/*
 * 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.settings.development;

import static com.android.settings.development.DevelopmentOptionsActivityRequestCodes
        .REQUEST_CODE_ENABLE_OEM_UNLOCK;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.res.Resources;
import android.os.UserHandle;
import android.os.UserManager;
import android.service.oemlock.OemLockManager;
import android.support.annotation.VisibleForTesting;
import android.support.v7.preference.Preference;
import android.support.v7.preference.PreferenceScreen;
import android.telephony.TelephonyManager;

import com.android.settings.R;
import com.android.settings.core.PreferenceControllerMixin;
import com.android.settings.password.ChooseLockSettingsHelper;
import com.android.settingslib.RestrictedSwitchPreference;
import com.android.settingslib.development.DeveloperOptionsPreferenceController;

public class OemUnlockPreferenceController extends DeveloperOptionsPreferenceController implements
        Preference.OnPreferenceChangeListener, PreferenceControllerMixin, OnActivityResultListener {

    private static final String PREFERENCE_KEY = "oem_unlock_enable";

    private final OemLockManager mOemLockManager;
    private final UserManager mUserManager;
    private final TelephonyManager mTelephonyManager;
    private final DevelopmentSettingsDashboardFragment mFragment;
    private final ChooseLockSettingsHelper mChooseLockSettingsHelper;
    private RestrictedSwitchPreference mPreference;

    public OemUnlockPreferenceController(Context context, Activity activity,
            DevelopmentSettingsDashboardFragment fragment) {
        super(context);
        mOemLockManager = (OemLockManager) context.getSystemService(Context.OEM_LOCK_SERVICE);
        mUserManager = (UserManager) context.getSystemService(Context.USER_SERVICE);
        mTelephonyManager = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
        mFragment = fragment;
        if (activity != null || mFragment != null) {
            mChooseLockSettingsHelper = new ChooseLockSettingsHelper(activity, mFragment);
        } else {
            mChooseLockSettingsHelper = null;
        }
    }

    @Override
    public boolean isAvailable() {
        return mOemLockManager != null;
    }

    @Override
    public String getPreferenceKey() {
        return PREFERENCE_KEY;
    }

    @Override
    public void displayPreference(PreferenceScreen screen) {
        super.displayPreference(screen);

        mPreference = (RestrictedSwitchPreference) screen.findPreference(getPreferenceKey());
    }

    @Override
    public boolean onPreferenceChange(Preference preference, Object newValue) {
        boolean isUnlocked = (Boolean) newValue;
        if (isUnlocked) {
            if (!showKeyguardConfirmation(mContext.getResources(),
                    REQUEST_CODE_ENABLE_OEM_UNLOCK)) {
                confirmEnableOemUnlock();
            }
        } else {
            mOemLockManager.setOemUnlockAllowedByUser(false);
            OemLockInfoDialog.show(mFragment);
        }
        return true;
    }

    @Override
    public void updateState(Preference preference) {
        super.updateState(preference);
        mPreference.setChecked(isOemUnlockedAllowed());
        updateOemUnlockSettingDescription();
        // Showing mEnableOemUnlock preference as device has persistent data block.
        mPreference.setDisabledByAdmin(null);
        mPreference.setEnabled(enableOemUnlockPreference());
        if (mPreference.isEnabled()) {
            // Check restriction, disable mEnableOemUnlock and apply policy transparency.
            mPreference.checkRestrictionAndSetDisabled(UserManager.DISALLOW_FACTORY_RESET);
        }
    }

    @Override
    public boolean onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == REQUEST_CODE_ENABLE_OEM_UNLOCK) {
            if (resultCode == Activity.RESULT_OK) {
                if (mPreference.isChecked()) {
                    confirmEnableOemUnlock();
                } else {
                    mOemLockManager.setOemUnlockAllowedByUser(false);
                }
            }
            return true;
        }
        return false;
    }

    @Override
    protected void onDeveloperOptionsSwitchEnabled() {
        handleDeveloperOptionsToggled();
    }

    public void onOemUnlockConfirmed() {
        mOemLockManager.setOemUnlockAllowedByUser(true);
    }

    public void onOemUnlockDismissed() {
        if (mPreference == null) {
            return;
        }
        updateState(mPreference);
    }

    private void handleDeveloperOptionsToggled() {
        mPreference.setEnabled(enableOemUnlockPreference());
        if (mPreference.isEnabled()) {
            // Check restriction, disable mEnableOemUnlock and apply policy transparency.
            mPreference.checkRestrictionAndSetDisabled(UserManager.DISALLOW_FACTORY_RESET);
        }
    }

    private void updateOemUnlockSettingDescription() {
        int oemUnlockSummary = R.string.oem_unlock_enable_summary;
        if (isBootloaderUnlocked()) {
            oemUnlockSummary = R.string.oem_unlock_enable_disabled_summary_bootloader_unlocked;
        } else if (isSimLockedDevice()) {
            oemUnlockSummary = R.string.oem_unlock_enable_disabled_summary_sim_locked_device;
        } else if (!isOemUnlockAllowedByUserAndCarrier()) {
            // If the device isn't SIM-locked but OEM unlock is disallowed by some party, this
            // means either some other carrier restriction is in place or the device hasn't been
            // able to confirm which restrictions (SIM-lock or otherwise) apply.
            oemUnlockSummary =
                    R.string.oem_unlock_enable_disabled_summary_connectivity_or_locked;
        }
        mPreference.setSummary(mContext.getResources().getString(oemUnlockSummary));
    }

    /** Returns {@code true} if the device is SIM-locked. Otherwise, returns {@code false}. */
    private boolean isSimLockedDevice() {
        int phoneCount = mTelephonyManager.getPhoneCount();
        for (int i = 0; i < phoneCount; i++) {
            if (mTelephonyManager.getAllowedCarriers(i).size() > 0) {
                return true;
            }
        }
        return false;
    }

    /**
     * Returns {@code true} if the bootloader has been unlocked. Otherwise, returns {code false}.
     */
    @VisibleForTesting
    boolean isBootloaderUnlocked() {
        return mOemLockManager.isDeviceOemUnlocked();
    }

    private boolean enableOemUnlockPreference() {
        return !isBootloaderUnlocked() && isOemUnlockAllowedByUserAndCarrier();
    }


    @VisibleForTesting
    boolean showKeyguardConfirmation(Resources resources, int requestCode) {
        return mChooseLockSettingsHelper.launchConfirmationActivity(
                requestCode, resources.getString(R.string.oem_unlock_enable));
    }

    @VisibleForTesting
    void confirmEnableOemUnlock() {
        EnableOemUnlockSettingWarningDialog.show(mFragment);
    }

    /**
     * Returns whether OEM unlock is allowed by the user and carrier.
     *
     * This does not take into account any restrictions imposed by the device policy.
     */
    @VisibleForTesting
    boolean isOemUnlockAllowedByUserAndCarrier() {
        final UserHandle userHandle = UserHandle.of(UserHandle.myUserId());
        return mOemLockManager.isOemUnlockAllowedByCarrier()
                && !mUserManager.hasBaseUserRestriction(UserManager.DISALLOW_FACTORY_RESET,
                userHandle);
    }

    @VisibleForTesting
    boolean isOemUnlockedAllowed() {
        return mOemLockManager.isOemUnlockAllowed();
    }

}