// 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;
using System.Diagnostics.CodeAnalysis;

using Microsoft.VisualStudio.TestPlatform.ObjectModel;
using Microsoft.VisualStudio.TestPlatform.ObjectModel.Logging;
using Microsoft.VisualStudio.TestPlatform.Utilities;

using ObjectModelCommonResources = Microsoft.VisualStudio.TestPlatform.ObjectModel.Resources.CommonResources;

namespace Microsoft.VisualStudio.TestPlatform.Common.Logging;

/// <summary>
/// The test session message logger.
/// </summary>
internal class TestSessionMessageLogger : IMessageLogger
{
    private static TestSessionMessageLogger? s_instance;

    /// <summary>
    /// Initializes a new instance of the <see cref="TestSessionMessageLogger"/> class.
    /// </summary>
    protected TestSessionMessageLogger()
    {
        TreatTestAdapterErrorsAsWarnings = Constants.DefaultTreatTestAdapterErrorsAsWarnings;
    }

    /// <summary>
    /// Raised when a discovery message is received.
    /// </summary>
    internal event EventHandler<TestRunMessageEventArgs>? TestRunMessage;

    /// <summary>
    /// Gets the instance of the singleton.
    /// </summary>
    [AllowNull]
    public static TestSessionMessageLogger Instance
    {
        get
        {
            return s_instance ??= new TestSessionMessageLogger();
        }
        set
        {
            s_instance = value;
        }
    }

    /// <summary>
    /// Gets or sets a value indicating whether to treat test adapter errors as warnings.
    /// </summary>
    internal bool TreatTestAdapterErrorsAsWarnings
    {
        get;
        set;
    }

    /// <summary>
    /// Sends a message to all listeners.
    /// </summary>
    /// <param name="testMessageLevel">Level of the message.</param>
    /// <param name="message">The message to be sent.</param>
    public void SendMessage(TestMessageLevel testMessageLevel, string message)
    {
        if (message.IsNullOrWhiteSpace())
        {
            throw new ArgumentException(ObjectModelCommonResources.CannotBeNullOrEmpty, nameof(message));
        }

        if (TreatTestAdapterErrorsAsWarnings
            && testMessageLevel == TestMessageLevel.Error)
        {
            // Downgrade the message severity to Warning...
            testMessageLevel = TestMessageLevel.Warning;
        }

        if (TestRunMessage != null)
        {
            var args = new TestRunMessageEventArgs(testMessageLevel, message);
            TestRunMessage.SafeInvoke(this, args, "TestRunMessageLoggerProxy.SendMessage");
        }
    }
}