/*
 * Copyright (C) 2020 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.network;

import android.annotation.IntDef;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.provider.Settings;
import android.telephony.SubscriptionInfo;
import android.telephony.SubscriptionManager;
import android.telephony.TelephonyManager;
import android.telephony.UiccCardInfo;
import android.telephony.UiccSlotInfo;
import android.telephony.UiccSlotMapping;
import android.util.Log;

import com.android.internal.annotations.VisibleForTesting;
import com.android.settingslib.utils.ThreadUtils;

import com.google.common.collect.ImmutableList;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Comparator;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;
import java.util.stream.IntStream;

// ToDo: to do the refactor for renaming
public class UiccSlotUtil {

    private static final String TAG = "UiccSlotUtil";

    static final long DEFAULT_WAIT_AFTER_SWITCH_TIMEOUT_MILLIS = 25 * 1000L;

    public static final int INVALID_LOGICAL_SLOT_ID = -1;
    public static final int INVALID_PHYSICAL_SLOT_ID = -1;
    public static final int INVALID_PORT_ID = -1;

    @VisibleForTesting
    static class SimCardStateChangeReceiver extends BroadcastReceiver{
        private final CountDownLatch mLatch;
        SimCardStateChangeReceiver(CountDownLatch latch) {
            mLatch = latch;
        }

        public void registerOn(Context context) {
            context.registerReceiver(this,
                    new IntentFilter(TelephonyManager.ACTION_SIM_CARD_STATE_CHANGED),
                    Context.RECEIVER_NOT_EXPORTED);
        }

        @Override
        public void onReceive(Context context, Intent intent) {
            Log.i(TAG, "Action: " + intent.getAction());
            if (!TelephonyManager.ACTION_SIM_CARD_STATE_CHANGED.equals(intent.getAction())) {
                return;
            }
            final int simState = intent.getIntExtra(
                    TelephonyManager.EXTRA_SIM_STATE, TelephonyManager.SIM_STATE_UNKNOWN);
            Log.i(TAG, "simState: " + simState);
            if (simState != TelephonyManager.SIM_STATE_UNKNOWN
                    && simState != TelephonyManager.SIM_STATE_ABSENT) {
                mLatch.countDown();
            }
        }
    }

    /**
     * Mode for switching to eSIM slot which decides whether there is cleanup process, e.g.
     * disabling test profile, after eSIM slot is activated and whether we will wait it finished.
     */
    @Retention(RetentionPolicy.SOURCE)
    @IntDef({
            SwitchingEsimMode.NO_CLEANUP,
            SwitchingEsimMode.ASYNC_CLEANUP,
            SwitchingEsimMode.SYNC_CLEANUP
    })
    public @interface SwitchingEsimMode {
        /** No cleanup process after switching to eSIM slot */
        int NO_CLEANUP = 0;
        /** Has cleanup process, but we will not wait it finished. */
        int ASYNC_CLEANUP = 1;
        /** Has cleanup process and we will wait until it's finished */
        int SYNC_CLEANUP = 2;
    }

    /**
     * Returns an immutable list of all UICC slots. If TelephonyManager#getUiccSlotsInfo returns, it
     * returns an empty list instead.
     */
    public static ImmutableList<UiccSlotInfo> getSlotInfos(TelephonyManager telMgr) {
        UiccSlotInfo[] slotInfos = telMgr.getUiccSlotsInfo();
        if (slotInfos == null) {
            return ImmutableList.of();
        }
        return ImmutableList.copyOf(slotInfos);
    }

    /**
     * Switches to the removable slot. It waits for SIM_STATE_LOADED after switch. If slotId is
     * INVALID_PHYSICAL_SLOT_ID, the method will use the first detected inactive removable slot.
     *
     * @param slotId  the physical removable slot id.
     * @param context the application context.
     * @throws UiccSlotsException if there is an error.
     */
    //ToDo: delete this api and refactor the related code.
    public static synchronized void switchToRemovableSlot(int slotId, Context context)
            throws UiccSlotsException {
        switchToRemovableSlot(context, slotId, null);
    }

    /**
     * Switches to the removable slot. It waits for SIM_STATE_LOADED after switch. If slotId is
     * INVALID_PHYSICAL_SLOT_ID, the method will use the first detected inactive removable slot.
     *
     * @param slotId  the physical removable slot id.
     * @param context the application context.
     * @param removedSubInfo In the DSDS+MEP mode, if the all of slots have sims, it should
     *                        remove the one of active sim.
     *                       If the removedSubInfo is null, then use the default value.
     *                       The default value is the esim slot and portId 0.
     * @throws UiccSlotsException if there is an error.
     */
    public static synchronized void switchToRemovableSlot(Context context, int slotId,
            SubscriptionInfo removedSubInfo) throws UiccSlotsException {
        if (ThreadUtils.isMainThread()) {
            throw new IllegalThreadStateException(
                    "Do not call switchToRemovableSlot on the main thread.");
        }
        TelephonyManager telMgr = context.getSystemService(TelephonyManager.class);
        int inactiveRemovableSlot = getInactiveRemovableSlot(telMgr.getUiccSlotsInfo(), slotId);
        Log.d(TAG, "The InactiveRemovableSlot: " + inactiveRemovableSlot);
        if (inactiveRemovableSlot == INVALID_PHYSICAL_SLOT_ID) {
            // The slot is invalid slot id, then to skip this.
            // The slot is active, then the sim can enable directly.
            return;
        }

        Collection<UiccSlotMapping> uiccSlotMappings = telMgr.getSimSlotMapping();
        Log.d(TAG, "The SimSlotMapping: " + uiccSlotMappings);

        SubscriptionManager subscriptionManager = context.getSystemService(
                SubscriptionManager.class).createForAllUserProfiles();
        int excludedLogicalSlotIndex = getExcludedLogicalSlotIndex(uiccSlotMappings,
                SubscriptionUtil.getActiveSubscriptions(subscriptionManager), removedSubInfo,
                telMgr.isMultiSimEnabled());
        performSwitchToSlot(telMgr,
                prepareUiccSlotMappings(uiccSlotMappings,
                        /*slot is psim*/ true,
                        inactiveRemovableSlot,
                        /*removable sim's port Id*/ TelephonyManager.DEFAULT_PORT_INDEX,
                        excludedLogicalSlotIndex),
                context);
    }

    /**
     * Switches to the Euicc slot. It waits for SIM_STATE_LOADED after switch.
     *
     * @param context the application context.
     * @param physicalSlotId the Euicc slot id.
     * @param port the Euicc slot port id.
     * @param removedSubInfo In the DSDS+MEP mode, if the all of slots have sims, it should
     *                       remove the one of active sim.
     *                       If the removedSubInfo is null, then it uses the default value.
     *                       The default value is the esim slot and portId 0.
     * @throws UiccSlotsException if there is an error.
     */
    public static synchronized void switchToEuiccSlot(Context context, int physicalSlotId, int port,
            SubscriptionInfo removedSubInfo) throws UiccSlotsException {
        if (ThreadUtils.isMainThread()) {
            throw new IllegalThreadStateException(
                    "Do not call switchToRemovableSlot on the main thread.");
        }
        TelephonyManager telMgr = context.getSystemService(TelephonyManager.class);
        Collection<UiccSlotMapping> uiccSlotMappings = telMgr.getSimSlotMapping();
        Log.d(TAG, "The SimSlotMapping: " + uiccSlotMappings);

        if (isTargetSlotActive(uiccSlotMappings, physicalSlotId, port)) {
            Log.d(TAG, "The slot is active, then the sim can enable directly.");
            return;
        }

        SubscriptionManager subscriptionManager = context.getSystemService(
                SubscriptionManager.class).createForAllUserProfiles();
        int excludedLogicalSlotIndex = getExcludedLogicalSlotIndex(uiccSlotMappings,
                SubscriptionUtil.getActiveSubscriptions(subscriptionManager), removedSubInfo,
                telMgr.isMultiSimEnabled());
        performSwitchToSlot(telMgr,
                prepareUiccSlotMappings(uiccSlotMappings, /*slot is not psim*/ false,
                        physicalSlotId, port, excludedLogicalSlotIndex),
                context);
    }

    /**
     * @param context the application context.
     * @return the esim slot. If the value is -1, there is not the esim.
     */
    public static int getEsimSlotId(Context context, int subId) {
        TelephonyManager telMgr = context.getSystemService(TelephonyManager.class);
        List<UiccCardInfo> uiccCardInfos = telMgr.getUiccCardsInfo();
        ImmutableList<UiccSlotInfo> slotInfos = UiccSlotUtil.getSlotInfos(telMgr);
        SubscriptionManager subscriptionManager = context.getSystemService(
                SubscriptionManager.class).createForAllUserProfiles();
        SubscriptionInfo subInfo = SubscriptionUtil.getSubById(subscriptionManager, subId);

        // checking whether this is the removable esim. If it is, then return the removable slot id.
        if (subInfo != null && subInfo.isEmbedded()) {
            for (UiccCardInfo uiccCardInfo : uiccCardInfos) {
                if (uiccCardInfo.getCardId() == subInfo.getCardId()
                        && uiccCardInfo.getCardId() > TelephonyManager.UNSUPPORTED_CARD_ID
                        && uiccCardInfo.isEuicc()
                        && uiccCardInfo.isRemovable()) {
                    Log.d(TAG, "getEsimSlotId: This subInfo is a removable esim.");
                    return uiccCardInfo.getPhysicalSlotIndex();
                }
            }
        }

        int firstEsimSlot = IntStream.range(0, slotInfos.size())
                .filter(
                        index -> {
                            UiccSlotInfo slotInfo = slotInfos.get(index);
                            if (slotInfo == null) {
                                return false;
                            }
                            return slotInfo.getIsEuicc();
                        })
                .findFirst().orElse(-1);

        Log.i(TAG, "firstEsimSlot: " + firstEsimSlot);
        return firstEsimSlot;
    }

    private static boolean isTargetSlotActive(Collection<UiccSlotMapping> uiccSlotMappings,
            int physicalSlotId, int port) {
        return uiccSlotMappings.stream()
                .anyMatch(
                        uiccSlotMapping -> uiccSlotMapping.getPhysicalSlotIndex() == physicalSlotId
                                && uiccSlotMapping.getPortIndex() == port);
    }

    @VisibleForTesting
    static void performSwitchToSlot(TelephonyManager telMgr,
            Collection<UiccSlotMapping> uiccSlotMappings, Context context)
            throws UiccSlotsException {
        BroadcastReceiver receiver = null;
        long waitingTimeMillis =
                Settings.Global.getLong(
                        context.getContentResolver(),
                        Settings.Global.EUICC_SWITCH_SLOT_TIMEOUT_MILLIS,
                        DEFAULT_WAIT_AFTER_SWITCH_TIMEOUT_MILLIS);
        Log.d(TAG, "Set waitingTime as " + waitingTimeMillis);

        try {
            CountDownLatch latch = new CountDownLatch(1);
            if (isMultipleEnabledProfilesSupported(telMgr)) {
                receiver = new SimCardStateChangeReceiver(latch);
                ((SimCardStateChangeReceiver) receiver).registerOn(context);
            } else {
                receiver = new CarrierConfigChangedReceiver(latch);
                ((CarrierConfigChangedReceiver) receiver).registerOn(context);
            }
            telMgr.setSimSlotMapping(uiccSlotMappings);
            latch.await(waitingTimeMillis, TimeUnit.MILLISECONDS);
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
            Log.e(TAG, "Failed switching to physical slot.", e);
        } finally {
            if (receiver != null) {
                context.unregisterReceiver(receiver);
            }
        }
    }

    /**
     * @param slots  The UiccSlotInfo list.
     * @param slotId The physical removable slot id.
     * @return The inactive physical removable slot id. If the physical removable slot id is
     * active, then return -1.
     * @throws UiccSlotsException if there is an error.
     */
    private static int getInactiveRemovableSlot(UiccSlotInfo[] slots, int slotId)
            throws UiccSlotsException {
        if (slots == null) {
            throw new UiccSlotsException("UiccSlotInfo is null");
        }
        if (slotId == INVALID_PHYSICAL_SLOT_ID) {
            for (int i = 0; i < slots.length; i++) {
                if (slots[i] != null
                        && slots[i].isRemovable()
                        && !slots[i].getIsEuicc()
                        && !slots[i].getPorts().stream().findFirst().get().isActive()
                        && slots[i].getCardStateInfo() != UiccSlotInfo.CARD_STATE_INFO_ERROR
                        && slots[i].getCardStateInfo() != UiccSlotInfo.CARD_STATE_INFO_RESTRICTED) {
                    return i;
                }
            }
        } else {
            if (slotId >= slots.length || slots[slotId] == null || !slots[slotId].isRemovable()) {
                Log.d(TAG, "The given slotId is not a removable slot: " + slotId);
                return INVALID_PHYSICAL_SLOT_ID;
            }
            if (!slots[slotId].getPorts().stream().findFirst().get().isActive()) {
                return slotId;
            }
        }
        return INVALID_PHYSICAL_SLOT_ID;
    }

    @VisibleForTesting
    static Collection<UiccSlotMapping> prepareUiccSlotMappings(
            Collection<UiccSlotMapping> uiccSlotMappings, boolean isPsim, int physicalSlotId,
            int port, int removedLogicalSlotId) {
        if (removedLogicalSlotId == INVALID_LOGICAL_SLOT_ID) {
            Log.d(TAG, "There is no removedLogicalSlotId. Do nothing.");
            return uiccSlotMappings;
        }
        Log.d(TAG,
                String.format(
                        "Create new SimSlotMapping. Remove the UiccSlotMapping of logicalSlot%d"
                                + ", and insert PhysicalSlotId%d-Port%d",
                        removedLogicalSlotId, physicalSlotId, port));
        Collection<UiccSlotMapping> newUiccSlotMappings = new ArrayList<>();
        int logicalSlotIndex = 0;
        if (isPsim) {
            // The target slot is psim. The psim is always the first index at LogicalSlot.
            newUiccSlotMappings.add(
                    new UiccSlotMapping(port, physicalSlotId, logicalSlotIndex++));
        }
        Collection<UiccSlotMapping> tempUiccSlotMappings =
                uiccSlotMappings.stream()
                        .sorted(Comparator.comparingInt(UiccSlotMapping::getLogicalSlotIndex))
                        .collect(Collectors.toList());
        for (UiccSlotMapping uiccSlotMapping : tempUiccSlotMappings) {
            if (uiccSlotMapping.getLogicalSlotIndex() == removedLogicalSlotId) {
                if (!isPsim) {
                    // Replace this uiccSlotMapping
                    newUiccSlotMappings.add(new UiccSlotMapping(port, physicalSlotId,
                            uiccSlotMapping.getLogicalSlotIndex()));
                }
                continue;
            }

            // If the psim is inserted, then change the logicalSlotIndex for another
            // uiccSlotMappings.
            newUiccSlotMappings.add(isPsim
                    ? new UiccSlotMapping(uiccSlotMapping.getPortIndex(),
                    uiccSlotMapping.getPhysicalSlotIndex(), logicalSlotIndex++)
                    : uiccSlotMapping);
        }

        Log.d(TAG, "The new SimSlotMapping: " + newUiccSlotMappings);
        return newUiccSlotMappings;
    }

    /**
     * To get the excluded logical slot index from uiccSlotMapping list. If the sim which is
     * enabled by user does not have the corresponding slot, then it needs to do the
     * SimSlotMapping changed. This method can find the logical slot index of the corresponding slot
     * before the Frameworks do the SimSlotMapping changed.
     *
     * @param uiccSlotMappings The uiccSlotMapping list from the Telephony Frameworks.
     * @param activeSubInfos The active subscriptionInfo list.
     * @param removedSubInfo The removed sim card which is selected by the user. If the user
     *                       don't select removed sim , then the value is null.
     * @param isMultiSimEnabled whether the device is in the DSDS mode or not.
     * @return The logical slot index of removed slot. If it can't find the removed slot, it
     * returns {@link #INVALID_LOGICAL_SLOT_ID}.
     */
    @VisibleForTesting
    static int getExcludedLogicalSlotIndex(Collection<UiccSlotMapping> uiccSlotMappings,
            Collection<SubscriptionInfo> activeSubInfos, SubscriptionInfo removedSubInfo,
            boolean isMultiSimEnabled) {
        if (!isMultiSimEnabled) {
            Log.i(TAG, "In the ss mode.");
            return 0;
        }
        if (removedSubInfo != null) {
            // Use removedSubInfo's logicalSlotIndex
            Log.i(TAG, "The removedSubInfo is not null");
            return removedSubInfo.getSimSlotIndex();
        }
        // If it needs to do simSlotMapping when user enables sim and there is an empty slot which
        // there is no enabled sim in this slot, then the empty slot can be removed.
        Log.i(TAG, "The removedSubInfo is null");
        return uiccSlotMappings.stream()
                .filter(uiccSlotMapping -> {
                    // find the empty slots.
                    for (SubscriptionInfo subInfo : activeSubInfos) {
                        if (subInfo.getSimSlotIndex() == uiccSlotMapping.getLogicalSlotIndex()) {
                            return false;
                        }
                    }
                    return true;
                })
                .sorted(Comparator.comparingInt(UiccSlotMapping::getLogicalSlotIndex))
                .mapToInt(uiccSlotMapping -> uiccSlotMapping.getLogicalSlotIndex())
                .findFirst()
                .orElse(INVALID_LOGICAL_SLOT_ID);
    }

    /**
     * Return whether the removable psim is enabled.
     *
     * @param telMgr is a TelephonyManager.
     * @return whether the removable psim is enabled.
     */
    public static boolean isRemovableSimEnabled(TelephonyManager telMgr) {
        if (telMgr == null) {
            return false;
        }
        List<UiccSlotInfo> slotInfos = UiccSlotUtil.getSlotInfos(telMgr);
        return isRemovableSimEnabled(slotInfos);
    }

    /**
     * Return whether the removable psim is enabled.
     *
     * @param slotInfos is a List of UiccSlotInfo.
     * @return whether the removable psim is enabled.
     */
    public static boolean isRemovableSimEnabled(List<UiccSlotInfo> slotInfos) {
        boolean isRemovableSimEnabled =
                slotInfos.stream()
                        .anyMatch(
                                slot -> slot != null
                                        && slot.isRemovable()
                                        && !slot.getIsEuicc()
                                        && slot.getPorts().stream()
                                                .anyMatch(port -> port.isActive())
                                        && slot.getCardStateInfo()
                                        == UiccSlotInfo.CARD_STATE_INFO_PRESENT);
        Log.i(TAG, "isRemovableSimEnabled: " + isRemovableSimEnabled);
        return isRemovableSimEnabled;
    }

    private static boolean isMultipleEnabledProfilesSupported(TelephonyManager telMgr) {
        List<UiccCardInfo> cardInfos = telMgr.getUiccCardsInfo();
        if (cardInfos == null) {
            Log.w(TAG, "UICC cards info list is empty.");
            return false;
        }
        return cardInfos.stream().anyMatch(
                cardInfo -> cardInfo.isMultipleEnabledProfilesSupported());
    }
}