////////////////////////////////////////////////////////////////////////////////
// checkstyle: Checks Java source code for adherence to a set of rules.
// Copyright (C) 2001-2020 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.javadoc;

import java.util.Arrays;
import java.util.Collections;
import java.util.Map;
import java.util.stream.Collectors;

import com.puppycrawl.tools.checkstyle.api.DetailAST;
import com.puppycrawl.tools.checkstyle.api.Scope;
import com.puppycrawl.tools.checkstyle.api.TokenTypes;
import com.puppycrawl.tools.checkstyle.utils.ScopeUtil;

/**
 * This enum defines the various Javadoc tags and there properties.
 *
 * <p>
 * This class was modeled after documentation located at
 * <a href="https://docs.oracle.com/javase/8/docs/technotes/tools/windows/javadoc.html">
 * javadoc</a>
 *
 * and
 *
 * <a href="https://www.oracle.com/technetwork/java/javase/documentation/index-137868.html">
 * how to write</a>.
 * </p>
 *
 * <p>
 * Some of this documentation was a little incomplete (ex: valid placement of
 * code, value, and literal tags).
 * </p>
 *
 * <p>
 * Whenever an inconsistency was found the author's judgment was used.
 * </p>
 *
 * <p>
 * For now, the number of required/optional tag arguments are not included
 * because some Javadoc tags have very complex rules for determining this
 * (ex: {@code {@value}} tag).
 * </p>
 *
 * <p>
 * Also, the {@link #isValidOn(DetailAST) isValidOn} method does not consider
 * classes defined in a local code block (method, init block, etc.).
 * </p>
 *
 */
public enum JavadocTagInfo {

    /**
     * {@code @author}.
     */
    AUTHOR("@author", "author", Type.BLOCK) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            return astType == TokenTypes.PACKAGE_DEF
                || astType == TokenTypes.CLASS_DEF
                || astType == TokenTypes.INTERFACE_DEF
                || astType == TokenTypes.ENUM_DEF
                || astType == TokenTypes.ANNOTATION_DEF;
        }

    },

    /**
     * {@code {@code}}.
     */
    CODE("{@code}", "code", Type.INLINE) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            return Arrays.binarySearch(DEF_TOKEN_TYPES, astType) >= 0
                && !ScopeUtil.isLocalVariableDef(ast);
        }

    },

    /**
     * {@code {@docRoot}}.
     */
    DOC_ROOT("{@docRoot}", "docRoot", Type.INLINE) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            return Arrays.binarySearch(DEF_TOKEN_TYPES, astType) >= 0
                && !ScopeUtil.isLocalVariableDef(ast);
        }

    },

    /**
     * {@code @deprecated}.
     */
    DEPRECATED("@deprecated", "deprecated", Type.BLOCK) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            return Arrays.binarySearch(DEF_TOKEN_TYPES_DEPRECATED, astType) >= 0
                && !ScopeUtil.isLocalVariableDef(ast);
        }

    },

    /**
     * {@code @exception}.
     */
    EXCEPTION("@exception", "exception", Type.BLOCK) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            return astType == TokenTypes.METHOD_DEF || astType == TokenTypes.CTOR_DEF;
        }

    },

    /**
     * {@code {@inheritDoc}}.
     */
    INHERIT_DOC("{@inheritDoc}", "inheritDoc", Type.INLINE) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();

            return astType == TokenTypes.METHOD_DEF
                && ast.findFirstToken(TokenTypes.MODIFIERS)
                    .findFirstToken(TokenTypes.LITERAL_STATIC) == null
                && ScopeUtil.getScopeFromMods(ast
                    .findFirstToken(TokenTypes.MODIFIERS)) != Scope.PRIVATE;
        }

    },

    /**
     * {@code {@link}}.
     */
    LINK("{@link}", "link", Type.INLINE) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            return Arrays.binarySearch(DEF_TOKEN_TYPES, astType) >= 0
                && !ScopeUtil.isLocalVariableDef(ast);
        }

    },

    /**
     * {@code {@linkplain}}.
     */
    LINKPLAIN("{@linkplain}", "linkplain", Type.INLINE) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            return Arrays.binarySearch(DEF_TOKEN_TYPES, astType) >= 0
                && !ScopeUtil.isLocalVariableDef(ast);
        }

    },

    /**
     * {@code {@literal}}.
     */
    LITERAL("{@literal}", "literal", Type.INLINE) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            return Arrays.binarySearch(DEF_TOKEN_TYPES, astType) >= 0
                && !ScopeUtil.isLocalVariableDef(ast);
        }

    },

    /**
     * {@code @param}.
     */
    PARAM("@param", "param", Type.BLOCK) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            return astType == TokenTypes.CLASS_DEF
                || astType == TokenTypes.INTERFACE_DEF
                || astType == TokenTypes.METHOD_DEF
                || astType == TokenTypes.CTOR_DEF;
        }

    },

    /**
     * {@code @return}.
     */
    RETURN("@return", "return", Type.BLOCK) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            final DetailAST returnType = ast.findFirstToken(TokenTypes.TYPE);

            return astType == TokenTypes.METHOD_DEF
                && returnType.getFirstChild().getType() != TokenTypes.LITERAL_VOID;
        }

    },

    /**
     * {@code @see}.
     */
    SEE("@see", "see", Type.BLOCK) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            return Arrays.binarySearch(DEF_TOKEN_TYPES, astType) >= 0
                && !ScopeUtil.isLocalVariableDef(ast);
        }

    },

    /**
     * {@code @serial}.
     */
    SERIAL("@serial", "serial", Type.BLOCK) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();

            return astType == TokenTypes.VARIABLE_DEF
                && !ScopeUtil.isLocalVariableDef(ast);
        }

    },

    /**
     * {@code @serialData}.
     */
    SERIAL_DATA("@serialData", "serialData", Type.BLOCK) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            final DetailAST methodNameAst = ast.findFirstToken(TokenTypes.IDENT);
            final String methodName = methodNameAst.getText();

            return astType == TokenTypes.METHOD_DEF
                && ("writeObject".equals(methodName)
                    || "readObject".equals(methodName)
                    || "writeExternal".equals(methodName)
                    || "readExternal".equals(methodName)
                    || "writeReplace".equals(methodName)
                    || "readResolve".equals(methodName));
        }

    },

    /**
     * {@code @serialField}.
     */
    SERIAL_FIELD("@serialField", "serialField", Type.BLOCK) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            final DetailAST varType = ast.findFirstToken(TokenTypes.TYPE);

            return astType == TokenTypes.VARIABLE_DEF
                && varType.getFirstChild().getType() == TokenTypes.ARRAY_DECLARATOR
                && "ObjectStreamField".equals(varType.getFirstChild().getText());
        }

    },

    /**
     * {@code @since}.
     */
    SINCE("@since", "since", Type.BLOCK) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            return Arrays.binarySearch(DEF_TOKEN_TYPES, astType) >= 0
                && !ScopeUtil.isLocalVariableDef(ast);
        }

    },

    /**
     * {@code @throws}.
     */
    THROWS("@throws", "throws", Type.BLOCK) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            return astType == TokenTypes.METHOD_DEF
                || astType == TokenTypes.CTOR_DEF;
        }

    },

    /**
     * {@code {@value}}.
     */
    VALUE("{@value}", "value", Type.INLINE) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            return Arrays.binarySearch(DEF_TOKEN_TYPES, astType) >= 0
                && !ScopeUtil.isLocalVariableDef(ast);
        }

    },

    /**
     * {@code @version}.
     */
    VERSION("@version", "version", Type.BLOCK) {

        @Override
        public boolean isValidOn(final DetailAST ast) {
            final int astType = ast.getType();
            return astType == TokenTypes.PACKAGE_DEF
                || astType == TokenTypes.CLASS_DEF
                || astType == TokenTypes.INTERFACE_DEF
                || astType == TokenTypes.ENUM_DEF
                || astType == TokenTypes.ANNOTATION_DEF;
        }

    };

    /** Default token types for DEPRECATED Javadoc tag.*/
    private static final int[] DEF_TOKEN_TYPES_DEPRECATED = {
        TokenTypes.CTOR_DEF,
        TokenTypes.METHOD_DEF,
        TokenTypes.VARIABLE_DEF,
        TokenTypes.CLASS_DEF,
        TokenTypes.INTERFACE_DEF,
        TokenTypes.ENUM_DEF,
        TokenTypes.ENUM_CONSTANT_DEF,
        TokenTypes.ANNOTATION_DEF,
        TokenTypes.ANNOTATION_FIELD_DEF,
    };

    /** Default token types.*/
    private static final int[] DEF_TOKEN_TYPES = {
        TokenTypes.CTOR_DEF,
        TokenTypes.METHOD_DEF,
        TokenTypes.VARIABLE_DEF,
        TokenTypes.CLASS_DEF,
        TokenTypes.INTERFACE_DEF,
        TokenTypes.PACKAGE_DEF,
        TokenTypes.ENUM_DEF,
        TokenTypes.ANNOTATION_DEF,
    };

    /** Holds tag text to tag enum mappings. **/
    private static final Map<String, JavadocTagInfo> TEXT_TO_TAG;
    /** Holds tag name to tag enum mappings. **/
    private static final Map<String, JavadocTagInfo> NAME_TO_TAG;

    static {
        TEXT_TO_TAG = Collections.unmodifiableMap(Arrays.stream(JavadocTagInfo.values())
            .collect(Collectors.toMap(JavadocTagInfo::getText, tagText -> tagText)));
        NAME_TO_TAG = Collections.unmodifiableMap(Arrays.stream(JavadocTagInfo.values())
            .collect(Collectors.toMap(JavadocTagInfo::getName, tagName -> tagName)));

        //Arrays sorting for binary search
        Arrays.sort(DEF_TOKEN_TYPES);
        Arrays.sort(DEF_TOKEN_TYPES_DEPRECATED);
    }

    /** The tag text. **/
    private final String text;
    /** The tag name. **/
    private final String name;
    /** The tag type. **/
    private final Type type;

    /**
     * Sets the various properties of a Javadoc tag.
     *
     * @param text the tag text
     * @param name the tag name
     * @param type the type of tag
     */
    JavadocTagInfo(final String text, final String name,
        final Type type) {
        this.text = text;
        this.name = name;
        this.type = type;
    }

    /**
     * Checks if a particular Javadoc tag is valid within a Javadoc block of a
     * given AST.
     *
     * <p>
     * If passing in a DetailAST representing a non-void METHOD_DEF
     * {@code true } would be returned. If passing in a DetailAST
     * representing a CLASS_DEF {@code false } would be returned because
     * CLASS_DEF's cannot return a value.
     * </p>
     *
     * @param ast the AST representing a type that can be Javadoc'd
     * @return true if tag is valid.
     */
    public abstract boolean isValidOn(DetailAST ast);

    /**
     * Gets the tag text.
     * @return the tag text
     */
    public String getText() {
        return text;
    }

    /**
     * Gets the tag name.
     * @return the tag name
     */
    public String getName() {
        return name;
    }

    /**
     * Gets the Tag type defined by {@link Type Type}.
     * @return the Tag type
     */
    public Type getType() {
        return type;
    }

    /**
     * Returns a JavadocTag from the tag text.
     * @param text String representing the tag text
     * @return Returns a JavadocTag type from a String representing the tag
     * @throws NullPointerException if the text is null
     * @throws IllegalArgumentException if the text is not a valid tag
     */
    public static JavadocTagInfo fromText(final String text) {
        if (text == null) {
            throw new IllegalArgumentException("the text is null");
        }

        final JavadocTagInfo tag = TEXT_TO_TAG.get(text);

        if (tag == null) {
            throw new IllegalArgumentException("the text [" + text
                + "] is not a valid Javadoc tag text");
        }

        return tag;
    }

    /**
     * Returns a JavadocTag from the tag name.
     * @param name String name of the tag
     * @return Returns a JavadocTag type from a String representing the tag
     * @throws NullPointerException if the text is null
     * @throws IllegalArgumentException if the text is not a valid tag. The name
     *     can be checked using {@link JavadocTagInfo#isValidName(String)}
     */
    public static JavadocTagInfo fromName(final String name) {
        if (name == null) {
            throw new IllegalArgumentException("the name is null");
        }

        final JavadocTagInfo tag = NAME_TO_TAG.get(name);

        if (tag == null) {
            throw new IllegalArgumentException("the name [" + name
                + "] is not a valid Javadoc tag name");
        }

        return tag;
    }

    /**
     * Returns whether the provided name is for a valid tag.
     * @param name the tag name to check.
     * @return whether the provided name is for a valid tag.
     */
    public static boolean isValidName(final String name) {
        return NAME_TO_TAG.containsKey(name);
    }

    @Override
    public String toString() {
        return "text [" + text + "] name [" + name
            + "] type [" + type + "]";
    }

    /**
     * The Javadoc Type.
     *
     * <p>For example a {@code @param} tag is a block tag while a
     * {@code {@link}} tag is a inline tag.
     *
     */
    public enum Type {

        /** Block type. **/
        BLOCK,

        /** Inline type. **/
        INLINE

    }

}
