///////////////////////////////////////////////////////////////////////////////////////////////
   // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
   // Copyright (C) 2001-2025 the original author or authors.
   //
   // This library is free software; you can redistribute it and/or
   // modify it under the terms of the GNU Lesser General Public
   // License as published by the Free Software Foundation; either
   // version 2.1 of the License, or (at your option) any later version.
   //
  // This library is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  // Lesser General Public License for more details.
  //
  // You should have received a copy of the GNU Lesser General Public
  // License along with this library; if not, write to the Free Software
  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  ///////////////////////////////////////////////////////////////////////////////////////////////
  
  package com.puppycrawl.tools.checkstyle.checks.coding;
  
  import java.util.BitSet;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Set;
  import java.util.regex.Pattern;
  
  import com.puppycrawl.tools.checkstyle.FileStatefulCheck;
  import com.puppycrawl.tools.checkstyle.PropertyType;
  import com.puppycrawl.tools.checkstyle.XdocsPropertyType;
  import com.puppycrawl.tools.checkstyle.api.AbstractCheck;
  import com.puppycrawl.tools.checkstyle.api.DetailAST;
  import com.puppycrawl.tools.checkstyle.api.FullIdent;
  import com.puppycrawl.tools.checkstyle.api.TokenTypes;
  import com.puppycrawl.tools.checkstyle.utils.AnnotationUtil;
  import com.puppycrawl.tools.checkstyle.utils.TokenUtil;
  
  /**
   * <div>
   * Checks that particular classes or interfaces are never used.
   * </div>
   *
   * <p>
   * Rationale: Helps reduce coupling on concrete classes.
   * </p>
   *
   * <p>
   * For additional restriction of type usage see also:
   * <a href="https://checkstyle.org/checks/coding/illegalinstantiation.html">
   * IllegalInstantiation</a>,
   * <a href="https://checkstyle.org/checks/imports/illegalimport.html">
   * IllegalImport</a>
   * </p>
   *
   * <p>
   * Notes:
   * It is possible to set illegal class names via short or
   * <a href="https://docs.oracle.com/javase/specs/jls/se11/html/jls-6.html#jls-6.7">canonical</a>
   * name. Specifying illegal type invokes analyzing imports and Check puts violations at
   * corresponding declarations (of variables, methods or parameters).
   * This helps to avoid ambiguous cases, e.g.: {@code java.awt.List} was set as
   * illegal class name, then, code like:
   * </p>
   * <div class="wrapper"><pre class="prettyprint"><code class="language-java">
   * import java.util.List;
   * ...
   * List list; //No violation here
   * </code></pre></div>
   *
   * <p>
   * will be ok.
   * </p>
   *
   * <p>
   * In most cases it's justified to put following classes to <b>illegalClassNames</b>:
   * </p>
   * <ul>
   * <li>GregorianCalendar</li>
   * <li>Hashtable</li>
   * <li>ArrayList</li>
   * <li>LinkedList</li>
   * <li>Vector</li>
   * </ul>
   *
   * <p>
   * as methods that are differ from interface methods are rarely used, so in most cases user will
   * benefit from checking for them.
   * </p>
   *
   * @since 3.2
   */
  @FileStatefulCheck
  public final class IllegalTypeCheck extends AbstractCheck {
  
      /**
       * A key is pointing to the warning message text in "messages.properties"
       * file.
       */
      public static final String MSG_KEY = "illegal.type";
 
     /** Types illegal by default. */
     private static final String[] DEFAULT_ILLEGAL_TYPES = {
         "HashSet",
         "HashMap",
         "LinkedHashMap",
         "LinkedHashSet",
         "TreeSet",
         "TreeMap",
         "java.util.HashSet",
         "java.util.HashMap",
         "java.util.LinkedHashMap",
         "java.util.LinkedHashSet",
         "java.util.TreeSet",
         "java.util.TreeMap",
     };
 
     /** Default ignored method names. */
     private static final String[] DEFAULT_IGNORED_METHOD_NAMES = {
         "getInitialContext",
         "getEnvironment",
     };
 
     /**
      * Specify classes that should not be used as types in variable declarations,
      * return values or parameters.
      */
     private final Set<String> illegalClassNames = new HashSet<>();
     /** Illegal short classes. */
     private final Set<String> illegalShortClassNames = new HashSet<>();
     /** Define abstract classes that may be used as types. */
     private final Set<String> legalAbstractClassNames = new HashSet<>();
     /** Specify methods that should not be checked. */
     private final Set<String> ignoredMethodNames = new HashSet<>();
     /**
      * Control whether to check only methods and fields with any of the specified modifiers.
      * This property does not affect method calls nor method references nor record components.
      */
     @XdocsPropertyType(PropertyType.TOKEN_ARRAY)
     private BitSet memberModifiers = new BitSet();
 
     /** Specify RegExp for illegal abstract class names. */
     private Pattern illegalAbstractClassNameFormat = Pattern.compile("^(.*[.])?Abstract.*$");
 
     /**
      * Control whether to validate abstract class names.
      */
     private boolean validateAbstractClassNames;
 
     /** Creates new instance of the check. */
     public IllegalTypeCheck() {
         setIllegalClassNames(DEFAULT_ILLEGAL_TYPES);
         setIgnoredMethodNames(DEFAULT_IGNORED_METHOD_NAMES);
     }
 
     /**
      * Setter to specify RegExp for illegal abstract class names.
      *
      * @param pattern a pattern.
      * @since 3.2
      */
     public void setIllegalAbstractClassNameFormat(Pattern pattern) {
         illegalAbstractClassNameFormat = pattern;
     }
 
     /**
      * Setter to control whether to validate abstract class names.
      *
      * @param validateAbstractClassNames whether abstract class names must be ignored.
      * @since 6.10
      */
     public void setValidateAbstractClassNames(boolean validateAbstractClassNames) {
         this.validateAbstractClassNames = validateAbstractClassNames;
     }
 
     @Override
     public int[] getDefaultTokens() {
         return getAcceptableTokens();
     }
 
     @Override
     public int[] getAcceptableTokens() {
         return new int[] {
             TokenTypes.ANNOTATION_FIELD_DEF,
             TokenTypes.CLASS_DEF,
             TokenTypes.IMPORT,
             TokenTypes.INTERFACE_DEF,
             TokenTypes.METHOD_CALL,
             TokenTypes.METHOD_DEF,
             TokenTypes.METHOD_REF,
             TokenTypes.PARAMETER_DEF,
             TokenTypes.VARIABLE_DEF,
             TokenTypes.PATTERN_VARIABLE_DEF,
             TokenTypes.RECORD_DEF,
             TokenTypes.RECORD_COMPONENT_DEF,
             TokenTypes.RECORD_PATTERN_DEF,
         };
     }
 
     @Override
     public void beginTree(DetailAST rootAST) {
         illegalShortClassNames.clear();
         illegalShortClassNames.addAll(illegalClassNames);
     }
 
     @Override
     public int[] getRequiredTokens() {
         return new int[] {TokenTypes.IMPORT};
     }
 
     @Override
     public void visitToken(DetailAST ast) {
         switch (ast.getType()) {
             case TokenTypes.CLASS_DEF,
                  TokenTypes.INTERFACE_DEF,
                  TokenTypes.RECORD_DEF -> visitTypeDef(ast);
 
             case TokenTypes.METHOD_CALL,
                  TokenTypes.METHOD_REF -> visitMethodCallOrRef(ast);
 
             case TokenTypes.METHOD_DEF -> visitMethodDef(ast);
 
             case TokenTypes.VARIABLE_DEF,
                  TokenTypes.ANNOTATION_FIELD_DEF,
                  TokenTypes.PATTERN_VARIABLE_DEF -> visitVariableDef(ast);
 
             case TokenTypes.RECORD_COMPONENT_DEF,
                  TokenTypes.RECORD_PATTERN_DEF -> checkClassName(ast);
 
             case TokenTypes.PARAMETER_DEF -> visitParameterDef(ast);
 
             case TokenTypes.IMPORT -> visitImport(ast);
 
             default -> throw new IllegalStateException(ast.toString());
         }
     }
 
     /**
      * Checks if current method's return type or variable's type is verifiable
      * according to <b>memberModifiers</b> option.
      *
      * @param methodOrVariableDef METHOD_DEF or VARIABLE_DEF ast node.
      * @return true if member is verifiable according to <b>memberModifiers</b> option.
      */
     private boolean isVerifiable(DetailAST methodOrVariableDef) {
         boolean result = true;
         if (!memberModifiers.isEmpty()) {
             final DetailAST modifiersAst = methodOrVariableDef
                     .findFirstToken(TokenTypes.MODIFIERS);
             result = isContainVerifiableType(modifiersAst);
         }
         return result;
     }
 
     /**
      * Checks is modifiers contain verifiable type.
      *
      * @param modifiers
      *            parent node for all modifiers
      * @return true if method or variable can be verified
      */
     private boolean isContainVerifiableType(DetailAST modifiers) {
         boolean result = false;
         for (DetailAST modifier = modifiers.getFirstChild(); modifier != null;
                  modifier = modifier.getNextSibling()) {
             if (memberModifiers.get(modifier.getType())) {
                 result = true;
                 break;
             }
         }
         return result;
     }
 
     /**
      * Checks the super type and implemented interfaces of a given type.
      *
      * @param typeDef class or interface for check.
      */
     private void visitTypeDef(DetailAST typeDef) {
         if (isVerifiable(typeDef)) {
             checkTypeParameters(typeDef);
             final DetailAST extendsClause = typeDef.findFirstToken(TokenTypes.EXTENDS_CLAUSE);
             if (extendsClause != null) {
                 checkBaseTypes(extendsClause);
             }
             final DetailAST implementsClause = typeDef.findFirstToken(TokenTypes.IMPLEMENTS_CLAUSE);
             if (implementsClause != null) {
                 checkBaseTypes(implementsClause);
             }
         }
     }
 
     /**
      * Checks return type of a given method.
      *
      * @param methodDef method for check.
      */
     private void visitMethodDef(DetailAST methodDef) {
         if (isCheckedMethod(methodDef)) {
             checkClassName(methodDef);
         }
     }
 
     /**
      * Checks type of parameters.
      *
      * @param parameterDef parameter list for check.
      */
     private void visitParameterDef(DetailAST parameterDef) {
         final DetailAST grandParentAST = parameterDef.getParent().getParent();
 
         if (grandParentAST.getType() == TokenTypes.METHOD_DEF && isCheckedMethod(grandParentAST)) {
             checkClassName(parameterDef);
         }
     }
 
     /**
      * Checks type of given variable.
      *
      * @param variableDef variable to check.
      */
     private void visitVariableDef(DetailAST variableDef) {
         if (isVerifiable(variableDef)) {
             checkClassName(variableDef);
         }
     }
 
     /**
      * Checks the type arguments of given method call/reference.
      *
      * @param methodCallOrRef method call/reference to check.
      */
     private void visitMethodCallOrRef(DetailAST methodCallOrRef) {
         checkTypeArguments(methodCallOrRef);
     }
 
     /**
      * Checks imported type (as static and star imports are not supported by Check,
      *  only type is in the consideration).<br>
      * If this type is illegal due to Check's options - puts violation on it.
      *
      * @param importAst {@link TokenTypes#IMPORT Import}
      */
     private void visitImport(DetailAST importAst) {
         if (!isStarImport(importAst)) {
             final String canonicalName = getImportedTypeCanonicalName(importAst);
             extendIllegalClassNamesWithShortName(canonicalName);
         }
     }
 
     /**
      * Checks if current import is star import. E.g.:
      *
      * <p>
      * {@code
      * import java.util.*;
      * }
      * </p>
      *
      * @param importAst {@link TokenTypes#IMPORT Import}
      * @return true if it is star import
      */
     private static boolean isStarImport(DetailAST importAst) {
         boolean result = false;
         DetailAST toVisit = importAst;
         while (toVisit != null) {
             toVisit = getNextSubTreeNode(toVisit, importAst);
             if (toVisit != null && toVisit.getType() == TokenTypes.STAR) {
                 result = true;
                 break;
             }
         }
         return result;
     }
 
     /**
      * Checks type and type arguments/parameters of given method, parameter, variable or
      * method call/reference.
      *
      * @param ast node to check.
      */
     private void checkClassName(DetailAST ast) {
         final DetailAST type = ast.findFirstToken(TokenTypes.TYPE);
         checkType(type);
         checkTypeParameters(ast);
     }
 
     /**
      * Checks the identifier of the given type.
      *
      * @param type node to check.
      */
     private void checkIdent(DetailAST type) {
         final FullIdent ident = FullIdent.createFullIdent(type);
         if (isMatchingClassName(ident.getText())) {
             log(ident.getDetailAst(), MSG_KEY, ident.getText());
         }
     }
 
     /**
      * Checks the {@code extends} or {@code implements} statement.
      *
      * @param clause DetailAST for either {@link TokenTypes#EXTENDS_CLAUSE} or
      *               {@link TokenTypes#IMPLEMENTS_CLAUSE}
      */
     private void checkBaseTypes(DetailAST clause) {
         DetailAST child = clause.getFirstChild();
         while (child != null) {
             if (child.getType() == TokenTypes.IDENT) {
                 checkIdent(child);
             }
             else {
                 TokenUtil.forEachChild(child, TokenTypes.TYPE_ARGUMENT, this::checkType);
             }
             child = child.getNextSibling();
         }
     }
 
     /**
      * Checks the given type, its arguments and parameters.
      *
      * @param type node to check.
      */
     private void checkType(DetailAST type) {
         checkIdent(type.getFirstChild());
         checkTypeArguments(type);
         checkTypeBounds(type);
     }
 
     /**
      * Checks the upper and lower bounds for the given type.
      *
      * @param type node to check.
      */
     private void checkTypeBounds(DetailAST type) {
         final DetailAST upperBounds = type.findFirstToken(TokenTypes.TYPE_UPPER_BOUNDS);
         if (upperBounds != null) {
             checkType(upperBounds);
         }
         final DetailAST lowerBounds = type.findFirstToken(TokenTypes.TYPE_LOWER_BOUNDS);
         if (lowerBounds != null) {
             checkType(lowerBounds);
         }
     }
 
     /**
      * Checks the type parameters of the node.
      *
      * @param node node to check.
      */
     private void checkTypeParameters(final DetailAST node) {
         final DetailAST typeParameters = node.findFirstToken(TokenTypes.TYPE_PARAMETERS);
         if (typeParameters != null) {
             TokenUtil.forEachChild(typeParameters, TokenTypes.TYPE_PARAMETER, this::checkType);
         }
     }
 
     /**
      * Checks the type arguments of the node.
      *
      * @param node node to check.
      */
     private void checkTypeArguments(final DetailAST node) {
         DetailAST typeArguments = node.findFirstToken(TokenTypes.TYPE_ARGUMENTS);
         if (typeArguments == null) {
             typeArguments = node.getFirstChild().findFirstToken(TokenTypes.TYPE_ARGUMENTS);
         }
 
         if (typeArguments != null) {
             TokenUtil.forEachChild(typeArguments, TokenTypes.TYPE_ARGUMENT, this::checkType);
         }
     }
 
     /**
      * Returns true if given class name is one of illegal classes or else false.
      *
      * @param className class name to check.
      * @return true if given class name is one of illegal classes
      *         or if it matches to abstract class names pattern.
      */
     private boolean isMatchingClassName(String className) {
         final String shortName = className.substring(className.lastIndexOf('.') + 1);
         return illegalClassNames.contains(className)
                 || illegalShortClassNames.contains(shortName)
                 || validateAbstractClassNames
                     && !legalAbstractClassNames.contains(className)
                     && illegalAbstractClassNameFormat.matcher(className).find();
     }
 
     /**
      * Extends illegal class names set via imported short type name.
      *
      * @param canonicalName
      *     <a href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-6.html#jls-6.7">
      *     Canonical</a> name of imported type.
      */
     private void extendIllegalClassNamesWithShortName(String canonicalName) {
         if (illegalClassNames.contains(canonicalName)) {
             final String shortName = canonicalName
                 .substring(canonicalName.lastIndexOf('.') + 1);
             illegalShortClassNames.add(shortName);
         }
     }
 
     /**
      * Gets imported type's
      * <a href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-6.html#jls-6.7">
      *  canonical name</a>.
      *
      * @param importAst {@link TokenTypes#IMPORT Import}
      * @return Imported canonical type's name.
      */
     private static String getImportedTypeCanonicalName(DetailAST importAst) {
         final StringBuilder canonicalNameBuilder = new StringBuilder(256);
         DetailAST toVisit = importAst;
         while (toVisit != null) {
             toVisit = getNextSubTreeNode(toVisit, importAst);
             if (toVisit != null && toVisit.getType() == TokenTypes.IDENT) {
                 if (!canonicalNameBuilder.isEmpty()) {
                     canonicalNameBuilder.append('.');
                 }
                 canonicalNameBuilder.append(toVisit.getText());
             }
         }
         return canonicalNameBuilder.toString();
     }
 
     /**
      * Gets the next node of a syntactical tree (child of a current node or
      * sibling of a current node, or sibling of a parent of a current node).
      *
      * @param currentNodeAst Current node in considering
      * @param subTreeRootAst SubTree root
      * @return Current node after bypassing, if current node reached the root of a subtree
      *        method returns null
      */
     private static DetailAST
         getNextSubTreeNode(DetailAST currentNodeAst, DetailAST subTreeRootAst) {
         DetailAST currentNode = currentNodeAst;
         DetailAST toVisitAst = currentNode.getFirstChild();
         while (toVisitAst == null) {
             toVisitAst = currentNode.getNextSibling();
             if (currentNode.getParent().equals(subTreeRootAst)) {
                 break;
             }
             currentNode = currentNode.getParent();
         }
         return toVisitAst;
     }
 
     /**
      * Returns true if method has to be checked or false.
      *
      * @param ast method def to check.
      * @return true if we should check this method.
      */
     private boolean isCheckedMethod(DetailAST ast) {
         final String methodName =
             ast.findFirstToken(TokenTypes.IDENT).getText();
         return isVerifiable(ast) && !ignoredMethodNames.contains(methodName)
                 && !AnnotationUtil.hasOverrideAnnotation(ast);
     }
 
     /**
      * Setter to specify classes that should not be used as types in variable declarations,
      * return values or parameters.
      *
      * @param classNames array of illegal variable types
      * @noinspection WeakerAccess
      * @noinspectionreason WeakerAccess - we avoid 'protected' when possible
      * @since 3.2
      */
     public void setIllegalClassNames(String... classNames) {
         illegalClassNames.clear();
         Collections.addAll(illegalClassNames, classNames);
     }
 
     /**
      * Setter to specify methods that should not be checked.
      *
      * @param methodNames array of ignored method names
      * @noinspection WeakerAccess
      * @noinspectionreason WeakerAccess - we avoid 'protected' when possible
      * @since 3.2
      */
     public void setIgnoredMethodNames(String... methodNames) {
         ignoredMethodNames.clear();
         Collections.addAll(ignoredMethodNames, methodNames);
     }
 
     /**
      * Setter to define abstract classes that may be used as types.
      *
      * @param classNames array of legal abstract class names
      * @noinspection WeakerAccess
      * @noinspectionreason WeakerAccess - we avoid 'protected' when possible
      * @since 4.2
      */
     public void setLegalAbstractClassNames(String... classNames) {
         Collections.addAll(legalAbstractClassNames, classNames);
     }
 
     /**
      * Setter to control whether to check only methods and fields with any of
      * the specified modifiers.
      * This property does not affect method calls nor method references nor record components.
      *
      * @param modifiers String contains modifiers.
      * @since 6.3
      */
     public void setMemberModifiers(String modifiers) {
         memberModifiers = TokenUtil.asBitSet(modifiers.split(","));
     }
 
 }