added auto reimport feature

Signed-off-by: Louis Vallat <louis@louis-vallat.xyz>

app/src/main/java/xyz/vallat/louis/App.java

@@ -4,6 +4,11 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import xyz.vallat.louis.managers.database.DBManager;
 import xyz.vallat.louis.managers.discord.DiscordManager;
+import xyz.vallat.louis.timertasks.AutoReimport;
+
+import java.util.Calendar;
+import java.util.Timer;
+import java.util.concurrent.TimeUnit;
 
 public class App {
 
@@ -18,6 +23,7 @@ public class App {
         DBManager.testConnection();
         DBManager.initializeDatabase();
         DiscordManager.login();
+        setTimers();
 
         Runtime.getRuntime().addShutdownHook(new Thread(() -> {
             logger.info("Received shut down signal. Bye!");
@@ -26,4 +32,15 @@ public class App {
 
         DiscordManager.onDisconnect();
     }
+
+    private static void setTimers() {
+        Calendar midday = Calendar.getInstance();
+        midday.set(Calendar.HOUR_OF_DAY, 12);
+        midday.set(Calendar.MINUTE, 30);
+        midday.set(Calendar.SECOND, 0);
+
+        Timer reimportCron = new Timer();
+        reimportCron.schedule(new AutoReimport(), midday.getTime(),
+                TimeUnit.MILLISECONDS.convert(12, TimeUnit.HOURS));
+    }
 }

app/src/main/java/xyz/vallat/louis/managers/database/EventManager.java

@@ -8,8 +8,7 @@ import xyz.vallat.louis.managers.database.dao.Student;
 
 import java.sql.*;
 import java.time.Instant;
-import java.time.LocalDateTime;
+import java.util.HashMap;
-import java.time.ZoneOffset;
 import java.util.List;
 import java.util.Map;
 
@@ -20,16 +19,49 @@ public final class EventManager {
     private EventManager() {
     }
 
+    public static int reimportAllEvents() {
+        int importedEvents;
+        try (Connection connection = DBManager.getConnection()) {
+            connection.setAutoCommit(false);
+            flushEvents(connection);
+            Map<Student, List<VEvent>> studentEvents = new HashMap<>();
+            StudentManager.getStudentsFromDatabase()
+                    .forEach(s -> studentEvents.put(s, CalendarManager.getEventsFromResource(s.getAde())));
+            importedEvents = importEvents(studentEvents);
+            if (importedEvents == 0) {
+                logger.error("No events were re-imported. Rolling back.");
+                connection.rollback();
+            } else {
+                try {
+                    connection.commit();
+                } catch (SQLException e) {
+                    connection.rollback();
+                }
+            }
+        } catch (SQLException e) {
+            logger.error("SQLError:", e);
+            return 0;
+        }
+        return importedEvents;
+    }
+
+    private static void flushEvents(Connection connection) throws SQLException {
+        String sql = "TRUNCATE events RESTART IDENTITY;";
+        try (Statement stmt = connection.createStatement()) {
+            stmt.executeUpdate(sql);
+        }
+    }
+
     public static int importEvents(Map<Student, List<VEvent>> events) {
-        int imported_events = 0;
+        int importedEvents = 0;
         try (Connection connection = DBManager.getConnection()) {
             connection.setAutoCommit(false);
             for (Map.Entry<Student, List<VEvent>> e : events.entrySet()) {
                 if (e.getValue().isEmpty()) continue;
-                e.getKey().setId(StudentManager
+                if (e.getKey().getId() == 0) e.getKey().setId(StudentManager
                         .addStudent(e.getKey().getSnowflake(), e.getKey().getAde(), connection));
                 for (VEvent event : e.getValue())
-                    if (importEvent(e.getKey(), event, connection) != 0) imported_events++;
+                    if (importEvent(e.getKey(), event, connection) != 0) importedEvents++;
             }
             try {
                 connection.commit();
@@ -38,10 +70,10 @@ public final class EventManager {
                 return 0;
             }
         } catch (SQLException e) {
-            logger.error("Couldn't import events.", e);
+            logger.error("SQLError while importing events.", e);
             return 0;
         }
-        return imported_events;
+        return importedEvents;
     }
 
     private static int importEvent(Student student, VEvent event, Connection connection) throws SQLException {

app/src/main/java/xyz/vallat/louis/managers/database/StudentManager.java

@@ -8,6 +8,8 @@ import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
 import java.sql.Statement;
+import java.util.ArrayList;
+import java.util.List;
 
 public final class StudentManager {
 
@@ -62,6 +64,25 @@ public final class StudentManager {
         return null;
     }
 
+    public static List<Student> getStudentsFromDatabase() {
+        List<Student> studentList = new ArrayList<>();
+        try (Connection connection = DBManager.getConnection()) {
+            String sql = "SELECT id, snowflake, ade_resource FROM students;";
+            try (Statement stmt = connection.createStatement()) {
+                stmt.execute(sql);
+                while (stmt.getResultSet().next()) {
+                    studentList.add(new Student(stmt.getResultSet().getString("snowflake"),
+                            stmt.getResultSet().getInt("ade_resource"))
+                            .setId(stmt.getResultSet().getInt("id")));
+                }
+            }
+        } catch (SQLException e) {
+            logger.error("SQLException while getting all students.", e);
+            return new ArrayList<>();
+        }
+        return studentList;
+    }
+
     public static boolean deleteFromSnowflake(String snowflake) {
         logger.debug("Deleting student {}.", snowflake);
         try (Connection connection = DBManager.getConnection()) {

app/src/main/java/xyz/vallat/louis/timertasks/AutoReimport.java

@@ -0,0 +1,18 @@
+package xyz.vallat.louis.timertasks;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import xyz.vallat.louis.managers.database.EventManager;
+
+import java.util.TimerTask;
+
+public class AutoReimport extends TimerTask {
+
+    private static final Logger logger = LoggerFactory.getLogger(AutoReimport.class.getCanonicalName());
+
+    @Override
+    public void run() {
+        logger.info("Reimporting all events.");
+        logger.info("Done reimporting {} events.", EventManager.reimportAllEvents());
+    }
+}