// 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 System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Classification;
using Microsoft.CodeAnalysis.Text;
 
namespace Microsoft.CodeAnalysis.ExternalAccess.FSharp.Classification;
 
internal interface IFSharpClassificationService
{
    /// <summary>
    /// Produce the classifications for the span of text specified.  Classification should be
    /// performed as quickly as possible, and should process the text in a lexical fashion.
    /// This allows classification results to be shown to the user when a file is opened before
    /// any additional compiler information is available for the text.
    /// 
    /// Important: The classification should not consider the context the text exists in, and how
    /// that may affect the final classifications.  This may result in incorrect classification
    /// (i.e. identifiers being classified as keywords).  These incorrect results will be patched
    /// up when the lexical results are superseded by the calls to AddSyntacticClassifications.
    /// </summary>
    void AddLexicalClassifications(SourceText text, TextSpan textSpan, List<ClassifiedSpan> result, CancellationToken cancellationToken);
 
    /// <summary>
    /// Produce the classifications for the span of text specified.  The syntax of the document 
    /// can be accessed to provide more correct classifications.  For example, the syntax can
    /// be used to determine if a piece of text that looks like a keyword should actually be
    /// considered an identifier in its current context.
    /// </summary>
    Task AddSyntacticClassificationsAsync(Document document, TextSpan textSpan, List<ClassifiedSpan> result, CancellationToken cancellationToken);
 
    /// <summary>
    /// Produce the classifications for the span of text specified.  Semantics of the language
    /// can be used to provide richer information for constructs where syntax is insufficient.
    /// For example, semantic information can be used to determine if an identifier should be
    /// classified as a type, structure, or something else entirely. 
    /// </summary>
    Task AddSemanticClassificationsAsync(Document document, TextSpan textSpan, List<ClassifiedSpan> result, CancellationToken cancellationToken);
 
    /// <summary>
    /// Adjust a classification from a previous version of text accordingly based on the current
    /// text.  For example, if a piece of text was classified as an identifier in a previous version,
    /// but a character was added that would make it into a keyword, then indicate that here.
    /// 
    /// This allows the classified to quickly fix up old classifications as the user types.  These
    /// adjustments are allowed to be incorrect as they will be superseded by calls to get the
    /// syntactic and semantic classifications for this version later.
    /// </summary>
    ClassifiedSpan AdjustStaleClassification(SourceText text, ClassifiedSpan classifiedSpan);
}