/*
 * Copyright (C) 2018 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.systemui.statusbar.policy;

import static com.android.systemui.Dependency.MAIN_HANDLER_NAME;

import android.app.RemoteInput;
import android.content.Context;
import android.content.res.Resources;
import android.os.Handler;
import android.provider.DeviceConfig;
import android.text.TextUtils;
import android.util.KeyValueListParser;
import android.util.Log;

import com.android.internal.annotations.VisibleForTesting;
import com.android.internal.config.sysui.SystemUiDeviceConfigFlags;
import com.android.systemui.R;

import javax.inject.Inject;
import javax.inject.Named;
import javax.inject.Singleton;

@Singleton
public final class SmartReplyConstants {

    private static final String TAG = "SmartReplyConstants";

    private final boolean mDefaultEnabled;
    private final boolean mDefaultRequiresP;
    private final int mDefaultMaxSqueezeRemeasureAttempts;
    private final boolean mDefaultEditChoicesBeforeSending;
    private final boolean mDefaultShowInHeadsUp;
    private final int mDefaultMinNumSystemGeneratedReplies;
    private final int mDefaultMaxNumActions;

    // These fields are updated on the UI thread but can be accessed on both the UI thread and
    // background threads. We use the volatile keyword here instead of synchronization blocks since
    // we only care about variable updates here being visible to other threads (and not for example
    // whether the variables we are reading were updated in the same go).
    private volatile boolean mEnabled;
    private volatile boolean mRequiresTargetingP;
    private volatile int mMaxSqueezeRemeasureAttempts;
    private volatile boolean mEditChoicesBeforeSending;
    private volatile boolean mShowInHeadsUp;
    private volatile int mMinNumSystemGeneratedReplies;
    private volatile int mMaxNumActions;

    private final Handler mHandler;
    private final Context mContext;
    private final KeyValueListParser mParser = new KeyValueListParser(',');

    @Inject
    public SmartReplyConstants(@Named(MAIN_HANDLER_NAME) Handler handler, Context context) {
        mHandler = handler;
        mContext = context;
        final Resources resources = mContext.getResources();
        mDefaultEnabled = resources.getBoolean(
                R.bool.config_smart_replies_in_notifications_enabled);
        mDefaultRequiresP = resources.getBoolean(
                R.bool.config_smart_replies_in_notifications_requires_targeting_p);
        mDefaultMaxSqueezeRemeasureAttempts = resources.getInteger(
                R.integer.config_smart_replies_in_notifications_max_squeeze_remeasure_attempts);
        mDefaultEditChoicesBeforeSending = resources.getBoolean(
                R.bool.config_smart_replies_in_notifications_edit_choices_before_sending);
        mDefaultShowInHeadsUp = resources.getBoolean(
                R.bool.config_smart_replies_in_notifications_show_in_heads_up);
        mDefaultMinNumSystemGeneratedReplies = resources.getInteger(
                R.integer.config_smart_replies_in_notifications_min_num_system_generated_replies);
        mDefaultMaxNumActions = resources.getInteger(
                R.integer.config_smart_replies_in_notifications_max_num_actions);

        registerDeviceConfigListener();
        updateConstants();
    }

    private void registerDeviceConfigListener() {
        DeviceConfig.addOnPropertyChangedListener(
                DeviceConfig.NAMESPACE_SYSTEMUI,
                this::postToHandler,
                this::onDeviceConfigPropertyChanged);
    }

    private void postToHandler(Runnable r) {
        this.mHandler.post(r);
    }

    @VisibleForTesting
    void onDeviceConfigPropertyChanged(String namespace, String name, String value) {
        if (!DeviceConfig.NAMESPACE_SYSTEMUI.equals(namespace)) {
            Log.e(TAG, "Received update from DeviceConfig for unrelated namespace: "
                    + namespace + " " + name + "=" + value);
            return;
        }

        updateConstants();
    }

    private void updateConstants() {
        synchronized (SmartReplyConstants.this) {
            mEnabled = readDeviceConfigBooleanOrDefaultIfEmpty(
                    SystemUiDeviceConfigFlags.SSIN_ENABLED,
                    mDefaultEnabled);
            mRequiresTargetingP = readDeviceConfigBooleanOrDefaultIfEmpty(
                    SystemUiDeviceConfigFlags.SSIN_REQUIRES_TARGETING_P,
                    mDefaultRequiresP);
            mMaxSqueezeRemeasureAttempts = readDeviceConfigIntegerOrDefaultIfEmpty(
                    SystemUiDeviceConfigFlags.SSIN_MAX_SQUEEZE_REMEASURE_ATTEMPTS,
                    mDefaultMaxSqueezeRemeasureAttempts);
            mEditChoicesBeforeSending = readDeviceConfigBooleanOrDefaultIfEmpty(
                    SystemUiDeviceConfigFlags.SSIN_EDIT_CHOICES_BEFORE_SENDING,
                    mDefaultEditChoicesBeforeSending);
            mShowInHeadsUp = readDeviceConfigBooleanOrDefaultIfEmpty(
                    SystemUiDeviceConfigFlags.SSIN_SHOW_IN_HEADS_UP,
                    mDefaultShowInHeadsUp);
            mMinNumSystemGeneratedReplies = readDeviceConfigIntegerOrDefaultIfEmpty(
                    SystemUiDeviceConfigFlags.SSIN_MIN_NUM_SYSTEM_GENERATED_REPLIES,
                    mDefaultMinNumSystemGeneratedReplies);
            mMaxNumActions = readDeviceConfigIntegerOrDefaultIfEmpty(
                    SystemUiDeviceConfigFlags.SSIN_MAX_NUM_ACTIONS,
                    mDefaultMaxNumActions);
        }
    }

    private static boolean readDeviceConfigBooleanOrDefaultIfEmpty(String propertyName,
            boolean defaultValue) {
        String value = DeviceConfig.getProperty(DeviceConfig.NAMESPACE_SYSTEMUI, propertyName);
        if (TextUtils.isEmpty(value)) {
            return defaultValue;
        }
        if ("true".equals(value)) {
            return true;
        }
        if ("false".equals(value)) {
            return false;
        }
        // For invalid configs we return the default value.
        return defaultValue;
    }

    private static int readDeviceConfigIntegerOrDefaultIfEmpty(String propertyName,
            int defaultValue) {
        String value = DeviceConfig.getProperty(DeviceConfig.NAMESPACE_SYSTEMUI, propertyName);
        if (TextUtils.isEmpty(value)) {
            return defaultValue;
        }
        try {
            return Integer.parseInt(value);
        } catch (NumberFormatException e) {
            Log.e(TAG, "Tried to read an integer flag, property name="
                    + propertyName + ", value=" + value);
            return defaultValue;
        }
    }

    /** Returns whether smart replies in notifications are enabled. */
    public boolean isEnabled() {
        return mEnabled;
    }

    /**
     * Returns whether smart replies in notifications should be disabled when the app targets a
     * version of Android older than P.
     */
    public boolean requiresTargetingP() {
        return mRequiresTargetingP;
    }

    /**
     * Returns the maximum number of times {@link SmartReplyView#onMeasure(int, int)} will try to
     * find a better (narrower) line-break for a double-line smart reply button.
     */
    public int getMaxSqueezeRemeasureAttempts() {
        return mMaxSqueezeRemeasureAttempts;
    }

    /**
     * Returns whether by tapping on a choice should let the user edit the input before it
     * is sent to the app.
     *
     * @param remoteInputEditChoicesBeforeSending The value from
     *         {@link RemoteInput#getEditChoicesBeforeSending()}
     */
    public boolean getEffectiveEditChoicesBeforeSending(
            @RemoteInput.EditChoicesBeforeSending int remoteInputEditChoicesBeforeSending) {
        switch (remoteInputEditChoicesBeforeSending) {
            case RemoteInput.EDIT_CHOICES_BEFORE_SENDING_DISABLED:
                return false;
            case RemoteInput.EDIT_CHOICES_BEFORE_SENDING_ENABLED:
                return true;
            case RemoteInput.EDIT_CHOICES_BEFORE_SENDING_AUTO:
            default:
                return mEditChoicesBeforeSending;
        }
    }

    /**
     * Returns whether smart suggestions should be enabled in heads-up notifications.
     */
    public boolean getShowInHeadsUp() {
        return mShowInHeadsUp;
    }

    /**
     * Returns the minimum number of system generated replies to show in a notification.
     * If we cannot show at least this many system generated replies we should show none.
     */
    public int getMinNumSystemGeneratedReplies() {
        return mMinNumSystemGeneratedReplies;
    }

    /**
     * Returns the maximum number smart actions to show in a notification, or -1 if there shouldn't
     * be a limit.
     */
    public int getMaxNumActions() {
        return mMaxNumActions;
    }
}