TimedStatsTracker.java

package org.commcare.logging.analytics;

import android.content.SharedPreferences;
import android.util.Log;

import org.commcare.CommCareApplication;
import org.commcare.google.services.analytics.GoogleAnalyticsFields;
import org.commcare.google.services.analytics.GoogleAnalyticsUtils;

import java.util.Date;

/**
 * Utils for keeping track of the length of some app events, and then reporting them to Google
 * analytics
 *
 * @author amstone
 */
public class TimedStatsTracker {

    private static final String TAG = TimedStatsTracker.class.getSimpleName();

    private static final String KEY_LAST_FORM_ID = "last-form-id";
    private static final String KEY_LAST_FORM_START_TIME = "last-form-start-time";
    private static final String KEY_LAST_SESSION_START_TIME = "last-session-start-time";
    private static final String KEY_LAST_LOGGED_IN_USER = "last-logged-in-user";

    public static void registerEnterForm(int formID) {
        SharedPreferences.Editor editor =
                CommCareApplication.instance().getCurrentApp().getAppPreferences().edit();
        editor.putInt(KEY_LAST_FORM_ID, formID)
                .putLong(KEY_LAST_FORM_START_TIME, currentTime())
                .commit();
    }

    public static void registerExitForm(int formID) {
        SharedPreferences prefs = CommCareApplication.instance().getCurrentApp().getAppPreferences();
        long enterTime = prefs.getLong(KEY_LAST_FORM_START_TIME, -1);
        if (enterTime != -1) {
            int formLastEntered = prefs.getInt(KEY_LAST_FORM_ID, -1);
            if (formLastEntered == formID) {
                reportTimedEvent(GoogleAnalyticsFields.ACTION_TIME_IN_A_FORM,
                        computeElapsedTimeInSeconds(enterTime, currentTime()));
            } else {
                Log.i(TAG, "Attempting to report exit form time for a different form than the " +
                        "last form logged as entered");
            }
        } else {
            Log.i(TAG, "Attempting to report exit form time when there was no start form time " +
                    "saved in prefs");
        }
    }

    public static void registerStartSession() {
        SharedPreferences.Editor editor =
                CommCareApplication.instance().getCurrentApp().getAppPreferences().edit();
        String currentUserId = CommCareApplication.instance().getCurrentUserId();
        if (!"".equals(currentUserId)) {
            editor.putLong(KEY_LAST_SESSION_START_TIME, currentTime())
                    .putString(KEY_LAST_LOGGED_IN_USER, currentUserId)
                    .commit();
        } else {
            Log.i(TAG, "Attempting to report starting a session with no logged in user available");
        }
    }

    public static void registerEndSession(String loggedOutUser) {
        if (loggedOutUser == null || "".equals(loggedOutUser)) {
            Log.i(TAG, "Attempting to report ending a session with no logged in user available");
            return;
        }
        SharedPreferences prefs = CommCareApplication.instance().getCurrentApp().getAppPreferences();
        String lastLoggedInUser = prefs.getString(KEY_LAST_LOGGED_IN_USER, "");
        if (!"".equals(lastLoggedInUser)) {
            if (lastLoggedInUser.equals(loggedOutUser)) {
                long startTime = prefs.getLong(KEY_LAST_SESSION_START_TIME, -1);
                reportTimedEvent(GoogleAnalyticsFields.ACTION_SESSION_LENGTH,
                        computeElapsedTimeInSeconds(startTime, currentTime()));
            } else {
                Log.i(TAG, "Attempting to report ending a session for a different user than the " +
                        "last user reported as logged in");
            }
        } else {
            Log.i(TAG, "Attempting to report ending a session when there is no last logged in " +
                    "user in prefs");
        }
    }

    private static int computeElapsedTimeInSeconds(long startTime, long endTime) {
        return (int)((endTime - startTime) / 1000);
    }

    private static long currentTime() {
        return (new Date()).getTime();
    }

    /**
     * Report the completion of a timed event and its length
     */
    private static void reportTimedEvent(String timedEvent, int timeInSeconds) {
        GoogleAnalyticsUtils.reportTimedEvent(timedEvent, timeInSeconds);
    }

}