// ***************************************************************************************************************************
// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
// * with the License.  You may obtain a copy of the License at                                                              *
// *                                                                                                                         *
// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
// *                                                                                                                         *
// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
// * specific language governing permissions and limitations under the License.                                              *
// ***************************************************************************************************************************
package org.apache.juneau.html;

import static org.apache.juneau.html.HtmlSerializer.*;
import static org.apache.juneau.html.HtmlSerializerSession.ContentResult.*;
import static org.apache.juneau.internal.StringUtils.*;

import java.io.*;
import java.util.*;
import java.util.regex.*;

import org.apache.juneau.*;
import org.apache.juneau.html.annotation.*;
import org.apache.juneau.internal.*;
import org.apache.juneau.serializer.*;
import org.apache.juneau.transform.*;
import org.apache.juneau.xml.*;
import org.apache.juneau.xml.annotation.*;

/**
 * Session object that lives for the duration of a single use of {@link HtmlSerializer}.
 * 
 * <p>
 * This class is NOT thread safe.
 * It is typically discarded after one-time use although it can be reused within the same thread.
 */
public class HtmlSerializerSession extends XmlSerializerSession {

   private final AnchorText anchorText;
   private final boolean
      detectLinksInStrings,
      lookForLabelParameters,
      addKeyValueTableHeaders,
      addBeanTypeProperties;
   private final Pattern urlPattern = Pattern.compile("http[s]?\\:\\/\\/.*");
   private final Pattern labelPattern;


   /**
    * Create a new session using properties specified in the context.
    * 
    * @param ctx
    *    The context creating this session object.
    *    The context contains all the configuration settings for this object.
    * @param args
    *    Runtime arguments.
    *    These specify session-level information such as locale and URI context.
    *    It also include session-level properties that override the properties defined on the bean and
    *    serializer contexts.
    */
   protected HtmlSerializerSession(HtmlSerializer ctx, SerializerSessionArgs args) {
      super(ctx, args);
      anchorText = getProperty(HTML_uriAnchorText, AnchorText.class, ctx.uriAnchorText);
      detectLinksInStrings = getProperty(HTML_detectLinksInStrings, boolean.class, ctx.detectLinksInStrings);
      lookForLabelParameters = getProperty(HTML_detectLabelParameters, boolean.class, ctx.lookForLabelParameters);
      addKeyValueTableHeaders = getProperty(HTML_addKeyValueTableHeaders, boolean.class, ctx.addKeyValueTableHeaders);
      addBeanTypeProperties = getProperty(HTML_addBeanTypeProperties, boolean.class, ctx.addBeanTypeProperties);
      String labelParameter = getProperty(HTML_labelParameter, String.class, ctx.labelParameter);
      labelPattern = Pattern.compile("[\\?\\&]" + Pattern.quote(labelParameter) + "=([^\\&]*)");
   }

   @Override /* Session */
   public ObjectMap asMap() {
      return super.asMap()
         .append("HtmlSerializerSession", new ObjectMap()
            .append("addBeanTypeProperties", addBeanTypeProperties)
            .append("addKeyValueTableHeaders", addKeyValueTableHeaders)
            .append("anchorText", anchorText)
            .append("detectLinksInStrings", detectLinksInStrings)
            .append("labelPattern", labelPattern)
            .append("lookForLabelParameters", lookForLabelParameters)
         );
   }

   /**
    * Converts the specified output target object to an {@link HtmlWriter}.
    * 
    * @param out The output target object.
    * @return The output target object wrapped in an {@link HtmlWriter}.
    * @throws Exception
    */
   protected final HtmlWriter getHtmlWriter(SerializerPipe out) throws Exception {
      Object output = out.getRawOutput();
      if (output instanceof HtmlWriter)
         return (HtmlWriter)output;
      HtmlWriter w = new HtmlWriter(out.getWriter(), isUseWhitespace(), getMaxIndent(), isTrimStrings(), getQuoteChar(),
         getUriResolver());
      out.setWriter(w);
      return w;
   }

   /**
    * Returns <jk>true</jk> if the specified object is a URL.
    * 
    * @param cm The ClassMeta of the object being serialized.
    * @param pMeta
    *    The property metadata of the bean property of the object.
    *    Can be <jk>null</jk> if the object isn't from a bean property.
    * @param o The object.
    * @return <jk>true</jk> if the specified object is a URL.
    */
   public boolean isUri(ClassMeta<?> cm, BeanPropertyMeta pMeta, Object o) {
      if (cm.isUri())
         return true;
      if (pMeta != null && pMeta.isUri())
         return true;
      if (detectLinksInStrings && o instanceof CharSequence && urlPattern.matcher(o.toString()).matches())
         return true;
      return false;
   }

   /**
    * Returns the anchor text to use for the specified URL object.
    * 
    * @param pMeta
    *    The property metadata of the bean property of the object.
    *    Can be <jk>null</jk> if the object isn't from a bean property.
    * @param o The URL object.
    * @return The anchor text to use for the specified URL object.
    */
   public String getAnchorText(BeanPropertyMeta pMeta, Object o) {
      String s = o.toString();
      if (lookForLabelParameters) {
         Matcher m = labelPattern.matcher(s);
         if (m.find())
            return urlDecode(m.group(1));
      }
      switch (anchorText) {
         case LAST_TOKEN:
            s = resolveUri(s);
            if (s.indexOf('/') != -1)
               s = s.substring(s.lastIndexOf('/')+1);
            if (s.indexOf('?') != -1)
               s = s.substring(0, s.indexOf('?'));
            if (s.indexOf('#') != -1)
               s = s.substring(0, s.indexOf('#'));
            if (s.isEmpty())
               s = "/";
            return urlDecode(s);
         case URI_ANCHOR:
            if (s.indexOf('#') != -1)
               s = s.substring(s.lastIndexOf('#')+1);
            return urlDecode(s);
         case PROPERTY_NAME:
            return pMeta == null ? s : pMeta.getName();
         case URI:
            return resolveUri(s);
         case CONTEXT_RELATIVE:
            return relativizeUri("context:/", s);
         case SERVLET_RELATIVE:
            return relativizeUri("servlet:/", s);
         case PATH_RELATIVE:
            return relativizeUri("request:/", s);
         default /* TO_STRING */:
            return s;
      }
   }

   /**
    * Returns the {@link HtmlSerializer#HTML_addKeyValueTableHeaders} setting value for this session.
    * 
    * @return The {@link HtmlSerializer#HTML_addKeyValueTableHeaders} setting value for this session.
    */
   public final boolean isAddKeyValueTableHeaders() {
      return addKeyValueTableHeaders;
   }

   /**
    * Returns the {@link HtmlSerializer#HTML_addBeanTypeProperties} setting value for this session.
    * 
    * @return The {@link HtmlSerializer#HTML_addBeanTypeProperties} setting value for this session.
    */
   @Override /* SerializerSession */
   public final boolean isAddBeanTypeProperties() {
      return addBeanTypeProperties;
   }

   @Override /* XmlSerializer */
   public boolean isHtmlMode() {
      return true;
   }

   @Override /* Serializer */
   protected void doSerialize(SerializerPipe out, Object o) throws Exception {
      doSerialize(o, getHtmlWriter(out));
   }

   /**
    * Main serialization routine.
    * 
    * @param session The serialization context object.
    * @param o The object being serialized.
    * @param w The writer to serialize to.
    * @return The same writer passed in.
    * @throws IOException If a problem occurred trying to send output to the writer.
    */
   private HtmlWriter doSerialize(Object o, HtmlWriter w) throws Exception {
      serializeAnything(w, o, getExpectedRootType(o), null, getInitialDepth()-1, null, true);
      return w;
   }

   /**
    * Serialize the specified object to the specified writer.
    * 
    * @param out The writer.
    * @param o The object to serialize.
    * @param eType The expected type of the object if this is a bean property.
    * @param name
    *    The attribute name of this object if this object was a field in a JSON object (i.e. key of a
    *    {@link java.util.Map.Entry} or property name of a bean).
    * @param xIndent The current indentation value.
    * @param pMeta The bean property being serialized, or <jk>null</jk> if we're not serializing a bean property.
    * @param isRoot <jk>true</jk> if this is the root element of the document.
    * @return The type of content encountered.  Either simple (no whitespace) or normal (elements with whitespace).
    * @throws Exception If a problem occurred trying to convert the output.
    */
   @SuppressWarnings({ "rawtypes", "unchecked" })
   protected ContentResult serializeAnything(HtmlWriter out, Object o,
         ClassMeta<?> eType, String name, int xIndent, BeanPropertyMeta pMeta, boolean isRoot) throws Exception {

      ClassMeta<?> aType = null;       // The actual type
      ClassMeta<?> wType = null;     // The wrapped type (delegate)
      ClassMeta<?> sType = object();   // The serialized type

      if (eType == null)
         eType = object();

      aType = push(name, o, eType);

      // Handle recursion
      if (aType == null) {
         o = null;
         aType = object();
      }

      indent += xIndent;

      ContentResult cr = CR_NORMAL;

      // Determine the type.
      if (o == null || (aType.isChar() && ((Character)o).charValue() == 0)) {
         out.tag("null");
         cr = ContentResult.CR_SIMPLE;

      } else {

         if (aType.isDelegate()) {
            wType = aType;
            aType = ((Delegate)o).getClassMeta();
         }

         sType = aType;

         String typeName = null;
         if (isAddBeanTypeProperties() && ! eType.equals(aType))
            typeName = aType.getDictionaryName();

         // Swap if necessary
         PojoSwap swap = aType.getPojoSwap(this);
         if (swap != null) {
            o = swap.swap(this, o);
            sType = swap.getSwapClassMeta(this);

            // If the getSwapClass() method returns Object, we need to figure out
            // the actual type now.
            if (sType.isObject())
               sType = getClassMetaForObject(o);
         }

         // Handle the case where we're serializing a raw stream.
         if (sType.isReader() || sType.isInputStream()) {
            pop();
            indent -= xIndent;
            IOUtils.pipe(o, out);
            return ContentResult.CR_SIMPLE;
         }

         HtmlClassMeta html = sType.getExtendedMeta(HtmlClassMeta.class);
         HtmlRender render = (pMeta == null ? null : pMeta.getExtendedMeta(HtmlBeanPropertyMeta.class).getRender());
         if (render == null)
            render = html.getRender();

         if (render != null) {
            Object o2 = render.getContent(this, o);
            if (o2 != o) {
               indent -= xIndent;
               pop();
               out.nl(indent);
               return serializeAnything(out, o2, null, typeName, xIndent, null, false);
            }
         }

         if (html.isAsXml() || (pMeta != null && pMeta.getExtendedMeta(HtmlBeanPropertyMeta.class).isAsXml())) {
            pop();
            indent++;
            super.serializeAnything(out, o, null, null, null, false, XmlFormat.MIXED, false, false, null);
            indent -= xIndent+1;
            return cr;

         } else if (html.isAsPlainText() || (pMeta != null && pMeta.getExtendedMeta(HtmlBeanPropertyMeta.class).isAsPlainText())) {
            out.write(o == null ? "null" : o.toString());
            cr = CR_SIMPLE;

         } else if (o == null || (sType.isChar() && ((Character)o).charValue() == 0)) {
            out.tag("null");
            cr = CR_SIMPLE;

         } else if (sType.isNumber()) {
            if (eType.isNumber() && ! isRoot)
               out.append(o);
            else
               out.sTag("number").append(o).eTag("number");
            cr = CR_SIMPLE;

         } else if (sType.isBoolean()) {
            if (eType.isBoolean() && ! isRoot)
               out.append(o);
            else
               out.sTag("boolean").append(o).eTag("boolean");
            cr = CR_SIMPLE;

         } else if (sType.isMap() || (wType != null && wType.isMap())) {
            out.nlIf(! isRoot, xIndent+1);
            if (o instanceof BeanMap)
               serializeBeanMap(out, (BeanMap)o, eType, pMeta);
            else
               serializeMap(out, (Map)o, sType, eType.getKeyType(), eType.getValueType(), typeName, pMeta);

         } else if (sType.isBean()) {
            BeanMap m = toBeanMap(o);
            Class<?> c = o.getClass();
            if (c.isAnnotationPresent(HtmlLink.class)) {
               HtmlLink h = o.getClass().getAnnotation(HtmlLink.class);
               Object urlProp = m.get(h.hrefProperty());
               Object nameProp = m.get(h.nameProperty());
               out.oTag("a").attrUri("href", urlProp).append('>').text(nameProp).eTag("a");
               cr = CR_SIMPLE;
            } else {
               out.nlIf(! isRoot, xIndent+2);
               serializeBeanMap(out, m, eType, pMeta);
            }

         } else if (sType.isCollection() || sType.isArray() || (wType != null && wType.isCollection())) {
            out.nlIf(! isRoot, xIndent+1);
            serializeCollection(out, o, sType, eType, name, pMeta);

         } else if (isUri(sType, pMeta, o)) {
            String label = getAnchorText(pMeta, o);
            out.oTag("a").attrUri("href", o).append('>');
            out.text(label);
            out.eTag("a");
            cr = CR_SIMPLE;

         } else {
            if (isRoot)
               out.sTag("string").text(toString(o)).eTag("string");
            else
               out.text(toString(o));
            cr = CR_SIMPLE;
         }
      }
      pop();
      indent -= xIndent;
      return cr;
   }

   /**
    * Identifies what the contents were of a serialized bean.
    */
   static enum ContentResult {
      CR_SIMPLE,    // Simple content.  Shouldn't use whitespace.
      CR_NORMAL     // Normal content.  Use whitespace.
   }

   @SuppressWarnings({ "rawtypes" })
   private void serializeMap(HtmlWriter out, Map m, ClassMeta<?> sType,
         ClassMeta<?> eKeyType, ClassMeta<?> eValueType, String typeName, BeanPropertyMeta ppMeta) throws Exception {

      ClassMeta<?> keyType = eKeyType == null ? string() : eKeyType;
      ClassMeta<?> valueType = eValueType == null ? object() : eValueType;
      ClassMeta<?> aType = getClassMetaForObject(m);       // The actual type

      int i = indent;

      out.oTag(i, "table");

      if (typeName != null && ppMeta != null && ppMeta.getClassMeta() != aType)
         out.attr(getBeanTypePropertyName(sType), typeName);

      out.append(">").nl(i+1);
      if (isAddKeyValueTableHeaders() && ! (aType.getExtendedMeta(HtmlClassMeta.class).isNoTableHeaders()
            || (ppMeta != null && ppMeta.getExtendedMeta(HtmlBeanPropertyMeta.class).isNoTableHeaders()))) {
         out.sTag(i+1, "tr").nl(i+2);
         out.sTag(i+2, "th").append("key").eTag("th").nl(i+3);
         out.sTag(i+2, "th").append("value").eTag("th").nl(i+3);
         out.ie(i+1).eTag("tr").nl(i+2);
      }
      for (Map.Entry e : (Set<Map.Entry>)m.entrySet()) {

         Object key = generalize(e.getKey(), keyType);
         Object value = null;
         try {
            value = e.getValue();
         } catch (StackOverflowError t) {
            throw t;
         } catch (Throwable t) {
            onError(t, "Could not call getValue() on property ''{0}'', {1}", e.getKey(), t.getLocalizedMessage());
         }

         String link = getLink(ppMeta);
         String style = getStyle(this, ppMeta, value);

         out.sTag(i+1, "tr").nl(i+2);
         out.oTag(i+2, "td");
         if (style != null)
            out.attr("style", style);
         out.cTag();
         if (link != null)
            out.oTag(i+3, "a").attrUri("href", link.replace("{#}", asString(value))).cTag();
         ContentResult cr = serializeAnything(out, key, keyType, null, 2, null, false);
         if (link != null)
            out.eTag("a");
         if (cr == CR_NORMAL)
            out.i(i+2);
         out.eTag("td").nl(i+2);
         out.sTag(i+2, "td");
         cr = serializeAnything(out, value, valueType, (key == null ? "_x0000_" : toString(key)), 2, null, false);
         if (cr == CR_NORMAL)
            out.ie(i+2);
         out.eTag("td").nl(i+2);
         out.ie(i+1).eTag("tr").nl(i+1);
      }
      out.ie(i).eTag("table").nl(i);
   }

   private void serializeBeanMap(HtmlWriter out, BeanMap<?> m, ClassMeta<?> eType,
         BeanPropertyMeta ppMeta) throws Exception {
      int i = indent;

      out.oTag(i, "table");

      String typeName = m.getMeta().getDictionaryName();
      if (typeName != null && eType != m.getClassMeta())
         out.attr(getBeanTypePropertyName(m.getClassMeta()), typeName);

      out.append('>').nl(i);
      if (isAddKeyValueTableHeaders() && ! (m.getClassMeta().getExtendedMeta(HtmlClassMeta.class).isNoTableHeaders()
            || (ppMeta != null && ppMeta.getExtendedMeta(HtmlBeanPropertyMeta.class).isNoTableHeaders()))) {
         out.sTag(i+1, "tr").nl(i+1);
         out.sTag(i+2, "th").append("key").eTag("th").nl(i+2);
         out.sTag(i+2, "th").append("value").eTag("th").nl(i+2);
         out.ie(i+1).eTag("tr").nl(i+1);
      }

      for (BeanPropertyValue p : m.getValues(isTrimNulls())) {
         BeanPropertyMeta pMeta = p.getMeta();
         ClassMeta<?> cMeta = p.getClassMeta();

         String key = p.getName();
         Object value = p.getValue();
         Throwable t = p.getThrown();
         if (t != null)
            onBeanGetterException(pMeta, t);

         if (canIgnoreValue(cMeta, key, value))
            continue;

         String link = null, anchorText = null;
         if (! cMeta.isCollectionOrArray()) {
            link = m.resolveVars(getLink(pMeta));
            anchorText = m.resolveVars(getAnchorText(pMeta));
         }

         if (anchorText != null)
            value = anchorText;

         out.sTag(i+1, "tr").nl(i+1);
         out.sTag(i+2, "td").text(key).eTag("td").nl(i+2);
         out.oTag(i+2, "td");
         String style = getStyle(this, pMeta, value);
         if (style != null)
            out.attr("style", style);
         out.cTag();

         try {
            if (link != null)
               out.oTag(i+3, "a").attrUri("href", link).cTag();
            ContentResult cr = serializeAnything(out, value, cMeta, key, 2, pMeta, false);
            if (cr == CR_NORMAL)
               out.i(i+2);
            if (link != null)
               out.eTag("a");
         } catch (SerializeException e) {
            throw e;
         } catch (Error e) {
            throw e;
         } catch (Throwable e) {
            e.printStackTrace();
            onBeanGetterException(pMeta, e);
         }
         out.eTag("td").nl(i+2);
         out.ie(i+1).eTag("tr").nl(i+1);
      }
      out.ie(i).eTag("table").nl(i);
   }

   @SuppressWarnings({ "rawtypes", "unchecked" })
   private void serializeCollection(HtmlWriter out, Object in, ClassMeta<?> sType,
         ClassMeta<?> eType, String name, BeanPropertyMeta ppMeta) throws Exception {

      ClassMeta<?> seType = sType.getElementType();
      if (seType == null)
         seType = object();

      Collection c = (sType.isCollection() ? (Collection)in : toList(sType.getInnerClass(), in));

      int i = indent;
      if (c.isEmpty()) {
         out.appendln(i, "<ul></ul>");
         return;
      }

      String type2 = null;
      if (sType != eType)
         type2 = sType.getDictionaryName();
      if (type2 == null)
         type2 = "array";

      c = sort(c);

      HtmlBeanPropertyMeta hbpMeta = (ppMeta == null ? null : ppMeta.getExtendedMeta(HtmlBeanPropertyMeta.class));
      String btpn = getBeanTypePropertyName(eType);

      // Look at the objects to see how we're going to handle them.  Check the first object to see how we're going to
      // handle this.
      // If it's a map or bean, then we'll create a table.
      // Otherwise, we'll create a list.
      Object[] th = getTableHeaders(c, hbpMeta);

      if (th != null) {

         out.oTag(i, "table").attr(btpn, type2).append('>').nl(i+1);
         out.sTag(i+1, "tr").nl(i+2);
         for (Object key : th) {
            out.sTag(i+2, "th");
            out.text(convertToType(key, String.class));
            out.eTag("th").nl(i+2);
         }
         out.ie(i+1).eTag("tr").nl(i+1);

         for (Object o : c) {
            ClassMeta<?> cm = getClassMetaForObject(o);

            if (cm != null && cm.getPojoSwap(this) != null) {
               PojoSwap swap = cm.getPojoSwap(this);
               o = swap.swap(this, o);
               cm = swap.getSwapClassMeta(this);
            }

            out.oTag(i+1, "tr");
            String typeName = (cm == null ? null : cm.getDictionaryName());
            String typeProperty = getBeanTypePropertyName(cm);

            if (typeName != null && eType.getElementType() != cm)
               out.attr(typeProperty, typeName);
            out.cTag().nl(i+2);

            if (cm == null) {
               out.i(i+2);
               serializeAnything(out, o, null, null, 1, null, false);
               out.nl(0);

            } else if (cm.isMap() && ! (cm.isBeanMap())) {
               Map m2 = sort((Map)o);

               for (Object k : th) {
                  out.sTag(i+2, "td");
                  ContentResult cr = serializeAnything(out, m2.get(k), eType.getElementType(), toString(k), 2, null, false);
                  if (cr == CR_NORMAL)
                     out.i(i+2);
                  out.eTag("td").nl(i+2);
               }
            } else {
               BeanMap m2 = null;
               if (o instanceof BeanMap)
                  m2 = (BeanMap)o;
               else
                  m2 = toBeanMap(o);

               for (Object k : th) {
                  BeanMapEntry p = m2.getProperty(toString(k));
                  BeanPropertyMeta pMeta = p.getMeta();
                  if (pMeta.canRead()) {
                     Object value = p.getValue();

                     String link = null, anchorText = null;
                     if (! pMeta.getClassMeta().isCollectionOrArray()) {
                        link = m2.resolveVars(getLink(pMeta));
                        anchorText = m2.resolveVars(getAnchorText(pMeta));
                     }

                     if (anchorText != null)
                        value = anchorText;

                     String style = getStyle(this, pMeta, value);
                     out.oTag(i+2, "td");
                     if (style != null)
                        out.attr("style", style);
                     out.cTag();
                     if (link != null)
                        out.oTag("a").attrUri("href", link).cTag();
                     ContentResult cr = serializeAnything(out, value, pMeta.getClassMeta(), p.getKey().toString(), 2, pMeta, false);
                     if (cr == CR_NORMAL)
                        out.i(i+2);
                     if (link != null)
                        out.eTag("a");
                     out.eTag("td").nl(i+2);
                  }
               }
            }
            out.ie(i+1).eTag("tr").nl(i+1);
         }
         out.ie(i).eTag("table").nl(i);

      } else {
         out.oTag(i, "ul");
         if (! type2.equals("array"))
            out.attr(btpn, type2);
         out.append('>').nl(i+1);
         for (Object o : c) {
            out.oTag(i+1, "li");
            String style = getStyle(this, ppMeta, o);
            String link = getLink(ppMeta);
            if (style != null)
               out.attr("style", style);
            out.cTag();
            if (link != null)
               out.oTag(i+2, "a").attrUri("href", link.replace("{#}", asString(o))).cTag();
            ContentResult cr = serializeAnything(out, o, eType.getElementType(), name, 1, null, false);
            if (link != null)
               out.eTag("a");
            if (cr == CR_NORMAL)
               out.ie(i+1);
            out.eTag("li").nl(i+1);
         }
         out.ie(i).eTag("ul").nl(i);
      }
   }

   private static HtmlRender<?> getRender(HtmlSerializerSession session, BeanPropertyMeta pMeta, Object value) {
      if (pMeta == null)
         return null;
      HtmlBeanPropertyMeta hpMeta = pMeta.getExtendedMeta(HtmlBeanPropertyMeta.class);
      HtmlRender<?> render = hpMeta.getRender();
      if (render != null)
         return render;
      ClassMeta<?> cMeta = session.getClassMetaForObject(value);
      render = cMeta == null ? null : cMeta.getExtendedMeta(HtmlClassMeta.class).getRender();
      return render;
   }

   @SuppressWarnings({"rawtypes","unchecked"})
   private static String getStyle(HtmlSerializerSession session, BeanPropertyMeta pMeta, Object value) {
      HtmlRender render = getRender(session, pMeta, value);
      return render == null ? null : render.getStyle(session, value);
   }

   private static String getLink(BeanPropertyMeta pMeta) {
      return pMeta == null ? null : pMeta.getExtendedMeta(HtmlBeanPropertyMeta.class).getLink();
   }

   private static String getAnchorText(BeanPropertyMeta pMeta) {
      return pMeta == null ? null : pMeta.getExtendedMeta(HtmlBeanPropertyMeta.class).getAnchorText();
   }

   /*
    * Returns the table column headers for the specified collection of objects.
    * Returns null if collection should not be serialized as a 2-dimensional table.
    * 2-dimensional tables are used for collections of objects that all have the same set of property names.
    */
   @SuppressWarnings({ "rawtypes", "unchecked" })
   private Object[] getTableHeaders(Collection c, HtmlBeanPropertyMeta hbpMeta) throws Exception {
      if (c.size() == 0)
         return null;
      c = sort(c);
      Object[] th;
      Set<ClassMeta> prevC = new HashSet<>();
      Object o1 = null;
      for (Object o : c)
         if (o != null) {
            o1 = o;
            break;
         }
      if (o1 == null)
         return null;
      ClassMeta<?> cm = getClassMetaForObject(o1);

      PojoSwap swap = cm.getPojoSwap(this);
      if (swap != null) {
         o1 = swap.swap(this, o1);
         cm = swap.getSwapClassMeta(this);
      }

      if (cm == null || ! cm.isMapOrBean())
         return null;
      if (cm.getInnerClass().isAnnotationPresent(HtmlLink.class))
         return null;
      HtmlClassMeta h = cm.getExtendedMeta(HtmlClassMeta.class);
      if (h.isNoTables() || (hbpMeta != null && hbpMeta.isNoTables()))
         return null;
      if (h.isNoTableHeaders() || (hbpMeta != null && hbpMeta.isNoTableHeaders()))
         return new Object[0];
      if (canIgnoreValue(cm, null, o1))
         return null;
      if (cm.isMap() && ! cm.isBeanMap()) {
         Set<Object> set = new LinkedHashSet<>();
         for (Object o : c) {
            if (! canIgnoreValue(cm, null, o)) {
               if (! cm.isInstance(o))
                  return null;
               Map m = sort((Map)o);
               for (Map.Entry e : (Set<Map.Entry>)m.entrySet()) {
                  if (e.getValue() != null)
                     set.add(e.getKey() == null ? null : e.getKey());
               }
            }
         }
         th = set.toArray(new Object[set.size()]);
      } else {
         Map<String,Boolean> m = new LinkedHashMap<>();
         for (Object o : c) {
            if (! canIgnoreValue(cm, null, o)) {
               if (! cm.isInstance(o))
                  return null;
               BeanMap<?> bm = (o instanceof BeanMap ? (BeanMap)o : toBeanMap(o));
               for (Map.Entry<String,Object> e : bm.entrySet()) {
                  String key = e.getKey();
                  if (e.getValue() != null)
                     m.put(key, true);
                  else if (! m.containsKey(key))
                     m.put(key, false);
               }
            }
         }
         for (Iterator<Boolean> i = m.values().iterator(); i.hasNext();)
            if (! i.next())
               i.remove();
         th = m.keySet().toArray(new Object[m.size()]);
      }
      prevC.add(cm);
      boolean isSortable = true;
      for (Object o : th)
         isSortable &= (o instanceof Comparable);
      Set<Object> s = (isSortable ? new TreeSet<>() : new LinkedHashSet<>());
      s.addAll(Arrays.asList(th));

      for (Object o : c) {
         if (o == null)
            continue;
         cm = getClassMetaForObject(o);

         PojoSwap ps = cm == null ? null : cm.getPojoSwap(this);
         if (ps != null) {
            o = ps.swap(this, o);
            cm = ps.getSwapClassMeta(this);
         }
         if (prevC.contains(cm))
            continue;
         if (cm == null || ! (cm.isMap() || cm.isBean()))
            return null;
         if (cm.getInnerClass().isAnnotationPresent(HtmlLink.class))
            return null;
         if (canIgnoreValue(cm, null, o))
            return null;
         if (cm.isMap() && ! cm.isBeanMap()) {
            Map m = (Map)o;
            if (th.length != m.keySet().size())
               return null;
            for (Object k : m.keySet())
               if (! s.contains(k.toString()))
                  return null;
         } else {
            BeanMap<?> bm = (o instanceof BeanMap ? (BeanMap)o : toBeanMap(o));
            int l = 0;
            for (String k : bm.keySet()) {
               if (! s.contains(k))
                  return null;
               l++;
            }
            if (s.size() != l)
               return null;
         }
      }
      return th;
   }
}