/*

 * Copyright (c) 2010, 2017, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.javadoc.internal.doclets.formats.html.markup;

import java.io.IOException;

import java.io.Writer;

import java.nio.charset.Charset;

import java.util.ArrayList;

import java.util.BitSet;

import java.util.Collections;

import java.util.Iterator;

import java.util.LinkedHashMap;

import java.util.List;

import java.util.Map;

import jdk.javadoc.internal.doclets.formats.html.markup.HtmlAttr.Role;

import jdk.javadoc.internal.doclets.toolkit.Content;

import jdk.javadoc.internal.doclets.toolkit.util.DocletConstants;

/**

 * Class for generating HTML tree for javadoc output.

 *

 *  <p><b>This is NOT part of any supported API.

 *  If you write code that depends on this, you do so at your own risk.

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 *

 * @author Bhavesh Patel

 */

public class HtmlTree extends Content {

    public final HtmlTag htmlTag;

    private Map<HtmlAttr,String> attrs = Collections.emptyMap();

    private List<Content> content = Collections.emptyList();

    public static final Content EMPTY = new StringContent("");

    /**

     * Constructor to construct HtmlTree object.

     *

     * @param tag HTML tag for the HtmlTree object

     */

    public HtmlTree(HtmlTag tag) {

        htmlTag = nullCheck(tag);

    }

    /**

     * Constructor to construct HtmlTree object.

     *

     * @param tag HTML tag for the HtmlTree object

     * @param contents contents to be added to the tree

     */

    public HtmlTree(HtmlTag tag, Content... contents) {

        this(tag);

        for (Content c: contents)

            addContent(c);

    }

    /**

     * Constructor to construct HtmlTree object.

     *

     * @param tag HTML tag for the HtmlTree object

     * @param contents contents to be added to the tree

     */

    public HtmlTree(HtmlTag tag, List<Content> contents) {

        this(tag);

        for (Content c: contents)

            addContent(c);

    }

    /**

     * Adds an attribute for the HTML tag.

     *

     * @param attrName name of the attribute

     * @param attrValue value of the attribute

     * @return this object

     */

    public HtmlTree addAttr(HtmlAttr attrName, String attrValue) {

        if (attrs.isEmpty())

            attrs = new LinkedHashMap<>(3);

        attrs.put(nullCheck(attrName), escapeHtmlChars(attrValue));

        return this;

    }

    /**

     * Sets the "title" attribute for this tag.

     * Any HTML tags in the content will be removed.

     *

     * @param body the content for the title attribute

     * @return this object

     */

    public HtmlTree setTitle(Content body) {

        addAttr(HtmlAttr.TITLE, stripHtml(body));

        return this;

    }

    /**

     * Sets the "role" attribute for this tag.

     *

     * @param role the role

     * @return this object

     */

    public HtmlTree setRole(Role role) {

        addAttr(HtmlAttr.ROLE, role.toString());

        return this;

    }

    /**

     * Sets the style for the HTML tag.

     *

     * @param style style to be added

     * @return this object

     */

    public HtmlTree setStyle(HtmlStyle style) {

        addAttr(HtmlAttr.CLASS, style.toString());

        return this;

    }

    /**

     * Adds content for the HTML tag.

     *

     * @param tagContent tag content to be added

     */

    @Override

    public void addContent(Content tagContent) {

        if (tagContent instanceof ContentBuilder) {

            for (Content c: ((ContentBuilder)tagContent).contents) {

                addContent(c);

            }

        }

        else if (tagContent == HtmlTree.EMPTY || tagContent.isValid()) {

            if (content.isEmpty())

                content = new ArrayList<>();

            content.add(tagContent);

        }

    }

    /**

     * Adds String content to the HTML tree. If the last content member

     * added is a StringContent, append the string to that StringContent or else

     * create a new StringContent and add it to the HTML tree.

     *

     * @param stringContent string content that needs to be added

     */

    @Override

    public void addContent(CharSequence stringContent) {

        if (!content.isEmpty()) {

            Content lastContent = content.get(content.size() - 1);

            if (lastContent instanceof StringContent)

                lastContent.addContent(stringContent);

            else

                addContent(new StringContent(stringContent));

        }

        else

            addContent(new StringContent(stringContent));

    }

    /**

     * {@inheritDoc}

     */

    @Override

    public int charCount() {

        int n = 0;

        for (Content c : content)

            n += c.charCount();

        return n;

    }

    /**

     * Given a string, escape all special HTML characters and

     * return the result.

     *

     * @param s The string to check.

     * @return the original string with all of the HTML characters escaped.

     */

    private static String escapeHtmlChars(String s) {

        for (int i = 0; i < s.length(); i++) {

            char ch = s.charAt(i);

            switch (ch) {

                // only start building a new string if we need to

                case '<': case '>': case '&':

                    StringBuilder sb = new StringBuilder(s.substring(0, i));

                    for ( ; i < s.length(); i++) {

                        ch = s.charAt(i);

                        switch (ch) {

                            case '<': sb.append("&lt;");  break;

                            case '>': sb.append(">");  break;

                            case '&': sb.append("&"); break;

                            default:  sb.append(ch);      break;

                        }

                    }

                    return sb.toString();

            }

        }

        return s;

    }

    /*

     * The sets of ASCII URI characters to be left unencoded.

     * See "Uniform Resource Identifier (URI): Generic Syntax"

     * IETF RFC 3986. https://tools.ietf.org/html/rfc3986

     */

    public static final BitSet MAIN_CHARS;

    public static final BitSet QUERY_FRAGMENT_CHARS;

    static {

        BitSet alphaDigit = bitSet(bitSet('A', 'Z'), bitSet('a', 'z'), bitSet('0', '9'));

        BitSet unreserved = bitSet(alphaDigit, bitSet("-._~"));

        BitSet genDelims = bitSet(":/?#[]@");

        BitSet subDelims = bitSet("!$&'()*+,;=");

        MAIN_CHARS = bitSet(unreserved, genDelims, subDelims);

        BitSet pchar = bitSet(unreserved, subDelims, bitSet(":@"));

        QUERY_FRAGMENT_CHARS = bitSet(pchar, bitSet("/?"));

    }

    private static BitSet bitSet(String s) {

        BitSet result = new BitSet();

        for (int i = 0; i < s.length(); i++) {

           result.set(s.charAt(i));

        }

        return result;

    }

    private static BitSet bitSet(char from, char to) {

        BitSet result = new BitSet();

        result.set(from, to + 1);

        return result;

    }

    private static BitSet bitSet(BitSet... sets) {

        BitSet result = new BitSet();

        for (BitSet set : sets) {

            result.or(set);

        }

        return result;

    }

    /**

     * Apply percent-encoding to a URL.

     * This is similar to {@link java.net.URLEncoder} but

     * is less aggressive about encoding some characters,

     * like '(', ')', ',' which are used in the anchor

     * names for Java methods in HTML5 mode.

     *

     * @param url the url to be percent-encoded.

     * @return a percent-encoded string.

     */

    public static String encodeURL(String url) {

        BitSet nonEncodingChars = MAIN_CHARS;

        StringBuilder sb = new StringBuilder();

        for (byte c : url.getBytes(Charset.forName("UTF-8"))) {

            if (c == '?' || c == '#') {

                sb.append((char) c);

                // switch to the more restrictive set inside

                // the query and/or fragment

                nonEncodingChars = QUERY_FRAGMENT_CHARS;

            } else if (nonEncodingChars.get(c & 0xFF)) {

                sb.append((char) c);

            } else {

                sb.append(String.format("%%%02X", c & 0xFF));

            }

        }

        return sb.toString();

    }

    /**

     * Generates an HTML anchor tag.

     *

     * @param ref reference url for the anchor tag

     * @param body content for the anchor tag

     * @return an HtmlTree object

     */

    public static HtmlTree A(String ref, Content body) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.A, nullCheck(body));

        htmltree.addAttr(HtmlAttr.HREF, encodeURL(ref));

        return htmltree;

    }

    /**

     * Generates an HTML anchor tag with id attribute and a body.

     *

     * @param id id for the anchor tag

     * @param body body for the anchor tag

     * @return an HtmlTree object

     */

    public static HtmlTree A_ID(String id, Content body) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.A);

        htmltree.addAttr(HtmlAttr.ID, nullCheck(id));

        htmltree.addContent(nullCheck(body));

        return htmltree;

    }

    /**

     * Generates an HTML anchor tag with a style class, id attribute and a body.

     *

     * @param styleClass stylesheet class for the tag

     * @param id id for the anchor tag

     * @param body body for the anchor tag

     * @return an HtmlTree object

     */

    public static HtmlTree A_ID(HtmlStyle styleClass, String id, Content body) {

        HtmlTree htmltree = A_ID(id, body);

        if (styleClass != null)

            htmltree.setStyle(styleClass);

        return htmltree;

    }

    /**

     * Generates a CAPTION tag with some content.

     *

     * @param body content for the tag

     * @return an HtmlTree object for the CAPTION tag

     */

    public static HtmlTree CAPTION(Content body) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.CAPTION, nullCheck(body));

        return htmltree;

    }

    /**

     * Generates a CODE tag with some content.

     *

     * @param body content for the tag

     * @return an HtmlTree object for the CODE tag

     */

    public static HtmlTree CODE(Content body) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.CODE, nullCheck(body));

        return htmltree;

    }

    /**

     * Generates a DD tag with some content.

     *

     * @param body content for the tag

     * @return an HtmlTree object for the DD tag

     */

    public static HtmlTree DD(Content body) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.DD, nullCheck(body));

        return htmltree;

    }

    /**

     * Generates a DL tag with some content.

     *

     * @param body content for the tag

     * @return an HtmlTree object for the DL tag

     */

    public static HtmlTree DL(Content body) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.DL, nullCheck(body));

        return htmltree;

    }

    /**

     * Generates a DIV tag with the style class attributes. It also encloses

     * a content.

     *

     * @param styleClass stylesheet class for the tag

     * @param body content for the tag

     * @return an HtmlTree object for the DIV tag

     */

    public static HtmlTree DIV(HtmlStyle styleClass, Content body) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.DIV, nullCheck(body));

        if (styleClass != null)

            htmltree.setStyle(styleClass);

        return htmltree;

    }

    /**

     * Generates a DIV tag with some content.

     *

     * @param body content for the tag

     * @return an HtmlTree object for the DIV tag

     */

    public static HtmlTree DIV(Content body) {

        return DIV(null, body);

    }

    /**

     * Generates a DT tag with some content.

     *

     * @param body content for the tag

     * @return an HtmlTree object for the DT tag

     */

    public static HtmlTree DT(Content body) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.DT, nullCheck(body));

        return htmltree;

    }

    /**

     * Generates a FOOTER tag with role attribute.

     *

     * @return an HtmlTree object for the FOOTER tag

     */

    public static HtmlTree FOOTER() {

        HtmlTree htmltree = new HtmlTree(HtmlTag.FOOTER);

        htmltree.setRole(Role.CONTENTINFO);

        return htmltree;

    }

    /**

     * Generates a HEADER tag with role attribute.

     *

     * @return an HtmlTree object for the HEADER tag

     */

    public static HtmlTree HEADER() {

        HtmlTree htmltree = new HtmlTree(HtmlTag.HEADER);

        htmltree.setRole(Role.BANNER);

        return htmltree;

    }

    /**

     * Generates a heading tag (h1 to h6) with the title and style class attributes. It also encloses

     * a content.

     *

     * @param headingTag the heading tag to be generated

     * @param printTitle true if title for the tag needs to be printed else false

     * @param styleClass stylesheet class for the tag

     * @param body content for the tag

     * @return an HtmlTree object for the tag

     */

    public static HtmlTree HEADING(HtmlTag headingTag, boolean printTitle,

            HtmlStyle styleClass, Content body) {

        HtmlTree htmltree = new HtmlTree(headingTag, nullCheck(body));

        if (printTitle)

            htmltree.setTitle(body);

        if (styleClass != null)

            htmltree.setStyle(styleClass);

        return htmltree;

    }

    /**

     * Generates a heading tag (h1 to h6) with style class attribute. It also encloses

     * a content.

     *

     * @param headingTag the heading tag to be generated

     * @param styleClass stylesheet class for the tag

     * @param body content for the tag

     * @return an HtmlTree object for the tag

     */

    public static HtmlTree HEADING(HtmlTag headingTag, HtmlStyle styleClass, Content body) {

        return HEADING(headingTag, false, styleClass, body);

    }

    /**

     * Generates a heading tag (h1 to h6) with the title attribute. It also encloses

     * a content.

     *

     * @param headingTag the heading tag to be generated

     * @param printTitle true if the title for the tag needs to be printed else false

     * @param body content for the tag

     * @return an HtmlTree object for the tag

     */

    public static HtmlTree HEADING(HtmlTag headingTag, boolean printTitle, Content body) {

        return HEADING(headingTag, printTitle, null, body);

    }

    /**

     * Generates a heading tag (h1 to h6)  with some content.

     *

     * @param headingTag the heading tag to be generated

     * @param body content for the tag

     * @return an HtmlTree object for the tag

     */

    public static HtmlTree HEADING(HtmlTag headingTag, Content body) {

        return HEADING(headingTag, false, null, body);

    }

    /**

     * Generates an HTML tag with lang attribute. It also adds head and body

     * content to the HTML tree.

     *

     * @param lang language for the HTML document

     * @param head head for the HTML tag

     * @param body body for the HTML tag

     * @return an HtmlTree object for the HTML tag

     */

    public static HtmlTree HTML(String lang, Content head, Content body) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.HTML, nullCheck(head), nullCheck(body));

        htmltree.addAttr(HtmlAttr.LANG, nullCheck(lang));

        return htmltree;

    }

    /**

     * Generates a IFRAME tag.

     *