/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2011, QOS.ch. All rights reserved.
    *
    * This program and the accompanying materials are dual-licensed under
    * either the terms of the Eclipse Public License v1.0 as published by
    * the Eclipse Foundation
    *
    *   or (per the licensee's choosing)
   *
   * under the terms of the GNU Lesser General Public License version 2.1
   * as published by the Free Software Foundation.
   */
  package ch.qos.logback.core.pattern;
  
  import java.util.HashMap;
  import java.util.Map;
  
  import ch.qos.logback.core.Context;
  import ch.qos.logback.core.CoreConstants;
  import ch.qos.logback.core.LayoutBase;
  import ch.qos.logback.core.pattern.parser.Node;
  import ch.qos.logback.core.pattern.parser.Parser;
  import ch.qos.logback.core.pattern.parser.ScanException;
  import ch.qos.logback.core.spi.ContextAware;
  import ch.qos.logback.core.status.ErrorStatus;
  import ch.qos.logback.core.status.StatusManager;
  
  abstract public class PatternLayoutBase<E> extends LayoutBase<E> {
  
    Converter<E> head;
    String pattern;
    protected PostCompileProcessor<E> postCompileProcessor;
  
  
    Map<String, String> instanceConverterMap = new HashMap<String, String>();
    protected boolean outputPatternAsHeader = false;
  
    /**
     * Concrete implementations of this class are responsible for elaborating the
     * mapping between pattern words and converters.
     * 
     * @return A map associating pattern words to the names of converter classes
     */
    abstract public Map<String, String> getDefaultConverterMap();
  
    /**
     * Returns a map where the default converter map is merged with the map
     * contained in the context.
     */
    public Map<String, String> getEffectiveConverterMap() {
      Map<String, String> effectiveMap = new HashMap<String, String>();
  
      // add the least specific map fist
      Map<String, String> defaultMap = getDefaultConverterMap();
      if (defaultMap != null) {
        effectiveMap.putAll(defaultMap);
      }
  
      // contextMap is more specific than the default map
      Context context = getContext();
      if (context != null) {
        @SuppressWarnings("unchecked")
        Map<String, String> contextMap = (Map<String, String>) context
            .getObject(CoreConstants.PATTERN_RULE_REGISTRY);
        if (contextMap != null) {
          effectiveMap.putAll(contextMap);
        }
      }
      // set the most specific map last
      effectiveMap.putAll(instanceConverterMap);
      return effectiveMap;
    }
  
    public void start() {
      if(pattern == null || pattern.length() == 0) {
        addError("Empty or null pattern.");
        return;
      }
      try { 
        Parser<E> p = new Parser<E>(pattern);
        if (getContext() != null) {
          p.setContext(getContext());
        }
        Node t = p.parse();
        this.head = p.compile(t, getEffectiveConverterMap());
        if (postCompileProcessor != null) {
          postCompileProcessor.process(head);
        }
        setContextForConverters(head);
        ConverterUtil.startConverters(this.head);
        super.start();
      } catch (ScanException sce) {
        StatusManager sm = getContext().getStatusManager();
        sm.add(new ErrorStatus("Failed to parse pattern \"" + getPattern()
            + "\".", this, sce));
      }
    }
  
   public void setPostCompileProcessor(
       PostCompileProcessor<E> postCompileProcessor) {
     this.postCompileProcessor = postCompileProcessor;
   }
 
   protected void setContextForConverters(Converter<E> head) {
     Context context = getContext();
     Converter c = head;
     while (c != null) {
       if (c instanceof ContextAware) {
         ((ContextAware) c).setContext(context);
       }
       c = c.getNext();
     }
   }
 
   protected String writeLoopOnConverters(E event) {
     StringBuilder buf = new StringBuilder(128);
     Converter<E> c = head;
     while (c != null) {
       c.write(buf, event);
       c = c.getNext();
     }
     return buf.toString();
   }
 
   public String getPattern() {
     return pattern;
   }
 
   public void setPattern(String pattern) {
     this.pattern = pattern;
   }
 
   public String toString() {
     return this.getClass().getName() + "(\"" + getPattern() + "\")";
   }
 
   public Map<String, String> getInstanceConverterMap() {
     return instanceConverterMap;
   }
 
   
   protected String getPresentationHeaderPrefix() {
     return CoreConstants.EMPTY_STRING;
   }
 
   public boolean isOutputPatternAsHeader() {
     return outputPatternAsHeader;
   }
 
   public void setOutputPatternAsHeader(boolean outputPatternAsHeader) {
     this.outputPatternAsHeader = outputPatternAsHeader;
   }
 
   @Override
   public String getPresentationHeader() {
     if(outputPatternAsHeader)
       return getPresentationHeaderPrefix()+pattern;
     else
       return super.getPresentationHeader();
   }
 }