/*
 * Copyright (C) 2024 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.notification.modes;

import android.annotation.Nullable;
import android.app.ActivityManager;
import android.app.AutomaticZenRule;
import android.app.NotificationManager;
import android.content.Context;
import android.net.Uri;
import android.provider.Settings;
import android.service.notification.Condition;
import android.service.notification.ZenModeConfig;
import android.util.Log;

import com.android.settings.R;

import java.time.Duration;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * Class used for Settings-NMS interactions related to Mode management.
 *
 * <p>This class converts {@link AutomaticZenRule} instances, as well as the manual zen mode,
 * into the unified {@link ZenMode} format.
 */
class ZenModesBackend {

    private static final String TAG = "ZenModeBackend";

    @Nullable // Until first usage
    private static ZenModesBackend sInstance;

    private final NotificationManager mNotificationManager;

    private final Context mContext;

    static ZenModesBackend getInstance(Context context) {
        if (sInstance == null) {
            sInstance = new ZenModesBackend(context.getApplicationContext());
        }
        return sInstance;
    }

    ZenModesBackend(Context context) {
        mContext = context;
        mNotificationManager = context.getSystemService(NotificationManager.class);
    }

    List<ZenMode> getModes() {
        ArrayList<ZenMode> modes = new ArrayList<>();
        ZenModeConfig currentConfig = mNotificationManager.getZenModeConfig();
        modes.add(getManualDndMode(currentConfig));

        Map<String, AutomaticZenRule> zenRules = mNotificationManager.getAutomaticZenRules();
        for (Map.Entry<String, AutomaticZenRule> zenRuleEntry : zenRules.entrySet()) {
            String ruleId = zenRuleEntry.getKey();
            modes.add(new ZenMode(ruleId, zenRuleEntry.getValue(),
                    isRuleActive(ruleId, currentConfig)));
        }

        modes.sort((l, r) -> {
            if (l.isManualDnd()) {
                return -1;
            } else if (r.isManualDnd()) {
                return 1;
            }
            return l.getRule().getName().compareTo(r.getRule().getName());
        });

        return modes;
    }

    @Nullable
    ZenMode getMode(String id) {
        ZenModeConfig currentConfig = mNotificationManager.getZenModeConfig();
        if (ZenMode.MANUAL_DND_MODE_ID.equals(id)) {
            return getManualDndMode(currentConfig);
        } else {
            AutomaticZenRule rule = mNotificationManager.getAutomaticZenRule(id);
            if (rule == null) {
                return null;
            }
            return new ZenMode(id, rule, isRuleActive(id, currentConfig));
        }
    }

    private ZenMode getManualDndMode(ZenModeConfig config) {
        ZenModeConfig.ZenRule manualRule = config.manualRule;
        // TODO: b/333682392 - Replace with final strings for name & trigger description
        AutomaticZenRule manualDndRule = new AutomaticZenRule.Builder(
                mContext.getString(R.string.zen_mode_settings_title), manualRule.conditionId)
                .setType(manualRule.type)
                .setZenPolicy(manualRule.zenPolicy)
                .setDeviceEffects(manualRule.zenDeviceEffects)
                .setManualInvocationAllowed(manualRule.allowManualInvocation)
                .setConfigurationActivity(null) // No further settings
                .setInterruptionFilter(NotificationManager.INTERRUPTION_FILTER_PRIORITY)
                .build();

        return ZenMode.manualDndMode(manualDndRule, config != null && config.isManualActive());
    }

    private static boolean isRuleActive(String id, ZenModeConfig config) {
        if (config == null) {
            // shouldn't happen if the config is coming from NM, but be safe
            return false;
        }
        ZenModeConfig.ZenRule configRule = config.automaticRules.get(id);
        return configRule != null && configRule.isAutomaticActive();
    }

    void updateMode(ZenMode mode) {
        if (mode.isManualDnd()) {
            try {
                NotificationManager.Policy dndPolicy =
                        new ZenModeConfig().toNotificationPolicy(mode.getPolicy());
                mNotificationManager.setNotificationPolicy(dndPolicy, /* fromUser= */ true);

                mNotificationManager.setManualZenRuleDeviceEffects(
                        mode.getRule().getDeviceEffects());
            } catch (Exception e) {
                Log.w(TAG, "Error updating manual mode", e);
            }
        } else {
            mNotificationManager.updateAutomaticZenRule(mode.getId(), mode.getRule(),
                    /* fromUser= */ true);
        }
    }

    void activateMode(ZenMode mode, @Nullable Duration forDuration) {
        if (mode.isManualDnd()) {
            Uri durationConditionId = null;
            if (forDuration != null) {
                durationConditionId = ZenModeConfig.toTimeCondition(mContext,
                        (int) forDuration.toMinutes(), ActivityManager.getCurrentUser(), true).id;
            }
            mNotificationManager.setZenMode(Settings.Global.ZEN_MODE_IMPORTANT_INTERRUPTIONS,
                    durationConditionId, TAG, /* fromUser= */ true);

        } else {
            if (forDuration != null) {
                throw new IllegalArgumentException(
                        "Only the manual DND mode can be activated for a specific duration");
            }
            mNotificationManager.setAutomaticZenRuleState(mode.getId(),
                    new Condition(mode.getRule().getConditionId(), "", Condition.STATE_TRUE,
                            Condition.SOURCE_USER_ACTION));
        }
    }

    void deactivateMode(ZenMode mode) {
        if (mode.isManualDnd()) {
            // When calling with fromUser=true this will not snooze other modes.
            mNotificationManager.setZenMode(Settings.Global.ZEN_MODE_OFF, null, TAG,
                    /* fromUser= */ true);
        } else {
            // TODO: b/333527800 - This should (potentially) snooze the rule if it was active.
            mNotificationManager.setAutomaticZenRuleState(mode.getId(),
                    new Condition(mode.getRule().getConditionId(), "", Condition.STATE_FALSE,
                            Condition.SOURCE_USER_ACTION));
        }
    }

    void removeMode(ZenMode mode) {
        if (!mode.canBeDeleted()) {
            throw new IllegalArgumentException("Mode " + mode + " cannot be deleted!");
        }
        mNotificationManager.removeAutomaticZenRule(mode.getId(), /* fromUser= */ true);
    }

    /**
     * Creates a new custom mode with the provided {@code name}. The mode will be "manual" (i.e.
     * not have a schedule), this can be later updated by the user in the mode settings page.
     *
     * @return the created mode. Only {@code null} if creation failed due to an internal error
     */
    @Nullable
    ZenMode addCustomMode(String name) {
        AutomaticZenRule rule = new AutomaticZenRule.Builder(name,
                ZenModeConfig.toCustomManualConditionId())
                .setPackage(ZenModeConfig.getCustomManualConditionProvider().getPackageName())
                .setType(AutomaticZenRule.TYPE_OTHER)
                .setOwner(ZenModeConfig.getCustomManualConditionProvider())
                .setManualInvocationAllowed(true)
                .build();

        String ruleId = mNotificationManager.addAutomaticZenRule(rule);
        return getMode(ruleId);
    }
}