/*

 * Copyright (c) 2010, 2013, 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 com.sun.tools.doclets.formats.html.markup;

import java.io.IOException;

import java.io.Writer;

import java.util.*;

import java.nio.charset.*;

import com.sun.tools.doclets.internal.toolkit.Content;

import com.sun.tools.doclets.internal.toolkit.util.*;

/**

 * 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 {

    private HtmlTag htmlTag;

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

    private List<Content> content = Collections.<Content>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 content: contents)

            addContent(content);

    }

    /**

     * Adds an attribute for the HTML tag.

     *

     * @param attrName name of the attribute

     * @param attrValue value of the attribute

     */

    public void addAttr(HtmlAttr attrName, String attrValue) {

        if (attrs.isEmpty())

            attrs = new LinkedHashMap<HtmlAttr,String>(3);

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

    }

    public void setTitle(Content body) {

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

    }

    /**

     * Adds a style for the HTML tag.

     *

     * @param style style to be added

     */

    public void addStyle(HtmlStyle style) {

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

    }

    /**

     * Adds content for the HTML tag.

     *

     * @param tagContent tag content to be added

     */

    public void addContent(Content tagContent) {

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

            if (content.isEmpty())

                content = new ArrayList<Content>();

            content.add(tagContent);

        }

    }

    /**

     * This method adds a string content to the htmltree. 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

     */

    public void addContent(String 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));

    }

    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;

    }

    /**

     * A set of ASCII URI characters to be left unencoded.

     */

    public static final BitSet NONENCODING_CHARS = new BitSet(256);

    static {

        // alphabetic characters

        for (int i = 'a'; i <= 'z'; i++) {

            NONENCODING_CHARS.set(i);

        }

        for (int i = 'A'; i <= 'Z'; i++) {

            NONENCODING_CHARS.set(i);

        }

        // numeric characters

        for (int i = '0'; i <= '9'; i++) {

            NONENCODING_CHARS.set(i);

        }

        // Reserved characters as per RFC 3986. These are set of delimiting characters.

        String noEnc = ":/?#[]@!$&'()*+,;=";

        // Unreserved characters as per RFC 3986 which should not be percent encoded.

        noEnc += "-._~";

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

            NONENCODING_CHARS.set(noEnc.charAt(i));

        }

    }

    private static String encodeURL(String url) {

        byte[] urlBytes = url.getBytes(Charset.forName("UTF-8"));

        StringBuilder sb = new StringBuilder();

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

            int c = urlBytes[i];

            if (NONENCODING_CHARS.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 name attribute and content.

     *

     * @param name name for the anchor tag

     * @param body content for the anchor tag

     * @return an HtmlTree object

     */

    public static HtmlTree A_NAME(String name, Content body) {

        HtmlTree htmltree = HtmlTree.A_NAME(name);

        htmltree.addContent(nullCheck(body));

        return htmltree;

    }

    /**

     * Generates an HTML anchor tag with name attribute.

     *

     * @param name name for the anchor tag

     * @return an HtmlTree object

     */

    public static HtmlTree A_NAME(String name) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.A);

        htmltree.addAttr(HtmlAttr.NAME, nullCheck(name));

        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.addStyle(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 FRAME tag.

     *

     * @param src the url of the document to be shown in the frame

     * @param name specifies the name of the frame

     * @param title the title for the frame

     * @param scrolling specifies whether to display scrollbars in the frame

     * @return an HtmlTree object for the FRAME tag

     */

    public static HtmlTree FRAME(String src, String name, String title, String scrolling) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.FRAME);

        htmltree.addAttr(HtmlAttr.SRC, nullCheck(src));

        htmltree.addAttr(HtmlAttr.NAME, nullCheck(name));

        htmltree.addAttr(HtmlAttr.TITLE, nullCheck(title));

        if (scrolling != null)

            htmltree.addAttr(HtmlAttr.SCROLLING, scrolling);

        return htmltree;

    }

    /**

     * Generates a Frame tag.

     *

     * @param src the url of the document to be shown in the frame

     * @param name specifies the name of the frame

     * @param title the title for the frame

     * @return an HtmlTree object for the SPAN tag

     */

    public static HtmlTree FRAME(String src, String name, String title) {

        return FRAME(src, name, title, null);

    }

    /**

     * Generates a FRAMESET tag.

     *

     * @param cols the size of columns in the frameset

     * @param rows the size of rows in the frameset

     * @param title the title for the frameset

     * @param onload the script to run when the document loads

     * @return an HtmlTree object for the FRAMESET tag

     */

    public static HtmlTree FRAMESET(String cols, String rows, String title, String onload) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.FRAMESET);

        if (cols != null)

            htmltree.addAttr(HtmlAttr.COLS, cols);

        if (rows != null)

            htmltree.addAttr(HtmlAttr.ROWS, rows);

        htmltree.addAttr(HtmlAttr.TITLE, nullCheck(title));

        htmltree.addAttr(HtmlAttr.ONLOAD, nullCheck(onload));

        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.addStyle(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 LI tag with some content.

     *

     * @param body content for the tag

     * @return an HtmlTree object for the LI tag

     */

    public static HtmlTree LI(Content body) {

        return LI(null, body);

    }

    /**

     * Generates a LI tag with some content.

     *

     * @param styleClass style for the tag

     * @param body content for the tag

     * @return an HtmlTree object for the LI tag

     */

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

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

        if (styleClass != null)

            htmltree.addStyle(styleClass);

        return htmltree;

    }

    /**

     * Generates a LINK tag with the rel, type, href and title attributes.

     *

     * @param rel relevance of the link

     * @param type type of link

     * @param href the path for the link

     * @param title title for the link

     * @return an HtmlTree object for the LINK tag

     */

    public static HtmlTree LINK(String rel, String type, String href, String title) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.LINK);

        htmltree.addAttr(HtmlAttr.REL, nullCheck(rel));

        htmltree.addAttr(HtmlAttr.TYPE, nullCheck(type));

        htmltree.addAttr(HtmlAttr.HREF, nullCheck(href));

        htmltree.addAttr(HtmlAttr.TITLE, nullCheck(title));

        return htmltree;

    }

    /**

     * Generates a META tag with the http-equiv, content and charset attributes.

     *

     * @param httpEquiv http equiv attribute for the META tag

     * @param content type of content

     * @param charSet character set used

     * @return an HtmlTree object for the META tag

     */

    public static HtmlTree META(String httpEquiv, String content, String charSet) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.META);

        String contentCharset = content + "; charset=" + charSet;

        htmltree.addAttr(HtmlAttr.HTTP_EQUIV, nullCheck(httpEquiv));

        htmltree.addAttr(HtmlAttr.CONTENT, contentCharset);

        return htmltree;

    }

    /**

     * Generates a META tag with the name and content attributes.

     *

     * @param name name attribute

     * @param content type of content

     * @return an HtmlTree object for the META tag

     */

    public static HtmlTree META(String name, String content) {

        HtmlTree htmltree = new HtmlTree(HtmlTag.META);

        htmltree.addAttr(HtmlAttr.NAME, nullCheck(name));

        htmltree.addAttr(HtmlAttr.CONTENT, nullCheck(content));

        return htmltree;

    }

    /**