// 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.Generic;
using System.Text;
using Microsoft.CodeAnalysis.EmbeddedLanguages.VirtualChars;
 
namespace Microsoft.CodeAnalysis.CSharp.EmbeddedLanguages.VirtualChars
{
    internal static class Extensions
    {
        public static bool TryGetEscapeCharacter(this VirtualChar ch, out char escapedChar)
            => TryGetEscapeCharacter(ch.Value, out escapedChar);
 
        public static bool TryGetEscapeCharacter(this Rune rune, out char escapedChar)
            => TryGetEscapeCharacter(rune.Value, out escapedChar);
 
        private static bool TryGetEscapeCharacter(int value, out char escapedChar)
        {
            // Keep in sync with CSharpVirtualCharService.TryAddSingleCharacterEscape
            switch (value)
            {
                // Note: we don't care about single quote as that doesn't need to be escaped when
                // producing a normal C# string literal.
 
                // case '\'':
 
                // escaped characters that translate to themselves.  
                case '"': escapedChar = '"'; return true;
                case '\\': escapedChar = '\\'; return true;
 
                // translate escapes as per C# spec 2.4.4.4
                case '\0': escapedChar = '0'; return true;
                case '\a': escapedChar = 'a'; return true;
                case '\b': escapedChar = 'b'; return true;
                case '\f': escapedChar = 'f'; return true;
                case '\n': escapedChar = 'n'; return true;
                case '\r': escapedChar = 'r'; return true;
                case '\t': escapedChar = 't'; return true;
                case '\v': escapedChar = 'v'; return true;
            }
 
            escapedChar = default;
            return false;
        }
    }
}