// Copyright 2012 Google Inc. All Rights Reserved.
//
// Licensed 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 com.hughes.android.dictionary.parser.wiktionary;

import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.regex.Pattern;

import com.hughes.android.dictionary.engine.EntrySource;
import com.hughes.android.dictionary.engine.EntryTypeName;
import com.hughes.android.dictionary.engine.IndexBuilder;
import com.hughes.android.dictionary.engine.IndexedEntry;
import com.hughes.android.dictionary.parser.Parser;
import com.hughes.android.dictionary.parser.WikiTokenizer;
import com.hughes.util.EnumUtil;

public abstract class AbstractWiktionaryParser implements Parser {

  static final Logger LOG = Logger.getLogger("WiktionaryParser");

  final SortedMap<String, AtomicInteger> counters = new TreeMap<String, AtomicInteger>();
  final Set<String> pairsAdded = new LinkedHashSet<String>();
  
  public EntrySource entrySource;
  public String title;


  abstract void parseSection(final String heading, final String text);
  
  abstract void removeUselessArgs(final Map<String, String> namedArgs);
  
  @Override
  public void parse(final File file, final EntrySource entrySource, final int pageLimit) throws IOException {
    this.entrySource = entrySource;
    int pageCount = 0;
    final DataInputStream dis = new DataInputStream(new BufferedInputStream(new FileInputStream(file)));
    try {
    while (true) {
      if (pageLimit >= 0 && pageCount >= pageLimit) {
        return;
      }
      
      try {
        title = dis.readUTF();
      } catch (EOFException e) {
        LOG.log(Level.INFO, "EOF reading split.");
        dis.close();
        return;
      }
      final String heading = dis.readUTF();
      final int bytesLength = dis.readInt();
      final byte[] bytes = new byte[bytesLength];
      dis.readFully(bytes);
      final String text = new String(bytes, "UTF8");
      
      parseSection(heading, text);

      ++pageCount;
      if (pageCount % 1000 == 0) {
        LOG.info("pageCount=" + pageCount);
      }
    }
    } finally {
      dis.close();
      LOG.info("***COUNTERS***");
      for (final Map.Entry<String, AtomicInteger> entry : counters.entrySet()) {
        LOG.info(entry.getKey() + ": " + entry.getValue());
      }
    }
  }
  
  static final Pattern whitespace = Pattern.compile("\\s+");
  static String trim(final String s) {
    return whitespace.matcher(s).replaceAll(" ").trim();
  }

  public void incrementCount(final String string) {
    AtomicInteger counter = counters.get(string);
    if (counter == null) {
      counter = new AtomicInteger();
      counters.put(string, counter);
    }
    counter.incrementAndGet();
  }
  
  public void addLinkToCurrentEntry(final String token, final EntryTypeName entryTypeName) {
      assert false;
  }

  
  // -------------------------------------------------------------------------
  
  static class AppendAndIndexWikiCallback<T extends AbstractWiktionaryParser> implements WikiTokenizer.Callback {

    final T parser;
    StringBuilder builder;
    IndexedEntry indexedEntry;
    IndexBuilder indexBuilder;
    final Map<String,FunctionCallback<T>> functionCallbacks = new LinkedHashMap<String, FunctionCallback<T>>();
    
    boolean entryTypeNameSticks = false;
    EntryTypeName entryTypeName = null;
    
    final Map<String,AtomicInteger> langCodeToTCount = new LinkedHashMap<String, AtomicInteger>();
    
    final NameAndArgs<T> nameAndArgs = new NameAndArgs<T>();
    
    public AppendAndIndexWikiCallback(final T parser) {
      this.parser = parser;
    }
    
    public void reset(final StringBuilder builder, final IndexedEntry indexedEntry) {
      this.builder = builder;
      this.indexedEntry = indexedEntry;
      this.indexBuilder = null;
      entryTypeName = null;
      entryTypeNameSticks = false;
    }
    
    public void dispatch(final String wikiText, final IndexBuilder indexBuilder, final EntryTypeName entryTypeName) {
      final IndexBuilder oldIndexBuilder = this.indexBuilder;
      final EntryTypeName oldEntryTypeName = this.entryTypeName;
      this.indexBuilder = indexBuilder;
      if (!entryTypeNameSticks) {
        this.entryTypeName = EnumUtil.min(entryTypeName, this.entryTypeName);
      }
      if (entryTypeName == null) this.entryTypeName = null;
      WikiTokenizer.dispatch(wikiText, false, this);
      this.indexBuilder = oldIndexBuilder;
      this.entryTypeName = oldEntryTypeName;
    }
    
    public String dispatch(final String wikiText, final EntryTypeName entryTypeName) {
      final int start = builder.length();
      dispatch(wikiText, this.indexBuilder, entryTypeName);
      return builder.substring(start);
    }

    @Override
    public void onPlainText(final String plainText) {
      // The only non-recursive callback.  Just appends to the builder, and indexes.
      builder.append(plainText);
      if (indexBuilder != null && entryTypeName != null && indexedEntry != null) {
        indexBuilder.addEntryWithString(indexedEntry, plainText, entryTypeName);
      }
    }

    @Override
    public void onWikiLink(WikiTokenizer wikiTokenizer) {
      final String text = wikiTokenizer.wikiLinkText();
      @SuppressWarnings("unused")
      final String link = wikiTokenizer.wikiLinkDest();
      dispatch(text, entryTypeName);
    }

    @Override
    public void onFunction(
        final WikiTokenizer wikiTokenizer,
        final String name,
        final List<String> args, 
        final Map<String, String> namedArgs) {
      
      FunctionCallback<T> functionCallback = functionCallbacks.get(name);
      if (functionCallback == null || !functionCallback.onWikiFunction(wikiTokenizer, name, args, namedArgs, parser, this)) {
        // Default function handling:
        parser.removeUselessArgs(namedArgs);
        final boolean single = args.isEmpty() && namedArgs.isEmpty();
        builder.append(single ? "{" : "{{");

        final IndexBuilder oldIndexBuilder = indexBuilder;
        indexBuilder = null;
        nameAndArgs.onWikiFunction(wikiTokenizer, name, args, namedArgs, parser, this);
        indexBuilder = oldIndexBuilder;

        builder.append(single ? "}" : "}}");
      }
    }
    
    @Override
    public void onHtml(WikiTokenizer wikiTokenizer) {
      // Unindexed for now.
      builder.append(wikiTokenizer.token());
    }

    @Override
    public void onMarkup(WikiTokenizer wikiTokenizer) {
      // Do nothing.
    }

    @Override
    public final void onComment(WikiTokenizer wikiTokenizer) {
      // Do nothing.
    }

    @Override
    public void onNewline(WikiTokenizer wikiTokenizer) {
      assert false;
    }

    @Override
    public void onHeading(WikiTokenizer wikiTokenizer) {
      assert false;
    }

    @Override
    public void onListItem(WikiTokenizer wikiTokenizer) {
      assert false;
    }

  }
  
  // --------------------------------------------------------------------
  
  static final class NameAndArgs<T extends AbstractWiktionaryParser> implements FunctionCallback<T> {
    @Override
    public boolean onWikiFunction(final WikiTokenizer wikiTokenizer, final String name, final List<String> args,
        final Map<String, String> namedArgs, final T parser,
        final AppendAndIndexWikiCallback<T> appendAndIndexWikiCallback) {
      
      if (name != null) {
        appendAndIndexWikiCallback.dispatch(name, null);
      }
      for (int i = 0; i < args.size(); ++i) {
        if (args.get(i).length() > 0) {
          appendAndIndexWikiCallback.builder.append("|");
          appendAndIndexWikiCallback.dispatch(args.get(i), null, null);
        }
      }
      appendNamedArgs(namedArgs, appendAndIndexWikiCallback);
      return true;
    }
  }
  static NameAndArgs<AbstractWiktionaryParser> NAME_AND_ARGS = new NameAndArgs<AbstractWiktionaryParser>();

  static void appendNamedArgs(final Map<String, String> namedArgs,
      final AppendAndIndexWikiCallback<?> appendAndIndexWikiCallback) {
    for (final Map.Entry<String, String> entry : namedArgs.entrySet()) {
      appendAndIndexWikiCallback.builder.append("|");
      appendAndIndexWikiCallback.dispatch(entry.getKey(), null, null);
      appendAndIndexWikiCallback.builder.append("=");
      EntryTypeName entryTypeName = null;
      IndexBuilder indexBuilder = null;
      // This doesn't work: we'd need to add to word-forms.
//      System.out.println(entry.getKey());
//      if (entry.getKey().equals("tr")) {
//        entryTypeName = EntryTypeName.WIKTIONARY_TRANSLITERATION;
//        indexBuilder = appendAndIndexWikiCallback.parser.foreignIndexBuilder;
//      }
      appendAndIndexWikiCallback.dispatch(entry.getValue(), indexBuilder, entryTypeName);
    }
  }

}