// Copyright 2011 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;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.Charset;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.Set;
import java.util.logging.Logger;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.hughes.android.dictionary.engine.DictionaryBuilder;
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.engine.Language;
import com.hughes.android.dictionary.engine.PairEntry;
import com.hughes.util.StringUtil;

public class DictFileParser implements Parser {

    static final Logger logger = Logger.getLogger(DictFileParser.class.getName());

    // Dictcc
    public static final String TAB = "\t";

    // Chemnitz
    public static final String DOUBLE_COLON = " :: ";
    public static final String PIPE = "|";

    static final Pattern SPACES = Pattern.compile("\\s+");

    static final Pattern CURLY_BRACED = Pattern.compile("\\{([^}]+)\\}");

    // http://www.regular-expressions.info/unicode.html
    static final Pattern NON_CHAR_DASH = Pattern.compile("[^-'\\p{L}\\p{M}\\p{N}]+");
    public static final Pattern NON_CHAR = Pattern.compile("[^\\p{L}\\p{M}\\p{N}]+");

    static final Pattern TRIM_PUNC = Pattern.compile("^[^\\p{L}\\p{M}\\p{N}]+|[^\\p{L}\\p{M}\\p{N}]+$");

    final Charset charset;
    final boolean flipCols;

    final String fieldSplit;
    final String subfieldSplit;

    final DictionaryBuilder dictBuilder;

    EntrySource entrySource;

    // final Set<String> alreadyDone = new HashSet<String>();

    public DictFileParser(final Charset charset, boolean flipCols,
                          final String fieldSplit, final String subfieldSplit,
                          final DictionaryBuilder dictBuilder) {
        this.charset = charset;
        this.flipCols = flipCols;
        this.fieldSplit = fieldSplit;
        this.subfieldSplit = subfieldSplit;
        this.dictBuilder = dictBuilder;
    }

    @Override
    public void parse(final File file, final EntrySource entrySouce, final int pageLimit) throws IOException {
        this.entrySource = entrySouce;
        final BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(file), charset));
        String line;
        int count = 0;
        while ((line = reader.readLine()) != null) {
            if (pageLimit >= 0 && count >= pageLimit) {
                return;
            }
            if (count % 10000 == 0) {
                logger.info("count=" + count + ", line=" + line);
            }
            parseLine(line);
            ++count;
        }
    }

    private void parseLine(final String line) {
        if (line.startsWith("#") || line.isEmpty()) {
            logger.info("Skipping comment line: " + line);
            return;
        }
        final String[] fields = StringUtil.split(line, fieldSplit);
        if (fields.length < 2 || fields.length > 4) {
            logger.warning("Malformed line, expected 3 or 4 fields, got " + fields.length + ": " + line);
            return;
        }

        fields[0] = SPACES.matcher(fields[0]).replaceAll(" ").trim();
        fields[1] = SPACES.matcher(fields[1]).replaceAll(" ").trim();
        if (flipCols) {
            final String temp = fields[0];
            fields[0] = fields[1];
            fields[1] = temp;
        }

        final String[][] subfields = new String[2][];
        if (subfieldSplit != null) {
            subfields[0] = StringUtil.split(fields[0], subfieldSplit);
            subfields[1] = StringUtil.split(fields[1], subfieldSplit);
            if (subfields[0].length != subfields[1].length) {
                logger.warning("Number of subfields doesn't match: " + line);
                return;
            }
        } else {
            subfields[0] = new String[] { fields[0] };
            subfields[1] = new String[] { fields[1] };
        }

        final PairEntry pairEntry = new PairEntry(entrySource);
        for (int i = 0; i < subfields[0].length; ++i) {
            subfields[0][i] = subfields[0][i].trim();
            subfields[1][i] = subfields[1][i].trim();
            if (subfields[0][i].isEmpty() && subfields[1][i].isEmpty()) {
                logger.warning("Empty pair: " + line);
                continue;
            }
            if (subfields[0][i].isEmpty()) {
                subfields[0][i] = "__";
            }
            if (subfields[1][i].isEmpty()) {
                subfields[1][i] = "__";
            }
            pairEntry.pairs.add(new PairEntry.Pair(subfields[0][i], subfields[1][i]));
        }
        final IndexedEntry entryData = new IndexedEntry(pairEntry);
        entryData.isValid = true;

        for (int l = 0; l < 2; ++l) {
            // alreadyDone.clear();

            final IndexBuilder indexBuilder = dictBuilder.indexBuilders.get(l);
            for (int j = 0; j < subfields[l].length; ++j) {
                String subfield = subfields[l][j];
                if (indexBuilder.index.sortLanguage == Language.de) {
                    subfield = parseField_DE(indexBuilder, subfield, entryData, j);
                } else if (indexBuilder.index.sortLanguage == Language.en) {
                    subfield = parseField_EN(indexBuilder, subfield, entryData, j);
                }
                parseFieldGeneric(indexBuilder, subfield, entryData, j, subfields[l].length);
            }
        }
    }

    private StringBuilder extractParenthesized(StringBuilder in, String startChar, String endChar) {
        StringBuilder res = new StringBuilder();
        int pos = 0;
        while ((pos = in.indexOf(startChar, pos)) != -1) {
            int end = in.indexOf(endChar, pos + 1);
            if (end == -1) break;
            res.append(in, pos + 1, end).append(" ");
            in.replace(pos, end + 1, " ");
            pos++; // skip the just appended space
        }
        return res;
    }

    private void parseFieldGeneric(final IndexBuilder indexBuilder, String field,
                                   final IndexedEntry entryData, final int subfieldIdx, final int numSubFields) {
        final StringBuilder fieldsb = new StringBuilder(field);
        // remove bracketed and parenthesized stuff.
        final StringBuilder bracketed = extractParenthesized(fieldsb, "[", "]");
        final StringBuilder parenthesized = extractParenthesized(fieldsb, "(", ")");

        field = fieldsb.toString().trim();

        // split words on non -A-z0-9, do them.
        final String[] tokens = NON_CHAR_DASH.split(field);

        final EntryTypeName entryTypeName;
        if (numSubFields == 1) {
            assert subfieldIdx == 0;
            if (tokens.length == 1) {
                entryTypeName = EntryTypeName.ONE_WORD;
            } else if (tokens.length == 2) {
                entryTypeName = EntryTypeName.TWO_WORDS;
            } else if (tokens.length == 3) {
                entryTypeName = EntryTypeName.THREE_WORDS;
            } else if (tokens.length == 4) {
                entryTypeName = EntryTypeName.FOUR_WORDS;
            } else {
                entryTypeName = EntryTypeName.FIVE_OR_MORE_WORDS;
            }
        } else {
            assert numSubFields > 1;
            if (subfieldIdx == 0) {
                if (tokens.length == 1) {
                    entryTypeName = EntryTypeName.MULTIROW_HEAD_ONE_WORD;
                } else {
                    entryTypeName = EntryTypeName.MULTIROW_HEAD_MANY_WORDS;
                }
            } else {
                assert subfieldIdx > 0;
                if (tokens.length == 1) {
                    entryTypeName = EntryTypeName.MULTIROW_TAIL_ONE_WORD;
                } else {
                    entryTypeName = EntryTypeName.MULTIROW_TAIL_MANY_WORDS;
                }
            }
        }

        for (String token : tokens) {
            token = TRIM_PUNC.matcher(token).replaceAll("");
            if (/*!alreadyDone.contains(token) && */!token.isEmpty()) {
                indexBuilder.addEntryWithTokens(entryData, Collections.singleton(token), entryTypeName);
                // alreadyDone.add(token);

                // also split words on dashes, do them, too.
                if (token.indexOf('-') != -1) {
                    final String[] dashed = StringUtil.split(token, "-");
                    for (final String dashedToken : dashed) {
                        if (/*!alreadyDone.contains(dashedToken) && */!dashedToken.isEmpty()) {
                            indexBuilder.addEntryWithTokens(entryData, Collections.singleton(dashedToken), EntryTypeName.PART_OF_HYPHENATED);
                        }
                    }
                }

            }  // if (!alreadyDone.contains(token)) {
        }  // for (final String token : tokens) {

        // process bracketed stuff (split on spaces and dashes always)
        if (bracketed.length() > 0) {
            final String[] bracketedTokens = NON_CHAR.split(bracketed.toString());
            for (final String token : bracketedTokens) {
                assert token.indexOf("-") == -1;
                if (/*!alreadyDone.contains(token) && */!token.isEmpty()) {
                    indexBuilder.addEntryWithTokens(entryData, Collections.singleton(token), EntryTypeName.BRACKETED);
                }
            }
        }

        // process paren stuff
        if (parenthesized.length() > 0) {
            final String[] parenTokens = NON_CHAR.split(parenthesized.toString());
            for (final String token : parenTokens) {
                assert token.indexOf("-") == -1;
                if (/*!alreadyDone.contains(token) && */!token.isEmpty()) {
                    indexBuilder.addEntryWithTokens(entryData, Collections.singleton(token), EntryTypeName.PARENTHESIZED);
                }
            }
        }

    }

    private String parseField_DE(final IndexBuilder indexBuilder, String field,
                                 final IndexedEntry entryData, final int subfieldIdx) {

//    final Matcher matcher = DE_NOUN.matcher(field);
//    while (matcher.find()) {
//      final String noun = matcher.group(1);
        //final String gender = matcher.group(2);
//      if (alreadyDone.add(noun)) {
        // System.out.println("Found DE noun " + noun + ", " + gender);
//        final List<EntryData> entries = indexBuilder.getOrCreateEntries(noun, EntryTypeName.NOUN);
//        entries.add(entryData);
//      }
//    }

        if (field.indexOf('{') == -1) return field;

        // In English, curly braces are used for different tenses.
        field = CURLY_BRACED.matcher(field).replaceAll(" ");

        return field;
    }

    private String parseField_EN(final IndexBuilder indexBuilder, String field,
                                 final IndexedEntry entryData, final int subfieldIdx) {
        if (field.startsWith("to ")) {
            field = field.substring(3);
        }
        return field;
    }

    public static Set<String> tokenize(final String text, final Pattern pattern) {
        final String[] split = pattern.split(text);
        final Set<String> result = new LinkedHashSet<>(Arrays.asList(split));
        result.remove("");
        return result;
    }


}