Fully implements the config command

src/main/java/net/knarcraft/stargate/command/CommandConfig.java

@@ -6,6 +6,7 @@ import org.bukkit.ChatColor;
 import org.bukkit.command.Command;
 import org.bukkit.command.CommandExecutor;
 import org.bukkit.command.CommandSender;
+import org.bukkit.configuration.file.FileConfiguration;
 import org.bukkit.entity.Player;
 import org.jetbrains.annotations.NotNull;
 
@@ -24,15 +25,98 @@ public class CommandConfig implements CommandExecutor {
             }
         }
 
+        if (args.length > 0) {
+            ConfigOption selectedOption = ConfigOption.getByName(args[0]);
+            if (selectedOption == null) {
+                return false;
+            }
             if (args.length > 1) {
-            //TODO: Do stuff
+                updateConfigValue(selectedOption, commandSender, args[1]);
             } else {
-            //TODO: Display list of config values
+                //Display info and the current value of the given config value
+                printConfigOptionValue(commandSender, selectedOption);
+            }
+            return true;
+        } else {
+            //Display all config options
             displayConfigValues(commandSender);
         }
         return true;
     }
 
+    /**
+     * Updates a config value
+     *
+     * @param selectedOption <p>The option which should be updated</p>
+     * @param commandSender  <p>The command sender that changed the value</p>
+     * @param value          <p>The new value of the config option</p>
+     */
+    private void updateConfigValue(ConfigOption selectedOption, CommandSender commandSender, String value) {
+        FileConfiguration configuration = Stargate.getInstance().getConfig();
+
+        //Validate any sign colors
+        if (selectedOption == ConfigOption.MAIN_SIGN_COLOR || selectedOption == ConfigOption.HIGHLIGHT_SIGN_COLOR) {
+            try {
+                ChatColor.valueOf(value.toUpperCase());
+            } catch (IllegalArgumentException | NullPointerException ignored) {
+                commandSender.sendMessage(ChatColor.RED + "Invalid color given");
+                return;
+            }
+        }
+
+        //Store the config values, accounting for the data type
+        switch (selectedOption.getDataType()) {
+            case BOOLEAN -> configuration.set(selectedOption.getConfigNode(), Boolean.parseBoolean(value));
+            case INTEGER -> {
+                try {
+                    configuration.set(selectedOption.getConfigNode(), Integer.parseInt(value));
+                } catch (NumberFormatException exception) {
+                    commandSender.sendMessage(ChatColor.RED + "Invalid number given");
+                    return;
+                }
+            }
+            case STRING -> {
+                if (selectedOption == ConfigOption.GATE_FOLDER || selectedOption == ConfigOption.PORTAL_FOLDER ||
+                        selectedOption == ConfigOption.DEFAULT_GATE_NETWORK) {
+                    if (value.contains("../") || value.contains("..\\")) {
+                        commandSender.sendMessage(ChatColor.RED + "Path traversal characters cannot be used");
+                        return;
+                    }
+                }
+                configuration.set(selectedOption.getConfigNode(), value);
+            }
+            default -> configuration.set(selectedOption.getConfigNode(), value);
+        }
+
+        //Save the config file and reload if necessary
+        Stargate.getInstance().saveConfig();
+        reloadIfNecessary(commandSender);
+    }
+
+    /**
+     * Reloads the config if necessary
+     *
+     * @param commandSender <p>The command sender initiating the reload</p>
+     */
+    private void reloadIfNecessary(CommandSender commandSender) {
+        //TODO: Only update the config values which have changed and do the least amount of work necessary to load the 
+        // changes. Only do a full reload if absolutely necessary, or when the partial reloading would be as 
+        // inefficient as a full reload.
+        Stargate.getStargateConfig().reload(commandSender);
+    }
+
+    /**
+     * Prints information about a config option and its current value
+     *
+     * @param sender <p>The command sender that sent the command</p>
+     * @param option <p>The config option to print information about</p>
+     */
+    private void printConfigOptionValue(CommandSender sender, ConfigOption option) {
+        Object value = Stargate.getStargateConfig().getConfigOptions().get(option);
+        sender.sendMessage(getOptionDescription(option));
+        sender.sendMessage(ChatColor.GREEN + "Current value: " + ChatColor.GOLD + value);
+    }
+
     /**
      * Displays the name and a small description of every config value
      *
@@ -42,9 +126,19 @@ public class CommandConfig implements CommandExecutor {
         sender.sendMessage(ChatColor.GREEN + Stargate.getBackupString("prefix") + ChatColor.GOLD +
                 "Config values:");
         for (ConfigOption option : ConfigOption.values()) {
-            sender.sendMessage(ChatColor.GOLD + option.getName() + ChatColor.WHITE + " - " + ChatColor.GREEN +
-                    option.getDescription() + " (" + option.getDefaultValue() + ")");
+            sender.sendMessage(getOptionDescription(option));
         }
     }
 
+    /**
+     * Gets the description of a single config option
+     *
+     * @param option <p>The option to describe</p>
+     * @return <p>A string describing the config option</p>
+     */
+    private String getOptionDescription(ConfigOption option) {
+        return ChatColor.GOLD + option.getName() + ChatColor.WHITE + " - " + ChatColor.GREEN + option.getDescription() +
+                ChatColor.DARK_GRAY + " (Default: " + ChatColor.GRAY + option.getDefaultValue() + ChatColor.DARK_GRAY + ")";
+    }
+
 }