/*
    Copyright (C) 2014-2019 de4dot@gmail.com

    This file is part of dnSpy

    dnSpy is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    dnSpy is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with dnSpy.  If not, see <http://www.gnu.org/licenses/>.
*/

using System;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Windows.Input;
using dnlib.DotNet;
using dnSpy.AsmEditor.Commands;
using dnSpy.AsmEditor.Properties;
using dnSpy.AsmEditor.ViewHelpers;
using dnSpy.Contracts.Decompiler;
using dnSpy.Contracts.MVVM;
using dnSpy.Contracts.Search;

namespace dnSpy.AsmEditor.DnlibDialogs {
	sealed class CustomAttributeVM : ViewModelBase {
		readonly CustomAttributeOptions origOptions;

		public IDnlibTypePicker DnlibTypePicker {
			set => dnlibTypePicker = value;
		}
		IDnlibTypePicker? dnlibTypePicker;

		public ICommand ReinitializeCommand => new RelayCommand(a => Reinitialize());
		public ICommand PickConstructorCommand => new RelayCommand(a => PickConstructor());

		public string TypeFullName {
			get {
				if (Constructor is MemberRef mrCtor)
					return mrCtor.GetDeclaringTypeFullName() ?? string.Empty;

				if (Constructor is MethodDef mdCtor) {
					var declType = mdCtor.DeclaringType;
					if (declType is not null)
						return declType.FullName;
				}

				return string.Empty;
			}
		}

		public string FullName {
			get {
				if (IsRawData)
					return dnSpy_AsmEditor_Resources.RawCustomAttributeBlob2;
				var sb = new StringBuilder();
				sb.Append(TypeFullName);
				sb.Append('(');
				bool first = true;
				foreach (var arg in ConstructorArguments) {
					if (!first)
						sb.Append(", ");
					first = false;
					sb.Append(arg.ToString());
				}
				foreach (var namedArg in CANamedArgumentsVM.Collection) {
					if (!first)
						sb.Append(", ");
					first = false;
					sb.Append(namedArg.ToString());
				}
				sb.Append(')');
				return sb.ToString();
			}
		}

		public bool IsRawData {
			get => isRawData;
			set {
				if (isRawData != value) {
					isRawData = value;
					ConstructorArguments.IsEnabled = !value;
					CANamedArgumentsVM.Collection.IsEnabled = !value;
					OnPropertyChanged(nameof(IsRawData));
					OnPropertyChanged(nameof(IsNotRawData));
					OnPropertyChanged(nameof(FullName));
					HasErrorUpdated();
				}
			}
		}
		bool isRawData;

		public bool IsNotRawData {
			get => !IsRawData;
			set => IsRawData = !value;
		}

		public HexStringVM RawData { get; }

		public ICustomAttributeType? Constructor {
			get => constructor;
			set {
				if (constructor != value) {
					constructor = value;
					OnPropertyChanged(nameof(Constructor));
					ConstructorArguments.Clear();
					CreateArguments();
					OnPropertyChanged(nameof(TypeFullName));
					OnPropertyChanged(nameof(FullName));
					HasErrorUpdated();
				}
			}
		}
		ICustomAttributeType? constructor;

		public MyObservableCollection<CAArgumentVM> ConstructorArguments { get; } = new MyObservableCollection<CAArgumentVM>();
		public CANamedArgumentsVM CANamedArgumentsVM { get; }

		readonly ModuleDef ownerModule;
		readonly IDecompilerService decompilerService;
		readonly TypeDef? ownerType;
		readonly MethodDef? ownerMethod;

		public CustomAttributeVM(CustomAttributeOptions options, ModuleDef ownerModule, IDecompilerService decompilerService, TypeDef? ownerType, MethodDef? ownerMethod) {
			origOptions = options;
			this.ownerModule = ownerModule;
			this.decompilerService = decompilerService;
			this.ownerType = ownerType;
			this.ownerMethod = ownerMethod;

			RawData = new HexStringVM(a => HasErrorUpdated());
			CANamedArgumentsVM = new CANamedArgumentsVM(ownerModule, decompilerService, ownerType, ownerMethod, a => !IsRawData && a.Collection.Count < ushort.MaxValue);
			ConstructorArguments.CollectionChanged += Args_CollectionChanged;
			CANamedArgumentsVM.Collection.CollectionChanged += Args_CollectionChanged;

			Reinitialize();
		}

		void Args_CollectionChanged(object? sender, NotifyCollectionChangedEventArgs e) {
			Hook(e);
			OnPropertyChanged(nameof(FullName));
			HasErrorUpdated();
		}

		void Hook(NotifyCollectionChangedEventArgs e) {
			if (e.OldItems is not null) {
				foreach (INotifyPropertyChanged? i in e.OldItems)
					i!.PropertyChanged -= arg_PropertyChanged;
			}
			if (e.NewItems is not null) {
				foreach (INotifyPropertyChanged? i in e.NewItems)
					i!.PropertyChanged += arg_PropertyChanged;
			}
		}

		void arg_PropertyChanged(object? sender, PropertyChangedEventArgs e) {
			OnPropertyChanged(nameof(FullName));
			HasErrorUpdated();
		}

		void CreateArguments() {
			int count = Constructor is null ? 0 : Constructor.MethodSig.GetParamCount();
			while (ConstructorArguments.Count > count)
				ConstructorArguments.RemoveAt(ConstructorArguments.Count - 1);
			while (ConstructorArguments.Count < count) {
				var type = Constructor!.MethodSig.Params[ConstructorArguments.Count];
				ConstructorArguments.Add(new CAArgumentVM(ownerModule, CreateCAArgument(type), new TypeSigCreatorOptions(ownerModule, decompilerService), type));
			}
		}

		static CAArgument CreateCAArgument(TypeSig type) => new CAArgument(type, ModelUtils.GetDefaultValue(type, true));

		void PickConstructor() {
			if (dnlibTypePicker is null)
				throw new InvalidOperationException();
			var newCtor = dnlibTypePicker.GetDnlibType(dnSpy_AsmEditor_Resources.Pick_Constructor, new FlagsDocumentTreeNodeFilter(VisibleMembersFlags.InstanceConstructor), Constructor, ownerModule);
			if (newCtor is not null)
				Constructor = newCtor;
		}

		void Reinitialize() => InitializeFrom(origOptions);
		public CustomAttributeOptions CreateCustomAttributeOptions() => CopyTo(new CustomAttributeOptions());

		void InitializeFrom(CustomAttributeOptions options) {
			IsRawData = options.RawData is not null;
			RawData.Value = options.RawData!;
			Constructor = options.Constructor;
			ConstructorArguments.Clear();
			var sig = Constructor is null ? null : Constructor.MethodSig;
			for (int i = 0; i < options.ConstructorArguments.Count; i++) {
				TypeSig? type = null;
				if (sig is not null && i < sig.Params.Count)
					type = sig.Params[i];
				ConstructorArguments.Add(new CAArgumentVM(ownerModule, options.ConstructorArguments[i], new TypeSigCreatorOptions(ownerModule, decompilerService), type));
			}
			CANamedArgumentsVM.InitializeFrom(options.NamedArguments);
			CreateArguments();
		}

		CustomAttributeOptions CopyTo(CustomAttributeOptions options) {
			options.Constructor = Constructor;
			options.ConstructorArguments.Clear();
			options.NamedArguments.Clear();
			if (IsRawData)
				options.RawData = RawData.Value.ToArray();
			else {
				options.RawData = null;
				int count = Constructor is null ? 0 : Constructor.MethodSig.GetParamCount();
				for (int i = 0; i < count; i++)
					options.ConstructorArguments.Add(ConstructorArguments[i].CreateCAArgument(Constructor!.MethodSig.Params[i]));
				options.NamedArguments.AddRange(CANamedArgumentsVM.Collection.Select(a => a.CreateCANamedArgument()));
			}
			return options;
		}

		public override bool HasError {
			get {
				return Constructor is null ||
					(IsRawData && RawData.HasError) ||
					(!IsRawData &&
						(ConstructorArguments.Any(a => a.HasError) ||
						CANamedArgumentsVM.Collection.Any(a => a.HasError)));
			}
		}
	}
}