// ClassicalSharp copyright 2014-2016 UnknownShadow200 | Licensed under MIT
using System;
using System.Collections.Generic;
using System.Text;

namespace ClassicalSharp.Commands {
	
	public class CommandManager : IGameComponent {
		
		public static bool IsCommandPrefix( string input ) {
			return Utils.CaselessStarts( input, "/client " ) ||
				Utils.CaselessEquals( input, "/client" );
		}
		
		protected Game game;
		public List<Command> RegisteredCommands = new List<Command>();
		public void Init( Game game ) {
			this.game = game;
			Register( new CommandsCommand() );
			Register( new GpuInfoCommand() );
			Register( new HelpCommand() );
			Register( new InfoCommand() );
			Register( new RenderTypeCommand() );
			
			if( game.Network.IsSinglePlayer ) {
				Register( new ModelCommand() );
				Register( new CuboidCommand() );
			}
		}

		public void Ready( Game game ) { }
		public void Reset( Game game ) { }
		public void OnNewMap( Game game ) { }
		public void OnNewMapLoaded( Game game ) { }
		
		public void Register( Command command ) {
			command.game = game;
			for( int i = 0; i < RegisteredCommands.Count; i++ ) {
				Command cmd = RegisteredCommands[i];
				if( Utils.CaselessEquals( cmd.Name, command.Name ) )
					throw new InvalidOperationException( "Another command already has name : " + command.Name );
			}
			RegisteredCommands.Add( command );
		}
		
		public Command GetMatch( string commandName ) {
			Command match = null;
			for( int i = 0; i < RegisteredCommands.Count; i++ ) {
				Command cmd = RegisteredCommands[i];
				if( !Utils.CaselessStarts( cmd.Name, commandName ) ) continue;
				
				if( match != null ) {
					game.Chat.Add( "&e/client: Multiple commands found that start with: \"&f" + commandName + "&e\"." );
					return null;
				}
				match = cmd;
			}
			
			if( match == null )
				game.Chat.Add( "&e/client: Unrecognised command: \"&f" + commandName + "&e\"." );
			return match;
		}
		
		public void Execute( string text ) {
			CommandReader reader = new CommandReader( text );
			if( reader.TotalArgs == 0 ) {
				game.Chat.Add( "&eList of client commands:" );
				PrintDefinedCommands( game );
				game.Chat.Add( "&eTo see a particular command's help, type /client help [cmd name]" );
				return;
			}
			string commandName = reader.Next();
			Command cmd = GetMatch( commandName );
			if( cmd != null ) {
				cmd.Execute( reader );
			}
		}
		
		public void PrintDefinedCommands( Game game ) {
			List<string> lines = new List<string>();
			StringBuilder buffer = new StringBuilder( 64 );
			for( int i = 0; i < RegisteredCommands.Count; i++ ) {
				Command cmd = RegisteredCommands[i];
				string name = cmd.Name;
				
				if( buffer.Length + name.Length > 64 ) {
					lines.Add( buffer.ToString() );
					buffer.Length = 0;
				}
				buffer.Append( name );
				buffer.Append( ", " );
			}
			
			if( buffer.Length > 0 )
				lines.Add( buffer.ToString() );			
			for( int i = 0; i < lines.Count; i++ )
				game.Chat.Add( lines[i] );
		}
		
		public void Dispose() {
			RegisteredCommands.Clear();
		}
	}
}