/*
 * Copyright (C) 2017 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.dialer.smartdial.map;

import android.content.Context;
import android.support.annotation.VisibleForTesting;
import android.support.v4.util.SimpleArrayMap;
import com.android.dialer.compat.CompatUtils;
import com.android.dialer.configprovider.ConfigProviderBindings;
import com.google.common.base.Optional;

/**
 * A utility class that combines the functionality of two implementations of {@link SmartDialMap} so
 * that we support smart dial for dual alphabets.
 *
 * <p>Of the two implementations of {@link SmartDialMap}, the default one always takes precedence.
 * The second one is consulted only when the default one is unable to provide a valid result.
 *
 * <p>Note that the second implementation can be absent if it is not defined for the system's 1st
 * language preference.
 */
@SuppressWarnings("Guava")
public class CompositeSmartDialMap {
  @VisibleForTesting
  public static final String FLAG_ENABLE_DUAL_ALPHABETS = "enable_dual_alphabets_on_t9";

  private static final SmartDialMap DEFAULT_MAP = LatinSmartDialMap.getInstance();

  // A map in which each key is an ISO 639-2 language code and the corresponding value is a
  // SmartDialMap
  private static final SimpleArrayMap<String, SmartDialMap> EXTRA_MAPS = new SimpleArrayMap<>();

  static {
    EXTRA_MAPS.put("bul", BulgarianSmartDialMap.getInstance());
    EXTRA_MAPS.put("rus", RussianSmartDialMap.getInstance());
    EXTRA_MAPS.put("ukr", UkrainianSmartDialMap.getInstance());
  }

  private CompositeSmartDialMap() {}

  /**
   * Returns true if the provided character can be mapped to a key on the dialpad.
   *
   * <p>The provided character is expected to be a normalized character. See {@link
   * SmartDialMap#normalizeCharacter(char)} for details.
   */
  public static boolean isValidDialpadCharacter(Context context, char ch) {
    if (DEFAULT_MAP.isValidDialpadCharacter(ch)) {
      return true;
    }

    Optional<SmartDialMap> extraMap = getExtraMap(context);
    return extraMap.isPresent() && extraMap.get().isValidDialpadCharacter(ch);
  }

  /**
   * Returns true if the provided character is a letter, and can be mapped to a key on the dialpad.
   *
   * <p>The provided character is expected to be a normalized character. See {@link
   * SmartDialMap#normalizeCharacter(char)} for details.
   */
  public static boolean isValidDialpadAlphabeticChar(Context context, char ch) {
    if (DEFAULT_MAP.isValidDialpadAlphabeticChar(ch)) {
      return true;
    }

    Optional<SmartDialMap> extraMap = getExtraMap(context);
    return extraMap.isPresent() && extraMap.get().isValidDialpadAlphabeticChar(ch);
  }

  /**
   * Returns true if the provided character is a digit, and can be mapped to a key on the dialpad.
   */
  public static boolean isValidDialpadNumericChar(Context context, char ch) {
    if (DEFAULT_MAP.isValidDialpadNumericChar(ch)) {
      return true;
    }

    Optional<SmartDialMap> extraMap = getExtraMap(context);
    return extraMap.isPresent() && extraMap.get().isValidDialpadNumericChar(ch);
  }

  /**
   * Get the index of the key on the dialpad which the character corresponds to.
   *
   * <p>The provided character is expected to be a normalized character. See {@link
   * SmartDialMap#normalizeCharacter(char)} for details.
   *
   * <p>If the provided character can't be mapped to a key on the dialpad, return -1.
   */
  public static byte getDialpadIndex(Context context, char ch) {
    Optional<Byte> dialpadIndex = DEFAULT_MAP.getDialpadIndex(ch);
    if (dialpadIndex.isPresent()) {
      return dialpadIndex.get();
    }

    Optional<SmartDialMap> extraMap = getExtraMap(context);
    if (extraMap.isPresent()) {
      dialpadIndex = extraMap.get().getDialpadIndex(ch);
    }

    return dialpadIndex.isPresent() ? dialpadIndex.get() : -1;
  }

  /**
   * Get the actual numeric character on the dialpad which the character corresponds to.
   *
   * <p>The provided character is expected to be a normalized character. See {@link
   * SmartDialMap#normalizeCharacter(char)} for details.
   *
   * <p>If the provided character can't be mapped to a key on the dialpad, return the character.
   */
  public static char getDialpadNumericCharacter(Context context, char ch) {
    Optional<Character> dialpadNumericChar = DEFAULT_MAP.getDialpadNumericCharacter(ch);
    if (dialpadNumericChar.isPresent()) {
      return dialpadNumericChar.get();
    }

    Optional<SmartDialMap> extraMap = getExtraMap(context);
    if (extraMap.isPresent()) {
      dialpadNumericChar = extraMap.get().getDialpadNumericCharacter(ch);
    }

    return dialpadNumericChar.isPresent() ? dialpadNumericChar.get() : ch;
  }

  /**
   * Converts uppercase characters to lower case ones, and on a best effort basis, strips accents
   * from accented characters.
   *
   * <p>If the provided character can't be mapped to a key on the dialpad, return the character.
   */
  public static char normalizeCharacter(Context context, char ch) {
    Optional<Character> normalizedChar = DEFAULT_MAP.normalizeCharacter(ch);
    if (normalizedChar.isPresent()) {
      return normalizedChar.get();
    }

    Optional<SmartDialMap> extraMap = getExtraMap(context);
    if (extraMap.isPresent()) {
      normalizedChar = extraMap.get().normalizeCharacter(ch);
    }

    return normalizedChar.isPresent() ? normalizedChar.get() : ch;
  }

  @VisibleForTesting
  static Optional<SmartDialMap> getExtraMap(Context context) {
    if (!ConfigProviderBindings.get(context).getBoolean(FLAG_ENABLE_DUAL_ALPHABETS, false)) {
      return Optional.absent();
    }

    String languageCode = CompatUtils.getLocale(context).getISO3Language();
    return EXTRA_MAPS.containsKey(languageCode)
        ? Optional.of(EXTRA_MAPS.get(languageCode))
        : Optional.absent();
  }
}