// dnlib: See LICENSE.txt for more info

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Reflection;
using System.Threading;
using dnlib.DotNet.MD;
using dnlib.DotNet.Pdb;

namespace dnlib.DotNet {
	/// <summary>
	/// A high-level representation of a row in the AssemblyRef table
	/// </summary>
	public abstract class AssemblyRef : IHasCustomAttribute, IImplementation, IResolutionScope, IHasCustomDebugInformation, IAssembly, IScope {
		/// <summary>
		/// An assembly ref that can be used to indicate that it references the current assembly
		/// when the current assembly is not known (eg. a type string without any assembly info
		/// when it references a type in the current assembly).
		/// </summary>
		public static readonly AssemblyRef CurrentAssembly = new AssemblyRefUser("<<<CURRENT_ASSEMBLY>>>");

		/// <summary>
		/// The row id in its table
		/// </summary>
		protected uint rid;

		/// <inheritdoc/>
		public MDToken MDToken => new MDToken(Table.AssemblyRef, rid);

		/// <inheritdoc/>
		public uint Rid {
			get => rid;
			set => rid = value;
		}

		/// <inheritdoc/>
		public int HasCustomAttributeTag => 15;

		/// <inheritdoc/>
		public int ImplementationTag => 1;

		/// <inheritdoc/>
		public int ResolutionScopeTag => 2;

		/// <inheritdoc/>
		public ScopeType ScopeType => ScopeType.AssemblyRef;

		/// <inheritdoc/>
		public string ScopeName => FullName;

		/// <summary>
		/// From columns AssemblyRef.MajorVersion, AssemblyRef.MinorVersion,
		/// AssemblyRef.BuildNumber, AssemblyRef.RevisionNumber
		/// </summary>
		/// <exception cref="ArgumentNullException">If <paramref name="value"/> is <c>null</c></exception>
		public Version Version {
			get => version;
			set => version = value ?? throw new ArgumentNullException(nameof(value));
		}
		/// <summary/>
		protected Version version;

		/// <summary>
		/// From column AssemblyRef.Flags
		/// </summary>
		public AssemblyAttributes Attributes {
			get => (AssemblyAttributes)attributes;
			set => attributes = (int)value;
		}
		/// <summary>Attributes</summary>
		protected int attributes;

		/// <summary>
		/// From column AssemblyRef.PublicKeyOrToken
		/// </summary>
		/// <exception cref="ArgumentNullException">If <paramref name="value"/> is <c>null</c></exception>
		public PublicKeyBase PublicKeyOrToken {
			get => publicKeyOrToken;
			set => publicKeyOrToken = value ?? throw new ArgumentNullException(nameof(value));
		}
		/// <summary/>
		protected PublicKeyBase publicKeyOrToken;

		/// <summary>
		/// From column AssemblyRef.Name
		/// </summary>
		public UTF8String Name {
			get => name;
			set => name = value;
		}
		/// <summary>Name</summary>
		protected UTF8String name;

		/// <summary>
		/// From column AssemblyRef.Locale
		/// </summary>
		public UTF8String Culture {
			get => culture;
			set => culture = value;
		}
		/// <summary>Culture</summary>
		protected UTF8String culture;

		/// <summary>
		/// From column AssemblyRef.HashValue
		/// </summary>
		public byte[] Hash {
			get => hashValue;
			set => hashValue = value;
		}
		/// <summary/>
		protected byte[] hashValue;

		/// <summary>
		/// Gets all custom attributes
		/// </summary>
		public CustomAttributeCollection CustomAttributes {
			get {
				if (customAttributes is null)
					InitializeCustomAttributes();
				return customAttributes;
			}
		}
		/// <summary/>
		protected CustomAttributeCollection customAttributes;
		/// <summary>Initializes <see cref="customAttributes"/></summary>
		protected virtual void InitializeCustomAttributes() =>
			Interlocked.CompareExchange(ref customAttributes, new CustomAttributeCollection(), null);

		/// <inheritdoc/>
		public bool HasCustomAttributes => CustomAttributes.Count > 0;

		/// <inheritdoc/>
		public int HasCustomDebugInformationTag => 15;

		/// <inheritdoc/>
		public bool HasCustomDebugInfos => CustomDebugInfos.Count > 0;

		/// <summary>
		/// Gets all custom debug infos
		/// </summary>
		public IList<PdbCustomDebugInfo> CustomDebugInfos {
			get {
				if (customDebugInfos is null)
					InitializeCustomDebugInfos();
				return customDebugInfos;
			}
		}
		/// <summary/>
		protected IList<PdbCustomDebugInfo> customDebugInfos;
		/// <summary>Initializes <see cref="customDebugInfos"/></summary>
		protected virtual void InitializeCustomDebugInfos() =>
			Interlocked.CompareExchange(ref customDebugInfos, new List<PdbCustomDebugInfo>(), null);

		/// <inheritdoc/>
		public string FullName => FullNameToken;

		/// <summary>
		/// Same as <see cref="FullName"/>, except that it uses the <c>PublicKey</c> if available.
		/// </summary>
		public string RealFullName => FullNameFactory.AssemblyFullName(this, false);

		/// <summary>
		/// Gets the full name of the assembly but use a public key token
		/// </summary>
		public string FullNameToken => FullNameFactory.AssemblyFullName(this, true);

		/// <summary>
		/// Modify <see cref="attributes"/> property: <see cref="attributes"/> =
		/// (<see cref="attributes"/> &amp; <paramref name="andMask"/>) | <paramref name="orMask"/>.
		/// </summary>
		/// <param name="andMask">Value to <c>AND</c></param>
		/// <param name="orMask">Value to OR</param>
		void ModifyAttributes(AssemblyAttributes andMask, AssemblyAttributes orMask) =>
			attributes = (attributes & (int)andMask) | (int)orMask;

		/// <summary>
		/// Set or clear flags in <see cref="attributes"/>
		/// </summary>
		/// <param name="set"><c>true</c> if flags should be set, <c>false</c> if flags should
		/// be cleared</param>
		/// <param name="flags">Flags to set or clear</param>
		void ModifyAttributes(bool set, AssemblyAttributes flags) {
			if (set)
				attributes |= (int)flags;
			else
				attributes &= ~(int)flags;
		}

		/// <summary>
		/// Gets/sets the <see cref="AssemblyAttributes.PublicKey"/> bit
		/// </summary>
		public bool HasPublicKey {
			get => ((AssemblyAttributes)attributes & AssemblyAttributes.PublicKey) != 0;
			set => ModifyAttributes(value, AssemblyAttributes.PublicKey);
		}

		/// <summary>
		/// Gets/sets the processor architecture
		/// </summary>
		public AssemblyAttributes ProcessorArchitecture {
			get => (AssemblyAttributes)attributes & AssemblyAttributes.PA_Mask;
			set => ModifyAttributes(~AssemblyAttributes.PA_Mask, value & AssemblyAttributes.PA_Mask);
		}

		/// <summary>
		/// Gets/sets the processor architecture
		/// </summary>
		public AssemblyAttributes ProcessorArchitectureFull {
			get => (AssemblyAttributes)attributes & AssemblyAttributes.PA_FullMask;
			set => ModifyAttributes(~AssemblyAttributes.PA_FullMask, value & AssemblyAttributes.PA_FullMask);
		}

		/// <summary>
		/// <c>true</c> if unspecified processor architecture
		/// </summary>
		public bool IsProcessorArchitectureNone => ((AssemblyAttributes)attributes & AssemblyAttributes.PA_Mask) == AssemblyAttributes.PA_None;

		/// <summary>
		/// <c>true</c> if neutral (PE32) architecture
		/// </summary>
		public bool IsProcessorArchitectureMSIL => ((AssemblyAttributes)attributes & AssemblyAttributes.PA_Mask) == AssemblyAttributes.PA_MSIL;

		/// <summary>
		/// <c>true</c> if x86 (PE32) architecture
		/// </summary>
		public bool IsProcessorArchitectureX86 => ((AssemblyAttributes)attributes & AssemblyAttributes.PA_Mask) == AssemblyAttributes.PA_x86;

		/// <summary>
		/// <c>true</c> if IA-64 (PE32+) architecture
		/// </summary>
		public bool IsProcessorArchitectureIA64 => ((AssemblyAttributes)attributes & AssemblyAttributes.PA_Mask) == AssemblyAttributes.PA_IA64;

		/// <summary>
		/// <c>true</c> if x64 (PE32+) architecture
		/// </summary>
		public bool IsProcessorArchitectureX64 => ((AssemblyAttributes)attributes & AssemblyAttributes.PA_Mask) == AssemblyAttributes.PA_AMD64;

		/// <summary>
		/// <c>true</c> if ARM (PE32) architecture
		/// </summary>
		public bool IsProcessorArchitectureARM => ((AssemblyAttributes)attributes & AssemblyAttributes.PA_Mask) == AssemblyAttributes.PA_ARM;

		/// <summary>
		/// <c>true</c> if eg. reference assembly (not runnable)
		/// </summary>
		public bool IsProcessorArchitectureNoPlatform => ((AssemblyAttributes)attributes & AssemblyAttributes.PA_Mask) == AssemblyAttributes.PA_NoPlatform;

		/// <summary>
		/// Gets/sets the <see cref="AssemblyAttributes.PA_Specified"/> bit
		/// </summary>
		public bool IsProcessorArchitectureSpecified {
			get => ((AssemblyAttributes)attributes & AssemblyAttributes.PA_Specified) != 0;
			set => ModifyAttributes(value, AssemblyAttributes.PA_Specified);
		}

		/// <summary>
		/// Gets/sets the <see cref="AssemblyAttributes.EnableJITcompileTracking"/> bit
		/// </summary>
		public bool EnableJITcompileTracking {
			get => ((AssemblyAttributes)attributes & AssemblyAttributes.EnableJITcompileTracking) != 0;
			set => ModifyAttributes(value, AssemblyAttributes.EnableJITcompileTracking);
		}

		/// <summary>
		/// Gets/sets the <see cref="AssemblyAttributes.DisableJITcompileOptimizer"/> bit
		/// </summary>
		public bool DisableJITcompileOptimizer {
			get => ((AssemblyAttributes)attributes & AssemblyAttributes.DisableJITcompileOptimizer) != 0;
			set => ModifyAttributes(value, AssemblyAttributes.DisableJITcompileOptimizer);
		}

		/// <summary>
		/// Gets/sets the <see cref="AssemblyAttributes.Retargetable"/> bit
		/// </summary>
		public bool IsRetargetable {
			get => ((AssemblyAttributes)attributes & AssemblyAttributes.Retargetable) != 0;
			set => ModifyAttributes(value, AssemblyAttributes.Retargetable);
		}

		/// <summary>
		/// Gets/sets the content type
		/// </summary>
		public AssemblyAttributes ContentType {
			get => (AssemblyAttributes)attributes & AssemblyAttributes.ContentType_Mask;
			set => ModifyAttributes(~AssemblyAttributes.ContentType_Mask, value & AssemblyAttributes.ContentType_Mask);
		}

		/// <summary>
		/// <c>true</c> if content type is <c>Default</c>
		/// </summary>
		public bool IsContentTypeDefault => ((AssemblyAttributes)attributes & AssemblyAttributes.ContentType_Mask) == AssemblyAttributes.ContentType_Default;

		/// <summary>
		/// <c>true</c> if content type is <c>WindowsRuntime</c>
		/// </summary>
		public bool IsContentTypeWindowsRuntime => ((AssemblyAttributes)attributes & AssemblyAttributes.ContentType_Mask) == AssemblyAttributes.ContentType_WindowsRuntime;

		/// <inheritdoc/>
		public override string ToString() => FullName;
	}

	/// <summary>
	/// An AssemblyRef row created by the user and not present in the original .NET file
	/// </summary>
	public class AssemblyRefUser : AssemblyRef {
		/// <summary>
		/// Creates a reference to CLR 1.0's mscorlib
		/// </summary>
		public static AssemblyRefUser CreateMscorlibReferenceCLR10() => new AssemblyRefUser("mscorlib", new Version(1, 0, 3300, 0), new PublicKeyToken("b77a5c561934e089"));

		/// <summary>
		/// Creates a reference to CLR 1.1's mscorlib
		/// </summary>
		public static AssemblyRefUser CreateMscorlibReferenceCLR11() => new AssemblyRefUser("mscorlib", new Version(1, 0, 5000, 0), new PublicKeyToken("b77a5c561934e089"));

		/// <summary>
		/// Creates a reference to CLR 2.0's mscorlib
		/// </summary>
		public static AssemblyRefUser CreateMscorlibReferenceCLR20() => new AssemblyRefUser("mscorlib", new Version(2, 0, 0, 0), new PublicKeyToken("b77a5c561934e089"));

		/// <summary>
		/// Creates a reference to CLR 4.0's mscorlib
		/// </summary>
		public static AssemblyRefUser CreateMscorlibReferenceCLR40() => new AssemblyRefUser("mscorlib", new Version(4, 0, 0, 0), new PublicKeyToken("b77a5c561934e089"));

		/// <summary>
		/// Default constructor
		/// </summary>
		public AssemblyRefUser()
			: this(UTF8String.Empty) {
		}

		/// <summary>
		/// Constructor
		/// </summary>
		/// <param name="name">Simple name</param>
		/// <exception cref="ArgumentNullException">If any of the args is invalid</exception>
		public AssemblyRefUser(UTF8String name)
			: this(name, new Version(0, 0, 0, 0)) {
		}

		/// <summary>
		/// Constructor
		/// </summary>
		/// <param name="name">Simple name</param>
		/// <param name="version">Version</param>
		/// <exception cref="ArgumentNullException">If any of the args is invalid</exception>
		public AssemblyRefUser(UTF8String name, Version version)
			: this(name, version, new PublicKey()) {
		}

		/// <summary>
		/// Constructor
		/// </summary>
		/// <param name="name">Simple name</param>
		/// <param name="version">Version</param>
		/// <param name="publicKey">Public key or public key token</param>
		/// <exception cref="ArgumentNullException">If any of the args is invalid</exception>
		public AssemblyRefUser(UTF8String name, Version version, PublicKeyBase publicKey)
			: this(name, version, publicKey, UTF8String.Empty) {
		}

		/// <summary>
		/// Constructor
		/// </summary>
		/// <param name="name">Simple name</param>
		/// <param name="version">Version</param>
		/// <param name="publicKey">Public key or public key token</param>
		/// <param name="locale">Locale</param>
		/// <exception cref="ArgumentNullException">If any of the args is invalid</exception>
		public AssemblyRefUser(UTF8String name, Version version, PublicKeyBase publicKey, UTF8String locale) {
			if (name is null)
				throw new ArgumentNullException(nameof(name));
			if (locale is null)
				throw new ArgumentNullException(nameof(locale));
			this.name = name;
			this.version = version ?? throw new ArgumentNullException(nameof(version));
			publicKeyOrToken = publicKey;
			culture = locale;
			attributes = (int)(publicKey is PublicKey ? AssemblyAttributes.PublicKey : AssemblyAttributes.None);
		}

		/// <summary>
		/// Constructor
		/// </summary>
		/// <param name="asmName">Assembly name info</param>
		/// <exception cref="ArgumentNullException">If <paramref name="asmName"/> is <c>null</c></exception>
		public AssemblyRefUser(AssemblyName asmName)
			: this(new AssemblyNameInfo(asmName)) => attributes = (int)asmName.Flags;

		/// <summary>
		/// Constructor
		/// </summary>
		/// <param name="assembly">Assembly</param>
		public AssemblyRefUser(IAssembly assembly) {
			if (assembly is null)
				throw new ArgumentNullException("asmName");

			version = assembly.Version ?? new Version(0, 0, 0, 0);
			publicKeyOrToken = assembly.PublicKeyOrToken;
			name = UTF8String.IsNullOrEmpty(assembly.Name) ? UTF8String.Empty : assembly.Name;
			culture = assembly.Culture;
			attributes = (int)((publicKeyOrToken is PublicKey ? AssemblyAttributes.PublicKey : AssemblyAttributes.None) | assembly.ContentType);
		}
	}

	/// <summary>
	/// Created from a row in the AssemblyRef table
	/// </summary>
	sealed class AssemblyRefMD : AssemblyRef, IMDTokenProviderMD {
		/// <summary>The module where this instance is located</summary>
		readonly ModuleDefMD readerModule;

		readonly uint origRid;

		/// <inheritdoc/>
		public uint OrigRid => origRid;

		/// <inheritdoc/>
		protected override void InitializeCustomAttributes() {
			var list = readerModule.Metadata.GetCustomAttributeRidList(Table.AssemblyRef, origRid);
			var tmp = new CustomAttributeCollection(list.Count, list, (list2, index) => readerModule.ReadCustomAttribute(list[index]));
			Interlocked.CompareExchange(ref customAttributes, tmp, null);
		}

		/// <inheritdoc/>
		protected override void InitializeCustomDebugInfos() {
			var list = new List<PdbCustomDebugInfo>();
			readerModule.InitializeCustomDebugInfos(new MDToken(MDToken.Table, origRid), new GenericParamContext(), list);
			Interlocked.CompareExchange(ref customDebugInfos, list, null);
		}

		/// <summary>
		/// Constructor
		/// </summary>
		/// <param name="readerModule">The module which contains this <c>AssemblyRef</c> row</param>
		/// <param name="rid">Row ID</param>
		/// <exception cref="ArgumentNullException">If <paramref name="readerModule"/> is <c>null</c></exception>
		/// <exception cref="ArgumentException">If <paramref name="rid"/> is invalid</exception>
		public AssemblyRefMD(ModuleDefMD readerModule, uint rid) {
#if DEBUG
			if (readerModule is null)
				throw new ArgumentNullException("readerModule");
			if (readerModule.TablesStream.AssemblyRefTable.IsInvalidRID(rid))
				throw new BadImageFormatException($"AssemblyRef rid {rid} does not exist");
#endif
			origRid = rid;
			this.rid = rid;
			this.readerModule = readerModule;
			bool b = readerModule.TablesStream.TryReadAssemblyRefRow(origRid, out var row);
			Debug.Assert(b);
			version = new Version(row.MajorVersion, row.MinorVersion, row.BuildNumber, row.RevisionNumber);
			attributes = (int)row.Flags;
			var pkData = readerModule.BlobStream.Read(row.PublicKeyOrToken);
			if ((attributes & (uint)AssemblyAttributes.PublicKey) != 0)
				publicKeyOrToken = new PublicKey(pkData);
			else
				publicKeyOrToken = new PublicKeyToken(pkData);
			name = readerModule.StringsStream.ReadNoNull(row.Name);
			culture = readerModule.StringsStream.ReadNoNull(row.Locale);
			hashValue = readerModule.BlobStream.Read(row.HashValue);
		}
	}
}