implemented new filter for tags when requesting list of events:

until now, filtering was done _after_ reading events from the db.
Now we first search viable appointment ids when tags are set and add these to the where clause for the actual request

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

de.srsoftware.cal.db/src/main/java/de/srsoftware/cal/db/Database.java

@@ -4,6 +4,7 @@ package de.srsoftware.cal.db;
 import de.srsoftware.cal.api.Appointment;
 import de.srsoftware.tools.Result;
 import java.time.LocalDateTime;
+import java.util.Collection;
 import java.util.List;
 import java.util.Set;
 
@@ -28,7 +29,7 @@ public interface Database {
 	 * @param till restrict appointments to times before this date time
 	 * @return list of appointments in this time span
 	 */
-	Result<List<Appointment>> list(LocalDateTime from, LocalDateTime till, Integer count, Integer offset);
+	Result<List<Appointment>> list(LocalDateTime from, LocalDateTime till, Integer count, Integer offset, Collection<String> tags);
 
 	/**
 	 * list appointments

de.srsoftware.cal.db/src/main/java/de/srsoftware/cal/db/MariaDB.java

@@ -26,13 +26,18 @@ import java.time.LocalDateTime;
 import java.util.*;
 
 public class MariaDB implements Database {
-	private static final System.Logger LOG	           = System.getLogger(MariaDB.class.getSimpleName());
-	private static final String	   APPOINTMENTS	           = "appointments";
-	private static final String	   APPOINTMENT_TAGS        = "appointment_tags";
-	private static final String	   APPOINTMENT_URLS        = "appointment_urls";
-	private static final String	   URLS	           = "urls";
-	private static final String	   APPOINTMENT_ATTACHMENTS = "appointment_attachments";
-	private static final String	   TAGS	           = "tags";
+	private static final System.Logger LOG	            = System.getLogger(MariaDB.class.getSimpleName());
+	private static final String	APPOINTMENTS	        = "appointments";
+	private static final String	APPOINTMENT_ATTACHMENTS = "appointment_attachments";
+	private static final String	APPOINTMENT_TAGS        = "appointment_tags";
+	private static final String APPOINTMENT_URLS        = "appointment_urls";
+	private static final String CONFIG                  = "config";
+	private static final Object DB_VERSION              = "dbversion";
+	private static final String KEYNAME                 = "keyname";
+	private static final String TAGS                    = "tags";
+	private static final String TAG_SEARCH              = "tag_search";
+	private static final String URLS	                = "urls";
+	private static final String VALUE                   = "value";
 	private Connection	   connection;
 
 	private MariaDB(Connection conn) throws SQLException {
@@ -42,15 +47,17 @@ public class MariaDB implements Database {
 
 	private void applyUpdates() throws SQLException {
 		LOG.log(INFO, "Checking for updates…");
-		var rs      = select("value").from("config").where("keyname", equal("dbversion")).exec(connection);
+		var rs      = select(VALUE).from(CONFIG).where(KEYNAME, equal(DB_VERSION)).exec(connection);
 		var version = 0;
 		if (rs.next()) {
-			version = rs.getInt("value");
+			version = rs.getInt(VALUE);
 		}
 		rs.close();
 		switch (version) {
 			case 0:
 				createTables();
+			case 1:
+				createTagSearch();
 		}
 	}
 
@@ -58,6 +65,11 @@ public class MariaDB implements Database {
 		throw new RuntimeException("%s.createTables() not implemented!");
 	}
 
+	private void createTagSearch() throws SQLException {
+		connection.prepareStatement("CREATE VIEW tag_search AS SELECT aid, GROUP_CONCAT(keyword) AS tags FROM appointment_tags LEFT JOIN tags ON appointment_tags.tid = tags.tid GROUP BY aid").execute();
+		Query.update(CONFIG).set(VALUE).where(KEYNAME,equal(DB_VERSION)).prepare(connection).apply(2);
+	}
+
 	@Override
 	public Result<Appointment> add(Appointment appointment) {
 		try {
@@ -162,13 +174,28 @@ public class MariaDB implements Database {
 	}
 
 	@Override
-	public Result<List<Appointment>> list(LocalDateTime from, LocalDateTime till, Integer count, Integer offset) {
+	public Result<List<Appointment>> list(LocalDateTime from, LocalDateTime till, Integer count, Integer offset, Collection<String> tags) {
+		List<Long> aids = null;
+		if (tags != null && !tags.isEmpty()){
+			var query = select(AID).from(TAG_SEARCH);
+			for (var tag : tags) query.where(TAGS,like("%"+tag+"%"));
+
+			try {
+				var rs = query.exec(connection);
+				aids = new ArrayList<>();
+				while (rs.next()) aids.add(rs.getLong(AID));
+				rs.close();
+			} catch (SQLException e) {
+				return SqlError.of(e,"Failed to read appointment ids for tags %s",tags);
+			}
+		}
 		var query = select("appointments.*", "GROUP_CONCAT(keyword) AS tags")
 			.from(APPOINTMENTS)
 			.leftJoin(AID, "appointment_tags", AID)
 			.leftJoin("tid", "tags", "tid")
 			.groupBy(AID)
 			.sort("start ASC");
+		if (aids != null && !aids.isEmpty()) query.where(APPOINTMENTS+"."+AID,in(aids.toArray()));
 		if (from != null) query.where(START, moreThan(Timestamp.valueOf(from)));
 		if (till != null) query.where(END, lessThan(Timestamp.valueOf(till)));
 		if (count != null) query.limit(count);
@@ -186,6 +213,7 @@ public class MariaDB implements Database {
 	}
 
 	private void addAttachments(ArrayList<Appointment> list) {
+		if (list.isEmpty()) return;
 		var map = new HashMap<Long,BaseAppointment>();
 
 		list.stream().filter(app -> app instanceof BaseAppointment)

de.srsoftware.cal.web/src/main/java/de/srsoftware/cal/ApiEndpoint.java

@@ -150,7 +150,7 @@ public class ApiEndpoint extends PathHandler {
 		Result<LocalDateTime> end = parseDate(param.get(END));
 		var     endDate = (end == null) ? null: end.optional().orElse(null);
 
-		return db.list(startDate, endDate, count, offset).map(res -> filterByTags(res, tags));
+		return db.list(startDate, endDate, count, offset, tags).map(res -> filterByTags(res, tags));
 	}
 
 	private Result<List<Appointment>> filterByTags(Result<List<Appointment>> res, List<String> tags) {