Display failed password attempt times for manager

Failed attempts are stored in the SharedPreferences and displayed when
a new attempt is made as an expandable notification.

Bug: 29976828
Change-Id: Icfde3c03b880ec0d1c8726ca10ccce88a995bae9

Author: Andre Lago

app/src/main/java/com/afwsamples/testdpc/DeviceAdminReceiver.java

@@ -19,10 +19,10 @@
 import android.accounts.Account;
 import android.accounts.AccountManager;
 import android.annotation.TargetApi;
-import android.app.admin.DevicePolicyManager;
 import android.app.Notification;
 import android.app.NotificationManager;
 import android.app.PendingIntent;
+import android.app.admin.DevicePolicyManager;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
@@ -40,18 +40,25 @@
 import android.util.Log;
 import android.widget.Toast;
 
-import com.afwsamples.testdpc.common.Util;
 import com.afwsamples.testdpc.common.LaunchIntentUtil;
 import com.afwsamples.testdpc.common.Util;
 import com.afwsamples.testdpc.cosu.EnableCosuActivity;
 
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.InputStreamReader;
 import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.text.DateFormat;
+import java.text.SimpleDateFormat;
 import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Date;
 import java.util.List;
 
 import static android.app.admin.DevicePolicyManager.EXTRA_PROVISIONING_ADMIN_EXTRAS_BUNDLE;
@@ -67,6 +74,11 @@ public class DeviceAdminReceiver extends android.app.admin.DeviceAdminReceiver {
     public static final String ACTION_PASSWORD_REQUIREMENTS_CHANGED =
             "com.afwsamples.testdpc.policy.PASSWORD_REQUIREMENTS_CHANGED";
 
+    private static final String LOGS_DIR = "logs";
+
+    private static final String FAILED_PASSWORD_LOG_FILE =
+            "failed_pw_attempts_timestamps.log";
+
     private static final int CHANGE_PASSWORD_NOTIFICATION_ID = 101;
     private static final int PASSWORD_FAILED_NOTIFICATION_ID = 102;
 
@@ -360,6 +372,17 @@ public void onPasswordFailed(Context context, Intent intent) {
 
         String title = context.getResources().getQuantityString(
                 R.plurals.password_failed_attempts_title, attempts, attempts);
+
+        ArrayList<Date> previousFailedAttempts = getFailedPasswordAttempts(context);
+        Date date = new Date();
+        previousFailedAttempts.add(date);
+        Collections.sort(previousFailedAttempts, Collections.<Date>reverseOrder());
+        try {
+            saveFailedPasswordAttempts(context, previousFailedAttempts);
+        } catch (IOException e) {
+            Log.e(TAG, "Unable to save failed password attempts", e);
+        }
+
         String content = maxAttempts == 0
                 ? context.getString(R.string.password_failed_no_limit_set)
                 : context.getResources().getQuantityString(
@@ -373,11 +396,78 @@ public void onPasswordFailed(Context context, Intent intent) {
                 .setContentIntent(PendingIntent.getActivity(context, /* requestCode */ -1,
                         new Intent(DevicePolicyManager.ACTION_SET_NEW_PASSWORD), /* flags */ 0));
 
+        Notification.InboxStyle inboxStyle = new Notification.InboxStyle();
+        inboxStyle.setBigContentTitle(title);
+
+        final DateFormat dateFormat = SimpleDateFormat.getDateTimeInstance();
+        for(Date d : previousFailedAttempts) {
+            inboxStyle.addLine(dateFormat.format(d));
+        }
+        warn.setStyle(inboxStyle);
+
         NotificationManager nm = (NotificationManager)
                 context.getSystemService(Context.NOTIFICATION_SERVICE);
         nm.notify(PASSWORD_FAILED_NOTIFICATION_ID, warn.getNotification());
     }
 
+    private static File logFile(Context context) {
+        File parent = context.getDir(LOGS_DIR, Context.MODE_PRIVATE);
+        return new File(parent, FAILED_PASSWORD_LOG_FILE);
+    }
+
+    private static ArrayList<Date> getFailedPasswordAttempts(Context context) {
+        File logFile = logFile(context);
+        ArrayList<Date> result = new ArrayList<Date>();
+
+        if(!logFile.exists()) {
+            return result;
+        }
+
+        FileInputStream fis = null;
+        try {
+            fis = new FileInputStream(logFile);
+            BufferedReader br = new BufferedReader(new InputStreamReader(fis));
+
+            String line = null;
+            while ((line = br.readLine()) != null && line.length() > 0) {
+                result.add(new Date(Long.parseLong(line)));
+            }
+
+            br.close();
+        } catch (IOException e) {
+            Log.e(TAG, "Unable to read failed password attempts", e);
+        } finally {
+            if(fis != null) {
+                try {
+                    fis.close();
+                } catch (IOException e) {
+                    Log.e(TAG, "Unable to close failed password attempts log file", e);
+                }
+            }
+        }
+
+        return result;
+    }
+
+    private static void saveFailedPasswordAttempts(Context context, ArrayList<Date> attempts)
+            throws IOException {
+        File logFile = logFile(context);
+
+        if(!logFile.exists()) {
+            logFile.createNewFile();
+        }
+
+        FileOutputStream fos = new FileOutputStream(logFile);
+        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fos));
+
+        for(Date date : attempts) {
+            bw.write(Long.toString(date.getTime()));
+            bw.newLine();
+        }
+
+        bw.close();
+    }
+
     @Override
     public void onPasswordChanged(Context context, Intent intent) {
         updatePasswordQualityNotification(context);