// 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;
using System.CommandLine.Completions;
using Microsoft.DotNet.Cli.Extensions;
using Microsoft.DotNet.Cli.Utils;
 
namespace Microsoft.DotNet.Cli.Commands.Hidden.Complete;
 
public class CompleteCommand
{
    public static int Run(ParseResult parseResult)
    {
        return RunWithReporter(parseResult, Reporter.Output);
    }
 
    public static int RunWithReporter(string[] args, IReporter reporter)
    {
        var result = Parser.Parse(["dotnet", "complete", ..args]);
        return RunWithReporter(result, reporter);
    }
 
    public static int RunWithReporter(ParseResult result, IReporter reporter)
    {
        if (reporter == null)
        {
            throw new ArgumentNullException(nameof(reporter));
        }
 
        try
        {
            result.HandleDebugSwitch();
 
            var completions = Completions(result);
 
            foreach (var completion in completions)
            {
                reporter.WriteLine(completion.Label);
            }
        }
        catch (Exception)
        {
            return 1;
        }
 
        return 0;
    }
 
    private static CompletionItem[] Completions(ParseResult complete)
    {
        var input = complete.GetValue(CompleteCommandParser.PathArgument) ?? string.Empty;
 
        var position = complete.GetValue(CompleteCommandParser.PositionOption);
 
        if (position > input.Length)
        {
            input += " ";
        }
 
        var result = Parser.Parse(input);
 
        return [.. result.GetCompletions(position).Distinct()];
    }
}