// 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.Xml.XPath;

namespace Microsoft.VisualStudio.TestPlatform.Utilities;

/// <summary>
/// Utility class for MaxCpuCount element of RunSetting
/// </summary>
public static class ParallelRunSettingsUtilities
{
    private static readonly string XpathOfRunSettings = @"/RunSettings";
    private static readonly string XpathOfRunConfiguration = @"/RunSettings/RunConfiguration";
    private static readonly string XpathOfMaxCpuCount = @"/RunSettings/RunConfiguration/MaxCpuCount";

    /// <summary>
    /// The MaxCpuCount setting template.
    /// </summary>
    private static readonly string MaxCpuCountSettingTemplate = @"<MaxCpuCount>0</MaxCpuCount>";

    /// <summary>
    /// The RunConfiguration with MaxCpuCount setting template.
    /// </summary>
    private static readonly string RunConfigurationWithMaxCpuCountSettingTemplate = @"<RunConfiguration>
                                                                                            <MaxCpuCount>0</MaxCpuCount>
                                                                                          </RunConfiguration>";

    /// <summary>
    /// This will update the RunSetting with MaxCpuCount 0 if RunSetting doesn't configured with this setting.
    /// </summary>
    /// <param name="navigator">XPATH navigator.</param>
    public static void UpdateRunSettingsWithParallelSettingIfNotConfigured(XPathNavigator navigator)
    {
        var node = navigator.SelectSingleNode(XpathOfMaxCpuCount);
        // run settings given by user takes precedence over parallel switch
        if (node != null)
        {
            return;
        }

        var runConfigurationNavigator = navigator.SelectSingleNode(XpathOfRunConfiguration);
        if (runConfigurationNavigator != null)
        {
            runConfigurationNavigator.AppendChild(MaxCpuCountSettingTemplate);
        }
        else
        {
            runConfigurationNavigator = navigator.SelectSingleNode(XpathOfRunSettings);
            runConfigurationNavigator?.AppendChild(RunConfigurationWithMaxCpuCountSettingTemplate);
        }
    }
}