// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System.Collections.Generic;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using CommunityToolkit.Mvvm.SourceGenerators.Extensions;

namespace CommunityToolkit.Mvvm.SourceGenerators;

/// <inheritdoc cref="ObservableValidatorValidateAllPropertiesGenerator"/>
public sealed partial class ObservableValidatorValidateAllPropertiesGenerator
{
    /// <summary>
    /// An <see cref="ISyntaxContextReceiver"/> that selects candidate nodes to process.
    /// </summary>
    private sealed class SyntaxReceiver : ISyntaxContextReceiver
    {
        /// <summary>
        /// The list of info gathered during exploration.
        /// </summary>
        private readonly List<INamedTypeSymbol> gatheredInfo = new();

        /// <summary>
        /// Gets the collection of gathered info to process.
        /// </summary>
        public IReadOnlyCollection<INamedTypeSymbol> GatheredInfo => this.gatheredInfo;

        /// <inheritdoc/>
        public void OnVisitSyntaxNode(GeneratorSyntaxContext context)
        {
            if (context.Node is ClassDeclarationSyntax classDeclaration &&
                context.SemanticModel.GetDeclaredSymbol(classDeclaration) is INamedTypeSymbol { IsGenericType: false } classSymbol &&
                context.SemanticModel.Compilation.GetTypeByMetadataName("CommunityToolkit.Mvvm.ComponentModel.ObservableValidator") is INamedTypeSymbol validatorSymbol &&
                classSymbol.InheritsFrom(validatorSymbol))
            {
                this.gatheredInfo.Add(classSymbol);
            }
        }
    }
}