/*
 * Copyright (C) 2010 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.browser;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.webkit.WebView;

/**
 * Handle network state changes
 */
public class NetworkStateHandler {

    Activity mActivity;
    Controller mController;

    // monitor platform changes
    private IntentFilter mNetworkStateChangedFilter;
    private BroadcastReceiver mNetworkStateIntentReceiver;
    private boolean mIsNetworkUp;

    /* hold a ref so we can auto-cancel if necessary */
    private AlertDialog mAlertDialog;

    public NetworkStateHandler(Activity activity, Controller controller) {
        mActivity = activity;
        mController = controller;
        // Find out if the network is currently up.
        ConnectivityManager cm = (ConnectivityManager) mActivity
                .getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo info = cm.getActiveNetworkInfo();
        if (info != null) {
            mIsNetworkUp = info.isAvailable();
        }

        /*
         * enables registration for changes in network status from http stack
         */
        mNetworkStateChangedFilter = new IntentFilter();
        mNetworkStateChangedFilter.addAction(
                ConnectivityManager.CONNECTIVITY_ACTION);
        mNetworkStateIntentReceiver = new BroadcastReceiver() {
            @Override
            public void onReceive(Context context, Intent intent) {
                if (intent.getAction().equals(
                        ConnectivityManager.CONNECTIVITY_ACTION)) {

                    NetworkInfo info = intent.getParcelableExtra(
                            ConnectivityManager.EXTRA_NETWORK_INFO);
                    String typeName = info.getTypeName();
                    String subtypeName = info.getSubtypeName();
                    sendNetworkType(typeName.toLowerCase(),
                            (subtypeName != null ? subtypeName.toLowerCase() : ""));

                    onNetworkToggle(info.isAvailable());
                }
            }
        };

    }

    void onPause() {
        // unregister network state listener
        mActivity.unregisterReceiver(mNetworkStateIntentReceiver);
    }

    void onResume() {
        mActivity.registerReceiver(mNetworkStateIntentReceiver,
                mNetworkStateChangedFilter);
    }

    /**
     * connectivity manager says net has come or gone... inform the user
     * @param up true if net has come up, false if net has gone down
     */
    void onNetworkToggle(boolean up) {
        if (up == mIsNetworkUp) {
            return;
        } else if (up) {
            mIsNetworkUp = true;
            if (mAlertDialog != null) {
                mAlertDialog.cancel();
                mAlertDialog = null;
            }
        } else {
            mIsNetworkUp = false;
            if (mController.isInLoad()) {
                createAndShowNetworkDialog();
           }
        }
        WebView w = mController.getCurrentWebView();
        if (w != null) {
            w.setNetworkAvailable(up);
        }
    }

    boolean isNetworkUp() {
        return mIsNetworkUp;
    }

    // This method shows the network dialog alerting the user that the net is
    // down. It will only show the dialog if mAlertDialog is null.
    void createAndShowNetworkDialog() {
        if (mAlertDialog == null) {
            mAlertDialog = new AlertDialog.Builder(mActivity)
                    .setTitle(R.string.loadSuspendedTitle)
                    .setMessage(R.string.loadSuspended)
                    .setPositiveButton(R.string.ok, null)
                    .show();
        }
    }

    private void sendNetworkType(String type, String subtype) {
        WebView w = mController.getCurrentWebView();
        if (w != null) {
            w.setNetworkType(type, subtype);
        }
    }

}