using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Collections.Generic;

try
{
	if (args.Length == 0 || args.Contains("-h") || args.Contains("--help"))
	{
		Console.WriteLine("Usage: MapShuffler <output.txt> <maps_directory>");
		return;
	}

	if (args.Length != 2)
	{
		Console.Error.WriteLine("Error: Expected exactly two arguments.");
		Console.WriteLine("Usage: MapShuffler <output.txt> <maps_directory>");
		Environment.ExitCode = 1;
		return;
	}

	var outputPath = args[0];
	var dirPath = args[1];

	if (!Directory.Exists(dirPath))
	{
		Console.Error.WriteLine($"Directory not found: {dirPath}");
		Environment.ExitCode = 2;
		return;
	}

	var bspFiles = Directory.EnumerateFiles(dirPath)
		.Where(f => string.Equals(Path.GetExtension(f), ".bsp", StringComparison.OrdinalIgnoreCase))
		.Select(f => Path.GetFileNameWithoutExtension(f))
		.ToList();

	Console.WriteLine($"Found {bspFiles.Count} .bsp file(s) in {dirPath}");

	if (bspFiles.Count == 0)
	{
		File.WriteAllText(outputPath, string.Empty, Encoding.UTF8);
		Console.WriteLine($"Wrote empty file to {outputPath}");
		Environment.ExitCode = 0;
		return;
	}

	var rnd = Random.Shared;
	for (int i = bspFiles.Count - 1; i > 0; i--)
	{
		int j = rnd.Next(i + 1);
		var tmp = bspFiles[i];
		bspFiles[i] = bspFiles[j];
		bspFiles[j] = tmp;
	}

	var parent = Path.GetDirectoryName(outputPath);
	if (!string.IsNullOrEmpty(parent) && !Directory.Exists(parent))
		Directory.CreateDirectory(parent);

	File.WriteAllLines(outputPath, bspFiles, Encoding.UTF8);
	Console.WriteLine($"Wrote {bspFiles.Count} entries to {outputPath}");
	Environment.ExitCode = 0;
}
catch (Exception ex)
{
	Console.Error.WriteLine($"Error: {ex.Message}");
	Environment.ExitCode = 99;
}