// 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;
using System.Collections.Immutable;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Formatting;
using Microsoft.CodeAnalysis.Host;

namespace Microsoft.CodeAnalysis.GenerateEqualsAndGetHashCodeFromMembers;

/// <summary>
/// Service that can be used to generate <see cref="object.Equals(object)"/> and
/// <see cref="object.GetHashCode"/> overloads for use from other IDE features.
/// </summary>
internal interface IGenerateEqualsAndGetHashCodeService : ILanguageService
{
    /// <summary>
    /// Formats only the members in the provided document that were generated by this interface.
    /// </summary>
    Task<Document> FormatDocumentAsync(Document document, SyntaxFormattingOptions options, CancellationToken cancellationToken);

    /// <summary>
    /// Generates an override of <see cref="object.Equals(object)"/> that works by comparing the
    /// provided <paramref name="members"/>.
    /// </summary>
    Task<IMethodSymbol> GenerateEqualsMethodAsync(Document document, INamedTypeSymbol namedType, ImmutableArray<ISymbol> members, string? localNameOpt, CancellationToken cancellationToken);

    /// <summary>
    /// Generates an override of <see cref="object.Equals(object)"/> that works by delegating to
    /// <see cref="IEquatable{T}.Equals(T)"/>.
    /// </summary>
    Task<IMethodSymbol> GenerateEqualsMethodThroughIEquatableEqualsAsync(Document document, INamedTypeSymbol namedType, CancellationToken cancellationToken);

    /// <summary>
    /// Generates an implementation of <see cref="IEquatable{T}.Equals"/> that works by
    /// comparing the provided <paramref name="members"/>.
    /// </summary>
    Task<IMethodSymbol> GenerateIEquatableEqualsMethodAsync(Document document, INamedTypeSymbol namedType, ImmutableArray<ISymbol> members, INamedTypeSymbol constructedEquatableType, CancellationToken cancellationToken);

    /// <summary>
    /// Generates an override of <see cref="object.GetHashCode"/> that computes a reasonable
    /// hash based on the provided <paramref name="members"/>.  The generated function will
    /// defer to HashCode.Combine if it exists.  Otherwise, it will determine if it should
    /// generate code directly in-line to compute the hash, or defer to something like
    /// <see cref="ValueTuple.GetHashCode"/> to provide a reasonable alternative.
    /// </summary>
    Task<IMethodSymbol> GenerateGetHashCodeMethodAsync(Document document, INamedTypeSymbol namedType, ImmutableArray<ISymbol> members, CancellationToken cancellationToken);
}