/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * 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.android.inputmethod.latin.makedict;

import com.android.inputmethod.latin.CollectionUtils;
import com.android.inputmethod.latin.UserHistoryDictIOUtils;
import com.android.inputmethod.latin.makedict.BinaryDictInputOutput.FusionDictionaryBufferInterface;
import com.android.inputmethod.latin.makedict.FormatSpec.FileHeader;
import com.android.inputmethod.latin.makedict.FusionDictionary.CharGroup;
import com.android.inputmethod.latin.makedict.FusionDictionary.Node;
import com.android.inputmethod.latin.makedict.FusionDictionary.WeightedString;

import android.test.AndroidTestCase;
import android.test.MoreAsserts;
import android.util.Log;
import android.util.SparseArray;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Random;
import java.util.Set;

/**
 * Unit tests for BinaryDictInputOutput
 */
public class BinaryDictIOTests extends AndroidTestCase {
    private static final String TAG = BinaryDictIOTests.class.getSimpleName();
    private static final int MAX_UNIGRAMS = 1000;
    private static final int UNIGRAM_FREQ = 10;
    private static final int BIGRAM_FREQ = 50;
    private static final int TOLERANCE_OF_BIGRAM_FREQ = 5;

    private static final int USE_BYTE_ARRAY = 1;
    private static final int USE_BYTE_BUFFER = 2;

    private static final List<String> sWords = CollectionUtils.newArrayList();
    private static final SparseArray<List<Integer>> sEmptyBigrams =
            CollectionUtils.newSparseArray();
    private static final SparseArray<List<Integer>> sStarBigrams = CollectionUtils.newSparseArray();
    private static final SparseArray<List<Integer>> sChainBigrams =
            CollectionUtils.newSparseArray();

    private static final FormatSpec.FormatOptions VERSION2 = new FormatSpec.FormatOptions(2);
    private static final FormatSpec.FormatOptions VERSION3_WITHOUT_PARENTADDRESS =
            new FormatSpec.FormatOptions(3, false /* hasParentAddress */);
    private static final FormatSpec.FormatOptions VERSION3_WITH_PARENTADDRESS =
            new FormatSpec.FormatOptions(3, true /* hasParentAddress */);
    private static final FormatSpec.FormatOptions VERSION3_WITH_LINKEDLIST_NODE =
            new FormatSpec.FormatOptions(3, true /* hasParentAddress */,
                    true /* hasLinkedListNode */);

    private static final String[] CHARACTERS = {
        "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m",
        "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"
    };

    public BinaryDictIOTests() {
        super();

        final Random random = new Random(123456);
        sWords.clear();
        generateWords(MAX_UNIGRAMS, random);

        for (int i = 0; i < sWords.size(); ++i) {
            sChainBigrams.put(i, new ArrayList<Integer>());
            if (i > 0) {
                sChainBigrams.get(i - 1).add(i);
            }
        }

        sStarBigrams.put(0, new ArrayList<Integer>());
        for (int i = 1; i < sWords.size(); ++i) {
            sStarBigrams.get(0).add(i);
        }
    }

    // Utilities for test

    /**
     * Makes new buffer according to BUFFER_TYPE.
     */
    private FusionDictionaryBufferInterface getBuffer(final File file, final int bufferType) {
        FileInputStream inStream = null;
        try {
            inStream = new FileInputStream(file);
            if (bufferType == USE_BYTE_ARRAY) {
                final byte[] array = new byte[(int)file.length()];
                inStream.read(array);
                return new UserHistoryDictIOUtils.ByteArrayWrapper(array);
            } else if (bufferType == USE_BYTE_BUFFER){
                final ByteBuffer buffer = inStream.getChannel().map(
                        FileChannel.MapMode.READ_ONLY, 0, file.length());
                return new BinaryDictInputOutput.ByteBufferWrapper(buffer);
            }
        } catch (IOException e) {
            Log.e(TAG, "IOException while making buffer: " + e);
        } finally {
            if (inStream != null) {
                try {
                    inStream.close();
                } catch (IOException e) {
                    Log.e(TAG, "IOException while closing stream: " + e);
                }
            }
        }
        return null;
    }

    /**
     * Generates a random word.
     */
    private String generateWord(final int value) {
        final int lengthOfChars = CHARACTERS.length;
        StringBuilder builder = new StringBuilder("a");
        long lvalue = Math.abs((long)value);
        while (lvalue > 0) {
            builder.append(CHARACTERS[(int)(lvalue % lengthOfChars)]);
            lvalue /= lengthOfChars;
        }
        return builder.toString();
    }

    private void generateWords(final int number, final Random random) {
        final Set<String> wordSet = CollectionUtils.newHashSet();
        while (wordSet.size() < number) {
            wordSet.add(generateWord(random.nextInt()));
        }
        sWords.addAll(wordSet);
    }

    /**
     * Adds unigrams to the dictionary.
     */
    private void addUnigrams(final int number, final FusionDictionary dict,
            final List<String> words, final Map<String, List<String>> shortcutMap) {
        for (int i = 0; i < number; ++i) {
            final String word = words.get(i);
            final ArrayList<WeightedString> shortcuts = CollectionUtils.newArrayList();
            if (shortcutMap != null && shortcutMap.containsKey(word)) {
                for (final String shortcut : shortcutMap.get(word)) {
                    shortcuts.add(new WeightedString(shortcut, UNIGRAM_FREQ));
                }
            }
            dict.add(word, UNIGRAM_FREQ, (shortcutMap == null) ? null : shortcuts,
                    false /* isNotAWord */);
        }
    }

    private void addBigrams(final FusionDictionary dict,
            final List<String> words,
            final SparseArray<List<Integer>> bigrams) {
        for (int i = 0; i < bigrams.size(); ++i) {
            final int w1 = bigrams.keyAt(i);
            for (int w2 : bigrams.valueAt(i)) {
                dict.setBigram(words.get(w1), words.get(w2), BIGRAM_FREQ);
            }
        }
    }

    private long timeWritingDictToFile(final File file, final FusionDictionary dict,
            final FormatSpec.FormatOptions formatOptions) {

        long now = -1, diff = -1;

        try {
            final FileOutputStream out = new FileOutputStream(file);

            now = System.currentTimeMillis();
            BinaryDictInputOutput.writeDictionaryBinary(out, dict, formatOptions);
            diff = System.currentTimeMillis() - now;

            out.flush();
            out.close();
        } catch (IOException e) {
            Log.e(TAG, "IO exception while writing file: " + e);
        } catch (UnsupportedFormatException e) {
            Log.e(TAG, "UnsupportedFormatException: " + e);
        }

        return diff;
    }

    private void checkDictionary(final FusionDictionary dict, final List<String> words,
            final SparseArray<List<Integer>> bigrams, final Map<String, List<String>> shortcutMap) {
        assertNotNull(dict);

        // check unigram
        for (final String word : words) {
            final CharGroup cg = FusionDictionary.findWordInTree(dict.mRoot, word);
            assertNotNull(cg);
        }

        // check bigram
        for (int i = 0; i < bigrams.size(); ++i) {
            final int w1 = bigrams.keyAt(i);
            for (final int w2 : bigrams.valueAt(i)) {
                final CharGroup cg = FusionDictionary.findWordInTree(dict.mRoot, words.get(w1));
                assertNotNull(words.get(w1) + "," + words.get(w2), cg.getBigram(words.get(w2)));
            }
        }

        // check shortcut
        if (shortcutMap != null) {
            for (final Map.Entry<String, List<String>> entry : shortcutMap.entrySet()) {
                final CharGroup group = FusionDictionary.findWordInTree(dict.mRoot, entry.getKey());
                for (final String word : entry.getValue()) {
                    assertNotNull("shortcut not found: " + entry.getKey() + ", " + word,
                            group.getShortcut(word));
                }
            }
        }
    }

    private String outputOptions(final int bufferType,
            final FormatSpec.FormatOptions formatOptions) {
        String result = " : buffer type = "
                + ((bufferType == USE_BYTE_BUFFER) ? "byte buffer" : "byte array");
        result += " : version = " + formatOptions.mVersion;
        return result + ", hasParentAddress = " + formatOptions.mHasParentAddress
                + ", hasLinkedListNode = " + formatOptions.mHasLinkedListNode;
    }

    // Tests for readDictionaryBinary and writeDictionaryBinary

    private long timeReadingAndCheckDict(final File file, final List<String> words,
            final SparseArray<List<Integer>> bigrams, final Map<String, List<String>> shortcutMap,
            final int bufferType) {
        long now, diff = -1;
        final FusionDictionaryBufferInterface buffer = getBuffer(file, bufferType);
        assertNotNull(buffer);

        FusionDictionary dict = null;
        try {
            now = System.currentTimeMillis();
            dict = BinaryDictInputOutput.readDictionaryBinary(buffer, null);
            diff  = System.currentTimeMillis() - now;
        } catch (IOException e) {
            Log.e(TAG, "IOException while reading dictionary: " + e);
        } catch (UnsupportedFormatException e) {
            Log.e(TAG, "Unsupported format: " + e);
        }

        checkDictionary(dict, words, bigrams, shortcutMap);
        return diff;
    }

    // Tests for readDictionaryBinary and writeDictionaryBinary
    private String runReadAndWrite(final List<String> words,
            final SparseArray<List<Integer>> bigrams, final Map<String, List<String>> shortcuts,
            final int bufferType, final FormatSpec.FormatOptions formatOptions,
            final String message) {
        File file = null;
        try {
            file = File.createTempFile("runReadAndWrite", ".dict");
        } catch (IOException e) {
            Log.e(TAG, "IOException: " + e);
        }
        assertNotNull(file);

        final FusionDictionary dict = new FusionDictionary(new Node(),
                new FusionDictionary.DictionaryOptions(new HashMap<String,String>(), false, false));
        addUnigrams(words.size(), dict, words, shortcuts);
        addBigrams(dict, words, bigrams);
        checkDictionary(dict, words, bigrams, shortcuts);

        final long write = timeWritingDictToFile(file, dict, formatOptions);
        final long read = timeReadingAndCheckDict(file, words, bigrams, shortcuts, bufferType);

        return "PROF: read=" + read + "ms, write=" + write + "ms :" + message
                + " : " + outputOptions(bufferType, formatOptions);
    }

    private void runReadAndWriteTests(final List<String> results, final int bufferType,
            final FormatSpec.FormatOptions formatOptions) {
        results.add(runReadAndWrite(sWords, sEmptyBigrams, null /* shortcuts */, bufferType,
                formatOptions, "unigram"));
        results.add(runReadAndWrite(sWords, sChainBigrams, null /* shortcuts */, bufferType,
                formatOptions, "chain"));
        results.add(runReadAndWrite(sWords, sStarBigrams, null /* shortcuts */, bufferType,
                formatOptions, "star"));
    }

    public void testReadAndWriteWithByteBuffer() {
        final List<String> results = CollectionUtils.newArrayList();

        runReadAndWriteTests(results, USE_BYTE_BUFFER, VERSION2);
        runReadAndWriteTests(results, USE_BYTE_BUFFER, VERSION3_WITHOUT_PARENTADDRESS);
        runReadAndWriteTests(results, USE_BYTE_BUFFER, VERSION3_WITH_PARENTADDRESS);
        runReadAndWriteTests(results, USE_BYTE_BUFFER, VERSION3_WITH_LINKEDLIST_NODE);

        for (final String result : results) {
            Log.d(TAG, result);
        }
    }

    public void testReadAndWriteWithByteArray() {
        final List<String> results = CollectionUtils.newArrayList();

        runReadAndWriteTests(results, USE_BYTE_ARRAY, VERSION2);
        runReadAndWriteTests(results, USE_BYTE_ARRAY, VERSION3_WITHOUT_PARENTADDRESS);
        runReadAndWriteTests(results, USE_BYTE_ARRAY, VERSION3_WITH_PARENTADDRESS);
        runReadAndWriteTests(results, USE_BYTE_ARRAY, VERSION3_WITH_LINKEDLIST_NODE);

        for (final String result : results) {
            Log.d(TAG, result);
        }
    }

    // Tests for readUnigramsAndBigramsBinary

    private void checkWordMap(final List<String> expectedWords,
            final SparseArray<List<Integer>> expectedBigrams,
            final Map<Integer, String> resultWords,
            final Map<Integer, Integer> resultFrequencies,
            final Map<Integer, ArrayList<PendingAttribute>> resultBigrams) {
        // check unigrams
        final Set<String> actualWordsSet = new HashSet<String>(resultWords.values());
        final Set<String> expectedWordsSet = new HashSet<String>(expectedWords);
        assertEquals(actualWordsSet, expectedWordsSet);

        for (int freq : resultFrequencies.values()) {
            assertEquals(freq, UNIGRAM_FREQ);
        }

        // check bigrams
        final Map<String, List<String>> expBigrams = new HashMap<String, List<String>>();
        for (int i = 0; i < expectedBigrams.size(); ++i) {
            final String word1 = expectedWords.get(expectedBigrams.keyAt(i));
            for (int w2 : expectedBigrams.valueAt(i)) {
                if (expBigrams.get(word1) == null) {
                    expBigrams.put(word1, new ArrayList<String>());
                }
                expBigrams.get(word1).add(expectedWords.get(w2));
            }
        }

        final Map<String, List<String>> actBigrams = new HashMap<String, List<String>>();
        for (Entry<Integer, ArrayList<PendingAttribute>> entry : resultBigrams.entrySet()) {
            final String word1 = resultWords.get(entry.getKey());
            final int unigramFreq = resultFrequencies.get(entry.getKey());
            for (PendingAttribute attr : entry.getValue()) {
                final String word2 = resultWords.get(attr.mAddress);
                if (actBigrams.get(word1) == null) {
                    actBigrams.put(word1, new ArrayList<String>());
                }
                actBigrams.get(word1).add(word2);

                final int bigramFreq = BinaryDictInputOutput.reconstructBigramFrequency(
                        unigramFreq, attr.mFrequency);
                assertTrue(Math.abs(bigramFreq - BIGRAM_FREQ) < TOLERANCE_OF_BIGRAM_FREQ);
            }
        }

        assertEquals(actBigrams, expBigrams);
    }

    private long timeAndCheckReadUnigramsAndBigramsBinary(final File file, final List<String> words,
            final SparseArray<List<Integer>> bigrams, final int bufferType) {
        FileInputStream inStream = null;

        final Map<Integer, String> resultWords = CollectionUtils.newTreeMap();
        final Map<Integer, ArrayList<PendingAttribute>> resultBigrams =
                CollectionUtils.newTreeMap();
        final Map<Integer, Integer> resultFreqs = CollectionUtils.newTreeMap();

        long now = -1, diff = -1;
        final FusionDictionaryBufferInterface buffer = getBuffer(file, bufferType);
        assertNotNull("Can't get buffer.", buffer);
        try {
            now = System.currentTimeMillis();
            BinaryDictIOUtils.readUnigramsAndBigramsBinary(buffer, resultWords, resultFreqs,
                    resultBigrams);
            diff = System.currentTimeMillis() - now;
        } catch (IOException e) {
            Log.e(TAG, "IOException " + e);
        } catch (UnsupportedFormatException e) {
            Log.e(TAG, "UnsupportedFormatException: " + e);
        } finally {
            if (inStream != null) {
                try {
                    inStream.close();
                } catch (IOException e) {
                    // do nothing
                }
            }
        }

        checkWordMap(words, bigrams, resultWords, resultFreqs, resultBigrams);
        return diff;
    }

    private String runReadUnigramsAndBigramsBinary(final List<String> words,
            final SparseArray<List<Integer>> bigrams, final int bufferType,
            final FormatSpec.FormatOptions formatOptions, final String message) {
        File file = null;
        try {
            file = File.createTempFile("runReadUnigrams", ".dict");
        } catch (IOException e) {
            Log.e(TAG, "IOException: " + e);
        }
        assertNotNull(file);

        // making the dictionary from lists of words.
        final FusionDictionary dict = new FusionDictionary(new Node(),
                new FusionDictionary.DictionaryOptions(
                        new HashMap<String, String>(), false, false));
        addUnigrams(words.size(), dict, words, null /* shortcutMap */);
        addBigrams(dict, words, bigrams);

        timeWritingDictToFile(file, dict, formatOptions);

        long wordMap = timeAndCheckReadUnigramsAndBigramsBinary(file, words, bigrams, bufferType);
        long fullReading = timeReadingAndCheckDict(file, words, bigrams, null /* shortcutMap */,
                bufferType);

        return "readDictionaryBinary=" + fullReading + ", readUnigramsAndBigramsBinary=" + wordMap
                + " : " + message + " : " + outputOptions(bufferType, formatOptions);
    }

    private void runReadUnigramsAndBigramsTests(final List<String> results, final int bufferType,
            final FormatSpec.FormatOptions formatOptions) {
        results.add(runReadUnigramsAndBigramsBinary(sWords, sEmptyBigrams, bufferType,
                formatOptions, "unigram"));
        results.add(runReadUnigramsAndBigramsBinary(sWords, sChainBigrams, bufferType,
                formatOptions, "chain"));
        results.add(runReadUnigramsAndBigramsBinary(sWords, sChainBigrams, bufferType,
                formatOptions, "star"));
    }

    public void testReadUnigramsAndBigramsBinaryWithByteBuffer() {
        final List<String> results = CollectionUtils.newArrayList();

        runReadUnigramsAndBigramsTests(results, USE_BYTE_BUFFER, VERSION2);
        runReadUnigramsAndBigramsTests(results, USE_BYTE_BUFFER, VERSION3_WITHOUT_PARENTADDRESS);
        runReadUnigramsAndBigramsTests(results, USE_BYTE_BUFFER, VERSION3_WITH_PARENTADDRESS);
        runReadUnigramsAndBigramsTests(results, USE_BYTE_BUFFER, VERSION3_WITH_LINKEDLIST_NODE);

        for (final String result : results) {
            Log.d(TAG, result);
        }
    }

    public void testReadUnigramsAndBigramsBinaryWithByteArray() {
        final List<String> results = CollectionUtils.newArrayList();

        runReadUnigramsAndBigramsTests(results, USE_BYTE_ARRAY, VERSION2);
        runReadUnigramsAndBigramsTests(results, USE_BYTE_ARRAY, VERSION3_WITHOUT_PARENTADDRESS);
        runReadUnigramsAndBigramsTests(results, USE_BYTE_ARRAY, VERSION3_WITH_PARENTADDRESS);
        runReadUnigramsAndBigramsTests(results, USE_BYTE_ARRAY, VERSION3_WITH_LINKEDLIST_NODE);

        for (final String result : results) {
            Log.d(TAG, result);
        }
    }

    // Tests for getTerminalPosition
    private String getWordFromBinary(final FusionDictionaryBufferInterface buffer,
            final int address) {
        if (buffer.position() != 0) buffer.position(0);

        FileHeader header = null;
        try {
            header = BinaryDictInputOutput.readHeader(buffer);
        } catch (IOException e) {
            return null;
        } catch (UnsupportedFormatException e) {
            return null;
        }
        if (header == null) return null;
        return BinaryDictInputOutput.getWordAtAddress(buffer, header.mHeaderSize,
                address - header.mHeaderSize, header.mFormatOptions);
    }

    private long runGetTerminalPosition(final FusionDictionaryBufferInterface buffer,
            final String word, int index, boolean contained) {
        final int expectedFrequency = (UNIGRAM_FREQ + index) % 255;
        long diff = -1;
        int position = -1;
        try {
            final long now = System.nanoTime();
            position = BinaryDictIOUtils.getTerminalPosition(buffer, word);
            diff = System.nanoTime() - now;
        } catch (IOException e) {
            Log.e(TAG, "IOException while getTerminalPosition: " + e);
        } catch (UnsupportedFormatException e) {
            Log.e(TAG, "UnsupportedFormatException while getTermianlPosition: " + e);
        }

        assertEquals(FormatSpec.NOT_VALID_WORD != position, contained);
        if (contained) assertEquals(getWordFromBinary(buffer, position), word);
        return diff;
    }

    public void testGetTerminalPosition() {
        File file = null;
        try {
            file = File.createTempFile("testGetTerminalPosition", ".dict");
        } catch (IOException e) {
            // do nothing
        }
        assertNotNull(file);

        final FusionDictionary dict = new FusionDictionary(new Node(),
                new FusionDictionary.DictionaryOptions(
                        new HashMap<String, String>(), false, false));
        addUnigrams(sWords.size(), dict, sWords, null /* shortcutMap */);
        timeWritingDictToFile(file, dict, VERSION3_WITH_LINKEDLIST_NODE);

        final FusionDictionaryBufferInterface buffer = getBuffer(file, USE_BYTE_ARRAY);

        try {
            // too long word
            final String longWord = "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz";
            assertEquals(FormatSpec.NOT_VALID_WORD,
                    BinaryDictIOUtils.getTerminalPosition(buffer, longWord));

            // null
            assertEquals(FormatSpec.NOT_VALID_WORD,
                    BinaryDictIOUtils.getTerminalPosition(buffer, null));

            // empty string
            assertEquals(FormatSpec.NOT_VALID_WORD,
                    BinaryDictIOUtils.getTerminalPosition(buffer, ""));
        } catch (IOException e) {
        } catch (UnsupportedFormatException e) {
        }

        // Test a word that is contained within the dictionary.
        long sum = 0;
        for (int i = 0; i < sWords.size(); ++i) {
            final long time = runGetTerminalPosition(buffer, sWords.get(i), i, true);
            sum += time == -1 ? 0 : time;
        }
        Log.d(TAG, "per a search : " + (((double)sum) / sWords.size() / 1000000));

        // Test a word that isn't contained within the dictionary.
        final Random random = new Random((int)System.currentTimeMillis());
        for (int i = 0; i < 1000; ++i) {
            final String word = generateWord(random.nextInt());
            if (sWords.indexOf(word) != -1) continue;
            runGetTerminalPosition(buffer, word, i, false);
        }
    }

    public void testDeleteWord() {
        File file = null;
        try {
            file = File.createTempFile("testGetTerminalPosition", ".dict");
        } catch (IOException e) {
            // do nothing
        }
        assertNotNull(file);

        final FusionDictionary dict = new FusionDictionary(new Node(),
                new FusionDictionary.DictionaryOptions(
                        new HashMap<String, String>(), false, false));
        addUnigrams(sWords.size(), dict, sWords, null /* shortcutMap */);
        timeWritingDictToFile(file, dict, VERSION3_WITH_LINKEDLIST_NODE);

        final FusionDictionaryBufferInterface buffer = getBuffer(file, USE_BYTE_ARRAY);

        try {
            MoreAsserts.assertNotEqual(FormatSpec.NOT_VALID_WORD,
                    BinaryDictIOUtils.getTerminalPosition(buffer, sWords.get(0)));
            BinaryDictIOUtils.deleteWord(buffer, sWords.get(0));
            assertEquals(FormatSpec.NOT_VALID_WORD,
                    BinaryDictIOUtils.getTerminalPosition(buffer, sWords.get(0)));

            MoreAsserts.assertNotEqual(FormatSpec.NOT_VALID_WORD,
                    BinaryDictIOUtils.getTerminalPosition(buffer, sWords.get(5)));
            BinaryDictIOUtils.deleteWord(buffer, sWords.get(5));
            assertEquals(FormatSpec.NOT_VALID_WORD,
                    BinaryDictIOUtils.getTerminalPosition(buffer, sWords.get(5)));
        } catch (IOException e) {
        } catch (UnsupportedFormatException e) {
        }
    }
}