/*
 * Copyright (C) 2007 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.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.ContentQueryMap;
import android.content.ContentResolver;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.pm.PackageManager.NameNotFoundException;
import android.database.Cursor;
import android.location.LocationManager;
import android.os.Bundle;
import android.preference.CheckBoxPreference;
import android.preference.EditTextPreference;
import android.preference.Preference;
import android.preference.PreferenceActivity;
import android.preference.PreferenceCategory;
import android.preference.PreferenceGroup;
import android.preference.PreferenceScreen;
import android.provider.Settings;
import android.security.Credentials;
import android.security.KeyStore;
import android.text.Html;
import android.text.TextUtils;
import android.text.method.LinkMovementMethod;
import android.util.Log;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

import com.android.internal.widget.LockPatternUtils;
import android.telephony.TelephonyManager;

import java.util.ArrayList;
import java.util.List;
import java.util.Observable;
import java.util.Observer;

/**
 * Gesture lock pattern settings.
 */
public class SecuritySettings extends PreferenceActivity {

    // Lock Settings

    private static final String KEY_LOCK_ENABLED = "lockenabled";
    private static final String KEY_VISIBLE_PATTERN = "visiblepattern";
    private static final String KEY_TACTILE_FEEDBACK_ENABLED = "tactilefeedback";
    private static final int CONFIRM_PATTERN_THEN_DISABLE_AND_CLEAR_REQUEST_CODE = 55;

    private static final String PREFS_NAME = "location_prefs";
    private static final String PREFS_USE_LOCATION = "use_location";

    private LockPatternUtils mLockPatternUtils;
    private CheckBoxPreference mLockEnabled;
    private CheckBoxPreference mVisiblePattern;
    private CheckBoxPreference mTactileFeedback;
    private Preference mChoosePattern;

    private CheckBoxPreference mShowPassword;

    // Location Settings
    private static final String LOCATION_CATEGORY = "location_category";
    private static final String LOCATION_NETWORK = "location_network";
    private static final String LOCATION_GPS = "location_gps";
    private static final String ASSISTED_GPS = "assisted_gps";

    // Credential storage
    private static final int CSTOR_MIN_PASSWORD_LENGTH = 8;

    private static final int CSTOR_INIT_DIALOG = 1;
    private static final int CSTOR_CHANGE_PASSWORD_DIALOG = 2;
    private static final int CSTOR_UNLOCK_DIALOG = 3;
    private static final int CSTOR_RESET_DIALOG = 4;

    private CstorHelper mCstorHelper = new CstorHelper();

    private CheckBoxPreference mNetwork;
    private CheckBoxPreference mGps;
    private CheckBoxPreference mAssistedGps;

    // These provide support for receiving notification when Location Manager settings change.
    // This is necessary because the Network Location Provider can change settings
    // if the user does not confirm enabling the provider.
    private ContentQueryMap mContentQueryMap;
    private final class SettingsObserver implements Observer {
        public void update(Observable o, Object arg) {
            updateToggles();
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.security_settings);

        mLockPatternUtils = new LockPatternUtils(getContentResolver());

        createPreferenceHierarchy();

        mNetwork = (CheckBoxPreference) getPreferenceScreen().findPreference(LOCATION_NETWORK);
        mGps = (CheckBoxPreference) getPreferenceScreen().findPreference(LOCATION_GPS);
        mAssistedGps = (CheckBoxPreference) getPreferenceScreen().findPreference(ASSISTED_GPS);

        updateToggles();

        // listen for Location Manager settings changes
        Cursor settingsCursor = getContentResolver().query(Settings.Secure.CONTENT_URI, null,
                "(" + Settings.System.NAME + "=?)",
                new String[]{Settings.Secure.LOCATION_PROVIDERS_ALLOWED},
                null);
        mContentQueryMap = new ContentQueryMap(settingsCursor, Settings.System.NAME, true, null);
        mContentQueryMap.addObserver(new SettingsObserver());

        mCstorHelper.handleIntent(getIntent());
    }

    private PreferenceScreen createPreferenceHierarchy() {
        // Root
        PreferenceScreen root = this.getPreferenceScreen();

        // Inline preferences
        PreferenceCategory inlinePrefCat = new PreferenceCategory(this);
        inlinePrefCat.setTitle(R.string.lock_settings_title);
        root.addPreference(inlinePrefCat);

        // change pattern lock
        Intent intent = new Intent();
        intent.setClassName("com.android.settings",
                    "com.android.settings.ChooseLockPatternTutorial");
        mChoosePattern = getPreferenceManager().createPreferenceScreen(this);
        mChoosePattern.setIntent(intent);
        inlinePrefCat.addPreference(mChoosePattern);

        // autolock toggle
        mLockEnabled = new LockEnabledPref(this);
        mLockEnabled.setTitle(R.string.lockpattern_settings_enable_title);
        mLockEnabled.setSummary(R.string.lockpattern_settings_enable_summary);
        mLockEnabled.setKey(KEY_LOCK_ENABLED);
        inlinePrefCat.addPreference(mLockEnabled);

        // visible pattern
        mVisiblePattern = new CheckBoxPreference(this);
        mVisiblePattern.setKey(KEY_VISIBLE_PATTERN);
        mVisiblePattern.setTitle(R.string.lockpattern_settings_enable_visible_pattern_title);
        inlinePrefCat.addPreference(mVisiblePattern);

        // tactile feedback
        mTactileFeedback = new CheckBoxPreference(this);
        mTactileFeedback.setKey(KEY_TACTILE_FEEDBACK_ENABLED);
        mTactileFeedback.setTitle(R.string.lockpattern_settings_enable_tactile_feedback_title);
        inlinePrefCat.addPreference(mTactileFeedback);

        int activePhoneType = TelephonyManager.getDefault().getPhoneType();

        // do not display SIM lock for CDMA phone
        if (TelephonyManager.PHONE_TYPE_CDMA != activePhoneType)
        {
            PreferenceScreen simLockPreferences = getPreferenceManager()
                    .createPreferenceScreen(this);
            simLockPreferences.setTitle(R.string.sim_lock_settings_category);
            // Intent to launch SIM lock settings
            intent = new Intent();
            intent.setClassName("com.android.settings", "com.android.settings.IccLockSettings");
            simLockPreferences.setIntent(intent);

            PreferenceCategory simLockCat = new PreferenceCategory(this);
            simLockCat.setTitle(R.string.sim_lock_settings_title);
            root.addPreference(simLockCat);
            simLockCat.addPreference(simLockPreferences);
        }

        // Passwords
        PreferenceCategory passwordsCat = new PreferenceCategory(this);
        passwordsCat.setTitle(R.string.security_passwords_title);
        root.addPreference(passwordsCat);

        CheckBoxPreference showPassword = mShowPassword = new CheckBoxPreference(this);
        showPassword.setKey("show_password");
        showPassword.setTitle(R.string.show_password);
        showPassword.setSummary(R.string.show_password_summary);
        showPassword.setPersistent(false);
        passwordsCat.addPreference(showPassword);

        // Credential storage
        PreferenceCategory credStoreCat = new PreferenceCategory(this);
        credStoreCat.setTitle(R.string.cstor_settings_category);
        root.addPreference(credStoreCat);
        mCstorHelper.createPreferences(credStoreCat);

        return root;
    }

    @Override
    protected void onResume() {
        super.onResume();

        boolean patternExists = mLockPatternUtils.savedPatternExists();
        mLockEnabled.setEnabled(patternExists);
        mVisiblePattern.setEnabled(patternExists);
        mTactileFeedback.setEnabled(patternExists);

        mLockEnabled.setChecked(mLockPatternUtils.isLockPatternEnabled());
        mVisiblePattern.setChecked(mLockPatternUtils.isVisiblePatternEnabled());
        mTactileFeedback.setChecked(mLockPatternUtils.isTactileFeedbackEnabled());

        int chooseStringRes = mLockPatternUtils.savedPatternExists() ?
                R.string.lockpattern_settings_change_lock_pattern :
                R.string.lockpattern_settings_choose_lock_pattern;
        mChoosePattern.setTitle(chooseStringRes);

        mShowPassword.setChecked(Settings.System.getInt(getContentResolver(),
                Settings.System.TEXT_SHOW_PASSWORD, 1) != 0);
    }

    @Override
    public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen,
            Preference preference) {
        final String key = preference.getKey();

        if (KEY_LOCK_ENABLED.equals(key)) {
            mLockPatternUtils.setLockPatternEnabled(isToggled(preference));
        } else if (KEY_VISIBLE_PATTERN.equals(key)) {
            mLockPatternUtils.setVisiblePatternEnabled(isToggled(preference));
        } else if (KEY_TACTILE_FEEDBACK_ENABLED.equals(key)) {
            mLockPatternUtils.setTactileFeedbackEnabled(isToggled(preference));
        } else if (preference == mShowPassword) {
            Settings.System.putInt(getContentResolver(), Settings.System.TEXT_SHOW_PASSWORD,
                    mShowPassword.isChecked() ? 1 : 0);
        } else if (preference == mNetwork) {
            Settings.Secure.setLocationProviderEnabled(getContentResolver(),
                    LocationManager.NETWORK_PROVIDER, mNetwork.isChecked());
        } else if (preference == mGps) {
            boolean enabled = mGps.isChecked();
            Settings.Secure.setLocationProviderEnabled(getContentResolver(),
                    LocationManager.GPS_PROVIDER, enabled);
            if (mAssistedGps != null) {
                mAssistedGps.setEnabled(enabled);
            }
        } else if (preference == mAssistedGps) {
            Settings.Secure.putInt(getContentResolver(), Settings.Secure.ASSISTED_GPS_ENABLED,
                    mAssistedGps.isChecked() ? 1 : 0);
        }

        return false;
    }

    private void showPrivacyPolicy() {
        Intent intent = new Intent("android.settings.TERMS");
        startActivity(intent);
    }

    /*
     * Creates toggles for each available location provider
     */
    private void updateToggles() {
        ContentResolver res = getContentResolver();
        boolean gpsEnabled = Settings.Secure.isLocationProviderEnabled(
                res, LocationManager.GPS_PROVIDER);
        mNetwork.setChecked(Settings.Secure.isLocationProviderEnabled(
                res, LocationManager.NETWORK_PROVIDER));
        mGps.setChecked(gpsEnabled);
        if (mAssistedGps != null) {
            mAssistedGps.setChecked(Settings.Secure.getInt(res,
                    Settings.Secure.ASSISTED_GPS_ENABLED, 2) == 1);
            mAssistedGps.setEnabled(gpsEnabled);
        }
    }

    private boolean isToggled(Preference pref) {
        return ((CheckBoxPreference) pref).isChecked();
    }

    /**
     * For the user to disable keyguard, we first make them verify their
     * existing pattern.
     */
    private class LockEnabledPref extends CheckBoxPreference {

        public LockEnabledPref(Context context) {
            super(context);
        }

        @Override
        protected void onClick() {
            if (mLockPatternUtils.savedPatternExists() && isChecked()) {
                confirmPatternThenDisableAndClear();
            } else {
                super.onClick();
            }
        }
    }

    /**
     * Launch screen to confirm the existing lock pattern.
     * @see #onActivityResult(int, int, android.content.Intent)
     */
    private void confirmPatternThenDisableAndClear() {
        final Intent intent = new Intent();
        intent.setClassName("com.android.settings", "com.android.settings.ConfirmLockPattern");
        startActivityForResult(intent, CONFIRM_PATTERN_THEN_DISABLE_AND_CLEAR_REQUEST_CODE);
    }

    /**
     * @see #confirmPatternThenDisableAndClear
     */
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        final boolean resultOk = resultCode == Activity.RESULT_OK;

        if ((requestCode == CONFIRM_PATTERN_THEN_DISABLE_AND_CLEAR_REQUEST_CODE)
                && resultOk) {
            mLockPatternUtils.setLockPatternEnabled(false);
            mLockPatternUtils.saveLockPattern(null);
        }
    }

    @Override
    protected Dialog onCreateDialog(int id) {
        switch (id) {
            case CSTOR_INIT_DIALOG:
            case CSTOR_CHANGE_PASSWORD_DIALOG:
                return mCstorHelper.createSetPasswordDialog(id);

            case CSTOR_UNLOCK_DIALOG:
                return mCstorHelper.createUnlockDialog();

            case CSTOR_RESET_DIALOG:
                return mCstorHelper.createResetDialog();

            default:
                return null;
        }
    }

    private class CstorHelper implements DialogInterface.OnClickListener,
            DialogInterface.OnDismissListener {
        private KeyStore mKeyStore = KeyStore.getInstance();
        private int mState;

        private View mView;
        private int mDialogId;
        private boolean mRetry = false;
        private CheckBoxPreference mAccessCheckBox;
        private Preference mResetButton;

        private Intent mExternalIntent;

        CstorHelper() {
            mState = mKeyStore.test();
        }

        void handleIntent(Intent intent) {
            if (intent == null) return;
            String action = intent.getAction();

            if (Credentials.UNLOCK_ACTION.equals(action)) {
                mExternalIntent = intent;
                showCstorDialog(mState == KeyStore.UNINITIALIZED
                        ? CSTOR_INIT_DIALOG : CSTOR_UNLOCK_DIALOG);
            } else if (Credentials.SYSTEM_INSTALL_ACTION.equals(action)) {
                mExternalIntent = intent;
                // TODO: unlock and install.
            }
        }

        private void updatePreferences(int state) {
            mAccessCheckBox.setEnabled(state != KeyStore.UNINITIALIZED);
            mAccessCheckBox.setChecked(state == KeyStore.NO_ERROR);
            mResetButton.setEnabled(state != KeyStore.UNINITIALIZED);

            // Show a toast message if the state is changed.
            if (mState == state) return;
            if (state == KeyStore.NO_ERROR) {
                Toast.makeText(SecuritySettings.this, R.string.cstor_is_enabled,
                        Toast.LENGTH_SHORT).show();
            } else if (state == KeyStore.UNINITIALIZED) {
                Toast.makeText(SecuritySettings.this, R.string.cstor_is_reset,
                        Toast.LENGTH_LONG).show();
            }
            // TODO: disabled?
            mState = state;
        }

        private void lockCstor() {
            mKeyStore.lock();
            updatePreferences(KeyStore.LOCKED);
        }

        private int unlockCstor(String passwd) {
            mKeyStore.unlock(passwd);
            return mKeyStore.getLastError();
        }

        private int changeCstorPassword(String oldPasswd, String newPasswd) {
            mKeyStore.password(oldPasswd, newPasswd);
            return mKeyStore.getLastError();
        }

        private void initCstor(String passwd) {
            mKeyStore.password(passwd);
            updatePreferences(KeyStore.NO_ERROR);
        }

        private void resetCstor() {
            mKeyStore.reset();
            updatePreferences(KeyStore.UNINITIALIZED);
        }

        private void showCstorDialog(int dialogId) {
            mDialogId = dialogId;
            showDialog(dialogId);
        }

        public void onClick(DialogInterface dialog, int which) {
            if (which == DialogInterface.BUTTON_NEGATIVE) return;

            switch (mDialogId) {
                case CSTOR_INIT_DIALOG:
                case CSTOR_CHANGE_PASSWORD_DIALOG:
                    mRetry = !checkPasswords((Dialog) dialog);
                    break;

                case CSTOR_UNLOCK_DIALOG:
                    mRetry = !checkPassword((Dialog) dialog);
                    break;

                case CSTOR_RESET_DIALOG:
                    resetCstor();
                    break;
            }
        }

        public void onDismiss(DialogInterface dialog) {
            if (mRetry) {
                showCstorDialog(mDialogId);
            } else {
                removeDialog(mDialogId);

                if (mExternalIntent != null) {
                    if (Credentials.SYSTEM_INSTALL_ACTION.equals(
                                    mExternalIntent.getAction())) {
                        // TODO: install if unlocked.
                    } else {
                        finish();
                    }
                }
            }
        }

        // returns false if there is no error.
        private boolean checkError(int error) {
            if (error == KeyStore.NO_ERROR) {
                updatePreferences(KeyStore.NO_ERROR);
                return false;
            }
            if (error == KeyStore.UNINITIALIZED) {
                updatePreferences(KeyStore.UNINITIALIZED);
                return false;
            }
            if (error < KeyStore.WRONG_PASSWORD) {
                return false;
            }
            int count = error - KeyStore.WRONG_PASSWORD + 1;
            if (count > 3) {
                showError(R.string.cstor_password_error);
                return true;
            }
            TextView v = showError(R.string.cstor_password_error_reset_warning);
            if (count == 1) {
                v.setText(R.string.cstor_password_error_reset_warning);
            } else {
                String format = getString(
                        R.string.cstor_password_error_reset_warning_plural);
                v.setText(String.format(format, count));
            }
            return true;
        }

        // returns true if the password is correct
        private boolean checkPassword(Dialog d) {
            hideError();

            String passwd = getText(R.id.cstor_password);
            if (TextUtils.isEmpty(passwd)) {
                showError(R.string.cstor_password_empty_error);
                return false;
            }

            return !checkError(unlockCstor(passwd));
        }

        // returns true if the passwords are correct
        private boolean checkPasswords(Dialog d) {
            hideError();

            String oldPasswd = getText(R.id.cstor_old_password);
            String newPasswd = getText(R.id.cstor_new_password);
            String confirmPasswd = getText(R.id.cstor_confirm_password);

            if ((mDialogId == CSTOR_CHANGE_PASSWORD_DIALOG)
                    && TextUtils.isEmpty(oldPasswd)) {
                showError(R.string.cstor_password_empty_error);
            } else if (TextUtils.isEmpty(newPasswd)
                    || TextUtils.isEmpty(confirmPasswd)) {
                showError(R.string.cstor_passwords_empty_error);
            } else if (newPasswd.length() < CSTOR_MIN_PASSWORD_LENGTH) {
                showError(R.string.cstor_password_verification_error);
            } else if (!newPasswd.equals(confirmPasswd)) {
                showError(R.string.cstor_passwords_error);
            } else {
                if (mDialogId == CSTOR_CHANGE_PASSWORD_DIALOG) {
                    return !checkError(changeCstorPassword(oldPasswd, newPasswd));
                } else {
                    initCstor(newPasswd);
                    return true;
                }
            }
            return false;
        }

        private TextView showError(int messageId) {
            TextView v = (TextView) mView.findViewById(R.id.cstor_error);
            v.setText(messageId);
            if (v != null) v.setVisibility(View.VISIBLE);
            return v;
        }

        private void hideError() {
            hide(R.id.cstor_error);
        }

        private void hide(int viewId) {
            View v = mView.findViewById(viewId);
            if (v != null) v.setVisibility(View.GONE);
        }

        private String getText(int viewId) {
            return ((TextView) mView.findViewById(viewId)).getText().toString();
        }

        private void createPreferences(PreferenceCategory category) {
            mAccessCheckBox = new CheckBoxPreference(SecuritySettings.this);
            mAccessCheckBox.setTitle(R.string.cstor_access_title);
            mAccessCheckBox.setSummary(R.string.cstor_access_summary);
            mAccessCheckBox.setOnPreferenceChangeListener(
                    new Preference.OnPreferenceChangeListener() {
                        public boolean onPreferenceChange(
                                Preference pref, Object value) {
                            if (((Boolean) value)) {
                                showCstorDialog(CSTOR_UNLOCK_DIALOG);
                            } else {
                                lockCstor();
                            }
                            return true;
                        }
                    });
            category.addPreference(mAccessCheckBox);

            Preference install = new Preference(SecuritySettings.this);
            install.setTitle(R.string.cstor_cert_install_title);
            install.setSummary(R.string.cstor_cert_install_summary);
            install.setOnPreferenceClickListener(
                    new Preference.OnPreferenceClickListener() {
                        public boolean onPreferenceClick(Preference pref) {
                            Credentials.getInstance().installFromSdCard(
                                            SecuritySettings.this);
                            return true;
                        }
                    });
            category.addPreference(install);

            Preference password = new Preference(SecuritySettings.this);
            password.setTitle(R.string.cstor_set_passwd_title);
            password.setSummary(R.string.cstor_set_passwd_summary);
            password.setOnPreferenceClickListener(
                    new Preference.OnPreferenceClickListener() {
                        public boolean onPreferenceClick(Preference pref) {
                            showCstorDialog(mState == KeyStore.UNINITIALIZED
                                    ? CSTOR_INIT_DIALOG
                                    : CSTOR_CHANGE_PASSWORD_DIALOG);
                            return true;
                        }
                    });
            category.addPreference(password);

            mResetButton = new Preference(SecuritySettings.this);
            mResetButton.setTitle(R.string.cstor_reset_title);
            mResetButton.setSummary(R.string.cstor_reset_summary);
            mResetButton.setOnPreferenceClickListener(
                    new Preference.OnPreferenceClickListener() {
                        public boolean onPreferenceClick(Preference pref) {
                            showCstorDialog(CSTOR_RESET_DIALOG);
                            return true;
                        }
                    });
            category.addPreference(mResetButton);

            updatePreferences(mState);
        }

        private Dialog createUnlockDialog() {
            mView = View.inflate(SecuritySettings.this,
                    R.layout.cstor_unlock_dialog_view, null);
            hideError();

            // show extra hint only when the action comes from outside
            if (mExternalIntent == null) {
                hide(R.id.cstor_access_dialog_hint_from_action);
            }

            Dialog d = new AlertDialog.Builder(SecuritySettings.this)
                    .setView(mView)
                    .setTitle(R.string.cstor_access_dialog_title)
                    .setPositiveButton(android.R.string.ok, this)
                    .setNegativeButton(android.R.string.cancel, this)
                    .create();
            d.setOnDismissListener(this);
            return d;
        }

        private Dialog createSetPasswordDialog(int id) {
            mView = View.inflate(SecuritySettings.this,
                    R.layout.cstor_set_password_dialog_view, null);
            hideError();

            switch (id) {
                case CSTOR_INIT_DIALOG:
                    mView.findViewById(R.id.cstor_old_password_block)
                            .setVisibility(View.GONE);
                    break;

                case CSTOR_CHANGE_PASSWORD_DIALOG:
                    mView.findViewById(R.id.cstor_first_time_hint)
                            .setVisibility(View.GONE);
                    break;

                default:
                    throw new RuntimeException(
                            "Unknown dialog id: " + mDialogId);
            }

            Dialog d = new AlertDialog.Builder(SecuritySettings.this)
                    .setView(mView)
                    .setTitle(R.string.cstor_set_passwd_dialog_title)
                    .setPositiveButton(android.R.string.ok, this)
                    .setNegativeButton(android.R.string.cancel, this)
                    .create();
            d.setOnDismissListener(this);
            return d;
        }

        private Dialog createResetDialog() {
            return new AlertDialog.Builder(SecuritySettings.this)
                    .setTitle(android.R.string.dialog_alert_title)
                    .setIcon(android.R.drawable.ic_dialog_alert)
                    .setMessage(R.string.cstor_reset_hint)
                    .setPositiveButton(getString(android.R.string.ok), this)
                    .setNegativeButton(getString(android.R.string.cancel), this)
                    .create();
        }
    }
}