package org.bukkit.command;

import org.bukkit.Bukkit;

import java.util.ArrayList;

public class FormattedCommandAlias extends Command
{
	private final String[] formatStrings;

	public FormattedCommandAlias(String alias, String[] formatStrings)
	{
		super(alias);
		this.formatStrings = formatStrings;
	}

	@Override
	public boolean execute(CommandSender sender, String commandLabel, String[] args)
	{
		boolean result = false;
		ArrayList<String> commands = new ArrayList<String>();
		for(String formatString : formatStrings)
		{
			try
			{
				commands.add(buildCommand(formatString, args));
			} catch(Throwable throwable)
			{
				if(throwable instanceof IllegalArgumentException)
				{
					sender.sendMessage(throwable.getMessage());
				}
				else
				{
					sender.sendMessage(org.bukkit.ChatColor.RED + "An internal error occurred while attempting to perform this command");
				}
				return false;
			}
		}

		for(String command : commands)
		{
			result |= Bukkit.dispatchCommand(sender, command);
		}

		return result;
	}

	private String buildCommand(String formatString, String[] args)
	{
		int index = formatString.indexOf("$");
		while(index != -1)
		{
			int start = index;

			if(index > 0 && formatString.charAt(start - 1) == '\\')
			{
				formatString = formatString.substring(0, start - 1) + formatString.substring(start);
				index = formatString.indexOf("$", index);
				continue;
			}

			boolean required = false;
			if(formatString.charAt(index + 1) == '$')
			{
				required = true;
				// Move index past the second $
				index++;
			}

			// Move index past the $
			index++;
			int argStart = index;
			while(index < formatString.length() && inRange(((int) formatString.charAt(index)) - 48, 0, 9))
			{
				// Move index past current digit
				index++;
			}

			// No numbers found
			if(argStart == index)
			{
				throw new IllegalArgumentException("Invalid replacement token");
			}

			int position = Integer.valueOf(formatString.substring(argStart, index));

			// Arguments are not 0 indexed
			if(position == 0)
			{
				throw new IllegalArgumentException("Invalid replacement token");
			}

			// Convert position to 0 index
			position--;

			boolean rest = false;
			if(index < formatString.length() && formatString.charAt(index) == '-')
			{
				rest = true;
				// Move index past the -
				index++;
			}

			int end = index;

			if(required && position >= args.length)
			{
				throw new IllegalArgumentException("Missing required argument " + (position + 1));
			}

			StringBuilder replacement = new StringBuilder();
			if(rest && position < args.length)
			{
				for(int i = position; i < args.length; i++)
				{
					if(i != position)
					{
						replacement.append(' ');
					}
					replacement.append(args[i]);
				}
			}
			else if(position < args.length)
			{
				replacement.append(args[position]);
			}

			formatString = formatString.substring(0, start) + replacement.toString() + formatString.substring(end);
			// Move index past the replaced data so we don't process it again
			index = start + replacement.length();

			// Move to the next replacement token
			index = formatString.indexOf("$", index);
		}

		return formatString;
	}

	private static boolean inRange(int i, int j, int k)
	{
		return i >= j && i <= k;
	}
}