// 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.
 
#nullable disable
 
using System.Collections.Immutable;
using System.Linq;
using Microsoft.CodeAnalysis.Shared.Extensions;
 
namespace Microsoft.CodeAnalysis.Diagnostics.Analyzers.NamingStyles;
 
internal sealed class NamingStyleRules(ImmutableArray<NamingRule> namingRules)
{
    public ImmutableArray<NamingRule> NamingRules { get; } = namingRules;
 
    private readonly ImmutableArray<SymbolKind> _symbolKindsThatCanBeOverridden =
        [SymbolKind.Method, SymbolKind.Property, SymbolKind.Event];
 
    internal bool TryGetApplicableRule(ISymbol symbol, out NamingRule applicableRule)
    {
        if (NamingRules != null &&
            IsSymbolNameAnalyzable(symbol))
        {
            foreach (var namingRule in NamingRules)
            {
                if (namingRule.SymbolSpecification.AppliesTo(symbol))
                {
                    applicableRule = namingRule;
                    return true;
                }
            }
        }
 
        applicableRule = default;
        return false;
    }
 
    private bool IsSymbolNameAnalyzable(ISymbol symbol)
    {
        if (_symbolKindsThatCanBeOverridden.Contains(symbol.Kind) && DoesSymbolImplementAnotherSymbol(symbol))
        {
            return false;
        }
 
        if (symbol is IMethodSymbol method)
        {
            return method.MethodKind is MethodKind.Ordinary or
                   MethodKind.LocalFunction;
        }
 
        if (symbol is IPropertySymbol property)
        {
            return !property.IsIndexer;
        }
 
        return true;
    }
 
    private static bool DoesSymbolImplementAnotherSymbol(ISymbol symbol)
    {
        if (symbol.IsStatic)
        {
            return false;
        }
 
        var containingType = symbol.ContainingType;
        if (containingType.TypeKind is not TypeKind.Class and not TypeKind.Struct)
        {
            return false;
        }
 
        return symbol.IsOverride ||
            symbol.ExplicitInterfaceImplementations().Any() ||
            IsInterfaceImplementation(symbol);
    }
 
    /// <summary>
    /// This does not handle the case where a method in a base type implicitly implements an
    /// interface method on behalf of one of its derived types.
    /// </summary>
    private static bool IsInterfaceImplementation(ISymbol symbol)
    {
        if (symbol.DeclaredAccessibility != Accessibility.Public)
        {
            return false;
        }
 
        var containingType = symbol.ContainingType;
        var implementedInterfaces = containingType.AllInterfaces;
 
        foreach (var implementedInterface in implementedInterfaces)
        {
            var implementedInterfaceMembersWithSameName = implementedInterface.GetMembers(symbol.Name);
            foreach (var implementedInterfaceMember in implementedInterfaceMembersWithSameName)
            {
                if (symbol.Equals(containingType.FindImplementationForInterfaceMember(implementedInterfaceMember)))
                {
                    return true;
                }
            }
        }
 
        return false;
    }
}