Cleans up sign code quite a lot #14

src/main/java/net/knarcraft/bookswithoutborders/command/CommandAddTitlePage.java

@@ -34,7 +34,7 @@ public class CommandAddTitlePage implements TabExecutor {
             return true;
         }
 
-        // Note: There are two different book checks as an book is accepted normally, but a written book is required for
+        // Note: There are two different book checks as a book is accepted normally, but a written book is required for
         // adding an author title page at the beginning. 
         ItemStack heldBook = InventoryUtil.getHeldBook(player);
         if (heldBook == null) {

src/main/java/net/knarcraft/bookswithoutborders/command/CommandDelete.java

@@ -32,7 +32,8 @@ public class CommandDelete implements TabExecutor {
             return true;
         }
 
-        return deleteBook(sender, arguments, false, label);
+        deleteBook(sender, arguments, false, label);
+        return true;
     }
 
     /**
@@ -42,25 +43,23 @@ public class CommandDelete implements TabExecutor {
      * @param arguments    <p>The arguments given</p>
      * @param deletePublic <p>Whether to delete a public book</p>
      * @param commandName  <p>The name of the command calling this method</p>
-     * @return <p>True if the book was deleted successfully</p>
      */
-    protected boolean deleteBook(@NotNull CommandSender sender, @NotNull String[] arguments, boolean deletePublic,
+    protected void deleteBook(@NotNull CommandSender sender, @NotNull String[] arguments, boolean deletePublic,
-                                 @NotNull String commandName) {
+                              @NotNull String commandName) {
         if (PagedBookIndex.displayPage(arguments, sender, deletePublic, commandName)) {
-            return true;
+            return;
         }
 
         //Delete the file
         List<String> availableBooks = BooksWithoutBorders.getAvailableBooks(sender, deletePublic);
         if (availableBooks.isEmpty()) {
             new FormatBuilder(Translatable.ERROR_DELETE_EMPTY).error(sender);
-            return true;
+            return;
         }
 
         performBookDeletion(sender, InputParsingUtil.mergeArguments(arguments, 0), deletePublic);
         //Update the book list
         BooksWithoutBorders.updateBooks(sender, deletePublic);
-        return true;
     }
 
     /**

src/main/java/net/knarcraft/bookswithoutborders/command/CommandDeletePublic.java

@@ -15,7 +15,8 @@ public class CommandDeletePublic extends CommandDelete implements TabExecutor {
     @Override
     public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
                              @NotNull String[] arguments) {
-        return deleteBook(sender, arguments, true, label);
+        deleteBook(sender, arguments, true, label);
+        return true;
     }
 
     @Override

src/main/java/net/knarcraft/bookswithoutborders/command/CommandEncrypt.java

@@ -22,6 +22,7 @@ import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 
 /**
  * Command executor for the encrypt command
@@ -36,7 +37,8 @@ public class CommandEncrypt implements TabExecutor {
             return false;
         }
 
-        EncryptionStyle encryptionStyle = arguments.length == 2 ? EncryptionStyle.getFromString(arguments[1]) : EncryptionStyle.AES;
+        EncryptionStyle encryptionStyle = arguments.length == 2 ? Objects.requireNonNullElse(
+                EncryptionStyle.getFromString(arguments[1]), EncryptionStyle.AES) : EncryptionStyle.AES;
 
         // AES is the only reliable method for retaining the plaintext
         BwBConfig config = BooksWithoutBorders.getConfiguration();

src/main/java/net/knarcraft/bookswithoutborders/command/CommandGroupEncrypt.java

@@ -11,6 +11,7 @@ import org.bukkit.inventory.meta.BookMeta;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.List;
+import java.util.Objects;
 
 /**
  * Command executor for the group encrypt command
@@ -39,7 +40,8 @@ public class CommandGroupEncrypt extends CommandEncrypt implements TabExecutor {
             return true;
         }
 
-        EncryptionStyle encryptionStyle = arguments.length == 3 ? EncryptionStyle.getFromString(arguments[2]) : EncryptionStyle.AES;
+        EncryptionStyle encryptionStyle = arguments.length == 3 ? Objects.requireNonNullElse(
+                EncryptionStyle.getFromString(arguments[2]), EncryptionStyle.AES) : EncryptionStyle.AES;
         return encryptBook(encryptionStyle, player, arguments[1], arguments[0], false);
     }
 

src/main/java/net/knarcraft/bookswithoutborders/command/CommandSave.java

@@ -36,7 +36,8 @@ public class CommandSave implements TabExecutor {
 
     @Override
     public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, String[] arguments) {
-        return saveHeldBook(sender, arguments, false, label);
+        saveHeldBook(sender, arguments, false, label);
+        return true;
     }
 
     /**
@@ -46,13 +47,12 @@ public class CommandSave implements TabExecutor {
      * @param arguments  <p>The arguments given</p>
      * @param savePublic <p>Whether to save the book in the public directory or the player directory</p>
      * @param command    <p>The command executed to trigger this method</p>
-     * @return <p>True if a book was saved successfully</p>
      */
-    protected boolean saveHeldBook(@NotNull CommandSender sender, @NotNull String[] arguments, boolean savePublic,
+    protected void saveHeldBook(@NotNull CommandSender sender, @NotNull String[] arguments, boolean savePublic,
-                                   @NotNull String command) {
+                                @NotNull String command) {
         if (!(sender instanceof Player player)) {
             new FormatBuilder(Translatable.ERROR_PLAYER_ONLY).error(sender);
-            return true;
+            return;
         }
 
         ItemStack heldBook = InventoryUtil.getHeldBook(player);
@@ -62,7 +62,6 @@ public class CommandSave implements TabExecutor {
         } else {
             new FormatBuilder(Translatable.ERROR_NOT_HOLDING_ANY_BOOK).error(sender);
         }
-        return true;
     }
 
     /**

src/main/java/net/knarcraft/bookswithoutborders/command/CommandSavePublic.java

@@ -13,7 +13,8 @@ public class CommandSavePublic extends CommandSave implements TabExecutor {
     @Override
     public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label,
                              @NotNull String[] arguments) {
-        return saveHeldBook(sender, arguments, true, label);
+        saveHeldBook(sender, arguments, true, label);
+        return true;
     }
 
 }

src/main/java/net/knarcraft/bookswithoutborders/command/CommandSetBookPrice.java

@@ -62,7 +62,8 @@ public class CommandSetBookPrice implements TabExecutor {
         if (arguments[0].equalsIgnoreCase("item")) {
             return setItemPrice(sender, price);
         } else if (arguments[0].equalsIgnoreCase(StaticMessage.COST_ECONOMY.toString())) {
-            return setEconomyPrice(sender, price);
+            setEconomyPrice(sender, price);
+            return true;
         } else {
             new FormatBuilder(CostMessage.ERROR_COST_INVALID_TYPE).error(sender);
             return false;
@@ -123,9 +124,8 @@ public class CommandSetBookPrice implements TabExecutor {
      *
      * @param sender <p>The sender of the command</p>
      * @param price  <p>The new price</p>
-     * @return <p>True if the price was changed successfully</p>
      */
-    private boolean setEconomyPrice(@NotNull CommandSender sender, double price) {
+    private void setEconomyPrice(@NotNull CommandSender sender, double price) {
         EconomyManager economyManager = BooksWithoutBorders.getConfiguration().getEconomyManager();
         if (economyManager.getEconomy() != null) {
             BwBConfig config = BooksWithoutBorders.getConfiguration();
@@ -141,7 +141,6 @@ public class CommandSetBookPrice implements TabExecutor {
         } else {
             new FormatBuilder(StaticMessage.EXCEPTION_VAULT_PRICE_NOT_CHANGED.toString()).error(sender);
         }
-        return true;
     }
 
     @Override

src/main/java/net/knarcraft/bookswithoutborders/config/StaticMessage.java

@@ -50,6 +50,7 @@ public enum StaticMessage {
     EXCEPTION_GET_HELD_BOOK_INVALID_MATERIAL("Invalid required material specified for method"),
     EXCEPTION_ITEM_SLOT_INVALID("Attempting to get item from an invalid item slot"),
 
+
     /**
      * The cost type used to specify economy
      */

src/main/java/net/knarcraft/bookswithoutborders/config/translation/Placeholder.java

@@ -17,8 +17,6 @@ public enum Placeholder implements TranslatableMessage {
     COST,
     TITLE,
     DISPLAY_NAME,
-    LINE,
-    PASSWORD,
     COMMAND,
     EXCEPTION,
     PATH,

src/main/java/net/knarcraft/bookswithoutborders/config/translation/SignText.java

@@ -28,21 +28,6 @@ public enum SignText implements TranslatableMessage {
      */
     SIGN_GIVE,
 
-    /**
-     * The format for displaying the password on the sign
-     */
-    SIGN_PASSWORD,
-
-    /**
-     * The format for marking a sign line as invalid
-     */
-    SIGN_INVALID,
-
-    /**
-     * The format for marking a sign line as valid
-     */
-    SIGN_VALID,
-
     /**
      * The error displayed when a player creates an invalid BwB sign
      */

src/main/java/net/knarcraft/bookswithoutborders/config/translation/Translatable.java

@@ -344,11 +344,6 @@ public enum Translatable implements TranslatableMessage {
      */
     ERROR_BOOK_NOT_FOUND,
 
-    /**
-     * The error displayed if attempting to list books while no books have been saved
-     */
-    ERROR_NO_BOOKS_TO_LIST,
-
     /**
      * The error displayed if attempting to decrypt a group encrypted book without the necessary permissions
      */
@@ -374,11 +369,6 @@ public enum Translatable implements TranslatableMessage {
      */
     ERROR_MIGRATION_BOOK_FAILED,
 
-    /**
-     * The error displayed when an unrecognized book directory is encountered
-     */
-    ERROR_BOOK_DIRECTORY_UNKNOWN,
-
     /**
      * The error displayed when unable to get blank book metadata from the item factory
      */

src/main/java/net/knarcraft/bookswithoutborders/encryption/EncryptionStyle.java

@@ -1,6 +1,7 @@
 package net.knarcraft.bookswithoutborders.encryption;
 
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 /**
  * This enum represents the different available encryption styles
@@ -65,14 +66,14 @@ public enum EncryptionStyle {
      * @param name <p>The name of the encryption style</p>
      * @return <p>An encryption style or null if no match is found</p>
      */
-    @NotNull
+    @Nullable
     public static EncryptionStyle getFromString(@NotNull String name) {
         for (EncryptionStyle style : EncryptionStyle.values()) {
             if (style.name.equalsIgnoreCase(name)) {
                 return style;
             }
         }
-        return AES;
+        return null;
     }
 
     @Override

src/main/java/net/knarcraft/bookswithoutborders/listener/SignEventListener.java

@@ -1,6 +1,5 @@
 package net.knarcraft.bookswithoutborders.listener;
 
-import net.knarcraft.bookswithoutborders.BooksWithoutBorders;
 import net.knarcraft.bookswithoutborders.config.Permission;
 import net.knarcraft.bookswithoutborders.config.translation.GiveMessage;
 import net.knarcraft.bookswithoutborders.config.translation.Placeholder;
@@ -13,7 +12,6 @@ import net.knarcraft.bookswithoutborders.state.SignType;
 import net.knarcraft.bookswithoutborders.utility.BookFileUtil;
 import net.knarcraft.bookswithoutborders.utility.BookLoaderUtil;
 import net.knarcraft.bookswithoutborders.utility.EncryptedBookUtil;
-import net.knarcraft.bookswithoutborders.utility.InputCleaningUtil;
 import net.knarcraft.knarlib.formatting.FormatBuilder;
 import net.md_5.bungee.api.ChatColor;
 import org.bukkit.Material;
@@ -34,13 +32,18 @@ import org.bukkit.inventory.PlayerInventory;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-import static net.knarcraft.bookswithoutborders.utility.BookFileUtil.isBookListIndex;
+import java.util.Objects;
 
 /**
  * A listener for relevant sign events such as clicking a decryption sign
  */
 public class SignEventListener implements Listener {
 
+    private final static ChatColor ERROR_COLOR = ChatColor.DARK_RED;
+    private final static ChatColor SUCCESS_COLOR = ChatColor.DARK_GREEN;
+    private final static ChatColor META_COLOR = ChatColor.DARK_BLUE;
+    private final static ChatColor PASSWORD_COLOR = ChatColor.MAGIC;
+
     @EventHandler
     public void onSignChange(@NotNull SignChangeEvent event) {
         if (event.isCancelled()) {
@@ -51,34 +54,19 @@ public class SignEventListener implements Listener {
         Player player = event.getPlayer();
 
         //Check if creating a Books Without Borders Sign and if the player has permission
-        if (SignType.fromString(lines[0]) != SignType.BOOKS_WITHOUT_BORDERS ||
+        if (getSignType(lines[0]) != SignType.BOOKS_WITHOUT_BORDERS ||
                 !player.hasPermission(Permission.SIGNS.toString())) {
             return;
         }
 
-        //Mark the sign as active
+        // Check and mark the sign
-        event.setLine(0, new FormatBuilder(SignText.SIGN_HEADER).color().toString());
+        if (isSignInvalid(lines, true)) {
-
-        //Check if the sign is of a valid type
-        SignType type = SignType.fromString(lines[1]);
-        if (type == null || lines[2].trim().isEmpty()) {
-            //Mark the second line as invalid
-            event.setLine(1, new FormatBuilder(SignText.SIGN_INVALID).replace(Placeholder.LINE, lines[1]).color().toString());
             new FormatBuilder(SignText.ERROR_SIGN_INVALID).error(player);
-            return;
         }
 
-        //Mark the second line as valid
+        // Update any changed lines
-        event.setLine(1, new FormatBuilder(SignText.SIGN_VALID).replace(Placeholder.LINE, lines[1]).color().toString());
+        for (int i = 0; i < lines.length; i++) {
-        lines = event.getLines();
+            event.setLine(i, lines[i]);
-
-        //Mark valid encryption/decryption sign
-        if (type == SignType.GIVE) {
-            //Generate book giving sign
-            generateGiveSign(event, lines, player);
-        } else {
-            event.setLine(2, new FormatBuilder(SignText.SIGN_PASSWORD).replace(Placeholder.PASSWORD, lines[2]).color().toString());
-            event.setLine(3, new FormatBuilder(SignText.SIGN_VALID).replace(Placeholder.LINE, lines[3]).color().toString());
         }
     }
 
@@ -102,6 +90,11 @@ public class SignEventListener implements Listener {
             return;
         }
 
+        // Return if not a valid sign
+        if (isSignInvalid(((Sign) event.getClickedBlock().getState()).getSide(Side.FRONT).getLines(), false)) {
+            return;
+        }
+
         //The player right-clicked a sign
         checkSign(event, (Sign) event.getClickedBlock().getState(), heldItemType, hand);
     }
@@ -117,22 +110,18 @@ public class SignEventListener implements Listener {
     private void checkSign(@NotNull PlayerInteractEvent event, @NotNull Sign sign, @NotNull Material heldItemType,
                            @NotNull EquipmentSlot hand) {
         Player player = event.getPlayer();
-        if (SignType.fromString(sign.getSide(Side.FRONT).getLine(0)) != SignType.BOOKS_WITHOUT_BORDERS) {
-            return;
-        }
-
         event.setUseItemInHand(Event.Result.DENY);
         event.setCancelled(true);
 
-        SignType signType = SignType.fromString(sign.getSide(Side.FRONT).getLine(1));
+        SignSide front = sign.getSide(Side.FRONT);
+        SignType signType = getSignType(front.getLine(1));
         if (signType == SignType.ENCRYPT) {
             encryptHeldBookUsingSign(sign, heldItemType, player, hand);
         } else if (signType == SignType.DECRYPT) {
             decryptHeldBookUsingSign(sign, heldItemType, player, hand);
-        } else if (signType == SignType.GIVE && getSignLine2Color(sign) == ChatColor.DARK_GREEN) {
+        } else if (signType == SignType.GIVE) {
             giveBook(sign, player);
         } else {
-            SignSide front = sign.getSide(Side.FRONT);
             new FormatBuilder(SignText.ERROR_SIGN_COMMAND_INVALID).replace(Placeholder.ACTION, front.getLine(1)).
                     replace(Placeholder.DATA, front.getLine(2)).error(player);
         }
@@ -156,12 +145,11 @@ public class SignEventListener implements Listener {
         player.closeInventory();
 
         //Converts user supplied key into integer form
-        String lineText = InputCleaningUtil.stripColor(sign.getSide(Side.FRONT).getLine(2));
+        String password = getPassword(sign.getSide(Side.FRONT).getLines());
 
-
+        ItemStack book = EncryptedBookUtil.loadEncryptedBook(player, password, false, false);
-        ItemStack book = EncryptedBookUtil.loadEncryptedBook(player, lineText, false, false);
         if (book == null) {
-            book = EncryptedBookUtil.loadEncryptedBookLegacy(player, lineText, false);
+            book = EncryptedBookUtil.loadEncryptedBookLegacy(player, password, false);
         }
 
         if (book != null) {
@@ -170,63 +158,6 @@ public class SignEventListener implements Listener {
         }
     }
 
-    /**
-     * Gets the color of a line on a sign
-     *
-     * @param sign <p>The sign to check</p>
-     * @return <p>The color of the sign</p>
-     */
-    @Nullable
-    private ChatColor getSignLine2Color(@NotNull Sign sign) {
-        String line = sign.getSide(Side.FRONT).getLine(2);
-        if (!InputCleaningUtil.stripColor(line).equals(line)) {
-            return ChatColor.getByChar(sign.getSide(Side.FRONT).getLine(2).substring(1, 2).charAt(0));
-        } else {
-            return null;
-        }
-    }
-
-    /**
-     * Changes an edited sign into a sign to give books
-     *
-     * @param event  <p>The event caused by changing the sign</p>
-     * @param lines  <p>The lines on the sign</p>
-     * @param player <p>The player which edited the sign</p>
-     */
-    private void generateGiveSign(@NotNull SignChangeEvent event, @NotNull String[] lines,
-                                  @NotNull Player player) {
-        //Tests if a full file name has been supplied and points to an actual file
-        String signFile = lines[2] + lines[3];
-        if (BookFileUtil.getFile(BookDirectory.PUBLIC, null, signFile) != null) {
-            markGiveSignValidity(event, true);
-            return;
-        } else {
-            if (isBookListIndex(lines[2])) {
-                BooksWithoutBorders.updateBooks(player, true);
-                markGiveSignValidity(event, true);
-                return;
-            }
-        }
-        markGiveSignValidity(event, false);
-    }
-
-    /**
-     * Marks a give sign as valid or invalid
-     *
-     * @param event   <p>The event causing the creation of the give sign</p>
-     * @param isValid <p>Whether the created sign is valid</p>
-     */
-    private void markGiveSignValidity(@NotNull SignChangeEvent event, boolean isValid) {
-        String[] lines = event.getLines();
-        if (isValid) {
-            event.setLine(2, ChatColor.DARK_GREEN + lines[2]);
-            event.setLine(3, ChatColor.DARK_GREEN + lines[3]);
-        } else {
-            event.setLine(2, ChatColor.DARK_RED + lines[2]);
-            event.setLine(3, ChatColor.DARK_RED + lines[3]);
-        }
-    }
-
     /**
      * Encrypts and replaces the player's used book
      *
@@ -237,15 +168,15 @@ public class SignEventListener implements Listener {
      */
     private void encryptHeldBookUsingSign(@NotNull Sign sign, @NotNull Material heldItemType, @NotNull Player player,
                                           @NotNull EquipmentSlot hand) {
-        ItemStack eBook;
         String[] lines = sign.getSide(Side.FRONT).getLines();
-        if (heldItemType == Material.WRITTEN_BOOK) {
+        if (heldItemType != Material.WRITTEN_BOOK) {
-            player.closeInventory();
+            return;
-            eBook = EncryptedBookUtil.encryptBook(player, ItemSlot.fromEquipmentSlot(hand), InputCleaningUtil.stripColor(lines[2]),
+        }
-                    EncryptionStyle.getFromString(InputCleaningUtil.stripColor(lines[3])), false);
+        player.closeInventory();
-            if (eBook != null) {
+        ItemStack eBook = EncryptedBookUtil.encryptBook(player, ItemSlot.fromEquipmentSlot(hand), getPassword(lines),
-                player.getInventory().setItem(hand, eBook);
+                getEncryptionStyle(lines), false);
-            }
+        if (eBook != null) {
+            player.getInventory().setItem(hand, eBook);
         }
     }
 
@@ -256,23 +187,12 @@ public class SignEventListener implements Listener {
      * @param player <p>The player which clicked the sign</p>
      */
     private void giveBook(@NotNull Sign sign, @NotNull Player player) {
-        String fileName = InputCleaningUtil.stripColor(sign.getSide(Side.FRONT).getLine(2));
+        String fileName = getBookName(sign.getSide(Side.FRONT).getLines());
-        boolean isLoadListNumber = false;
+        if (fileName.isBlank()) {
-
+            new FormatBuilder(GiveMessage.ERROR_GIVE_LOAD_FAILED).error(player);
-        try {
+            return;
-            Integer.parseInt(fileName);
-            isLoadListNumber = true;
-        } catch (NumberFormatException ignored) {
         }
-
-        //Add the third line to the second line for the full filename
-        String thirdLine = sign.getSide(Side.FRONT).getLine(3);
-        if (!isLoadListNumber && thirdLine.length() >= 2) {
-            fileName += InputCleaningUtil.stripColor(thirdLine);
-        }
-
         ItemStack newBook = BookLoaderUtil.loadBook(player, fileName, true, BookDirectory.PUBLIC, 1);
-
         if (newBook != null) {
             player.getInventory().addItem(newBook);
             new FormatBuilder(SignText.SUCCESS_SIGN_GIVE).success(player);
@@ -281,4 +201,185 @@ public class SignEventListener implements Listener {
         }
     }
 
+    /**
+     * Checks whether the given sign lines belong to a valid sign
+     *
+     * @param lines    <p>The lines to verify</p>
+     * @param markSign <p>Whether to mark the sign's validity after verifying</p>
+     * @return <p>True if the lines belong to a valid sign</p>
+     */
+    private boolean isSignInvalid(@NotNull String[] lines, boolean markSign) {
+        // Check and optionally mark the [BwB] header
+        if (getSignType(lines[0]) != SignType.BOOKS_WITHOUT_BORDERS) {
+            if (markSign) {
+                lines[0] = ERROR_COLOR + lines[0];
+            }
+            return true;
+        } else if (markSign) {
+            lines[0] = SUCCESS_COLOR + lines[0];
+        }
+
+        // Check and optionally mark the sign type
+        if (lines[1].startsWith(ERROR_COLOR.toString())) {
+            return true;
+        }
+        SignType type = getSignType(lines[1]);
+        if (type == null || type == SignType.BOOKS_WITHOUT_BORDERS) {
+            if (markSign) {
+                lines[1] = ERROR_COLOR + lines[1];
+            }
+            return true;
+        } else if (markSign) {
+            lines[1] = META_COLOR + lines[1];
+        }
+
+        // Check and optionally mark 
+        if (type == SignType.GIVE) {
+            return !isValidBook(lines, markSign);
+        } else if (type == SignType.DECRYPT || type == SignType.ENCRYPT) {
+            return !isValidPassword(lines, markSign);
+        }
+        throw new IllegalStateException();
+    }
+
+    /**
+     * Gets the sign type from the given sign line
+     *
+     * @param line <p>The line to get sign type from</p>
+     * @return <p>The sign type</p>
+     */
+    @Nullable
+    private SignType getSignType(@NotNull String line) {
+        return SignType.fromString(getCleanLine(line));
+    }
+
+    /**
+     * Gets a cleaned valid sign line
+     *
+     * @param line <p>The line to clean initial color code from</p>
+     * @return <p>The cleaned line</p>
+     */
+    @NotNull
+    private String getCleanLine(@NotNull String line) {
+        if (line.startsWith(META_COLOR.toString())) {
+            return line.replaceFirst(META_COLOR.toString(), "");
+        } else if (line.startsWith(SUCCESS_COLOR.toString())) {
+            return line.replaceFirst(SUCCESS_COLOR.toString(), "");
+        } else if (line.startsWith(PASSWORD_COLOR.toString())) {
+            return line.replaceFirst(PASSWORD_COLOR.toString(), "");
+        } else {
+            return line;
+        }
+    }
+
+    /**
+     * Checks whether the given sign lines specify a valid book
+     *
+     * @param lines    <p>The lines to check</p>
+     * @param markSign <p>Whether to mark the sign's validity after verifying</p>
+     * @return <p>True if the lines point to a valid book</p>
+     */
+    private boolean isValidBook(@NotNull String[] lines, boolean markSign) {
+        if (isInvalid(lines)) {
+            return false;
+        }
+        String bookName = getBookName(lines);
+        boolean isValid = BookFileUtil.getFile(BookDirectory.PUBLIC, null, bookName) != null ||
+                BookFileUtil.isBookListIndex(bookName);
+        if (markSign) {
+            if (isValid) {
+                markLine(lines, 2, SUCCESS_COLOR);
+                markLine(lines, 3, SUCCESS_COLOR);
+            } else {
+                markLine(lines, 2, ERROR_COLOR);
+                markLine(lines, 3, ERROR_COLOR);
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Checks whether the given sign lines specify a valid password
+     *
+     * @param lines    <p>The lines to check</p>
+     * @param markSign <p>Whether to mark the sign's validity after verifying</p>
+     * @return <p>True if the lines specify a valid password</p>
+     */
+    private boolean isValidPassword(@NotNull String[] lines, boolean markSign) {
+        if (isInvalid(lines)) {
+            return false;
+        }
+        boolean isValid = !getPassword(lines).isBlank() && (lines[3].isBlank() ||
+                EncryptionStyle.getFromString(getCleanLine(lines[3])) != null);
+        if (markSign) {
+            if (isValid) {
+                markLine(lines, 2, PASSWORD_COLOR);
+                markLine(lines, 3, META_COLOR);
+            } else {
+                markLine(lines, 2, ERROR_COLOR);
+                markLine(lines, 3, ERROR_COLOR);
+            }
+        }
+        return isValid;
+    }
+
+    /**
+     * Gets the encryption style specified on the given sign
+     *
+     * @param lines <p>The lines to parse</p>
+     * @return <p>The encryption style</p>
+     */
+    @NotNull
+    private EncryptionStyle getEncryptionStyle(@NotNull String[] lines) {
+        return Objects.requireNonNullElse(EncryptionStyle.getFromString(getCleanLine(lines[3])), EncryptionStyle.AES);
+    }
+
+    /**
+     * Gets the password specified on the given sign
+     *
+     * @param lines <p>The lines to parse</p>
+     * @return <p>The password</p>
+     */
+    private String getPassword(@NotNull String[] lines) {
+        return getCleanLine(lines[2]);
+    }
+
+    /**
+     * Gets the book name specified in the given lines
+     *
+     * @param lines <p>The lines to parse</p>
+     * @return <p>The name of the book</p>
+     */
+    @NotNull
+    private String getBookName(@NotNull String[] lines) {
+        String bookSpecifier = getCleanLine(lines[2]) + getCleanLine(lines[3]);
+        if (bookSpecifier.contains(":")) {
+            return bookSpecifier.split(":")[1];
+        } else {
+            return bookSpecifier;
+        }
+    }
+
+    /**
+     * Checks whether the specified sign lines are marked as invalid
+     *
+     * @param lines <p>The lines to check</p>
+     * @return <p>True if the lines belong to an invalid sign</p>
+     */
+    private boolean isInvalid(@NotNull String[] lines) {
+        return lines[2].startsWith(ERROR_COLOR.toString()) || lines[3].startsWith(ERROR_COLOR.toString()) ||
+                lines[2].isBlank();
+    }
+
+    /**
+     * Marks the specified line by prepending the specified chat color
+     *
+     * @param lines     <p>The lines to mark an index of</p>
+     * @param index     <p>The index to mark</p>
+     * @param chatColor <p>The color to mark with</p>
+     */
+    private void markLine(@NotNull String[] lines, int index, @NotNull ChatColor chatColor) {
+        lines[index] = chatColor + lines[index];
+    }
+
 }

src/main/java/net/knarcraft/bookswithoutborders/utility/BookFileReaderWriterUtil.java

@@ -20,6 +20,7 @@ import java.io.FileInputStream;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Objects;
 import java.util.logging.Level;
 
 /**
@@ -152,7 +153,8 @@ public final class BookFileReaderWriterUtil {
         if (encryptionStyleName == null) {
             return null;
         }
-        EncryptionStyle encryptionStyle = EncryptionStyle.getFromString(encryptionStyleName);
+        EncryptionStyle encryptionStyle = Objects.requireNonNullElse(EncryptionStyle.getFromString(encryptionStyleName),
+                EncryptionStyle.AES);
 
         AESConfiguration aesConfiguration = null;
         if (encryptionStyle == EncryptionStyle.AES) {

src/main/java/net/knarcraft/bookswithoutborders/utility/BookFileUtil.java

@@ -38,6 +38,9 @@ public final class BookFileUtil {
      * @return <p>True if the number is a book index</p>
      */
     public static boolean isBookListIndex(@NotNull String possibleIndex) {
+        if (possibleIndex.isBlank()) {
+            return false;
+        }
         File bookDirectory = new File(BooksWithoutBorders.getConfiguration().getBookFolder().replaceAll("[\\\\/]$", ""));
 
         try {

src/main/resources/strings.yml

@@ -104,13 +104,11 @@ en:
     An encrypted version of this book is already saved.
     Please decrypt your previously encrypted copy first.
   ERROR_BOOK_NOT_FOUND: "Could not find a book to replace!"
-  ERROR_NO_BOOKS_TO_LIST: "No books have been saved!"
   ERROR_GROUP_DECRYPT_NO_PERMISSION: "You are not allowed to decrypt that book"
   ERROR_GROUP_DECRYPT_NOT_FOUND: "Unable to find encrypted book"
   ERROR_GROUP_DECRYPT_LOAD_FAILED: "Unable to load the unencrypted book!"
   ERROR_MIGRATION_FAILED: "Failed to migrate all books"
   ERROR_MIGRATION_BOOK_FAILED: "Failed to migrate book: {file} Cause: {exception}"
-  ERROR_BOOK_DIRECTORY_UNKNOWN: "Unrecognized book directory!"
   ERROR_METADATA_CREATION_FAILED: "Unable to create blank book metadata!"
   ERROR_LOAD_BOOK_EMPTY: "File was blank!!"
   ERROR_AUTHOR_ONLY: "You must be the author of this book to use this command!"
@@ -173,16 +171,16 @@ en:
   # -----------------------------------------#
   NEUTRAL_UNKNOWN_AUTHOR: "Unknown"
   NEUTRAL_UNKNOWN_TITLE: "Untitled"
-  # ---------------------- #
+  # --------------------------- #
-  # Sign text and messages #
+  # Sign headers and specifiers #
-  # ---------------------- #
+  # --------------------------- #
-  SIGN_HEADER: "&2[BwB]"
+  SIGN_HEADER: "[BwB]"
   SIGN_ENCRYPT: "[Encrypt]"
   SIGN_DECRYPT: "[Decrypt]"
   SIGN_GIVE: "[Give]"
-  SIGN_PASSWORD: "&k{password}"
+  # -------------- #
-  SIGN_INVALID: "&4{line}"
+  # Sign responses #
-  SIGN_VALID: "&1{line}"
+  # -------------- #
   ERROR_SIGN_INVALID: "Invalid sign!"
   ERROR_SIGN_COMMAND_INVALID: "Sign command {action} {data} is invalid"
   SUCCESS_SIGN_GIVE: "Received book!"
@@ -202,8 +200,6 @@ en:
   COST: "{cost}"
   TITLE: "{title}"
   DISPLAY_NAME: "{displayName}"
-  LINE: "{line}"
-  PASSWORD: "{password}"
   COMMAND: "{command}"
   EXCEPTION: "{exception}"
   PATH: "{path}"