// 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.Composition;
using System.Linq;
using Microsoft.CodeAnalysis.CodeFixes;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.UseCompoundAssignment;
 
namespace Microsoft.CodeAnalysis.CSharp.UseCompoundAssignment;
 
[ExportCodeFixProvider(LanguageNames.CSharp, Name = PredefinedCodeFixProviderNames.UseCompoundAssignment), Shared]
[method: ImportingConstructor]
[method: Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
internal sealed class CSharpUseCompoundAssignmentCodeFixProvider()
    : AbstractUseCompoundAssignmentCodeFixProvider<SyntaxKind, AssignmentExpressionSyntax, ExpressionSyntax>(Utilities.Kinds)
{
    protected override SyntaxToken Token(SyntaxKind kind)
        => SyntaxFactory.Token(kind);
 
    protected override AssignmentExpressionSyntax Assignment(
        SyntaxKind assignmentOpKind, ExpressionSyntax left, SyntaxToken syntaxToken, ExpressionSyntax right)
    {
        return SyntaxFactory.AssignmentExpression(assignmentOpKind, left, syntaxToken, right);
    }
 
    protected override ExpressionSyntax Increment(ExpressionSyntax left, bool postfix)
        => postfix
            ? Postfix(SyntaxKind.PostIncrementExpression, left)
            : Prefix(SyntaxKind.PreIncrementExpression, left);
 
    protected override ExpressionSyntax Decrement(ExpressionSyntax left, bool postfix)
        => postfix
            ? Postfix(SyntaxKind.PostDecrementExpression, left)
            : Prefix(SyntaxKind.PreDecrementExpression, left);
 
    private static ExpressionSyntax Postfix(SyntaxKind kind, ExpressionSyntax operand)
        => SyntaxFactory.PostfixUnaryExpression(kind, operand);
 
    private static ExpressionSyntax Prefix(SyntaxKind kind, ExpressionSyntax operand)
        => SyntaxFactory.PrefixUnaryExpression(kind, operand);
 
    protected override SyntaxTriviaList PrepareRightExpressionLeadingTrivia(SyntaxTriviaList initialTrivia) => initialTrivia.SkipWhile(el => el.Kind() is SyntaxKind.WhitespaceTrivia or SyntaxKind.EndOfLineTrivia).ToSyntaxTriviaList();
 
    protected override bool PreferPostfix(ISyntaxFactsService syntaxFacts, AssignmentExpressionSyntax currentAssignment)
    {
        // in `for (...; x = x + 1)` we prefer to translate that idiomatically as `for (...; x++)`
        if (currentAssignment.Parent is ForStatementSyntax forStatement &&
            forStatement.Incrementors.Contains(currentAssignment))
        {
            return true;
        }
 
        return base.PreferPostfix(syntaxFacts, currentAssignment);
    }
}