/***************************************************************************
 *                                Commands.cs
 *                            -------------------
 *   begin                : May 1, 2002
 *   copyright            : (C) The RunUO Software Team
 *   email                : info@runuo.com
 *
 *   $Id$
 *
 ***************************************************************************/

/***************************************************************************
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 ***************************************************************************/

using System;
using System.Collections.Generic;
using Server.Network;

namespace Server.Commands
{
	public delegate void CommandEventHandler( CommandEventArgs e );

	public class CommandEventArgs : EventArgs
	{
		public Mobile Mobile { get; }

		public string Command { get; }

		public string ArgString { get; }

		public string[] Arguments { get; }

		public int Length => Arguments.Length;

		public string GetString( int index )
		{
			if ( index < 0 || index >= Arguments.Length )
				return "";

			return Arguments[index];
		}

		public int GetInt32( int index )
		{
			if ( index < 0 || index >= Arguments.Length )
				return 0;

			return Utility.ToInt32( Arguments[index] );
		}

		public bool GetBoolean( int index )
		{
			if ( index < 0 || index >= Arguments.Length )
				return false;

			return Utility.ToBoolean( Arguments[index] );
		}

		public double GetDouble( int index )
		{
			if ( index < 0 || index >= Arguments.Length )
				return 0.0;

			return Utility.ToDouble( Arguments[index] );
		}

		public TimeSpan GetTimeSpan( int index )
		{
			if ( index < 0 || index >= Arguments.Length )
				return TimeSpan.Zero;

			return Utility.ToTimeSpan( Arguments[index] );
		}

		public CommandEventArgs( Mobile mobile, string command, string argString, string[] arguments )
		{
			Mobile = mobile;
			Command = command;
			ArgString = argString;
			Arguments = arguments;
		}
	}

	public class CommandEntry : IComparable
	{
		public string Command { get; }

		public CommandEventHandler Handler { get; }

		public AccessLevel AccessLevel { get; }

		public CommandEntry( string command, CommandEventHandler handler, AccessLevel accessLevel )
		{
			Command = command;
			Handler = handler;
			AccessLevel = accessLevel;
		}

		public int CompareTo( object obj )
		{
			if ( obj == this )
				return 0;
			if ( obj == null )
				return 1;

			if ( !(obj is CommandEntry e) )
				throw new ArgumentException();

			return Command.CompareTo( e.Command );
		}
	}

	public static class CommandSystem
	{
		public static string Prefix { get; set; } = "[";

		public static string[] Split( string value )
		{
			char[] array = value.ToCharArray();
			List<string> list = new List<string>();

			int start = 0;

			while ( start < array.Length )
			{
				char c = array[start];

				if ( c == '"' )
				{
					++start;
					int end = start;

					while ( end < array.Length )
					{
						if ( array[end] != '"' || array[end - 1] == '\\' )
							++end;
						else
							break;
					}

					list.Add( value.Substring( start, end - start ) );

					start = end + 2;
				}
				else if ( c != ' ' )
				{
					int end = start;

					while ( end < array.Length )
					{
						if ( array[end] != ' ' )
							++end;
						else
							break;
					}

					list.Add( value.Substring( start, end - start ) );

					start = end + 1;
				}
				else
				{
					++start;
				}
			}

			return list.ToArray();
		}

		public static Dictionary<string, CommandEntry> Entries { get; }

		static CommandSystem()
		{
			Entries = new Dictionary<string, CommandEntry>( StringComparer.OrdinalIgnoreCase );
		}

		public static void Register( string command, AccessLevel access, CommandEventHandler handler )
		{
			Entries[command] = new CommandEntry( command, handler, access );
		}

		public static AccessLevel BadCommandIgnoreLevel { get; set; } = AccessLevel.Player;

		public static bool Handle( Mobile from, string text )
		{
			return Handle( from, text, MessageType.Regular );
		}

		public static bool Handle( Mobile from, string text, MessageType type )
		{
			if ( text.StartsWith( Prefix ) || type == MessageType.Command )
			{
				if ( type != MessageType.Command )
					text = text.Substring( Prefix.Length );

				int indexOf = text.IndexOf( ' ' );

				string command;
				string[] args;
				string argString;

				if ( indexOf >= 0 )
				{
					argString = text.Substring( indexOf + 1 );

					command = text.Substring( 0, indexOf );
					args = Split( argString );
				}
				else
				{
					argString = "";
					command = text.ToLower();
					args = new string[0];
				}

				Entries.TryGetValue( command, out CommandEntry entry );

				if ( entry != null )
				{
					if ( from.AccessLevel >= entry.AccessLevel )
					{
						if ( entry.Handler != null )
						{
							CommandEventArgs e = new CommandEventArgs( from, command, argString, args );
							entry.Handler( e );
							EventSink.InvokeCommand( e );
						}
					}
					else
					{
						if ( from.AccessLevel <= BadCommandIgnoreLevel )
							return false;

						from.SendMessage( "You do not have access to that command." );
					}
				}
				else
				{
					if ( from.AccessLevel <= BadCommandIgnoreLevel )
						return false;

					from.SendMessage( "That is not a valid command." );
				}

				return true;
			}

			return false;
		}
	}
}