// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

using System.Collections.Generic;
using System.Text;

namespace Microsoft.VisualStudio.TestPlatform.Utilities;

public static class StringExtensions
{
    public static IEnumerable<string> Tokenize(this string? input, char separator, char escape)
    {
        if (input.IsNullOrEmpty())
            yield break;

        var buffer = new StringBuilder();
        var escaping = false;
        foreach (var c in input)
        {
            if (escaping)
            {
                buffer.Append(c);
                escaping = false;
            }
            else if (c == escape)
            {
                escaping = true;
            }
            else if (c == separator)
            {
                yield return buffer.Flush();
            }
            else
            {
                buffer.Append(c);
            }
        }
        if (buffer.Length > 0 || input[input.Length - 1] == separator)
            yield return buffer.Flush();
    }

    private static string Flush(this StringBuilder stringBuilder)
    {
        var result = stringBuilder.ToString();
        stringBuilder.Clear();
        return result;
    }
}