// 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.Generic;
using Microsoft.CodeAnalysis.Host;
using Microsoft.CodeAnalysis.Text;

namespace Microsoft.CodeAnalysis.ExtractMethod;

internal enum TriviaLocation
{
    BeforeBeginningOfSpan = 0,
    AfterBeginningOfSpan,
    BeforeEndOfSpan,
    AfterEndOfSpan
}

internal struct PreviousNextTokenPair
{
    public SyntaxToken PreviousToken { get; set; }
    public SyntaxToken NextToken { get; set; }
}

internal struct LeadingTrailingTriviaPair
{
    public IEnumerable<SyntaxTrivia> LeadingTrivia { get; set; }
    public IEnumerable<SyntaxTrivia> TrailingTrivia { get; set; }
}

internal delegate SyntaxToken AnnotationResolver(SyntaxNode root, TriviaLocation location, SyntaxAnnotation annotation);
internal delegate IEnumerable<SyntaxTrivia> TriviaResolver(TriviaLocation location, PreviousNextTokenPair tokenPair, Dictionary<SyntaxToken, LeadingTrailingTriviaPair> triviaMap);

/// <summary>
/// contains information to restore trivia later on to the annotated tree
/// </summary>
internal interface ITriviaSavedResult
{
    /// <summary>
    /// root node of the annotated tree.
    /// </summary>
    SyntaxNode Root { get; }

    /// <summary>
    /// restore saved trivia to given tree
    /// </summary>
    /// <param name="root">root node to the annotated tree</param>
    /// <param name="annotationResolver">it provides a custom way of resolving annotations to retrieve right tokens to attach trivia</param>
    /// <param name="triviaResolver">it provides a custom way of creating trivia list between two tokens</param>
    /// <returns>root node to a trivia restored tree</returns>
    SyntaxNode RestoreTrivia(SyntaxNode root, AnnotationResolver annotationResolver = null, TriviaResolver triviaResolver = null);
}

/// <summary>
/// syntax trivia related services
/// </summary>
internal interface ISyntaxTriviaService : ILanguageService
{
    /// <summary>
    /// save trivia around span and let user restore trivia later
    /// </summary>
    /// <param name="root">root node of a tree</param>
    /// <param name="textSpan">selection whose trivia around its edges will be saved</param>
    /// <returns>object that holds onto enough information to restore trivia later</returns>
    ITriviaSavedResult SaveTriviaAroundSelection(SyntaxNode root, TextSpan textSpan);
}