/*
 * Copyright (C) 2006 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.settings;

import android.app.AlertDialog;
import android.app.Dialog;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.Resources;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.preference.EditTextPreference;
import android.preference.ListPreference;
import android.preference.MultiSelectListPreference;
import android.preference.Preference;
import android.preference.SwitchPreference;
import android.provider.Telephony;
import android.telephony.ServiceState;
import android.telephony.SubscriptionManager;
import android.telephony.TelephonyManager;
import android.text.TextUtils;
import android.util.Log;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import com.android.internal.logging.MetricsLogger;

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

public class ApnEditor extends InstrumentedPreferenceActivity
        implements SharedPreferences.OnSharedPreferenceChangeListener,
                    Preference.OnPreferenceChangeListener {

    private final static String TAG = ApnEditor.class.getSimpleName();

    private final static String SAVED_POS = "pos";
    private final static String KEY_AUTH_TYPE = "auth_type";
    private final static String KEY_PROTOCOL = "apn_protocol";
    private final static String KEY_ROAMING_PROTOCOL = "apn_roaming_protocol";
    private final static String KEY_CARRIER_ENABLED = "carrier_enabled";
    private final static String KEY_BEARER_MULTI = "bearer_multi";
    private final static String KEY_MVNO_TYPE = "mvno_type";

    private final static String PROTOCOL_IPV4V6= "IPV4V6";

    private static final int MENU_DELETE = Menu.FIRST;
    private static final int MENU_SAVE = Menu.FIRST + 1;
    private static final int MENU_CANCEL = Menu.FIRST + 2;
    private static final int ERROR_DIALOG_ID = 0;
    private static final int DUPLICATE_DIALOG_ID = 1;

    private static String sNotSet;
    private EditTextPreference mName;
    private EditTextPreference mApn;
    private EditTextPreference mProxy;
    private EditTextPreference mPort;
    private EditTextPreference mUser;
    private EditTextPreference mServer;
    private EditTextPreference mPassword;
    private EditTextPreference mMmsc;
    private EditTextPreference mMcc;
    private EditTextPreference mMnc;
    private EditTextPreference mMmsProxy;
    private EditTextPreference mMmsPort;
    private ListPreference mAuthType;
    private EditTextPreference mApnType;
    private ListPreference mProtocol;
    private ListPreference mRoamingProtocol;
    private SwitchPreference mCarrierEnabled;
    private MultiSelectListPreference mBearerMulti;
    private ListPreference mMvnoType;
    private EditTextPreference mMvnoMatchData;
    private EditTextPreference mPppNumber;

    private String mCurMnc;
    private String mCurMcc;
    private boolean mDisableEditor = false;

    private Uri mUri;
    private Cursor mCursor;
    private boolean mNewApn;
    private boolean mFirstTime;
    private int mSubId;
    private Resources mRes;
    private TelephonyManager mTelephonyManager;
    private int mBearerInitialVal = 0;
    private String mMvnoTypeStr;
    private String mMvnoMatchDataStr;

    /**
     * Standard projection for the interesting columns of a normal note.
     */
    private static final String[] sProjection = new String[] {
            Telephony.Carriers._ID,     // 0
            Telephony.Carriers.NAME,    // 1
            Telephony.Carriers.APN,     // 2
            Telephony.Carriers.PROXY,   // 3
            Telephony.Carriers.PORT,    // 4
            Telephony.Carriers.USER,    // 5
            Telephony.Carriers.SERVER,  // 6
            Telephony.Carriers.PASSWORD, // 7
            Telephony.Carriers.MMSC, // 8
            Telephony.Carriers.MCC, // 9
            Telephony.Carriers.MNC, // 10
            Telephony.Carriers.NUMERIC, // 11
            Telephony.Carriers.MMSPROXY,// 12
            Telephony.Carriers.MMSPORT, // 13
            Telephony.Carriers.AUTH_TYPE, // 14
            Telephony.Carriers.TYPE, // 15
            Telephony.Carriers.PROTOCOL, // 16
            Telephony.Carriers.CARRIER_ENABLED, // 17
            Telephony.Carriers.BEARER, // 18
            Telephony.Carriers.BEARER_BITMASK, // 19
            Telephony.Carriers.ROAMING_PROTOCOL, // 20
            Telephony.Carriers.MVNO_TYPE,   // 21
            Telephony.Carriers.MVNO_MATCH_DATA,  // 22
            "ppp_number"  // 23
    };

    private static final int ID_INDEX = 0;
    private static final int NAME_INDEX = 1;
    private static final int APN_INDEX = 2;
    private static final int PROXY_INDEX = 3;
    private static final int PORT_INDEX = 4;
    private static final int USER_INDEX = 5;
    private static final int SERVER_INDEX = 6;
    private static final int PASSWORD_INDEX = 7;
    private static final int MMSC_INDEX = 8;
    private static final int MCC_INDEX = 9;
    private static final int MNC_INDEX = 10;
    private static final int MMSPROXY_INDEX = 12;
    private static final int MMSPORT_INDEX = 13;
    private static final int AUTH_TYPE_INDEX = 14;
    private static final int TYPE_INDEX = 15;
    private static final int PROTOCOL_INDEX = 16;
    private static final int CARRIER_ENABLED_INDEX = 17;
    private static final int BEARER_INDEX = 18;
    private static final int BEARER_BITMASK_INDEX = 19;
    private static final int ROAMING_PROTOCOL_INDEX = 20;
    private static final int MVNO_TYPE_INDEX = 21;
    private static final int MVNO_MATCH_DATA_INDEX = 22;
    private static final int PPP_NUMBER_INDEX = 23;


    @Override
    protected void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        addPreferencesFromResource(R.xml.apn_editor);

        sNotSet = getResources().getString(R.string.apn_not_set);
        mName = (EditTextPreference) findPreference("apn_name");
        mApn = (EditTextPreference) findPreference("apn_apn");
        mProxy = (EditTextPreference) findPreference("apn_http_proxy");
        mPort = (EditTextPreference) findPreference("apn_http_port");
        mUser = (EditTextPreference) findPreference("apn_user");
        mServer = (EditTextPreference) findPreference("apn_server");
        mPassword = (EditTextPreference) findPreference("apn_password");
        mMmsProxy = (EditTextPreference) findPreference("apn_mms_proxy");
        mMmsPort = (EditTextPreference) findPreference("apn_mms_port");
        mMmsc = (EditTextPreference) findPreference("apn_mmsc");
        mMcc = (EditTextPreference) findPreference("apn_mcc");
        mMnc = (EditTextPreference) findPreference("apn_mnc");
        mApnType = (EditTextPreference) findPreference("apn_type");
        mPppNumber = (EditTextPreference) findPreference("apn_ppp_number");

        mAuthType = (ListPreference) findPreference(KEY_AUTH_TYPE);
        mAuthType.setOnPreferenceChangeListener(this);

        mProtocol = (ListPreference) findPreference(KEY_PROTOCOL);
        mProtocol.setOnPreferenceChangeListener(this);

        mRoamingProtocol = (ListPreference) findPreference(KEY_ROAMING_PROTOCOL);
        mRoamingProtocol.setOnPreferenceChangeListener(this);

        mCarrierEnabled = (SwitchPreference) findPreference(KEY_CARRIER_ENABLED);

        mBearerMulti = (MultiSelectListPreference) findPreference(KEY_BEARER_MULTI);
        mBearerMulti.setOnPreferenceChangeListener(this);

        mMvnoType = (ListPreference) findPreference(KEY_MVNO_TYPE);
        mMvnoType.setOnPreferenceChangeListener(this);
        mMvnoMatchData = (EditTextPreference) findPreference("mvno_match_data");

        mRes = getResources();

        final Intent intent = getIntent();
        final String action = intent.getAction();
        mSubId = intent.getIntExtra(ApnSettings.SUB_ID,
                SubscriptionManager.INVALID_SUBSCRIPTION_ID);
        mDisableEditor = intent.getBooleanExtra("DISABLE_EDITOR", false);
        if (mDisableEditor) {
            getPreferenceScreen().setEnabled(false);
            Log.d(TAG, "ApnEditor form is disabled.");
        }

        mFirstTime = icicle == null;

        if (action.equals(Intent.ACTION_EDIT)) {
            mUri = intent.getData();
        } else if (action.equals(Intent.ACTION_INSERT)) {
            if (mFirstTime || icicle.getInt(SAVED_POS) == 0) {
                ContentValues values = new ContentValues();
                values.put(Telephony.Carriers.PROTOCOL, PROTOCOL_IPV4V6);
                values.put(Telephony.Carriers.ROAMING_PROTOCOL, PROTOCOL_IPV4V6);
                mUri = getContentResolver().insert(intent.getData(), values);
            } else {
                mUri = ContentUris.withAppendedId(Telephony.Carriers.CONTENT_URI,
                        icicle.getInt(SAVED_POS));
            }
            mNewApn = true;
            mMvnoTypeStr = intent.getStringExtra(ApnSettings.MVNO_TYPE);
            mMvnoMatchDataStr = intent.getStringExtra(ApnSettings.MVNO_MATCH_DATA);
            // If we were unable to create a new note, then just finish
            // this activity.  A RESULT_CANCELED will be sent back to the
            // original activity if they requested a result.
            if (mUri == null) {
                Log.w(TAG, "Failed to insert new telephony provider into "
                        + getIntent().getData());
                finish();
                return;
            }

            // The new entry was created, so assume all will end well and
            // set the result to be returned.
            setResult(RESULT_OK, (new Intent()).setAction(mUri.toString()));

        } else {
            finish();
            return;
        }

        mCursor = managedQuery(mUri, sProjection, null, null);
        mCursor.moveToFirst();

        mTelephonyManager = (TelephonyManager) getSystemService(TELEPHONY_SERVICE);

        fillUi();
    }

    @Override
    protected int getMetricsCategory() {
        return MetricsLogger.APN_EDITOR;
    }

    @Override
    public void onResume() {
        super.onResume();
        getPreferenceScreen().getSharedPreferences()
                .registerOnSharedPreferenceChangeListener(this);
    }

    @Override
    public void onPause() {
        getPreferenceScreen().getSharedPreferences()
                .unregisterOnSharedPreferenceChangeListener(this);
        super.onPause();
    }

    private void fillUi() {
        if (mFirstTime) {
            mFirstTime = false;
            String numeric = mTelephonyManager.getIccOperatorNumericForData(mSubId);
            // Fill in all the values from the db in both text editor and summary
            mName.setText(mCursor.getString(NAME_INDEX));
            mApn.setText(mCursor.getString(APN_INDEX));
            mProxy.setText(mCursor.getString(PROXY_INDEX));
            mPort.setText(mCursor.getString(PORT_INDEX));
            mUser.setText(mCursor.getString(USER_INDEX));
            mServer.setText(mCursor.getString(SERVER_INDEX));
            mPassword.setText(mCursor.getString(PASSWORD_INDEX));
            mMmsProxy.setText(mCursor.getString(MMSPROXY_INDEX));
            mMmsPort.setText(mCursor.getString(MMSPORT_INDEX));
            mMmsc.setText(mCursor.getString(MMSC_INDEX));
            mMcc.setText(mCursor.getString(MCC_INDEX));
            mMnc.setText(mCursor.getString(MNC_INDEX));
            mApnType.setText(mCursor.getString(TYPE_INDEX));
            if (mNewApn) {
                // MCC is first 3 chars and then in 2 - 3 chars of MNC
                if (numeric != null && numeric.length() > 4) {
                    // Country code
                    String mcc = numeric.substring(0, 3);
                    // Network code
                    String mnc = numeric.substring(3);
                    // Auto populate MNC and MCC for new entries, based on what SIM reports
                    mMcc.setText(mcc);
                    mMnc.setText(mnc);
                    mCurMnc = mnc;
                    mCurMcc = mcc;
                }
                mApnType.setText(checkNull(getString(R.string.config_default_new_apn_type)));
            }
            int authVal = mCursor.getInt(AUTH_TYPE_INDEX);
            if (authVal != -1) {
                mAuthType.setValueIndex(authVal);
            } else {
                mAuthType.setValue(null);
            }

            mProtocol.setValue(mCursor.getString(PROTOCOL_INDEX));
            mRoamingProtocol.setValue(mCursor.getString(ROAMING_PROTOCOL_INDEX));
            mCarrierEnabled.setChecked(mCursor.getInt(CARRIER_ENABLED_INDEX)==1);
            mBearerInitialVal = mCursor.getInt(BEARER_INDEX);

            HashSet<String> bearers = new HashSet<String>();
            int bearerBitmask = mCursor.getInt(BEARER_BITMASK_INDEX);
            if (bearerBitmask == 0) {
                if (mBearerInitialVal == 0) {
                    bearers.add("" + 0);
                }
            } else {
                int i = 1;
                while (bearerBitmask != 0) {
                    if ((bearerBitmask & 1) == 1) {
                        bearers.add("" + i);
                    }
                    bearerBitmask >>= 1;
                    i++;
                }
            }

            if (mBearerInitialVal != 0 && bearers.contains("" + mBearerInitialVal) == false) {
                // add mBearerInitialVal to bearers
                bearers.add("" + mBearerInitialVal);
            }
            mBearerMulti.setValues(bearers);

            mMvnoType.setValue(mCursor.getString(MVNO_TYPE_INDEX));
            mMvnoMatchData.setEnabled(false);
            mMvnoMatchData.setText(mCursor.getString(MVNO_MATCH_DATA_INDEX));
            if (mNewApn && mMvnoTypeStr != null && mMvnoMatchDataStr != null) {
                mMvnoType.setValue(mMvnoTypeStr);
                mMvnoMatchData.setText(mMvnoMatchDataStr);
            }

            String pppNumber = mCursor.getString(PPP_NUMBER_INDEX);
            mPppNumber.setText(pppNumber);
            if (pppNumber == null) {
                if (!mNewApn) {
                    getPreferenceScreen().removePreference(mPppNumber);
                } else if (getResources().getBoolean(R.bool.config_ppp_enabled)) {
                    getPreferenceScreen().removePreference(mPppNumber);
                }
            }
        }

        mName.setSummary(checkNull(mName.getText()));
        mApn.setSummary(checkNull(mApn.getText()));
        mProxy.setSummary(checkNull(mProxy.getText()));
        mPort.setSummary(checkNull(mPort.getText()));
        mUser.setSummary(checkNull(mUser.getText()));
        mServer.setSummary(checkNull(mServer.getText()));
        mPassword.setSummary(starify(mPassword.getText()));
        mMmsProxy.setSummary(checkNull(mMmsProxy.getText()));
        mMmsPort.setSummary(checkNull(mMmsPort.getText()));
        mMmsc.setSummary(checkNull(mMmsc.getText()));
        mMcc.setSummary(checkNull(mMcc.getText()));
        mMnc.setSummary(checkNull(mMnc.getText()));
        mApnType.setSummary(checkNull(mApnType.getText()));

        String pppNumber = mPppNumber.getText();
        if (pppNumber != null) {
            // Remove this preference if PPP number is not present
            // in the APN settings
            mPppNumber.setSummary(checkNull(pppNumber));
        }

        String authVal = mAuthType.getValue();
        if (authVal != null) {
            int authValIndex = Integer.parseInt(authVal);
            mAuthType.setValueIndex(authValIndex);

            String []values = mRes.getStringArray(R.array.apn_auth_entries);
            mAuthType.setSummary(values[authValIndex]);
        } else {
            mAuthType.setSummary(sNotSet);
        }

        mProtocol.setSummary(
                checkNull(protocolDescription(mProtocol.getValue(), mProtocol)));
        mRoamingProtocol.setSummary(
                checkNull(protocolDescription(mRoamingProtocol.getValue(), mRoamingProtocol)));
        mBearerMulti.setSummary(
                checkNull(bearerMultiDescription(mBearerMulti.getValues())));
        mMvnoType.setSummary(
                checkNull(mvnoDescription(mMvnoType.getValue())));
        mMvnoMatchData.setSummary(checkNull(mMvnoMatchData.getText()));
        // allow user to edit carrier_enabled for some APN
        boolean ceEditable = getResources().getBoolean(R.bool.config_allow_edit_carrier_enabled);
        if (ceEditable) {
            mCarrierEnabled.setEnabled(true);
        } else {
            mCarrierEnabled.setEnabled(false);
        }
    }

    /**
     * Returns the UI choice (e.g., "IPv4/IPv6") corresponding to the given
     * raw value of the protocol preference (e.g., "IPV4V6"). If unknown,
     * return null.
     */
    private String protocolDescription(String raw, ListPreference protocol) {
        int protocolIndex = protocol.findIndexOfValue(raw);
        if (protocolIndex == -1) {
            return null;
        } else {
            String[] values = mRes.getStringArray(R.array.apn_protocol_entries);
            try {
                return values[protocolIndex];
            } catch (ArrayIndexOutOfBoundsException e) {
                return null;
            }
        }
    }

    private String bearerDescription(String raw) {
        int mBearerIndex = mBearerMulti.findIndexOfValue(raw);
        if (mBearerIndex == -1) {
            return null;
        } else {
            String[] values = mRes.getStringArray(R.array.bearer_entries);
            try {
                return values[mBearerIndex];
            } catch (ArrayIndexOutOfBoundsException e) {
                return null;
            }
        }
    }

    private String bearerMultiDescription(Set<String> raw) {
        String[] values = mRes.getStringArray(R.array.bearer_entries);
        StringBuilder retVal = new StringBuilder();
        boolean first = true;
        for (String bearer : raw) {
            int bearerIndex = mBearerMulti.findIndexOfValue(bearer);
            try {
                if (first) {
                    retVal.append(values[bearerIndex]);
                    first = false;
                } else {
                    retVal.append(", " + values[bearerIndex]);
                }
            } catch (ArrayIndexOutOfBoundsException e) {
                // ignore
            }
        }
        String val = retVal.toString();
        if (!TextUtils.isEmpty(val)) {
            return val;
        }
        return null;
    }

    private String mvnoDescription(String newValue) {
        int mvnoIndex = mMvnoType.findIndexOfValue(newValue);
        String oldValue = mMvnoType.getValue();

        if (mvnoIndex == -1) {
            return null;
        } else {
            String[] values = mRes.getStringArray(R.array.mvno_type_entries);
            if (values[mvnoIndex].equals("None")) {
                mMvnoMatchData.setEnabled(false);
            } else {
                mMvnoMatchData.setEnabled(true);
            }
            if (newValue != null && newValue.equals(oldValue) == false) {
                if (values[mvnoIndex].equals("SPN")) {
                    mMvnoMatchData.setText(mTelephonyManager.getSimOperatorName());
                } else if (values[mvnoIndex].equals("IMSI")) {
                    String numeric = mTelephonyManager.getIccOperatorNumericForData(mSubId);
                    mMvnoMatchData.setText(numeric + "x");
                } else if (values[mvnoIndex].equals("GID")) {
                    mMvnoMatchData.setText(mTelephonyManager.getGroupIdLevel1());
                }
            }

            try {
                return values[mvnoIndex];
            } catch (ArrayIndexOutOfBoundsException e) {
                return null;
            }
        }
    }

    public boolean onPreferenceChange(Preference preference, Object newValue) {
        String key = preference.getKey();
        if (KEY_AUTH_TYPE.equals(key)) {
            try {
                int index = Integer.parseInt((String) newValue);
                mAuthType.setValueIndex(index);

                String []values = mRes.getStringArray(R.array.apn_auth_entries);
                mAuthType.setSummary(values[index]);
            } catch (NumberFormatException e) {
                return false;
            }
        } else if (KEY_PROTOCOL.equals(key)) {
            String protocol = protocolDescription((String) newValue, mProtocol);
            if (protocol == null) {
                return false;
            }
            mProtocol.setSummary(protocol);
            mProtocol.setValue((String) newValue);
        } else if (KEY_ROAMING_PROTOCOL.equals(key)) {
            String protocol = protocolDescription((String) newValue, mRoamingProtocol);
            if (protocol == null) {
                return false;
            }
            mRoamingProtocol.setSummary(protocol);
            mRoamingProtocol.setValue((String) newValue);
        } else if (KEY_BEARER_MULTI.equals(key)) {
            String bearer = bearerMultiDescription((Set<String>) newValue);
            if (bearer == null) {
                return false;
            }
            mBearerMulti.setValues((Set<String>) newValue);
            mBearerMulti.setSummary(bearer);
        } else if (KEY_MVNO_TYPE.equals(key)) {
            String mvno = mvnoDescription((String) newValue);
            if (mvno == null) {
                return false;
            }
            mMvnoType.setValue((String) newValue);
            mMvnoType.setSummary(mvno);
        }

        return true;
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);
        if (mDisableEditor) {
            Log.d(TAG, "Form is disabled. Do not create the options menu.");
            return true;
        }
        // If it's a new APN, then cancel will delete the new entry in onPause
        if (!mNewApn) {
            menu.add(0, MENU_DELETE, 0, R.string.menu_delete)
                .setIcon(R.drawable.ic_menu_delete);
        }
        menu.add(0, MENU_SAVE, 0, R.string.menu_save)
            .setIcon(android.R.drawable.ic_menu_save);
        menu.add(0, MENU_CANCEL, 0, R.string.menu_cancel)
            .setIcon(android.R.drawable.ic_menu_close_clear_cancel);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
        case MENU_DELETE:
            deleteApn();
            return true;
        case MENU_SAVE:
            if (validateAndSave(false)) {
                finish();
            }
            return true;
        case MENU_CANCEL:
            if (mNewApn) {
                getContentResolver().delete(mUri, null, null);
            }
            finish();
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        switch (keyCode) {
            case KeyEvent.KEYCODE_BACK: {
                if (validateAndSave(false)) {
                    finish();
                }
                return true;
            }
        }
        return super.onKeyDown(keyCode, event);
    }

    @Override
    protected void onSaveInstanceState(Bundle icicle) {
        super.onSaveInstanceState(icicle);
        if (validateAndSave(true)) {
            icicle.putInt(SAVED_POS, mCursor.getInt(ID_INDEX));
        }
    }

    /**
     * Check the key fields' validity and save if valid.
     * @param force save even if the fields are not valid, if the app is
     *        being suspended
     * @return true if the data was saved
     */
    private boolean validateAndSave(boolean force) {

        // If the form is not editable, do nothing and return.
        if (mDisableEditor){
            Log.d(TAG, "Form is disabled. Nothing to save.");
            return true;
        }

        String name = checkNotSet(mName.getText());
        String apn = checkNotSet(mApn.getText());
        String mcc = checkNotSet(mMcc.getText());
        String mnc = checkNotSet(mMnc.getText());

        if (getErrorMsg() != null && !force) {
            showDialog(ERROR_DIALOG_ID);
            return false;
        }

        if (!mCursor.moveToFirst()) {
            Log.w(TAG,
                    "Could not go to the first row in the Cursor when saving data.");
            return false;
        }

        // If it's a new APN and a name or apn haven't been entered, then erase the entry
        if (force && mNewApn && name.length() < 1 && apn.length() < 1) {
            getContentResolver().delete(mUri, null, null);
            return false;
        }

        ContentValues values = new ContentValues();

        // Add a dummy name "Untitled", if the user exits the screen without adding a name but
        // entered other information worth keeping.
        values.put(Telephony.Carriers.NAME,
                name.length() < 1 ? getResources().getString(R.string.untitled_apn) : name);
        values.put(Telephony.Carriers.APN, apn);
        values.put(Telephony.Carriers.PROXY, checkNotSet(mProxy.getText()));
        values.put(Telephony.Carriers.PORT, checkNotSet(mPort.getText()));
        values.put(Telephony.Carriers.MMSPROXY, checkNotSet(mMmsProxy.getText()));
        values.put(Telephony.Carriers.MMSPORT, checkNotSet(mMmsPort.getText()));
        values.put(Telephony.Carriers.USER, checkNotSet(mUser.getText()));
        values.put(Telephony.Carriers.SERVER, checkNotSet(mServer.getText()));
        values.put(Telephony.Carriers.PASSWORD, checkNotSet(mPassword.getText()));
        values.put(Telephony.Carriers.MMSC, checkNotSet(mMmsc.getText()));

        String authVal = mAuthType.getValue();
        if (authVal != null) {
            values.put(Telephony.Carriers.AUTH_TYPE, Integer.parseInt(authVal));
        }

        values.put(Telephony.Carriers.PROTOCOL, checkNotSet(mProtocol.getValue()));
        values.put(Telephony.Carriers.ROAMING_PROTOCOL, checkNotSet(mRoamingProtocol.getValue()));

        values.put(Telephony.Carriers.TYPE, checkNotSet(mApnType.getText()));

        values.put(Telephony.Carriers.MCC, mcc);
        values.put(Telephony.Carriers.MNC, mnc);

        values.put(Telephony.Carriers.NUMERIC, mcc + mnc);

        String pppNumber = mPppNumber.getText();
        if (pppNumber != null) {
            values.put(getResources().getString(R.string.ppp_number), pppNumber);
        }

        if (mCurMnc != null && mCurMcc != null) {
            if (mCurMnc.equals(mnc) && mCurMcc.equals(mcc)) {
                values.put(Telephony.Carriers.CURRENT, 1);
            }
        }

        Set<String> bearerSet = mBearerMulti.getValues();
        int bearerBitmask = 0;
        for (String bearer : bearerSet) {
            if (Integer.parseInt(bearer) == 0) {
                bearerBitmask = 0;
                break;
            } else {
                bearerBitmask |= ServiceState.getBitmaskForTech(Integer.parseInt(bearer));
            }
        }
        values.put(Telephony.Carriers.BEARER_BITMASK, bearerBitmask);

        int bearerVal;
        if (bearerBitmask == 0 || mBearerInitialVal == 0) {
            bearerVal = 0;
        } else if (ServiceState.bitmaskHasTech(bearerBitmask, mBearerInitialVal)) {
            bearerVal = mBearerInitialVal;
        } else {
            // bearer field was being used but bitmask has changed now and does not include the
            // initial bearer value -- setting bearer to 0 but maybe better behavior is to choose a
            // random tech from the new bitmask??
            bearerVal = 0;
        }
        values.put(Telephony.Carriers.BEARER, bearerVal);

        values.put(Telephony.Carriers.MVNO_TYPE, checkNotSet(mMvnoType.getValue()));
        values.put(Telephony.Carriers.MVNO_MATCH_DATA, checkNotSet(mMvnoMatchData.getText()));

        values.put(Telephony.Carriers.CARRIER_ENABLED, mCarrierEnabled.isChecked() ? 1 : 0);

        if (isDuplicate(values)) {
            showDialog(DUPLICATE_DIALOG_ID);
            return false;
        }

        getContentResolver().update(mUri, values, null, null);

        return true;
    }

    private boolean isDuplicate(ContentValues row) {
        if (!getResources().getBoolean(R.bool.config_enable_duplicate_apn_checking)) {
            return false;
        }

        final Set<String> keys = row.keySet();

        StringBuilder queryBuilder = new StringBuilder();
        List<String> selectionArgsList = new ArrayList<>();

        final Iterator<String> iterator = keys.iterator();
        while (iterator.hasNext()) {
            final String key = iterator.next();

            if (!keyForDuplicateCheck(key) || row.getAsString(key).isEmpty()) {
                // Skip keys which don't interest us for the duplicate query.
                // Or if the user hasn't yet filled a field in (empty value), skip it.
                continue;
            }

            queryBuilder.append(key);
            queryBuilder.append("=?");
            queryBuilder.append(" AND ");

            selectionArgsList.add(row.getAsString(key));
        }
        // remove extra AND at the end
        queryBuilder.delete(queryBuilder.length() - " AND ".length(), queryBuilder.length());

        String[] selectionArgs = new String[selectionArgsList.size()];
        selectionArgsList.toArray(selectionArgs);

        try (Cursor query = getContentResolver().query(Telephony.Carriers.CONTENT_URI,
                sProjection, queryBuilder.toString(), selectionArgs, null)) {
            return query.getCount() > (mNewApn ? 0 : 1);
        } catch (Exception e) {
            Log.e(TAG, "error querying for duplicates", e);
            return false;
        }
    }

    /**
     * Helper method to decide what columns should be considered valid when checking for
     * potential duplicate APNs before allowing the user to add a new one.
     *
     * @param key the column of the row we want to check
     * @return whether to include this key-value pair in the duplicate query
     */
    private static boolean keyForDuplicateCheck(String key) {
        switch (key) {
            case Telephony.Carriers.APN:
            case Telephony.Carriers.MMSPROXY:
            case Telephony.Carriers.MMSPORT:
            case Telephony.Carriers.MMSC:
            case Telephony.Carriers.TYPE:
            case Telephony.Carriers.MCC:
            case Telephony.Carriers.MNC:
            case Telephony.Carriers.NUMERIC:
                return true;
            default:
                return false;
        }
    }

    private String getErrorMsg() {
        String errorMsg = null;

        String name = checkNotSet(mName.getText());
        String apn = checkNotSet(mApn.getText());
        String mcc = checkNotSet(mMcc.getText());
        String mnc = checkNotSet(mMnc.getText());

        if (name.length() < 1) {
            errorMsg = mRes.getString(R.string.error_name_empty);
        } else if (apn.length() < 1) {
            errorMsg = mRes.getString(R.string.error_apn_empty);
        } else if (mcc.length() != 3) {
            errorMsg = mRes.getString(R.string.error_mcc_not3);
        } else if ((mnc.length() & 0xFFFE) != 2) {
            errorMsg = mRes.getString(R.string.error_mnc_not23);
        }

        return errorMsg;
    }

    @Override
    protected Dialog onCreateDialog(int id) {

        if (id == ERROR_DIALOG_ID) {
            String msg = getErrorMsg();

            return new AlertDialog.Builder(this)
                    .setTitle(R.string.error_title)
                    .setPositiveButton(android.R.string.ok, null)
                    .setMessage(msg)
                    .create();
        } else if (id == DUPLICATE_DIALOG_ID) {
            return new AlertDialog.Builder(this)
                    .setTitle(R.string.duplicate_apn_error_title)
                    .setPositiveButton(android.R.string.ok, null)
                    .setMessage(getString(R.string.duplicate_apn_error_message))
                    .create();
        }

        return super.onCreateDialog(id);
    }

    @Override
    protected void onPrepareDialog(int id, Dialog dialog) {
        super.onPrepareDialog(id, dialog);

        if (id == ERROR_DIALOG_ID) {
            String msg = getErrorMsg();

            if (msg != null) {
                ((AlertDialog)dialog).setMessage(msg);
            }
        }
    }

    private void deleteApn() {
        getContentResolver().delete(mUri, null, null);
        finish();
    }

    private String starify(String value) {
        if (value == null || value.length() == 0) {
            return sNotSet;
        } else {
            char[] password = new char[value.length()];
            for (int i = 0; i < password.length; i++) {
                password[i] = '*';
            }
            return new String(password);
        }
    }

    private String checkNull(String value) {
        if (value == null || value.length() == 0) {
            return sNotSet;
        } else {
            return value;
        }
    }

    private String checkNotSet(String value) {
        if (value == null || value.equals(sNotSet)) {
            return "";
        } else {
            return value;
        }
    }

    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
        Preference pref = findPreference(key);
        if (pref != null) {
            if (pref.equals(mPassword)){
                pref.setSummary(starify(sharedPreferences.getString(key, "")));
            } else if (pref.equals(mCarrierEnabled) || pref.equals(mBearerMulti)) {
                // do nothing
            } else {
                pref.setSummary(checkNull(sharedPreferences.getString(key, "")));
            }
        }
    }
}
