#930 Change captcha storage to change code internally upon failure

- Within CaptchaStorage#checkCode, a player's captcha code is overridden with a new one on failure or cleared on success
- Fixes inconsistencies in the retrieval / regeneration of codes

src/main/java/fr/xephi/authme/command/executable/captcha/CaptchaCommand.java

@@ -53,7 +53,7 @@ public class CaptchaCommand extends PlayerCommand {
             commonService.send(player, MessageKey.LOGIN_MESSAGE);
             limboService.unmuteMessageTask(player);
         } else {
-            String newCode = loginCaptchaManager.generateCode(player.getName());
+            String newCode = loginCaptchaManager.getCaptchaCodeOrGenerateNew(player.getName());
             commonService.send(player, MessageKey.CAPTCHA_WRONG_ERROR, newCode);
         }
     }
@@ -64,7 +64,7 @@ public class CaptchaCommand extends PlayerCommand {
             commonService.send(player, MessageKey.CAPTCHA_SUCCESS);
             commonService.send(player, MessageKey.REGISTER_MESSAGE);
         } else {
-            String newCode = registrationCaptchaManager.generateCode(player.getName());
+            String newCode = registrationCaptchaManager.getCaptchaCodeOrGenerateNew(player.getName());
             commonService.send(player, MessageKey.CAPTCHA_WRONG_ERROR, newCode);
         }
     }

src/main/java/fr/xephi/authme/data/captcha/CaptchaCodeStorage.java

@@ -61,7 +61,7 @@ public class CaptchaCodeStorage {
      * @param name the name of the player to generate a code for
      * @return the generated code
      */
-    public String generateCode(String name) {
+    private String generateCode(String name) {
         String code = RandomStringUtils.generate(captchaLength);
         captchaCodes.put(name.toLowerCase(), code);
         return code;
@@ -69,6 +69,7 @@ public class CaptchaCodeStorage {
 
     /**
      * Checks the given code against the existing one. Upon success, the saved captcha code is removed from storage.
+     * Upon failure, a new code is generated.
      *
      * @param name the name of the player to check
      * @param code the supplied code
@@ -80,6 +81,8 @@ public class CaptchaCodeStorage {
         if (savedCode != null && savedCode.equalsIgnoreCase(code)) {
             captchaCodes.remove(nameLowerCase);
             return true;
+        } else {
+            generateCode(name);
         }
         return false;
     }

src/main/java/fr/xephi/authme/data/captcha/CaptchaManager.java

@@ -24,16 +24,10 @@ public interface CaptchaManager {
     String getCaptchaCodeOrGenerateNew(String name);
 
     /**
-     * Generates a code for the player and returns it.
-     *
-     * @param name the name of the player to generate a code for
-     * @return the generated code
-     */
-    String generateCode(String name);
-
-    /**
-     * Checks the given code against the existing one. This method may perform additional state changes
-     * on success or failure, such as modifying some counter or setting a player as verified.
+     * Checks the given code against the existing one. This method is not reentrant, i.e. it performs additional
+     * state changes on success or failure, such as modifying some counter or setting a player as verified.
+     * <p>
+     * On success, the code associated with the player is cleared; on failure, a new code is generated.
      *
      * @param player the player to check
      * @param code the supplied code

src/main/java/fr/xephi/authme/data/captcha/LoginCaptchaManager.java

@@ -51,11 +51,6 @@ public class LoginCaptchaManager implements CaptchaManager, SettingsDependent, H
         return captchaCodeStorage.getCodeOrGenerateNew(name);
     }
 
-    @Override
-    public String generateCode(String name) {
-        return captchaCodeStorage.generateCode(name);
-    }
-
     @Override
     public boolean checkCode(Player player, String code) {
         String nameLower = player.getName().toLowerCase();

src/main/java/fr/xephi/authme/data/captcha/RegistrationCaptchaManager.java

@@ -45,20 +45,14 @@ public class RegistrationCaptchaManager
         return captchaCodeStorage.getCodeOrGenerateNew(name);
     }
 
-    @Override
-    public String generateCode(String name) {
-        return captchaCodeStorage.generateCode(name);
-    }
-
     @Override
     public boolean checkCode(Player player, String code) {
         String nameLower = player.getName().toLowerCase();
         boolean isCodeCorrect = captchaCodeStorage.checkCode(nameLower, code);
         if (isCodeCorrect) {
             verifiedNamesForRegistration.add(nameLower);
-        } else {
-            limboService.resetMessageTask(player, false);
         }
+        limboService.resetMessageTask(player, false);
         return isCodeCorrect;
     }