/* LanguageTool, a natural language style checker 
 * Copyright (C) 2005 Daniel Naber (http://www.danielnaber.de)
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
 * USA
 */
package de.danielnaber.languagetool.rules.ro;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Queue;
import java.util.ResourceBundle;
import java.util.concurrent.ArrayBlockingQueue;

import de.danielnaber.languagetool.AnalyzedSentence;
import de.danielnaber.languagetool.AnalyzedTokenReadings;
import de.danielnaber.languagetool.JLanguageTool;
import de.danielnaber.languagetool.Language;
import de.danielnaber.languagetool.rules.AbstractSimpleReplaceRule;
import de.danielnaber.languagetool.rules.Category;
import de.danielnaber.languagetool.rules.Rule;
import de.danielnaber.languagetool.rules.RuleMatch;
import de.danielnaber.languagetool.tokenizers.Tokenizer;
import de.danielnaber.languagetool.tools.StringTools;

/**
 * A rule that matches words which should not be used and suggests correct ones instead. <br/> 
 * Romanian implementations. Loads the list of words from
 * <code>/ro/replace.txt</code>.<br/><br/>
 * 
 * Unlike AbstractSimpleReplaceRule, supports multiple words (Ex: "aqua forte" => "acvaforte").<br/><br/>
 * 
 * Note: Merge this into {@link AbstractSimpleReplaceRule} eventually and simply extend from AbstractSimpleReplaceRule.<br/>
 * 
 * @author Ionuț Păduraru
 * @version $Id$
 * 
 */
public class SimpleReplaceRule extends Rule {

	public static final String ROMANIAN_SIMPLE_REPLACE_RULE = "RO_SIMPLE_REPLACE";

	private static final String FILE_NAME = "/ro/replace.txt";
	private static final String FILE_ENCODING = "utf-8";
	// locale used on case-conversion
	private static Locale roLocale = new Locale("ro");

	// list of maps containing error-corrections pairs.
	// the n-th map contains key strings of (n+1) words 
	private List<Map<String, String>> wrongWords;

	public final String getFileName() {
		return FILE_NAME;
	}

	public SimpleReplaceRule(final ResourceBundle messages) throws IOException {
		super(messages);
		if (messages != null) {
			super.setCategory(new Category(messages.getString("category_misc")));
		}
		wrongWords = loadWords(JLanguageTool.getDataBroker().getFromRulesDirAsStream(getFileName()));
	}

	public final String getId() {
		return ROMANIAN_SIMPLE_REPLACE_RULE;
	}

	public String getDescription() {
		return "Cuvinte sau grupuri de cuvinte incorecte sau ieșite din uz";
	}

	public String getShort() {
		return "Cuvânt incorect sau ieșit din uz";
	}

	public String getSuggestion() {
		return " este incorect sau ieșit din uz, folosiți ";
	}

	/**
	 * @return the word used to separate multiple suggestions; used only before last suggestion, the rest are comma-separated.  
	 */
	public String getSuggestionsSeparator() {
		return " sau ";
	}

	/**
	 * use case-insensitive matching.
	 */
	public boolean isCaseSensitive() {
		return false;
	}

	/**
	 * locale used on case-conversion
	 */
	public Locale getLocale() {
		return roLocale;
	}

	public String getEncoding() {
		return FILE_ENCODING;
	}

	/**
	 * @return the word tokenizer used for tokenization on loading words.
	 */
	protected Tokenizer getWordTokenizer() {
		return Language.ROMANIAN.getWordTokenizer();
	}
	
	/**
	 * @return the list of wrong words for which this rule can suggest correction. The list cannot be modified.
	 */
	public List<Map<String, String>> getWrongWords() {
		return wrongWords;
	}
	
	/**
	 * Load the list of words. <br/>
	 * Same as {@link AbstractSimpleReplaceRule#loadWords} but allows multiple words.   
	 * @param file the file to load.
	 * @return the list of maps containing the error-corrections pairs. <br/>The n-th map contains key strings of (n+1) words.
	 * @throws IOException when the file contains errors.
	 * @see #getWordTokenizer
	 */
	private List<Map<String, String>> loadWords(final InputStream file)
			throws IOException {
		final List<Map<String, String>> list = new ArrayList<Map<String, String>>();
		InputStreamReader isr = null;
		BufferedReader br = null;
		try {
			isr = new InputStreamReader(file, getEncoding());
			br = new BufferedReader(isr);
			String line;

			while ((line = br.readLine()) != null) {
				line = line.trim();
				if (line.length() < 1 || line.charAt(0) == '#') { // ignore comments
					continue;
				}
				final String[] parts = line.split("=");
				if (parts.length != 2) {
					throw new IOException("Format error in file "
							+ JLanguageTool.getDataBroker().getFromRulesDirAsUrl(getFileName())
							+ ", line: " + line);
				}
				final String[] wrongForms = parts[0].split("\\|"); // multiple incorect forms
				for (String wrongForm : wrongForms) {
					int wordCount = 0;
					final List<String> tokens = getWordTokenizer().tokenize(wrongForm);
					for (String token : tokens) {
						if (!StringTools.isWhitespace(token)) {
							wordCount++;
						}
					}
					// grow if necessary
					for (int i = list.size(); i < wordCount; i++) {
						list.add(new HashMap<String, String>());
					}
					list.get(wordCount - 1).put(wrongForm, parts[1]);
				}
			}

		} finally {
			if (br != null) {
				br.close();
			}
			if (isr != null) {
				isr.close();
			}
		}
		// seal the result (prevent modification from outside this class)
		List<Map<String,String>> result = new ArrayList<Map<String, String>>();
		for (Map<String, String> map : list) {
			result.add(Collections.unmodifiableMap(map));
		}
		return Collections.unmodifiableList(result);
	}

	private void addToQueue(AnalyzedTokenReadings token,
			Queue<AnalyzedTokenReadings> prevTokens) {
		final boolean inserted = prevTokens.offer(token);
		if (!inserted) {
			prevTokens.poll();
			prevTokens.offer(token);
		}
	}

	public RuleMatch[] match(final AnalyzedSentence text) {
		final List<RuleMatch> ruleMatches = new ArrayList<RuleMatch>();
		final AnalyzedTokenReadings[] tokens = text
				.getTokensWithoutWhitespace();

		final Queue<AnalyzedTokenReadings> prevTokens = new ArrayBlockingQueue<AnalyzedTokenReadings>(wrongWords.size());

		for (int i = 1; i < tokens.length; i++) {
			addToQueue(tokens[i], prevTokens);
			final StringBuilder sb = new StringBuilder();
			final ArrayList<String> variants = new ArrayList<String>();
			final List<AnalyzedTokenReadings> prevTokensList = Arrays.asList(prevTokens.toArray(new AnalyzedTokenReadings[] {}));
			for (int j = prevTokensList.size() - 1; j >= 0; j--) {
				if (j != prevTokensList.size() - 1 && prevTokensList.get(j + 1).isWhitespaceBefore())
					sb.insert(0, " ");
				sb.insert(0, prevTokensList.get(j).getToken());
				variants.add(0, sb.toString());
			}
			final int len = variants.size(); // prevTokensList and variants have now the same length
			for (int j = 0; j < len; j++) { // longest words first
				final String crt = variants.get(j);
				final int crtWordCount = len - j;
				final String crtMatch = isCaseSensitive() ? wrongWords.get(crtWordCount - 1).get(crt) : wrongWords.get(crtWordCount- 1).get(crt.toLowerCase(getLocale()));
				if (crtMatch != null) { 
					final List<String> replacements = Arrays.asList(crtMatch.split("\\|"));
					String msg = crt + getSuggestion();
					for (int k = 0; k < replacements.size(); k++) {
						if (k > 0) {
							msg = msg + (k == replacements.size() - 1 ? getSuggestionsSeparator(): ", ");
						}
						msg += "<suggestion>" + replacements.get(k) + "</suggestion>";
					}
					final int startPos = prevTokensList.get(len - crtWordCount).getStartPos();
					final int endPos = prevTokensList.get(len - 1).getStartPos() + prevTokensList.get(len - 1).getToken().length();
					final RuleMatch potentialRuleMatch = new RuleMatch(this, startPos, endPos, msg, getShort());
					
					if (!isCaseSensitive() && StringTools.startsWithUppercase(crt)) {
						for (int k = 0; k < replacements.size(); k++) {
							replacements.set(k, StringTools.uppercaseFirstChar(replacements.get(k)));
						}
					}
					potentialRuleMatch.setSuggestedReplacements(replacements);
					ruleMatches.add(potentialRuleMatch);
					break;
				}
			}
		}
		return toRuleMatchArray(ruleMatches);
	}

	public void reset() {
	}

}