using System;
using System.Text;
using System.Collections;
using Server.Accounting;
using Server.Network;

namespace Server.RemoteAdmin
{
	public class AdminNetwork
	{
		private const string ProtocolVersion = "2";

		private static ArrayList m_Auth = new ArrayList();
		private static bool m_NewLine = true;
		private static StringBuilder m_ConsoleData = new StringBuilder();

		private const string DateFormat = "MMMM dd hh:mm:ss.f tt";

		public static void Configure()
		{
			PacketHandlers.Register( 0xF1, 0, false, OnReceive );

#if !MONO
			Core.MultiConsoleOut.Add( new EventTextWriter( OnConsoleChar, OnConsoleLine, OnConsoleString ) );
#endif
			Timer.DelayCall( TimeSpan.FromMinutes( 2.5 ), TimeSpan.FromMinutes( 2.5 ), CleanUp );
		}

		public static void OnConsoleString( string str )
		{
			string outStr;
			if ( m_NewLine )
			{
				outStr = $"[{DateTime.UtcNow.ToString(DateFormat)}]: {str}";
				m_NewLine = false;
			}
			else
			{
				outStr = str;
			}

			m_ConsoleData.Append( outStr );
			RoughTrimConsoleData();

			SendToAll( outStr );
		}

		public static void OnConsoleChar( char ch )
		{
			if ( m_NewLine )
			{
				string outStr;
				outStr = $"[{DateTime.UtcNow.ToString(DateFormat)}]: {ch}";

				m_ConsoleData.Append( outStr );
				SendToAll( outStr );

				m_NewLine = false;
			}
			else
			{
				m_ConsoleData.Append( ch );
				SendToAll( ch );
			}

			RoughTrimConsoleData();
		}

		public static void OnConsoleLine( string line )
		{
			string outStr;
			if ( m_NewLine )
				outStr = $"[{DateTime.UtcNow.ToString(DateFormat)}]: {line}{Console.Out.NewLine}";
			else
				outStr = $"{line}{Console.Out.NewLine}";

			m_ConsoleData.Append( outStr );
			RoughTrimConsoleData();

			SendToAll( outStr );

			m_NewLine = true;
		}

		static void SendToAll( string outStr )
		{
			SendToAll( new ConsoleData( outStr ) );
		}

		static void SendToAll( char ch )
		{
			SendToAll( new ConsoleData( ch ) );
		}

		static void SendToAll( ConsoleData packet )
		{
			packet.Acquire();
			for ( int i = 0; i < m_Auth.Count; i++ )
				((NetState)m_Auth[i]).Send( packet );
			packet.Release();
		}

		static void RoughTrimConsoleData()
		{
			if ( m_ConsoleData.Length >= 4096 )
				m_ConsoleData.Remove( 0, 2048 );
		}

		static void TightTrimConsoleData()
		{
			if ( m_ConsoleData.Length > 1024 )
				m_ConsoleData.Remove( 0, m_ConsoleData.Length - 1024 );
		}

		public static void OnReceive( NetState state, PacketReader pvSrc )
		{
			byte cmd = pvSrc.ReadByte();
			if ( cmd == 0x02 )
			{
				Authenticate( state, pvSrc );
			}
			else if ( cmd == 0xFE )
			{
				state.Send( new CompactServerInfo() );
				state.Dispose();
			}
			else if ( cmd == 0xFF )
			{
				string statStr =
					$", Name={Misc.ServerList.ServerName}, Age={(int) (DateTime.UtcNow - Items.Clock.ServerStart).TotalHours}, Clients={NetState.Instances.Count}, Items={World.Items.Count}, Chars={World.Mobiles.Count}, Mem={(int) (GC.GetTotalMemory(false) / 1024)}K, Ver={ProtocolVersion}";
				state.Send( new UOGInfo( statStr ) );
				state.Dispose();
			}
			else if ( !IsAuth( state ) )
			{
				Console.WriteLine( "ADMIN: Unauthorized packet from {0}, disconnecting", state );
				Disconnect( state );
			}
			else
			{
				if ( !RemoteAdminHandlers.Handle( cmd, state, pvSrc ) )
					Disconnect( state );
			}
		}

		private static void DelayedDisconnect( NetState state )
		{
			Timer.DelayCall( TimeSpan.FromSeconds( 15.0 ), new TimerStateCallback( Disconnect ), state );
		}

		private static void Disconnect( object state )
		{
			m_Auth.Remove( state );
			((NetState)state).Dispose();
		}

		public static void Authenticate( NetState state, PacketReader pvSrc )
		{
			string user = pvSrc.ReadString( 30 );
			string pw = pvSrc.ReadString( 30 );

			if ( !(Accounts.GetAccount( user ) is Account a) )
			{
				state.Send( new Login( LoginResponse.NoUser ) );
				Console.WriteLine( "ADMIN: Invalid username '{0}' from {1}", user, state );
				DelayedDisconnect( state );
			}
			else if ( !a.HasAccess( state ) )
			{
				state.Send( new Login( LoginResponse.BadIP ) );
				Console.WriteLine( "ADMIN: Access to '{0}' from {1} denied.", user, state );
				DelayedDisconnect( state );
			}
			else if ( !a.CheckPassword( pw ) )
			{
				state.Send( new Login( LoginResponse.BadPass ) );
				Console.WriteLine( "ADMIN: Invalid password for user '{0}' from {1}", user, state );
				DelayedDisconnect( state );
			}
			else if ( a.AccessLevel < AccessLevel.Administrator || a.Banned )
			{
				Console.WriteLine( "ADMIN: Account '{0}' does not have admin access. Connection Denied.", user );
				state.Send( new Login( LoginResponse.NoAccess ) );
				DelayedDisconnect( state );
			}
			else
			{
				Console.WriteLine( "ADMIN: Access granted to '{0}' from {1}", user, state );
				state.Account = a;
				a.LogAccess( state );
				a.LastLogin = DateTime.UtcNow;

				state.Send( new Login( LoginResponse.OK ) );
				TightTrimConsoleData();
				state.Send( Compress( new ConsoleData( m_ConsoleData.ToString() ) ) );
				m_Auth.Add( state );
			}
		}

		public static bool IsAuth( NetState state )
		{
			return m_Auth.Contains( state );
		}

		private static void CleanUp()
		{//remove dead instances from m_Auth
			ArrayList list = new ArrayList();
			for (int i=0;i<m_Auth.Count;i++)
			{
				NetState ns = (NetState) m_Auth[i];
				if ( ns.Running )
					list.Add( ns );
			}

			m_Auth = list;
		}

		public static Packet Compress( Packet p )
		{
			int length;
			byte[] source = p.Compile( false, out length );

			if ( length > 100 && length < 60000 )
			{
				byte[] dest = new byte[(int)(length * 1.001) + 10];
				int destSize = dest.Length;

				ZLibError error = Compression.Pack( dest, ref destSize, source, length, ZLibQuality.Default );

				if ( error != ZLibError.Okay )
				{
					Console.WriteLine( "WARNING: Unable to compress admin packet, zlib error: {0}", error );
					return p;
				}

				return new AdminCompressedPacket( dest, destSize, length );
			}

			return p;
		}
	}

	public class EventTextWriter : System.IO.TextWriter
	{
		public delegate void OnConsoleChar( char ch );
		public delegate void OnConsoleLine( string line );
		public delegate void OnConsoleStr( string str );

		private OnConsoleChar m_OnChar;
		private OnConsoleLine m_OnLine;
		private OnConsoleStr m_OnStr;

		public EventTextWriter( OnConsoleChar onChar, OnConsoleLine onLine, OnConsoleStr onStr )
		{
			m_OnChar = onChar;
			m_OnLine = onLine;
			m_OnStr = onStr;
		}

		public override void Write( char ch )
		{
			m_OnChar?.Invoke( ch );
		}

		public override void Write( string str )
		{
			m_OnStr?.Invoke( str );
		}

		public override void WriteLine( string line )
		{
			m_OnLine?.Invoke( line );
		}

		public override Encoding Encoding => Encoding.ASCII;
	}
}