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

namespace ClassicalSharp.Commands {
	
	public class CommandManager {
		
		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() );
		}
		
		public void Register( Command command ) {
			command.game = game;
			foreach( Command cmd in RegisteredCommands ) {
				if( Utils.CaselessEquals( cmd.Name, command.Name ) ) {
					throw new InvalidOperationException( "Another command already has name : " + command.Name );
				}
			}
			RegisteredCommands.Add( command );
		}
		
		public Command GetMatchingCommand( string commandName ) {
			bool matchFound = false;
			Command matchingCommand = null;
			foreach( Command cmd in RegisteredCommands ) {
				if( Utils.CaselessStarts( cmd.Name, commandName ) ) {
					if( matchFound ) {
						game.Chat.Add( "&e/client: Multiple commands found that start with: \"&f" + commandName + "&e\"." );
						return null;
					}
					matchFound = true;
					matchingCommand = cmd;
				}
			}
			
			if( matchingCommand == null ) {
				game.Chat.Add( "&e/client: Unrecognised command: \"&f" + commandName + "&e\"." );
			}
			return matchingCommand;
		}
		
		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 = GetMatchingCommand( commandName );
			if( cmd != null ) {
				cmd.Execute( reader );
			}
		}
		
		public void PrintDefinedCommands( Game game ) {
			List<string> lines = new List<string>();
			StringBuilder buffer = new StringBuilder( 64 );
			foreach( Command cmd in game.CommandManager.RegisteredCommands ) {
				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() );
			foreach( string part in lines ) {
				game.Chat.Add( part );
			}
		}
	}
}