1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.inputmethod.latin;
18
19import android.text.TextUtils;
20import android.util.Log;
21
22import java.util.ArrayList;
23import java.util.Map;
24
25public class AutoCorrection {
26    private static final boolean DBG = LatinImeLogger.sDBG;
27    private static final String TAG = AutoCorrection.class.getSimpleName();
28    private boolean mHasAutoCorrection;
29    private CharSequence mAutoCorrectionWord;
30    private double mNormalizedScore;
31
32    public void init() {
33        mHasAutoCorrection = false;
34        mAutoCorrectionWord = null;
35        mNormalizedScore = Integer.MIN_VALUE;
36    }
37
38    public boolean hasAutoCorrection() {
39        return mHasAutoCorrection;
40    }
41
42    public CharSequence getAutoCorrectionWord() {
43        return mAutoCorrectionWord;
44    }
45
46    public double getNormalizedScore() {
47        return mNormalizedScore;
48    }
49
50    public void updateAutoCorrectionStatus(Map<String, Dictionary> dictionaries,
51            WordComposer wordComposer, ArrayList<CharSequence> suggestions, int[] sortedScores,
52            CharSequence typedWord, double autoCorrectionThreshold, int correctionMode,
53            CharSequence whitelistedWord) {
54        if (hasAutoCorrectionForWhitelistedWord(whitelistedWord)) {
55            mHasAutoCorrection = true;
56            mAutoCorrectionWord = whitelistedWord;
57        } else if (hasAutoCorrectionForTypedWord(
58                dictionaries, wordComposer, suggestions, typedWord, correctionMode)) {
59            mHasAutoCorrection = true;
60            mAutoCorrectionWord = typedWord;
61        } else if (hasAutoCorrectionForBinaryDictionary(wordComposer, suggestions, correctionMode,
62                sortedScores, typedWord, autoCorrectionThreshold)) {
63            mHasAutoCorrection = true;
64            mAutoCorrectionWord = suggestions.get(0);
65        }
66    }
67
68    public static boolean isValidWord(
69            Map<String, Dictionary> dictionaries, CharSequence word, boolean ignoreCase) {
70        if (TextUtils.isEmpty(word)) {
71            return false;
72        }
73        final CharSequence lowerCasedWord = word.toString().toLowerCase();
74        for (final String key : dictionaries.keySet()) {
75            if (key.equals(Suggest.DICT_KEY_WHITELIST)) continue;
76            final Dictionary dictionary = dictionaries.get(key);
77            if (dictionary.isValidWord(word)
78                    || (ignoreCase && dictionary.isValidWord(lowerCasedWord))) {
79                return true;
80            }
81        }
82        return false;
83    }
84
85    public static boolean allowsToBeAutoCorrected(
86            Map<String, Dictionary> dictionaries, CharSequence word, boolean ignoreCase) {
87        final WhitelistDictionary whitelistDictionary =
88                (WhitelistDictionary)dictionaries.get(Suggest.DICT_KEY_WHITELIST);
89        // If "word" is in the whitelist dictionary, it should not be auto corrected.
90        if (whitelistDictionary != null
91                && whitelistDictionary.shouldForciblyAutoCorrectFrom(word)) {
92            return true;
93        }
94        return !isValidWord(dictionaries, word, ignoreCase);
95    }
96
97    private static boolean hasAutoCorrectionForWhitelistedWord(CharSequence whiteListedWord) {
98        return whiteListedWord != null;
99    }
100
101    private boolean hasAutoCorrectionForTypedWord(Map<String, Dictionary> dictionaries,
102            WordComposer wordComposer, ArrayList<CharSequence> suggestions, CharSequence typedWord,
103            int correctionMode) {
104        if (TextUtils.isEmpty(typedWord)) return false;
105        boolean allowsAutoCorrect = allowsToBeAutoCorrected(dictionaries, typedWord, false);
106        return wordComposer.size() > 1 && suggestions.size() > 0 && !allowsAutoCorrect
107                && (correctionMode == Suggest.CORRECTION_FULL
108                || correctionMode == Suggest.CORRECTION_FULL_BIGRAM);
109    }
110
111    private boolean hasAutoCorrectionForBinaryDictionary(WordComposer wordComposer,
112            ArrayList<CharSequence> suggestions, int correctionMode, int[] sortedScores,
113            CharSequence typedWord, double autoCorrectionThreshold) {
114        if (wordComposer.size() > 1 && (correctionMode == Suggest.CORRECTION_FULL
115                || correctionMode == Suggest.CORRECTION_FULL_BIGRAM)
116                && typedWord != null && suggestions.size() > 0 && sortedScores.length > 0) {
117            final CharSequence autoCorrectionSuggestion = suggestions.get(0);
118            final int autoCorrectionSuggestionScore = sortedScores[0];
119            // TODO: when the normalized score of the first suggestion is nearly equals to
120            //       the normalized score of the second suggestion, behave less aggressive.
121            mNormalizedScore = Utils.calcNormalizedScore(
122                    typedWord,autoCorrectionSuggestion, autoCorrectionSuggestionScore);
123            if (DBG) {
124                Log.d(TAG, "Normalized " + typedWord + "," + autoCorrectionSuggestion + ","
125                        + autoCorrectionSuggestionScore + ", " + mNormalizedScore
126                        + "(" + autoCorrectionThreshold + ")");
127            }
128            if (mNormalizedScore >= autoCorrectionThreshold) {
129                if (DBG) {
130                    Log.d(TAG, "Auto corrected by S-threshold.");
131                }
132                return true;
133            }
134        }
135        return false;
136    }
137
138}
139