added delete message function

database/messages.go

@@ -107,3 +107,45 @@ func checkMembership(db *sql.DB, userID uuid.UUID, conversationID uuid.UUID) (bo
 	}
 	return isMember, nil
 }
+
+func DeleteMessage(db *sql.DB, userID uuid.UUID, conversationID uuid.UUID, messageID int) error {
+	checkMessageOwnershipQuery := `
+    SELECT user_id FROM Messages WHERE message_id = $1;
+  `
+	deleteMessageQuery := `
+    DELETE FROM Messages WHERE message_id = $1;
+  `
+
+	var messageOwnerID uuid.UUID
+	err := db.QueryRow(checkMessageOwnershipQuery, messageID).Scan(&messageOwnerID)
+	if err != nil {
+		return helpers.NewError(helpers.ErrInternal, "Failed to delete message", fmt.Errorf("failed to check message ownership: %w", err))
+	}
+
+	var isSelfMessage bool
+	if messageOwnerID == userID {
+		isSelfMessage = true
+	}
+
+	isAdmin, err := IsAdmin(db, userID, conversationID)
+	if err != nil {
+		return err
+	}
+	if !isSelfMessage && !isAdmin {
+		return helpers.NewError(helpers.ErrForbidden, "You don't have permissions to delete that message ", nil)
+	}
+
+	row, err := db.Exec(deleteMessageQuery, messageID)
+	if err != nil {
+		return helpers.NewError(helpers.ErrInternal, "Failed to delete message", fmt.Errorf("failed to delete message: %w", err))
+	}
+	rowsAffected, err := row.RowsAffected()
+	if err != nil {
+		return helpers.NewError(helpers.ErrInternal, "Failed to delete message", fmt.Errorf("failed to get rows affected: %w", err))
+	}
+	if rowsAffected == 0 {
+		return helpers.NewError(helpers.ErrNotFound, "Message not found", nil)
+	}
+	return nil
+
+}