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

namespace PatchSwap
{
    class FileManager
    {
        private bool m_IsDownloadSuccessful;
        public bool IsDownloadSuccessful { get { return m_IsDownloadSuccessful; } set { m_IsDownloadSuccessful = value; } }

        private bool m_IsDownloading;
        public bool IsDownloading { get { return m_IsDownloading; } set { m_IsDownloading = value; } }

        public FileManager()
        {
        }

        public string GetFile( string to, string from, bool deleteOld )
        {
            Stream m_Stream = null;
            FileStream m_FileStream = null;

            try
            {
                m_IsDownloading = true;

                if( File.Exists( to ) && deleteOld )
                    File.Delete( to );
                
                if( !File.Exists( to ) )
                {
                    HttpWebRequest request = ( HttpWebRequest )WebRequest.Create( from );
                    HttpWebResponse response = ( HttpWebResponse )request.GetResponse();
                    m_Stream = response.GetResponseStream();

                    byte[] inBuffer = Read( m_Stream, 32768 );

                    m_FileStream = new FileStream( to, FileMode.OpenOrCreate, FileAccess.Write );
                    m_FileStream.Write( inBuffer, 0, inBuffer.Length - 1 );


                    m_FileStream.Close();
                    m_Stream.Close();
                }

                m_IsDownloadSuccessful = true;
                m_IsDownloading = false;
            }
            catch
            {
                m_IsDownloadSuccessful = false;
            }
            finally
            {
                if( m_FileStream != null )
                {
                    m_FileStream.Close();
                }

                if( m_Stream != null )
                {
                    m_Stream.Close();
                }
            }
            
            return to;
        }

        public byte[] Read( Stream stream, int initialLength )
        {
            if( initialLength < 1 )
            {
                initialLength = 32768;
            }

            byte[] buffer = new byte[initialLength];
            int read = 0;

            int chunk;

            while( ( chunk = stream.Read( buffer, read, buffer.Length - read ) ) > 0 )
            {
                read += chunk;

                if( read == buffer.Length )
                {
                    int nextByte = stream.ReadByte();

                    if( nextByte == -1 )
                    {
                        return buffer;
                    }

                    byte[] newBuffer = new byte[buffer.Length * 2];
                    Array.Copy( buffer, newBuffer, buffer.Length );
                    newBuffer[read] = ( byte )nextByte;
                    buffer = newBuffer;
                    read++;
                }
            }

            byte[] ret = new byte[read];
            Array.Copy( buffer, ret, read );
            return ret;
        }
    }
}