Track chat session lifecycles: added session start/end times, database schema, and persistence logic.

backend/src/main/java/com/alttd/altitudeweb/services/chat/event_publisher/EventPublisher.java

@@ -1,5 +1,10 @@
 package com.alttd.altitudeweb.services.chat.event_publisher;
 
+import com.alttd.altitudeweb.database.Databases;
+import com.alttd.altitudeweb.database.web_db.KeyPairMapper;
+import com.alttd.altitudeweb.database.web_db.chat_session.ChatSession;
+import com.alttd.altitudeweb.database.web_db.chat_session.ChatSessionMapper;
+import com.alttd.altitudeweb.setup.Connection;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.scheduling.annotation.Scheduled;
@@ -7,6 +12,8 @@ import org.springframework.stereotype.Service;
 import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;
 
 import java.io.IOException;
+import java.time.Duration;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
@@ -27,19 +34,10 @@ public class EventPublisher {
 
         emitterMap.computeIfAbsent(eventUser.uuid(), k -> new CopyOnWriteArrayList<>()).add(emitter);
         eventUserMap.put(eventUser.uuid(), eventUser);
+        Instant sessionStart = Instant.now();
         log.info("User {} subscribed, active emitters: {}", eventUser.uuid(), countActive());
 
-        Runnable cleanup = () -> {
+        Runnable cleanup = () -> handleCleanup(eventUser, emitter, sessionStart);
-            List<SseEmitter> userEmitters = emitterMap.get(eventUser.uuid());
-            if (userEmitters != null) {
-                userEmitters.remove(emitter);
-                if (userEmitters.isEmpty()) {
-                    emitterMap.remove(eventUser.uuid());
-                    eventUserMap.remove(eventUser.uuid());
-                }
-            }
-            log.info("Cleaned up emitter for {}, active emitters: {}", eventUser.uuid(), countActive());
-        };
 
         // covers: clean disconnect (tab closed normally), server-side timeout, write failure
         emitter.onCompletion(cleanup);
@@ -100,4 +98,39 @@ public class EventPublisher {
             sendToUser(emitter.uuid(), eventName, json);
         });
     }
+
+    private void handleCleanup(EventUser eventUser, SseEmitter emitter, Instant sessionStart) {
+        List<SseEmitter> userEmitters = emitterMap.get(eventUser.uuid());
+        if (userEmitters != null) {
+            userEmitters.remove(emitter);
+            if (userEmitters.isEmpty()) {
+                emitterMap.remove(eventUser.uuid());
+                eventUserMap.remove(eventUser.uuid());
+            }
+        }
+        Instant sessionEnd = Instant.now();
+        Duration between = Duration.between(sessionStart, sessionEnd);
+        log.info("Cleaned up emitter for {}, active emitters: {}, session duration: {}",
+                eventUser.uuid(), countActive(), between
+        );
+        ChatSession chatSession = ChatSession.builder()
+                .uuid(eventUser.uuid())
+                .session_start(sessionStart)
+                .session_end(sessionEnd)
+                .build();
+        saveSession(chatSession);
+    }
+
+    private void saveSession(ChatSession chatSession) {
+        Connection.getConnection(Databases.DEFAULT)
+            .runQuery(sqlSession -> {
+                log.debug("Saving chat session");
+                try {
+                    sqlSession.getMapper(ChatSessionMapper.class).storeSession(chatSession);
+                    log.debug("Saved chat session");
+                } catch (Exception e) {
+                    log.error("Failed to save chat session", e);
+                }
+            });
+    }
 }

database/src/main/java/com/alttd/altitudeweb/database/web_db/chat_session/ChatSession.java

@@ -0,0 +1,18 @@
+package com.alttd.altitudeweb.database.web_db.chat_session;
+
+import lombok.Builder;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+import java.time.Instant;
+import java.util.UUID;
+
+@Getter
+@Builder
+public class ChatSession {
+
+    private final UUID uuid;
+    private final Instant session_start;
+    private final Instant session_end;
+
+}

database/src/main/java/com/alttd/altitudeweb/database/web_db/chat_session/ChatSessionMapper.java

@@ -0,0 +1,13 @@
+package com.alttd.altitudeweb.database.web_db.chat_session;
+
+import org.apache.ibatis.annotations.Insert;
+
+public interface ChatSessionMapper {
+
+    @Insert("""
+        INSERT INTO chat_session (uuid, session_start, session_end)
+        VALUES (#{uuid}, #{session_start}, #{session_end})
+    """)
+    void storeSession(ChatSession chatSession);
+
+}

database/src/main/java/com/alttd/altitudeweb/setup/InitializeWebDb.java

@@ -4,6 +4,7 @@ import com.alttd.altitudeweb.database.Databases;
 import com.alttd.altitudeweb.database.web_db.KeyPairMapper;
 import com.alttd.altitudeweb.database.web_db.PrivilegedUserMapper;
 import com.alttd.altitudeweb.database.web_db.SettingsMapper;
+import com.alttd.altitudeweb.database.web_db.chat_session.ChatSessionMapper;
 import com.alttd.altitudeweb.database.web_db.forms.AppealMapper;
 import com.alttd.altitudeweb.database.web_db.forms.DiscordAppealMapper;
 import com.alttd.altitudeweb.database.web_db.forms.StaffApplicationMapper;
@@ -28,6 +29,7 @@ public class InitializeWebDb {
                       configuration.addMapper(DiscordAppealMapper.class);
                       configuration.addMapper(StaffApplicationMapper.class);
                       configuration.addMapper(EmailVerificationMapper.class);
+                      configuration.addMapper(ChatSessionMapper.class);
                   }).join()
                   .runQuery(sqlSession -> {
                       createSettingsTable(sqlSession);
@@ -38,6 +40,7 @@ public class InitializeWebDb {
                       createdDiscordAppealTable(sqlSession);
                       createStaffApplicationsTable(sqlSession);
                       createUserEmailsTable(sqlSession);
+                      createChatSessionTable(sqlSession);
                   });
         log.debug("Initialized WebDb");
     }
@@ -208,4 +211,21 @@ public class InitializeWebDb {
         }
     }
 
+    private static void createChatSessionTable(@NotNull SqlSession sqlSession) {
+        String query = """
+                CREATE TABLE IF NOT EXISTS chat_session (
+                    id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
+                    uuid UUID NOT NULL,
+                    session_start TIMESTAMP DEFAULT CURRENT_TIMESTAMP NOT NULL,
+                    session_end TIMESTAMP NULL,
+                    FOREIGN KEY (uuid) REFERENCES privileged_users(uuid) ON DELETE CASCADE ON UPDATE CASCADE
+                );
+                """;
+        try (Statement statement = sqlSession.getConnection().createStatement()) {
+            statement.execute(query);
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
 }