/*
	Copyright (c) 2015 Ki

	Permission is hereby granted, free of charge, to any person obtaining a copy
	of this software and associated documentation files (the "Software"), to deal
	in the Software without restriction, including without limitation the rights
	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	copies of the Software, and to permit persons to whom the Software is
	furnished to do so, subject to the following conditions:

	The above copyright notice and this permission notice shall be included in
	all copies or substantial portions of the Software.

	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	THE SOFTWARE.
*/

using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Reflection.Metadata;
using System.Threading;
using System.Xml.Linq;

using ICSharpCode.BamlDecompiler.Baml;
using ICSharpCode.BamlDecompiler.Xaml;
using ICSharpCode.Decompiler.TypeSystem;

namespace ICSharpCode.BamlDecompiler
{
	internal class XamlContext
	{
		XamlContext(IDecompilerTypeSystem typeSystem)
		{
			TypeSystem = typeSystem;
			NodeMap = new Dictionary<BamlRecord, BamlBlockNode>();
			XmlNs = new XmlnsDictionary();
			GeneratedMembers = new List<EntityHandle>();
			XClassNames = new List<string>();
		}

		Dictionary<ushort, XamlType> typeMap = new Dictionary<ushort, XamlType>();
		Dictionary<ushort, XamlProperty> propertyMap = new Dictionary<ushort, XamlProperty>();
		Dictionary<string, XNamespace> xmlnsMap = new Dictionary<string, XNamespace>();

		public IDecompilerTypeSystem TypeSystem { get; }
		public CancellationToken CancellationToken { get; private set; }
		public BamlDecompilerSettings Settings { get; private set; }

		public BamlContext Baml { get; private set; }
		public BamlNode RootNode { get; private set; }
		public IDictionary<BamlRecord, BamlBlockNode> NodeMap { get; }

		public List<string> XClassNames { get; }

		public List<EntityHandle> GeneratedMembers { get; }

		public XmlnsDictionary XmlNs { get; }

		public static XamlContext Construct(IDecompilerTypeSystem typeSystem, BamlDocument document, CancellationToken token, BamlDecompilerSettings bamlDecompilerOptions)
		{
			var ctx = new XamlContext(typeSystem);
			ctx.CancellationToken = token;
			ctx.Settings = bamlDecompilerOptions ?? new BamlDecompilerSettings();

			ctx.Baml = BamlContext.ConstructContext(typeSystem, document, token);
			ctx.RootNode = BamlNode.Parse(document, token);

			ctx.BuildPIMappings(document);
			ctx.BuildNodeMap(ctx.RootNode as BamlBlockNode);

			return ctx;
		}

		void BuildNodeMap(BamlBlockNode node)
		{
			if (node == null)
				return;

			NodeMap[node.Header] = node;

			foreach (var child in node.Children)
			{
				if (child is BamlBlockNode childBlock)
					BuildNodeMap(childBlock);
			}
		}

		void BuildPIMappings(BamlDocument document)
		{
			foreach (var record in document)
			{
				var piMap = record as PIMappingRecord;
				if (piMap == null)
					continue;

				XmlNs.SetPIMapping(piMap.XmlNamespace, piMap.ClrNamespace, Baml.ResolveAssembly(piMap.AssemblyId).FullAssemblyName);
			}
		}

		public XamlType ResolveType(ushort id)
		{
			if (typeMap.TryGetValue(id, out var xamlType))
				return xamlType;

			IType type;
			IModule assembly;
			string fullAssemblyName;

			if (id > 0x7fff)
			{
				type = Baml.KnownThings.Types((KnownTypes)(short)-unchecked((short)id));
				assembly = type.GetDefinition().ParentModule;
				fullAssemblyName = assembly.FullAssemblyName;
			}
			else
			{
				var typeRec = Baml.TypeIdMap[id];
				(fullAssemblyName, assembly) = Baml.ResolveAssembly(typeRec.AssemblyId);
				type = ReflectionHelper.ParseReflectionName(typeRec.TypeFullName, new SimpleTypeResolveContext(TypeSystem));
			}

			var clrNs = type.Namespace;
			var xmlNs = XmlNs.LookupXmlns(fullAssemblyName, clrNs, type.Name);

			typeMap[id] = xamlType = new XamlType(assembly, fullAssemblyName, clrNs, type.Name, GetXmlNamespace(xmlNs)) {
				ResolvedType = type
			};

			return xamlType;
		}

		public XamlProperty ResolveProperty(ushort id)
		{
			if (propertyMap.TryGetValue(id, out var xamlProp))
				return xamlProp;

			XamlType type;
			string name;
			IMember member;

			if (id > 0x7fff)
			{
				var knownProp = Baml.KnownThings.Members((KnownMembers)unchecked((short)-(short)id));
				type = ResolveType(unchecked((ushort)(short)-(short)knownProp.Parent));
				name = knownProp.Name;
				member = knownProp.Property;
			}
			else
			{
				var attrRec = Baml.AttributeIdMap[id];
				type = ResolveType(attrRec.OwnerTypeId);
				name = attrRec.Name;

				member = null;
			}

			propertyMap[id] = xamlProp = new XamlProperty(type, name) {
				ResolvedMember = member
			};
			xamlProp.TryResolve();

			return xamlProp;
		}

		public string ResolveString(ushort id)
		{
			if (id > 0x7fff)
				return Baml.KnownThings.Strings(unchecked((short)-id));
			else if (Baml.StringIdMap.ContainsKey(id))
				return Baml.StringIdMap[id].Value;

			return null;
		}

		public XNamespace GetXmlNamespace(string xmlns)
		{
			if (xmlns == null)
				return null;

			if (!xmlnsMap.TryGetValue(xmlns, out var ns))
			{
				// Every XNamespace is created here, so escaping the URI once keeps the xmlns
				// declaration and the names that use it in sync. Doing it later is not possible:
				// the URI is baked into every name built from this namespace.
				xmlnsMap[xmlns] = ns = XNamespace.Get(XamlUtils.EscapeInvalidXmlCharacters(xmlns));
			}
			return ns;
		}

		public const string KnownNamespace_Xaml = "http://schemas.microsoft.com/winfx/2006/xaml";
		public const string KnownNamespace_Presentation = "http://schemas.microsoft.com/winfx/2006/xaml/presentation";
		public const string KnownNamespace_PresentationOptions = "http://schemas.microsoft.com/winfx/2006/xaml/presentation/options";

		public static string TryGetXmlNamespace(IModule assembly, string typeNamespace, XElement context = null)
		{
			if (assembly == null)
				return null;

			HashSet<string> possibleXmlNs = new HashSet<string>();

			foreach (var attr in assembly.GetAssemblyAttributes().Where(a => a.AttributeType.FullName == "System.Windows.Markup.XmlnsDefinitionAttribute"))
			{
				Debug.Assert(attr.FixedArguments.Length == 2);
				if (attr.FixedArguments.Length != 2)
					continue;
				var xmlNs = attr.FixedArguments[0].Value as string;
				var typeNs = attr.FixedArguments[1].Value as string;
				Debug.Assert((object)xmlNs != null && (object)typeNs != null);
				if ((object)xmlNs == null || (object)typeNs == null)
					continue;

				if (typeNamespace == typeNs)
					possibleXmlNs.Add(xmlNs);
			}

			// An assembly may map one CLR namespace to several XML namespaces; PresentationFramework
			// for example maps its namespaces to both the winfx/2006 and the netfx/2007 presentation
			// namespace. Whenever the document itself declares one of the candidates, that one has to
			// win: picking a different candidate for an element whose start tag carries the xmlns
			// declaration redefines the prefix within that tag, which is not valid XML.
			var declared = possibleXmlNs.Where(ns => IsDeclaredIn(context, ns)).ToList();
			if (declared.Count > 0)
				possibleXmlNs = new HashSet<string>(declared);

			if (possibleXmlNs.Contains(KnownNamespace_Presentation))
				return KnownNamespace_Presentation;

			return possibleXmlNs.FirstOrDefault();
		}

		static bool IsDeclaredIn(XElement context, string xmlNamespace)
		{
			for (var elem = context; elem != null; elem = elem.Parent)
			{
				foreach (var attr in elem.Attributes())
				{
					if (attr.IsNamespaceDeclaration && attr.Value == xmlNamespace)
						return true;
				}
			}

			return false;
		}

		public XName GetKnownNamespace(string name, string xmlNamespace, XElement context = null)
		{
			var xNs = GetXmlNamespace(xmlNamespace);
			XName xName;
			if (context != null && xNs == context.GetDefaultNamespace())
				xName = name;
			else
				xName = xNs + name;
			return xName;
		}

		public XName GetPseudoName(string name) => XNamespace.Get("https://github.com/icsharpcode/ILSpy").GetName(name);
	}
}