/*
 * 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.wifi.tether;

import android.annotation.NonNull;
import android.content.Context;
import android.net.TetheringManager;
import android.net.wifi.SoftApConfiguration;
import android.net.wifi.WifiClient;
import android.net.wifi.WifiManager;
import android.text.BidiFormatter;

import androidx.annotation.VisibleForTesting;
import androidx.preference.Preference;
import androidx.preference.PreferenceScreen;

import com.android.settings.R;
import com.android.settings.Utils;
import com.android.settings.core.PreferenceControllerMixin;
import com.android.settingslib.core.AbstractPreferenceController;
import com.android.settingslib.core.lifecycle.Lifecycle;
import com.android.settingslib.core.lifecycle.LifecycleObserver;
import com.android.settingslib.core.lifecycle.events.OnStart;
import com.android.settingslib.core.lifecycle.events.OnStop;
import com.android.settingslib.wifi.WifiEnterpriseRestrictionUtils;
import com.android.settingslib.wifi.WifiUtils;

import java.util.List;

public class WifiTetherPreferenceController extends AbstractPreferenceController
        implements PreferenceControllerMixin, LifecycleObserver, OnStart, OnStop {

    private static final String WIFI_TETHER_SETTINGS = "wifi_tether";

    private boolean mIsWifiTetherable;
    private WifiManager mWifiManager;
    private boolean mIsWifiTetheringAllow;
    private int mSoftApState;
    @VisibleForTesting
    Preference mPreference;
    @VisibleForTesting
    WifiTetherSoftApManager mWifiTetherSoftApManager;

    public WifiTetherPreferenceController(Context context, Lifecycle lifecycle) {
        this(context, lifecycle,
                context.getSystemService(WifiManager.class),
                context.getSystemService(TetheringManager.class),
                true /* initSoftApManager */,
                WifiEnterpriseRestrictionUtils.isWifiTetheringAllowed(context));
    }

    @VisibleForTesting
    WifiTetherPreferenceController(
            Context context,
            Lifecycle lifecycle,
            WifiManager wifiManager,
            TetheringManager tetheringManager,
            boolean initSoftApManager,
            boolean isWifiTetheringAllow) {
        super(context);
        final String[] wifiRegexs = tetheringManager.getTetherableWifiRegexs();
        if (wifiRegexs != null && wifiRegexs.length != 0) {
            mIsWifiTetherable = true;
        }

        mIsWifiTetheringAllow = isWifiTetheringAllow;
        if (!isWifiTetheringAllow) return;

        mWifiManager = wifiManager;

        if (lifecycle != null) {
            lifecycle.addObserver(this);
        }
        if (initSoftApManager) {
            initWifiTetherSoftApManager();
        }
    }

    @Override
    public boolean isAvailable() {
        return mIsWifiTetherable && !Utils.isMonkeyRunning();
    }

    @Override
    public void displayPreference(PreferenceScreen screen) {
        super.displayPreference(screen);
        mPreference = screen.findPreference(WIFI_TETHER_SETTINGS);
        if (mPreference == null) {
            // unavailable
            return;
        }
        if (!mIsWifiTetheringAllow && mPreference.isEnabled()) {
            mPreference.setEnabled(false);
            mPreference.setSummary(R.string.not_allowed_by_ent);
        }
    }

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

    @Override
    public void onStart() {
        if (mPreference != null) {
            if (mWifiTetherSoftApManager != null) {
                mWifiTetherSoftApManager.registerSoftApCallback();
            }
        }
    }

    @Override
    public void onStop() {
        if (mPreference != null) {
            if (mWifiTetherSoftApManager != null) {
                mWifiTetherSoftApManager.unRegisterSoftApCallback();
            }
        }
    }

    @VisibleForTesting
    void initWifiTetherSoftApManager() {
        // This manager only handles the number of connected devices, other parts are handled by
        // normal BroadcastReceiver in this controller
        mWifiTetherSoftApManager = new WifiTetherSoftApManager(mWifiManager,
                new WifiTetherSoftApManager.WifiTetherSoftApCallback() {
                    @Override
                    public void onStateChanged(int state, int failureReason) {
                        mSoftApState = state;
                        handleWifiApStateChanged(state, failureReason);
                    }

                    @Override
                    public void onConnectedClientsChanged(List<WifiClient> clients) {
                        if (mPreference != null
                                && mSoftApState == WifiManager.WIFI_AP_STATE_ENABLED) {
                            // Only show the number of clients when state is on
                            mPreference.setSummary(
                                    WifiUtils.getWifiTetherSummaryForConnectedDevices(mContext,
                                            clients.size()));
                        }
                    }
                });
    }

    @VisibleForTesting
    void handleWifiApStateChanged(int state, int reason) {
        switch (state) {
            case WifiManager.WIFI_AP_STATE_ENABLING:
                mPreference.setSummary(R.string.wifi_tether_starting);
                break;
            case WifiManager.WIFI_AP_STATE_ENABLED:
                final SoftApConfiguration softApConfig = mWifiManager.getSoftApConfiguration();
                updateConfigSummary(softApConfig);
                break;
            case WifiManager.WIFI_AP_STATE_DISABLING:
                mPreference.setSummary(R.string.wifi_tether_stopping);
                break;
            case WifiManager.WIFI_AP_STATE_DISABLED:
                mPreference.setSummary(R.string.wifi_hotspot_off_subtext);
                break;
            default:
                if (reason == WifiManager.SAP_START_FAILURE_NO_CHANNEL) {
                    mPreference.setSummary(R.string.wifi_sap_no_channel_error);
                } else {
                    mPreference.setSummary(R.string.wifi_error);
                }
        }
    }

    private void updateConfigSummary(@NonNull SoftApConfiguration softApConfig) {
        if (softApConfig == null) {
            // Should never happen.
            return;
        }
        mPreference.setSummary(mContext.getString(R.string.wifi_tether_enabled_subtext,
                BidiFormatter.getInstance().unicodeWrap(softApConfig.getSsid())));
    }
}