/*
 * Copyright (C) 2011 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.spellcheck;

import com.android.inputmethod.keyboard.KeyDetector;
import com.android.inputmethod.keyboard.ProximityInfo;

import java.util.TreeMap;

public class SpellCheckerProximityInfo {
    final private static int NUL = KeyDetector.NOT_A_CODE;

    // This must be the same as MAX_PROXIMITY_CHARS_SIZE else it will not work inside
    // native code - this value is passed at creation of the binary object and reused
    // as the size of the passed array afterwards so they can't be different.
    final public static int ROW_SIZE = ProximityInfo.MAX_PROXIMITY_CHARS_SIZE;

    // Helper methods
    final protected static void buildProximityIndices(final int[] proximity,
            final TreeMap<Integer, Integer> indices) {
        for (int i = 0; i < proximity.length; i += ROW_SIZE) {
            if (NUL != proximity[i]) indices.put(proximity[i], i);
        }
    }
    final protected static int computeIndex(final int characterCode,
            final TreeMap<Integer, Integer> indices) {
        final Integer result = indices.get(characterCode);
        if (null == result) return -1;
        return result;
    }

    static class Latin {
        // This is a map from the code point to the index in the PROXIMITY array.
        // At the time the native code to read the binary dictionary needs the proximity info be
        // passed as a flat array spaced by MAX_PROXIMITY_CHARS_SIZE columns, one for each input
        // character.
        // Since we need to build such an array, we want to be able to search in our big proximity
        // data quickly by character, and a map is probably the best way to do this.
        final private static TreeMap<Integer, Integer> INDICES = new TreeMap<Integer, Integer>();

        // The proximity here is the union of
        // - the proximity for a QWERTY keyboard.
        // - the proximity for an AZERTY keyboard.
        // - the proximity for a QWERTZ keyboard.
        // ...plus, add all characters in the ('a', 'e', 'i', 'o', 'u') set to each other.
        //
        // The reasoning behind this construction is, almost any alphabetic text we may want
        // to spell check has been entered with one of the keyboards above. Also, specifically
        // to English, many spelling errors consist of the last vowel of the word being wrong
        // because in English vowels tend to merge with each other in pronunciation.
        final private static int[] PROXIMITY = {
            'q', 'w', 's', 'a', 'z', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'w', 'q', 'a', 's', 'd', 'e', 'x', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'e', 'w', 's', 'd', 'f', 'r', 'a', 'i', 'o', 'u', NUL, NUL, NUL, NUL, NUL, NUL,
            'r', 'e', 'd', 'f', 'g', 't', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            't', 'r', 'f', 'g', 'h', 'y', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'y', 't', 'g', 'h', 'j', 'u', 'a', 's', 'd', 'x', NUL, NUL, NUL, NUL, NUL, NUL,
            'u', 'y', 'h', 'j', 'k', 'i', 'a', 'e', 'o', NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'i', 'u', 'j', 'k', 'l', 'o', 'a', 'e', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'o', 'i', 'k', 'l', 'p', 'a', 'e', 'u', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'p', 'o', 'l', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,

            'a', 'z', 'x', 's', 'w', 'q', 'e', 'i', 'o', 'u', NUL, NUL, NUL, NUL, NUL, NUL,
            's', 'q', 'a', 'z', 'x', 'c', 'd', 'e', 'w', NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'd', 'w', 's', 'x', 'c', 'v', 'f', 'r', 'e', 'w', NUL, NUL, NUL, NUL, NUL, NUL,
            'f', 'e', 'd', 'c', 'v', 'b', 'g', 't', 'r', NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'g', 'r', 'f', 'v', 'b', 'n', 'h', 'y', 't', NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'h', 't', 'g', 'b', 'n', 'm', 'j', 'u', 'y', NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'j', 'y', 'h', 'n', 'm', 'k', 'i', 'u', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'k', 'u', 'j', 'm', 'l', 'o', 'i', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'l', 'i', 'k', 'p', 'o', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,

            'z', 'a', 's', 'd', 'x', 't', 'g', 'h', 'j', 'u', 'q', 'e', NUL, NUL, NUL, NUL,
            'x', 'z', 'a', 's', 'd', 'c', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'c', 'x', 's', 'd', 'f', 'v', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'v', 'c', 'd', 'f', 'g', 'b', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'b', 'v', 'f', 'g', 'h', 'n', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'n', 'b', 'g', 'h', 'j', 'm', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'm', 'n', 'h', 'j', 'k', 'l', 'o', 'p', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
        };
        static {
            buildProximityIndices(PROXIMITY, INDICES);
        }
        private static int getIndexOf(int characterCode) {
            return computeIndex(characterCode, INDICES);
        }
    }

    static class Cyrillic {
        final private static TreeMap<Integer, Integer> INDICES = new TreeMap<Integer, Integer>();
        final private static int[] PROXIMITY = {
            // TODO: This table is solely based on the keyboard layout. Consult with Russian
            // speakers on commonly misspelled words/letters.
            'й', 'ц', 'ф', 'ы', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'ц', 'й', 'ф', 'ы', 'в', 'у', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'у', 'ц', 'ы', 'в', 'а', 'к', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'к', 'у', 'в', 'а', 'п', 'е', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'е', 'к', 'а', 'п', 'р', 'н', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'н', 'е', 'п', 'р', 'о', 'г', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'г', 'н', 'р', 'о', 'л', 'ш', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'ш', 'г', 'о', 'л', 'д', 'щ', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'щ', 'ш', 'л', 'д', 'ж', 'з', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'з', 'щ', 'д', 'ж', 'э', 'х', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'х', 'з', 'ж', 'э', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,

            'ф', 'й', 'ц', 'ы', 'я', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'ы', 'й', 'ц', 'у', 'ф', 'в', 'я', 'ч', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'в', 'ц', 'у', 'к', 'ы', 'а', 'я', 'ч', 'с', NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'а', 'у', 'к', 'е', 'в', 'п', 'ч', 'с', 'м', NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'п', 'к', 'е', 'н', 'а', 'р', 'с', 'м', 'и', NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'р', 'е', 'н', 'г', 'п', 'о', 'м', 'и', 'т', NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'о', 'н', 'г', 'ш', 'р', 'л', 'и', 'т', 'ь', NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'л', 'г', 'ш', 'щ', 'о', 'д', 'т', 'ь', 'б', NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'д', 'ш', 'щ', 'з', 'л', 'ж', 'ь', 'б', 'ю', NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'ж', 'щ', 'з', 'х', 'д', 'э', 'б', 'ю', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'э', 'з', 'х', 'ю', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,

            'я', 'ф', 'ы', 'в', 'ч', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'ч', 'ы', 'в', 'а', 'я', 'с', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'с', 'в', 'а', 'п', 'ч', 'м', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'м', 'а', 'п', 'р', 'с', 'и', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'и', 'п', 'р', 'о', 'м', 'т', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'т', 'р', 'о', 'л', 'и', 'ь', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'ь', 'о', 'л', 'д', 'т', 'б', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'б', 'л', 'д', 'ж', 'ь', 'ю', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            'ю', 'д', 'ж', 'э', 'б', NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
            NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL, NUL,
        };
        static {
            buildProximityIndices(PROXIMITY, INDICES);
        }
        private static int getIndexOf(int characterCode) {
            return computeIndex(characterCode, INDICES);
        }
    }

    public static int[] getProximityForScript(final int script) {
        switch (script) {
            case AndroidSpellCheckerService.SCRIPT_LATIN:
                return Latin.PROXIMITY;
            case AndroidSpellCheckerService.SCRIPT_CYRILLIC:
                return Cyrillic.PROXIMITY;
            default:
                throw new RuntimeException("Wrong script supplied: " + script);
        }
    }
    public static int getIndexOfCodeForScript(final int characterCode, final int script) {
        switch (script) {
            case AndroidSpellCheckerService.SCRIPT_LATIN:
                return Latin.getIndexOf(characterCode);
            case AndroidSpellCheckerService.SCRIPT_CYRILLIC:
                return Cyrillic.getIndexOf(characterCode);
            default:
                throw new RuntimeException("Wrong script supplied: " + script);
        }
    }
}