using OSMDatastructure;

namespace OSMImporter
{
    public class RegionManager
    {
        private string workingDirectory { get; }
        private readonly Dictionary<ulong, Region> _regions = new();

        public RegionManager(string workingDirectory)
        {
            this.workingDirectory = workingDirectory;
        }

        public Region? GetRegion(Coordinates coordinates)
        {
            if(this._regions.ContainsKey(coordinates.GetRegionHash()))
                return this._regions[coordinates.GetRegionHash()];
            else
            {
                Region? loadedRegion = LoadRegion(coordinates);
                if(loadedRegion != null)
                    this._regions.Add(loadedRegion.regionHash, value: loadedRegion);
                return loadedRegion;
            }
        }

        public Region[] GetAllRegions()
        {
            return this._regions.Values.ToArray();
        }
        
        private Region? LoadRegion(Coordinates coordinates)
        {
            string fullPath = Path.Combine(workingDirectory, coordinates.GetRegionHash().ToString());
            Console.WriteLine(fullPath);
            if (!File.Exists(fullPath))
                return null;
            
            FileStream fileStream = new FileStream(fullPath, FileMode.Open);

            byte[] regionBytes = new byte[fileStream.Length];
            fileStream.Read(regionBytes, 0, regionBytes.Length);
            fileStream.Close();

            return ByteConverter.ToRegion(regionBytes);
        }
    }
}