// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

#nullable disable

using System.CommandLine.Completions;
using Microsoft.Build.Evaluation;
using Microsoft.DotNet.Cli.Utils;
using static System.Array;

namespace Microsoft.DotNet.Cli;

internal static class CliCompletion
{
    private static CompletionItem ToCompletionItem(string s) => new(s);

    public static IEnumerable<CompletionItem> TargetFrameworksFromProjectFile(CompletionContext _)
    {
        try
        {
            return GetMSBuildProject()?.GetTargetFrameworks().Select(tf => tf.GetShortFolderName()).Select(ToCompletionItem) ?? Empty<CompletionItem>();
        }
        catch (Exception)
        {
            return Empty<CompletionItem>();
        }
    }

    private static void Report(Exception e) =>
        Reporter.Verbose.WriteLine($"Exception occurred while getting completions: {e}");

    public static IEnumerable<CompletionItem> RuntimesFromProjectFile(CompletionContext _)
    {
        try
        {
            return GetMSBuildProject()?.GetRuntimeIdentifiers().Select(ToCompletionItem) ?? Empty<CompletionItem>();
        }
        catch (Exception)
        {
            return Empty<CompletionItem>();
        }
    }

    public static IEnumerable<CompletionItem> ProjectReferencesFromProjectFile(CompletionContext _)
    {
        try
        {
            return GetMSBuildProject()?.GetProjectToProjectReferences().Select(r => ToCompletionItem(r.Include)) ?? Empty<CompletionItem>();
        }
        catch (Exception)
        {
            return Empty<CompletionItem>();
        }
    }

    public static IEnumerable<CompletionItem> ConfigurationsFromProjectFileOrDefaults(CompletionContext _)
    {
        try
        {
            return (GetMSBuildProject()?.GetConfigurations() ?? ["Debug", "Release"]).Select(ToCompletionItem);
        }
        catch (Exception)
        {
            return Empty<CompletionItem>();
        }
    }

    private static MsbuildProject GetMSBuildProject()
    {
        try
        {
            return MsbuildProject.FromFileOrDirectory(
                new ProjectCollection(),
                Directory.GetCurrentDirectory(), interactive: false);
        }
        catch (Exception e)
        {
            Report(e);
            return null;
        }
    }
}