// 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.

#nullable disable

using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

namespace Microsoft.CodeAnalysis.Editing;

/// <summary>
/// An editor for making changes to multiple documents in a solution.
/// </summary>
public class SolutionEditor(Solution solution)
{
    private readonly Dictionary<DocumentId, DocumentEditor> _documentEditors = [];

    /// <summary>
    /// The <see cref="Solution"/> that was specified when the <see cref="SolutionEditor"/> was constructed.
    /// </summary>
    public Solution OriginalSolution => solution;

    /// <summary>
    /// Gets the <see cref="DocumentEditor"/> for the corresponding <see cref="DocumentId"/>.
    /// </summary>
    public async Task<DocumentEditor> GetDocumentEditorAsync(DocumentId id, CancellationToken cancellationToken = default)
    {
        if (!_documentEditors.TryGetValue(id, out var editor))
        {
            editor = await DocumentEditor.CreateAsync(solution.GetDocument(id), cancellationToken).ConfigureAwait(false);
            _documentEditors.Add(id, editor);
        }

        return editor;
    }

    /// <summary>
    /// Returns the changed <see cref="Solution"/>.
    /// </summary>
    public Solution GetChangedSolution()
    {
        var changedSolution = solution;

        foreach (var docEd in _documentEditors.Values)
        {
            var currentDoc = changedSolution.GetDocument(docEd.OriginalDocument.Id);
            var newDoc = currentDoc.WithSyntaxRoot(docEd.GetChangedRoot());
            changedSolution = newDoc.Project.Solution;
        }

        return changedSolution;
    }
}