
            All = Name | Group | Color | Description | Tags
        }
    }
}