// Copyright (c) .NET Foundation and contributors. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
using System.Diagnostics.CodeAnalysis;
using ILLink.Shared;
using Microsoft.CodeAnalysis;
 
namespace ILLink.RoslynAnalyzer
{
	public static class RequiresUnreferencedCodeUtils
	{
		private const string RequiresUnreferencedCodeAttribute = nameof (RequiresUnreferencedCodeAttribute);
 
		public static bool TryGetRequiresUnreferencedCodeAttribute (this ISymbol member, [NotNullWhen (returnValue: true)] out AttributeData? requiresAttributeData) =>
			member.DoesMemberRequireUnreferencedCodeAttribute (out requiresAttributeData) && VerifyRequiresUnreferencedCodeAttributeArguments (requiresAttributeData);
 
		// TODO: Consider sharing with ILLink DoesMethodRequireUnreferencedCode method
		/// <summary>
		/// True if the target of a call is considered to be annotated with the RequiresUnreferencedCode attribute
		/// </summary>
		public static bool DoesMemberRequireUnreferencedCodeAttribute (this ISymbol member, [NotNullWhen (returnValue: true)] out AttributeData? requiresAttributeData)
			=> member.DoesMemberRequire (RequiresUnreferencedCodeAttribute, out requiresAttributeData);
 
		// TODO: Consider sharing with ILLink IsMethodInRequiresUnreferencedCodeScope method
		/// <summary>
		/// True if the source of a call is considered to be annotated with the RequiresUnreferencedCode attribute
		/// </summary>
		public static bool IsInRequiresUnreferencedCodeAttributeScope (this ISymbol member, [NotNullWhen (true)] out AttributeData? requiresAttribute)
			=> member.IsInRequiresScope (RequiresUnreferencedCodeAttribute, out requiresAttribute);
 
		/// <summary>
		/// This method verifies that the arguments in an attribute have certain structure.
		/// </summary>
		/// <param name="attribute">Attribute data to compare.</param>
		/// <returns>True if the validation was successfull; otherwise, returns false.</returns>
		public static bool VerifyRequiresUnreferencedCodeAttributeArguments (AttributeData attribute)
			=> attribute.ConstructorArguments.Length >= 1 && attribute.ConstructorArguments is [ { Type.SpecialType: SpecialType.System_String }, ..];
 
		public static string GetMessageFromAttribute (AttributeData? requiresAttribute)
		{
			var message = (string) requiresAttribute!.ConstructorArguments[0].Value!;
			return MessageFormat.FormatRequiresAttributeMessageArg (message);
		}
	}
}