Begins implementing FS-7

should be good enough, but feedback would be lovely

src/main/java/me/totalfreedom/totalfreedommod/command/Command_coins.java

@@ -9,8 +9,11 @@ import org.bukkit.command.Command;
 import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
 
+import java.util.ArrayList;
+import java.util.List;
+
 @CommandPermissions(level = Rank.OP, source = SourceType.BOTH)
-@CommandParameters(description = "Shows the amount of coins you have or another player has", usage = "/<command> [playername]")
+@CommandParameters(description = "Shows the amount of coins you or another player has. ", usage = "/<command> [player] | pay <player> <amount>")
 public class Command_coins extends FreedomCommand
 {
     @Override
@@ -21,34 +24,119 @@ public class Command_coins extends FreedomCommand
             msg("The shop is currently disabled!", ChatColor.RED);
             return true;
         }
-        Player p;
+
         final String prefix = FUtil.colorize(ConfigEntry.SHOP_PREFIX.getString() + " ");
-        if (args.length > 0)
+
+        switch (args.length)
         {
-            if (getPlayer(args[0]) != null)
+            // Mode for seeing how many coins the sender has (doesn't work from console)
-            {
+            case 0:
-                p = getPlayer(args[0]);
-            }
-            else
-            {
-                msg(PLAYER_NOT_FOUND);
-                return true;
-            }
-        }
-        else
             {
                 if (senderIsConsole)
                 {
-                msg(prefix + ChatColor.RED + "You are not a player, use /coins <playername>");
+                    msg("When used from the console, you must define a target player.");
-                return true;
                 }
                 else
                 {
-                p = playerSender;
+                    PlayerData playerData = getData(playerSender);
+                    msg(prefix + ChatColor.GREEN + "You have " + ChatColor.RED + playerData.getCoins() + ChatColor.GREEN
+                            + " coins.");
                 }
-        }
-        PlayerData playerData = plugin.pl.getData(p);
-        msg(prefix + ChatColor.GREEN + (args.length > 0 ? p.getName() + " has " : "You have ") + ChatColor.RED + playerData.getCoins() + ChatColor.GREEN + " coins.");
                 return true;
             }
+
+            // Mode for seeing how many coins a player has.
+            case 1:
+            {
+                Player target = getPlayer(args[0]);
+
+                if (target == null)
+                {
+                    msg(PLAYER_NOT_FOUND);
+                }
+                else
+                {
+                    PlayerData playerData = getData(target);
+                    msg(prefix + ChatColor.GREEN + target.getName() + " has " + ChatColor.RED + playerData.getCoins() + ChatColor.GREEN + " coins.");
+                }
+                return true;
+            }
+
+            // Mode for paying another player coins
+            case 3:
+            {
+                if (args[0].equalsIgnoreCase("pay"))
+                {
+                    checkPlayer();
+
+                    final Player target = getPlayer(args[1]);
+                    final PlayerData senderData = getData(playerSender);
+
+                    int coinsToTransfer;
+
+                    // Processes args[2]
+                    try
+                    {
+                        // Prevents players from trying to be cheeky with negative numbers.
+                        coinsToTransfer = Math.max(Math.abs(Integer.parseInt(args[2])), 1);
+                    }
+                    catch (NumberFormatException ex)
+                    {
+                        msg("Invalid number: " + args[2], ChatColor.RED);
+                        return true;
+                    }
+
+                    // Prevents players from performing transactions they can't afford to do.
+                    if (senderData.getCoins() < coinsToTransfer)
+                    {
+                        msg("You don't have enough coins to perform this transaction.", ChatColor.RED);
+                        return true;
+                    }
+
+                    if (target == null)
+                    {
+                        msg(PLAYER_NOT_FOUND);
+                    }
+                    else
+                    {
+                        PlayerData playerData = getData(target);
+                        playerData.setCoins(playerData.getCoins() + coinsToTransfer);
+                        senderData.setCoins(senderData.getCoins() - coinsToTransfer);
+
+                        msg(target, sender.getName()
+                                + ChatColor.GREEN + " has given you "
+                                + ChatColor.GOLD + coinsToTransfer
+                                + ChatColor.GREEN + " coin" + (coinsToTransfer > 1 ? "s" : "") + "!", ChatColor.GOLD);
+
+                        msg("You have given "
+                                + ChatColor.GOLD + coinsToTransfer
+                                + ChatColor.GREEN + " coin" + (coinsToTransfer > 1 ? "s" : "")
+                                + " to " + ChatColor.GOLD + target.getName() + ChatColor.GREEN + ".", ChatColor.GREEN);
+                    }
+
+                    return true;
+                }
+            }
+
+            default:
+            {
+                return false;
+            }
+        }
+    }
+
+    @Override
+    public List<String> getTabCompleteOptions(CommandSender sender, Command command, String alias, String[] args)
+    {
+        if (args.length == 1)
+        {
+            List<String> options = new ArrayList<>(FUtil.getPlayerList());
+
+            options.add("pay");
+
+            return options;
+        }
+
+        return FUtil.getPlayerList();
+    }
 }