/*
 * Copyright (C) 2013 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.dialpad;

import android.content.Context;

import android.content.SharedPreferences;
import android.preference.PreferenceManager;
import android.telephony.TelephonyManager;
import android.text.TextUtils;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.collect.Lists;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Set;

/**
 * Smart Dial utility class to find prefixes of contacts. It contains both methods to find supported
 * prefix combinations for contact names, and also methods to find supported prefix combinations for
 * contacts' phone numbers. Each contact name is separated into several tokens, such as first name,
 * middle name, family name etc. Each phone number is also separated into country code, NANP area
 * code, and local number if such separation is possible.
 */
public class SmartDialPrefix {

    /** The number of starting and ending tokens in a contact's name considered for initials.
     * For example, if both constants are set to 2, and a contact's name is
     * "Albert Ben Charles Daniel Ed Foster", the first two tokens "Albert" "Ben", and last two
     * tokens "Ed" "Foster" can be replaced by their initials in contact name matching.
     * Users can look up this contact by combinations of his initials such as "AF" "BF" "EF" "ABF"
     * "BEF" "ABEF" etc, but can not use combinations such as "CF" "DF" "ACF" "ADF" etc.
     */
    private static final int LAST_TOKENS_FOR_INITIALS = 2;
    private static final int FIRST_TOKENS_FOR_INITIALS = 2;

    /** The country code of the user's sim card obtained by calling getSimCountryIso*/
    private static final String PREF_USER_SIM_COUNTRY_CODE =
            "DialtactsActivity_user_sim_country_code";
    private static final String PREF_USER_SIM_COUNTRY_CODE_DEFAULT = null;
    private static String sUserSimCountryCode = PREF_USER_SIM_COUNTRY_CODE_DEFAULT;

    /** Indicates whether user is in NANP regions.*/
    private static boolean sUserInNanpRegion = false;

    /** Set of country names that use NANP code.*/
    private static Set<String> sNanpCountries = null;

    /** Set of supported country codes in front of the phone number. */
    private static Set<String> sCountryCodes = null;

    /** Dialpad mapping. */
    private static final SmartDialMap mMap = new LatinSmartDialMap();

    private static boolean sNanpInitialized = false;

    /** Initializes the Nanp settings, and finds out whether user is in a NANP region.*/
    public static void initializeNanpSettings(Context context){
        final TelephonyManager manager = (TelephonyManager) context.getSystemService(
                Context.TELEPHONY_SERVICE);
        if (manager != null) {
            sUserSimCountryCode = manager.getSimCountryIso();
        }

        final SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);

        if (sUserSimCountryCode != null) {
            /** Updates shared preferences with the latest country obtained from getSimCountryIso.*/
            prefs.edit().putString(PREF_USER_SIM_COUNTRY_CODE, sUserSimCountryCode).apply();
        } else {
            /** Uses previously stored country code if loading fails. */
            sUserSimCountryCode = prefs.getString(PREF_USER_SIM_COUNTRY_CODE,
                    PREF_USER_SIM_COUNTRY_CODE_DEFAULT);
        }
        /** Queries the NANP country list to find out whether user is in a NANP region.*/
        sUserInNanpRegion = isCountryNanp(sUserSimCountryCode);
        sNanpInitialized = true;
    }

    /**
     * Explicitly setting the user Nanp to the given boolean
     */
    @VisibleForTesting
    public static void setUserInNanpRegion(boolean userInNanpRegion) {
        sUserInNanpRegion = userInNanpRegion;
    }

    /**
     * Class to record phone number parsing information.
     */
    public static class PhoneNumberTokens {
        /** Country code of the phone number. */
        final String countryCode;

        /** Offset of national number after the country code. */
        final int countryCodeOffset;

        /** Offset of local number after NANP area code.*/
        final int nanpCodeOffset;

        public PhoneNumberTokens(String countryCode, int countryCodeOffset, int nanpCodeOffset) {
            this.countryCode = countryCode;
            this.countryCodeOffset = countryCodeOffset;
            this.nanpCodeOffset = nanpCodeOffset;
        }
    }

    /**
     * Parses a contact's name into a list of separated tokens.
     *
     * @param contactName Contact's name stored in string.
     * @return A list of name tokens, for example separated first names, last name, etc.
     */
    public static ArrayList<String> parseToIndexTokens(String contactName) {
        final int length = contactName.length();
        final ArrayList<String> result = Lists.newArrayList();
        char c;
        final StringBuilder currentIndexToken = new StringBuilder();
        /**
         * Iterates through the whole name string. If the current character is a valid character,
         * append it to the current token. If the current character is not a valid character, for
         * example space " ", mark the current token as complete and add it to the list of tokens.
         */
        for (int i = 0; i < length; i++) {
            c = mMap.normalizeCharacter(contactName.charAt(i));
            if (mMap.isValidDialpadCharacter(c)) {
                /** Converts a character into the number on dialpad that represents the character.*/
                currentIndexToken.append(mMap.getDialpadIndex(c));
            } else {
                if (currentIndexToken.length() != 0) {
                    result.add(currentIndexToken.toString());
                }
                currentIndexToken.delete(0, currentIndexToken.length());
            }
        }

        /** Adds the last token in case it has not been added.*/
        if (currentIndexToken.length() != 0) {
            result.add(currentIndexToken.toString());
        }
        return result;
    }

    /**
     * Generates a list of strings that any prefix of any string in the list can be used to look
     * up the contact's name.
     *
     * @param index The contact's name in string.
     * @return A List of strings, whose prefix can be used to look up the contact.
     */
    public static ArrayList<String> generateNamePrefixes(String index) {
        final ArrayList<String> result = Lists.newArrayList();

        /** Parses the name into a list of tokens.*/
        final ArrayList<String> indexTokens = parseToIndexTokens(index);

        if (indexTokens.size() > 0) {
            /** Adds the full token combinations to the list. For example, a contact with name
             * "Albert Ben Ed Foster" can be looked up by any prefix of the following strings
             * "Foster" "EdFoster" "BenEdFoster" and "AlbertBenEdFoster". This covers all cases of
             * look up that contains only one token, and that spans multiple continuous tokens.
             */
            final StringBuilder fullNameToken = new StringBuilder();
            for (int i = indexTokens.size() - 1; i >= 0; i--) {
                fullNameToken.insert(0, indexTokens.get(i));
                result.add(fullNameToken.toString());
            }

            /** Adds initial combinations to the list, with the number of initials restricted by
             * {@link #LAST_TOKENS_FOR_INITIALS} and {@link #FIRST_TOKENS_FOR_INITIALS}.
             * For example, a contact with name "Albert Ben Ed Foster" can be looked up by any
             * prefix of the following strings "EFoster" "BFoster" "BEFoster" "AFoster" "ABFoster"
             * "AEFoster" and "ABEFoster". This covers all cases of initial lookup.
             */
            ArrayList<String> fullNames = Lists.newArrayList();
            fullNames.add(indexTokens.get(indexTokens.size() - 1));
            final int recursiveNameStart = result.size();
            int recursiveNameEnd = result.size();
            String initial = "";
            for (int i = indexTokens.size() - 2; i >= 0; i--) {
                if ((i >= indexTokens.size() - LAST_TOKENS_FOR_INITIALS) ||
                        (i < FIRST_TOKENS_FOR_INITIALS)) {
                    initial = indexTokens.get(i).substring(0, 1);

                    /** Recursively adds initial combinations to the list.*/
                    for (int j = 0; j < fullNames.size(); ++j) {
                        result.add(initial + fullNames.get(j));
                    }
                    for (int j = recursiveNameStart; j < recursiveNameEnd; ++j) {
                       result.add(initial + result.get(j));
                    }
                    recursiveNameEnd = result.size();
                    final String currentFullName = fullNames.get(fullNames.size() - 1);
                    fullNames.add(indexTokens.get(i) +  currentFullName);
                }
            }
        }

        return result;
    }

    /**
     * Computes a list of number strings based on tokens of a given phone number. Any prefix
     * of any string in the list can be used to look up the phone number. The list include the
     * full phone number, the national number if there is a country code in the phone number, and
     * the local number if there is an area code in the phone number following the NANP format.
     * For example, if a user has phone number +41 71 394 8392, the list will contain 41713948392
     * and 713948392. Any prefix to either of the strings can be used to look up the phone number.
     * If a user has a phone number +1 555-302-3029 (NANP format), the list will contain
     * 15553023029, 5553023029, and 3023029.
     *
     * @param number String of user's phone number.
     * @return A list of strings where any prefix of any entry can be used to look up the number.
     */
    public static ArrayList<String> parseToNumberTokens(String number) {
        final ArrayList<String> result = Lists.newArrayList();
        if (!TextUtils.isEmpty(number)) {
            /** Adds the full number to the list.*/
            result.add(SmartDialNameMatcher.normalizeNumber(number, mMap));

            final PhoneNumberTokens phoneNumberTokens = parsePhoneNumber(number);
            if (phoneNumberTokens == null) {
                return result;
            }

            if (phoneNumberTokens.countryCodeOffset != 0) {
                result.add(SmartDialNameMatcher.normalizeNumber(number,
                        phoneNumberTokens.countryCodeOffset, mMap));
            }

            if (phoneNumberTokens.nanpCodeOffset != 0) {
                result.add(SmartDialNameMatcher.normalizeNumber(number,
                        phoneNumberTokens.nanpCodeOffset, mMap));
            }
        }
        return result;
    }

    /**
     * Parses a phone number to find out whether it has country code and NANP area code.
     *
     * @param number Raw phone number.
     * @return a PhoneNumberToken instance with country code, NANP code information.
     */
    public static PhoneNumberTokens parsePhoneNumber(String number) {
        String countryCode = "";
        int countryCodeOffset = 0;
        int nanpNumberOffset = 0;

        if (!TextUtils.isEmpty(number)) {
            String normalizedNumber = SmartDialNameMatcher.normalizeNumber(number, mMap);
            if (number.charAt(0) == '+') {
                /** If the number starts with '+', tries to find valid country code. */
                for (int i = 1; i <= 1 + 3; i++) {
                    if (number.length() <= i) {
                        break;
                    }
                    countryCode = number.substring(1, i);
                    if (isValidCountryCode(countryCode)) {
                        countryCodeOffset = i;
                        break;
                    }
                }
            } else {
                /** If the number does not start with '+', finds out whether it is in NANP
                 * format and has '1' preceding the number.
                 */
                if ((normalizedNumber.length() == 11) && (normalizedNumber.charAt(0) == '1') &&
                        (sUserInNanpRegion)) {
                    countryCode = "1";
                    countryCodeOffset = number.indexOf(normalizedNumber.charAt(1));
                    if (countryCodeOffset == -1) {
                        countryCodeOffset = 0;
                    }
                }
            }

            /** If user is in NANP region, finds out whether a number is in NANP format.*/
            if (sUserInNanpRegion)  {
                String areaCode = "";
                if (countryCode.equals("") && normalizedNumber.length() == 10){
                    /** if the number has no country code but fits the NANP format, extracts the
                     * NANP area code, and finds out offset of the local number.
                     */
                    areaCode = normalizedNumber.substring(0, 3);
                } else if (countryCode.equals("1") && normalizedNumber.length() == 11) {
                    /** If the number has country code '1', finds out area code and offset of the
                     * local number.
                     */
                    areaCode = normalizedNumber.substring(1, 4);
                }
                if (!areaCode.equals("")) {
                    final int areaCodeIndex = number.indexOf(areaCode);
                    if (areaCodeIndex != -1) {
                        nanpNumberOffset = number.indexOf(areaCode) + 3;
                    }
                }
            }
        }
        return new PhoneNumberTokens(countryCode, countryCodeOffset, nanpNumberOffset);
    }

    /**
     * Checkes whether a country code is valid.
     */
    private static boolean isValidCountryCode(String countryCode) {
        if (sCountryCodes == null) {
            sCountryCodes = initCountryCodes();
        }
        return sCountryCodes.contains(countryCode);
    }

    private static Set<String> initCountryCodes() {
        final HashSet<String> result = new HashSet<String>();
        result.add("1");
        result.add("7");
        result.add("20");
        result.add("27");
        result.add("30");
        result.add("31");
        result.add("32");
        result.add("33");
        result.add("34");
        result.add("36");
        result.add("39");
        result.add("40");
        result.add("41");
        result.add("43");
        result.add("44");
        result.add("45");
        result.add("46");
        result.add("47");
        result.add("48");
        result.add("49");
        result.add("51");
        result.add("52");
        result.add("53");
        result.add("54");
        result.add("55");
        result.add("56");
        result.add("57");
        result.add("58");
        result.add("60");
        result.add("61");
        result.add("62");
        result.add("63");
        result.add("64");
        result.add("65");
        result.add("66");
        result.add("81");
        result.add("82");
        result.add("84");
        result.add("86");
        result.add("90");
        result.add("91");
        result.add("92");
        result.add("93");
        result.add("94");
        result.add("95");
        result.add("98");
        result.add("211");
        result.add("212");
        result.add("213");
        result.add("216");
        result.add("218");
        result.add("220");
        result.add("221");
        result.add("222");
        result.add("223");
        result.add("224");
        result.add("225");
        result.add("226");
        result.add("227");
        result.add("228");
        result.add("229");
        result.add("230");
        result.add("231");
        result.add("232");
        result.add("233");
        result.add("234");
        result.add("235");
        result.add("236");
        result.add("237");
        result.add("238");
        result.add("239");
        result.add("240");
        result.add("241");
        result.add("242");
        result.add("243");
        result.add("244");
        result.add("245");
        result.add("246");
        result.add("247");
        result.add("248");
        result.add("249");
        result.add("250");
        result.add("251");
        result.add("252");
        result.add("253");
        result.add("254");
        result.add("255");
        result.add("256");
        result.add("257");
        result.add("258");
        result.add("260");
        result.add("261");
        result.add("262");
        result.add("263");
        result.add("264");
        result.add("265");
        result.add("266");
        result.add("267");
        result.add("268");
        result.add("269");
        result.add("290");
        result.add("291");
        result.add("297");
        result.add("298");
        result.add("299");
        result.add("350");
        result.add("351");
        result.add("352");
        result.add("353");
        result.add("354");
        result.add("355");
        result.add("356");
        result.add("357");
        result.add("358");
        result.add("359");
        result.add("370");
        result.add("371");
        result.add("372");
        result.add("373");
        result.add("374");
        result.add("375");
        result.add("376");
        result.add("377");
        result.add("378");
        result.add("379");
        result.add("380");
        result.add("381");
        result.add("382");
        result.add("385");
        result.add("386");
        result.add("387");
        result.add("389");
        result.add("420");
        result.add("421");
        result.add("423");
        result.add("500");
        result.add("501");
        result.add("502");
        result.add("503");
        result.add("504");
        result.add("505");
        result.add("506");
        result.add("507");
        result.add("508");
        result.add("509");
        result.add("590");
        result.add("591");
        result.add("592");
        result.add("593");
        result.add("594");
        result.add("595");
        result.add("596");
        result.add("597");
        result.add("598");
        result.add("599");
        result.add("670");
        result.add("672");
        result.add("673");
        result.add("674");
        result.add("675");
        result.add("676");
        result.add("677");
        result.add("678");
        result.add("679");
        result.add("680");
        result.add("681");
        result.add("682");
        result.add("683");
        result.add("685");
        result.add("686");
        result.add("687");
        result.add("688");
        result.add("689");
        result.add("690");
        result.add("691");
        result.add("692");
        result.add("800");
        result.add("808");
        result.add("850");
        result.add("852");
        result.add("853");
        result.add("855");
        result.add("856");
        result.add("870");
        result.add("878");
        result.add("880");
        result.add("881");
        result.add("882");
        result.add("883");
        result.add("886");
        result.add("888");
        result.add("960");
        result.add("961");
        result.add("962");
        result.add("963");
        result.add("964");
        result.add("965");
        result.add("966");
        result.add("967");
        result.add("968");
        result.add("970");
        result.add("971");
        result.add("972");
        result.add("973");
        result.add("974");
        result.add("975");
        result.add("976");
        result.add("977");
        result.add("979");
        result.add("992");
        result.add("993");
        result.add("994");
        result.add("995");
        result.add("996");
        result.add("998");
        return result;
    }

    public static SmartDialMap getMap() {
        return mMap;
    }

    /**
     * Indicates whether the given country uses NANP numbers
     * @see <a href="https://en.wikipedia.org/wiki/North_American_Numbering_Plan">
     *     https://en.wikipedia.org/wiki/North_American_Numbering_Plan</a>
     *
     * @param country ISO 3166 country code (case doesn't matter)
     * @return True if country uses NANP numbers (e.g. US, Canada), false otherwise
     */
    @VisibleForTesting
    public static boolean isCountryNanp(String country) {
        if (TextUtils.isEmpty(country)) {
            return false;
        }
        if (sNanpCountries == null) {
            sNanpCountries = initNanpCountries();
        }
        return sNanpCountries.contains(country.toUpperCase());
    }

    private static Set<String> initNanpCountries() {
        final HashSet<String> result = new HashSet<String>();
        result.add("US"); // United States
        result.add("CA"); // Canada
        result.add("AS"); // American Samoa
        result.add("AI"); // Anguilla
        result.add("AG"); // Antigua and Barbuda
        result.add("BS"); // Bahamas
        result.add("BB"); // Barbados
        result.add("BM"); // Bermuda
        result.add("VG"); // British Virgin Islands
        result.add("KY"); // Cayman Islands
        result.add("DM"); // Dominica
        result.add("DO"); // Dominican Republic
        result.add("GD"); // Grenada
        result.add("GU"); // Guam
        result.add("JM"); // Jamaica
        result.add("PR"); // Puerto Rico
        result.add("MS"); // Montserrat
        result.add("MP"); // Northern Mariana Islands
        result.add("KN"); // Saint Kitts and Nevis
        result.add("LC"); // Saint Lucia
        result.add("VC"); // Saint Vincent and the Grenadines
        result.add("TT"); // Trinidad and Tobago
        result.add("TC"); // Turks and Caicos Islands
        result.add("VI"); // U.S. Virgin Islands
        return result;
    }

    /**
     * Returns whether the user is in a region that uses Nanp format based on the sim location.
     *
     * @return Whether user is in Nanp region.
     */
    public static boolean getUserInNanpRegion() {
        return sUserInNanpRegion;
    }
}