// 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 Mono.Cecil;

namespace Mono.Linker.Steps
{
    public class ValidateVirtualMethodAnnotationsStep : BaseStep
    {
        protected override void Process()
        {
            var annotations = Context.Annotations;
            foreach (var method in annotations.VirtualMethodsWithAnnotationsToValidate)
            {
                var baseOverrideInformations = annotations.GetBaseMethods(method);
                if (baseOverrideInformations != null)
                {
                    foreach (var baseOv in baseOverrideInformations)
                    {
                        annotations.FlowAnnotations.ValidateMethodAnnotationsAreSame(baseOv);
                        ValidateMethodRequiresUnreferencedCodeAreSame(baseOv);
                    }
                }

                var overrides = annotations.GetOverrides(method);
                if (overrides != null)
                {
                    foreach (var overrideInformation in overrides)
                    {
                        // Skip validation for cases where both base and override are in the list, we will validate the edge
                        // when validating the override from the list.
                        // This avoids validating the edge twice (it would produce the same warning twice)
                        if (annotations.VirtualMethodsWithAnnotationsToValidate.Contains(overrideInformation.Override))
                            continue;

                        annotations.FlowAnnotations.ValidateMethodAnnotationsAreSame(overrideInformation);
                        ValidateMethodRequiresUnreferencedCodeAreSame(overrideInformation);
                    }
                }
            }
        }

        void ValidateMethodRequiresUnreferencedCodeAreSame(OverrideInformation ov)
        {
            var method = ov.Override;
            var baseMethod = ov.Base;
            var annotations = Context.Annotations;
            bool methodSatisfies = annotations.IsInRequiresUnreferencedCodeScope(method, out _);
            bool baseRequires = annotations.DoesMethodRequireUnreferencedCode(baseMethod, out _);
            if ((baseRequires && !methodSatisfies) || (!baseRequires && annotations.DoesMethodRequireUnreferencedCode(method, out _)))
            {
                string message = MessageFormat.FormatRequiresAttributeMismatch(
                    methodSatisfies,
                    baseMethod.DeclaringType.IsInterface,
                    nameof(RequiresUnreferencedCodeAttribute),
                    method.GetDisplayName(),
                    baseMethod.GetDisplayName());
                IMemberDefinition origin = (ov.IsOverrideOfInterfaceMember && ov.InterfaceImplementor.Implementor != method.DeclaringType)
                    ? ov.InterfaceImplementor.Implementor
                    : method;
                Context.LogWarning(origin, DiagnosticId.RequiresUnreferencedCodeAttributeMismatch, message);
            }
        }
    }
}