using System;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;

namespace MergeLUA
{
    class Program
    {
        static Regex requireRegex = new Regex(@"local\s+(?<fieldName>\S+)\s*=\s*require\s+""(?<path>[^""]+)""");
        static bool needsSave = false;

        static void Main(string[] args)
        {
            var files = Directory.GetFiles(Directory.GetCurrentDirectory(), "*.lua", SearchOption.AllDirectories);

            foreach (var file in files)
            {
                needsSave = false;
                try
                {

                    Console.WriteLine("processing {0}", file);
                    var patched = LoadContent(file);

                    if (needsSave)
                    {

                        var combinedFile =  Path.GetFullPath("output/" + Path.GetFileNameWithoutExtension(file) + ".lua");
                        Console.WriteLine("combining to {0}", combinedFile);
                        File.WriteAllText(combinedFile, patched, Encoding.UTF8);
                        Console.WriteLine("combined");
                    }
                    else
                    {
                        Console.WriteLine("nothing to do");
                    }
                }
                catch
                {
                    Console.WriteLine("failed");
                }
            }
        }

        private static string LoadContent(string path)
        {
            var content = File.ReadAllText(path);
            MatchEvaluator replacer = match => Replace(match, path);
            return requireRegex.Replace(content, replacer);

        }

        private static string Replace(Match match, string path)
        {
            needsSave = true;
            var targetPath = match.Result("${path}");
            Console.WriteLine("  found {0}", targetPath);
            if (targetPath.StartsWith(".")) // enabled relative requires
            {
                targetPath = Path.Combine(Path.GetDirectoryName(path), targetPath);
            }
            targetPath = Path.GetFullPath(targetPath);
            Console.WriteLine("  resolving to {0}", targetPath);

            return match.Result(
                "local ${fieldName} = (function()" + Environment.NewLine +
                "-- inlined " + match.Result("${path}") + Environment.NewLine +
                LoadContent(targetPath + ".lua") + Environment.NewLine +
                "end)()");

        }
    }
}