using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace pyxis.gemini.Protocol
{
	public class Request
	{
		// 1024 meta
		// 2 status code
		// 1 separator space
		// 2 \r\n
		private const int MAX_REQUEST_LENGTH = 1024 + 2 + 1 + 2;

		public string Url { private set; get; }
		// TODO: Provide properties for fetching specific parts of the URL

		public void setUrl(string url)
		{
			this.Url = url;
		}

		public static int Parse(byte[] data, int length, out Request request)
		{
			int i;
			bool found_cr = false, found_lf = false;
			request = null;

			// Minimum request length would be 3 -- one byte url and \r\n. If it's less than that, just
			// bail now. This guards against any potential bug later when we start trying to trim the
			// crlf, etc.
			if (length < 3)
			{
				return 0;
			}

			for (i = 0; i < length; i++)
			{
				if (i >= MAX_REQUEST_LENGTH)
				{
					throw new Exception.ProtocolViolationException(String.Format("Request length exceeded maximum: %d", MAX_REQUEST_LENGTH));
				}

				if (data[i] == '\r')
				{
					found_cr = true;
				}
				else if (found_cr && data[i] == '\n')
				{
					found_lf = true;
					break;
				}
				else
				{
					found_cr = false;
					found_lf = false;
				}
			}

			if (!found_cr || !found_lf)
			{
				return 0;
			}

			request = new Request();
			request.setUrl(Encoding.UTF8.GetString(data, 0, i - 2 /* trim \r\n */));
			return i + 1;
		}

		public byte[] Serialize()
		{
			System.IO.MemoryStream ms = new System.IO.MemoryStream();
			System.IO.StreamWriter sw = new System.IO.StreamWriter(ms);

			// TODO: Validate URL

			sw.Write(this.Url);
			sw.Write("\r\n");
			sw.Close();

			return ms.ToArray();
		}
	}
}