// 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.Collections.Generic;
using System.IO;
using System.Xml;

using Microsoft.VisualStudio.TestPlatform.ObjectModel;
using Microsoft.VisualStudio.TestPlatform.Utilities.Helpers;
using Microsoft.VisualStudio.TestPlatform.Utilities.Helpers.Interfaces;

namespace Microsoft.TestPlatform.Extensions.BlameDataCollector;

/// <summary>
/// XmlReaderWriter class for reading and writing test sequences to file
/// </summary>
public class XmlReaderWriter : IBlameReaderWriter
{
    /// <summary>
    /// The file helper.
    /// </summary>
    private readonly IFileHelper _fileHelper;

    /// <summary>
    /// Initializes a new instance of the <see cref="XmlReaderWriter"/> class.
    /// </summary>
    internal XmlReaderWriter()
        : this(new FileHelper())
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="XmlReaderWriter"/> class.
    /// Protected for testing purposes
    /// </summary>
    /// <param name="fileHelper">
    /// The file helper.
    /// </param>
    protected XmlReaderWriter(IFileHelper fileHelper)
    {
        _fileHelper = fileHelper;
    }

    /// <summary>
    /// Writes test Sequence to file.
    /// Protected for testing purposes
    /// </summary>
    /// <param name="testSequence">
    /// Sequence of Guids
    /// </param>
    /// <param name="testObjectDictionary">
    /// Dictionary of test objects
    /// </param>
    /// <param name="filePath">
    /// The file Path.
    /// </param>
    /// <returns>File path</returns>
    public string WriteTestSequence(List<Guid> testSequence, Dictionary<Guid, BlameTestObject> testObjectDictionary, string filePath)
    {
        ValidateArg.NotNull(testSequence, nameof(testSequence));
        ValidateArg.NotNull(testObjectDictionary, nameof(testObjectDictionary));
        ValidateArg.NotNullOrEmpty(filePath, nameof(filePath));

        filePath += ".xml";

        // Writing test sequence
        var xmlDocument = new XmlDocument();
        var xmlDeclaration = xmlDocument.CreateNode(XmlNodeType.XmlDeclaration, string.Empty, string.Empty);
        var blameTestRoot = xmlDocument.CreateElement(Constants.BlameRootNode);
        xmlDocument.AppendChild(xmlDeclaration);

        foreach (var testGuid in testSequence)
        {
            if (testObjectDictionary.ContainsKey(testGuid))
            {
                var testObject = testObjectDictionary[testGuid];

                var testElement = xmlDocument.CreateElement(Constants.BlameTestNode);
                testElement.SetAttribute(Constants.TestNameAttribute, testObject.FullyQualifiedName);
                testElement.SetAttribute(Constants.TestDisplayNameAttribute, testObject.DisplayName);
                testElement.SetAttribute(Constants.TestSourceAttribute, testObject.Source);
                testElement.SetAttribute(Constants.TestCompletedAttribute, testObject.IsCompleted.ToString());

                blameTestRoot.AppendChild(testElement);
            }
        }

        xmlDocument.AppendChild(blameTestRoot);
        using (var stream = _fileHelper.GetStream(filePath, FileMode.Create))
        {
            xmlDocument.Save(stream);
        }

        return filePath;
    }

    /// <summary>
    /// Reads All test case from file
    /// </summary>
    /// <param name="filePath">The path of test sequence file</param>
    /// <returns>Test Case List</returns>
    public List<BlameTestObject> ReadTestSequence(string filePath)
    {
        ValidateArg.NotNull(filePath, nameof(filePath));

        if (!_fileHelper.Exists(filePath))
        {
            throw new FileNotFoundException();
        }

        var testCaseList = new List<BlameTestObject>();
        try
        {
            // Reading test sequence
            var xmlDocument = new XmlDocument();
            using (var stream = _fileHelper.GetStream(filePath, FileMode.Open))
            {
                xmlDocument.Load(stream);
            }

            var root = xmlDocument.LastChild;
            if (root == null)
            {
                return testCaseList;
            }

            foreach (XmlNode node in root)
            {
                if (node?.Attributes == null)
                {
                    continue;
                }

                var testCase = new BlameTestObject
                {
                    FullyQualifiedName =
                        node.Attributes[Constants.TestNameAttribute]?.Value,
                    Source = node.Attributes[Constants.TestSourceAttribute]?.Value,
                    DisplayName = node.Attributes[Constants.TestDisplayNameAttribute]?.Value,
                    IsCompleted = node.Attributes[Constants.TestCompletedAttribute]?.Value == "True"
                };
                testCaseList.Add(testCase);
            }
        }
        catch (XmlException xmlException)
        {
            EqtTrace.Warning("XmlReaderWriter : Exception ", xmlException);
        }

        return testCaseList;
    }
}