feat: snapshot retention and automatic cleanup (#63)

Add retention settings for content snapshots (max count, max age days)
in component options. System plugin runs cleanupOldSnapshots() alongside
existing backup cleanup, deleting JSON files and DB records.

Closes #63

source/packages/com_mokosuitebackup/config.xml

@@ -118,6 +118,27 @@
 		/>
 	</fieldset>
 
+	<fieldset name="snapshot_cleanup" label="COM_MOKOJOOMBACKUP_CONFIG_SNAPSHOT_RETENTION">
+		<field
+			name="snapshot_retention_count"
+			type="number"
+			label="COM_MOKOJOOMBACKUP_CONFIG_SNAPSHOT_MAX_COUNT"
+			description="COM_MOKOJOOMBACKUP_CONFIG_SNAPSHOT_MAX_COUNT_DESC"
+			default="20"
+			min="0"
+			max="100"
+		/>
+		<field
+			name="snapshot_retention_days"
+			type="number"
+			label="COM_MOKOJOOMBACKUP_CONFIG_SNAPSHOT_MAX_AGE"
+			description="COM_MOKOJOOMBACKUP_CONFIG_SNAPSHOT_MAX_AGE_DESC"
+			default="30"
+			min="0"
+			max="365"
+		/>
+	</fieldset>
+
 	<fieldset name="notifications" label="COM_MOKOJOOMBACKUP_CONFIG_NOTIFICATIONS">
 		<field
 			name="notify_email"

source/packages/com_mokosuitebackup/language/en-GB/com_mokosuitebackup.ini

@@ -269,6 +269,13 @@ COM_MOKOJOOMBACKUP_CONFIG_NOTIFY_SUCCESS_DESC="Send email when any backup comple
 COM_MOKOJOOMBACKUP_CONFIG_NOTIFY_FAILURE="Notify on Failure"
 COM_MOKOJOOMBACKUP_CONFIG_NOTIFY_FAILURE_DESC="Send email when any backup fails (unless overridden by profile)."
 
+; Snapshot Retention
+COM_MOKOJOOMBACKUP_CONFIG_SNAPSHOT_RETENTION="Snapshot Retention"
+COM_MOKOJOOMBACKUP_CONFIG_SNAPSHOT_MAX_COUNT="Max Snapshot Count"
+COM_MOKOJOOMBACKUP_CONFIG_SNAPSHOT_MAX_COUNT_DESC="Maximum number of content snapshots to keep. Oldest are removed first. Set to 0 for unlimited."
+COM_MOKOJOOMBACKUP_CONFIG_SNAPSHOT_MAX_AGE="Max Snapshot Age (days)"
+COM_MOKOJOOMBACKUP_CONFIG_SNAPSHOT_MAX_AGE_DESC="Delete snapshots older than this many days. Set to 0 for unlimited."
+
 ; Web Cron
 COM_MOKOJOOMBACKUP_CONFIG_WEBCRON="Web Cron"
 COM_MOKOJOOMBACKUP_CONFIG_WEBCRON_ENABLED="Enable Web Cron"

source/packages/plg_system_mokosuitebackup/src/Extension/MokoSuiteBackup.php

@@ -136,6 +136,7 @@ final class MokoSuiteBackup extends CMSPlugin implements SubscriberInterface
 		$session->set('mokosuitebackup.last_cleanup', time());
 
 		$this->cleanupOldBackups();
+		$this->cleanupOldSnapshots();
 	}
 
 	/**
@@ -152,6 +153,93 @@ final class MokoSuiteBackup extends CMSPlugin implements SubscriberInterface
 		}
 	}
 
+	/**
+	 * Remove old content snapshots per component retention settings.
+	 *
+	 * Respects snapshot_retention_days (max age) and snapshot_retention_count
+	 * (max number to keep). A value of 0 means unlimited for that setting.
+	 */
+	private function cleanupOldSnapshots(): void
+	{
+		try {
+			$this->doSnapshotCleanup();
+		} catch (\Throwable $e) {
+			error_log('MokoSuiteBackup: cleanupOldSnapshots() failed: ' . $e->getMessage());
+		}
+	}
+
+	private function doSnapshotCleanup(): void
+	{
+		$db            = Factory::getDbo();
+		$params        = ComponentHelper::getParams('com_mokosuitebackup');
+		$retentionDays = (int) $params->get('snapshot_retention_days', 30);
+		$retentionCount = (int) $params->get('snapshot_retention_count', 20);
+
+		// Delete snapshots older than retention_days
+		if ($retentionDays > 0) {
+			$cutoff = date('Y-m-d H:i:s', strtotime("-{$retentionDays} days"));
+			$query  = $db->getQuery(true)
+				->select([$db->quoteName('id'), $db->quoteName('data_file')])
+				->from($db->quoteName('#__mokosuitebackup_snapshots'))
+				->where($db->quoteName('created') . ' < ' . $db->quote($cutoff))
+				->order($db->quoteName('created') . ' DESC');
+			$db->setQuery($query);
+			$expired = $db->loadObjectList();
+
+			foreach ($expired as $snapshot) {
+				$this->deleteSnapshotRecord($db, $snapshot);
+			}
+		}
+
+		// Enforce max count (keep newest)
+		if ($retentionCount > 0) {
+			$query = $db->getQuery(true)
+				->select('COUNT(*)')
+				->from($db->quoteName('#__mokosuitebackup_snapshots'));
+			$db->setQuery($query);
+			$totalCount = (int) $db->loadResult();
+
+			if ($totalCount > $retentionCount) {
+				$excess = $totalCount - $retentionCount;
+				$query  = $db->getQuery(true)
+					->select([$db->quoteName('id'), $db->quoteName('data_file')])
+					->from($db->quoteName('#__mokosuitebackup_snapshots'))
+					->order($db->quoteName('created') . ' ASC');
+				$db->setQuery($query, 0, $excess);
+				$oldest = $db->loadObjectList();
+
+				foreach ($oldest as $snapshot) {
+					$this->deleteSnapshotRecord($db, $snapshot);
+				}
+			}
+		}
+	}
+
+	/**
+	 * Delete a snapshot record and its JSON data file.
+	 */
+	private function deleteSnapshotRecord(object $db, object $snapshot): void
+	{
+		if (!empty($snapshot->data_file) && is_file($snapshot->data_file)) {
+			if (!@unlink($snapshot->data_file)) {
+				error_log('MokoSuiteBackup: Could not delete snapshot file (id=' . $snapshot->id . '): ' . $snapshot->data_file);
+
+				return;
+			}
+		}
+
+		try {
+			$db->setQuery(
+				$db->getQuery(true)
+					->delete($db->quoteName('#__mokosuitebackup_snapshots'))
+					->where($db->quoteName('id') . ' = ' . (int) $snapshot->id)
+			);
+			$db->execute();
+		} catch (\Exception $e) {
+			error_log('MokoSuiteBackup: Could not delete snapshot record ' . $snapshot->id . ': ' . $e->getMessage());
+		}
+	}
+
 	private function doCleanup(): void
 	{
 		$db              = Factory::getDbo();