// 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;
using System.Collections.Immutable;
using System.Diagnostics;
using ILLink.RoslynAnalyzer.DataFlow;
using ILLink.Shared.DataFlow;
using ILLink.Shared.TrimAnalysis;
using Microsoft.CodeAnalysis;
using MultiValue = ILLink.Shared.DataFlow.ValueSet<ILLink.Shared.DataFlow.SingleValue>;
 
namespace ILLink.RoslynAnalyzer.TrimAnalysis
{
	internal readonly record struct TrimAnalysisMethodCallPattern
	{
		public IMethodSymbol CalledMethod { get; init; }
		public MultiValue Instance { get; init; }
		public ImmutableArray<MultiValue> Arguments { get; init; }
		public IOperation Operation { get; init; }
		public ISymbol OwningSymbol { get; init; }
		public FeatureContext FeatureContext { get; init; }
 
		public TrimAnalysisMethodCallPattern (
			IMethodSymbol calledMethod,
			MultiValue instance,
			ImmutableArray<MultiValue> arguments,
			IOperation operation,
			ISymbol owningSymbol,
			FeatureContext featureContext)
		{
			CalledMethod = calledMethod;
			Instance = instance.DeepCopy ();
			if (arguments.IsEmpty) {
				Arguments = ImmutableArray<MultiValue>.Empty;
			} else {
				var builder = ImmutableArray.CreateBuilder<MultiValue> ();
				foreach (var argument in arguments) {
					builder.Add (argument.DeepCopy ());
				}
				Arguments = builder.ToImmutableArray ();
			}
			Operation = operation;
			OwningSymbol = owningSymbol;
			FeatureContext = featureContext.DeepCopy ();
		}
 
		public TrimAnalysisMethodCallPattern Merge (
			ValueSetLattice<SingleValue> lattice,
			FeatureContextLattice featureContextLattice,
			TrimAnalysisMethodCallPattern other)
		{
			Debug.Assert (Operation == other.Operation);
			Debug.Assert (SymbolEqualityComparer.Default.Equals (CalledMethod, other.CalledMethod));
			Debug.Assert (SymbolEqualityComparer.Default.Equals (OwningSymbol, other.OwningSymbol));
			Debug.Assert (Arguments.Length == other.Arguments.Length);
 
			var argumentsBuilder = ImmutableArray.CreateBuilder<MultiValue> ();
			for (int i = 0; i < Arguments.Length; i++) {
				argumentsBuilder.Add (lattice.Meet (Arguments[i], other.Arguments[i]));
			}
 
			return new TrimAnalysisMethodCallPattern (
				CalledMethod,
				lattice.Meet (Instance, other.Instance),
				argumentsBuilder.ToImmutable (),
				Operation,
				OwningSymbol,
				featureContextLattice.Meet (FeatureContext, other.FeatureContext));
		}
 
		public void ReportDiagnostics (DataFlowAnalyzerContext context, Action<Diagnostic> reportDiagnostic)
		{
			var location = Operation.Syntax.GetLocation ();
			if (context.EnableTrimAnalyzer &&
				!OwningSymbol.IsInRequiresUnreferencedCodeAttributeScope(out _) &&
				!FeatureContext.IsEnabled (RequiresUnreferencedCodeAnalyzer.FullyQualifiedRequiresUnreferencedCodeAttribute))
			{
				TrimAnalysisVisitor.HandleCall(Operation, OwningSymbol, CalledMethod, Instance, Arguments, location, reportDiagnostic, default, out var _);
			}
 
			var diagnosticContext = new DiagnosticContext (location, reportDiagnostic);
			foreach (var requiresAnalyzer in context.EnabledRequiresAnalyzers)
			{
				if (!requiresAnalyzer.IsIntrinsicallyHandled (CalledMethod, Instance, Arguments))
					requiresAnalyzer.CheckAndCreateRequiresDiagnostic (Operation, CalledMethod, OwningSymbol, context, FeatureContext, in diagnosticContext);
			}
		}
	}
}