IndexManager.php

<?php

declare(strict_types=1);
/**
 * SPDX-FileCopyrightText: 2021 Nextcloud contributors
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */


namespace OCA\Polls\Db;

use Doctrine\DBAL\Schema\Exception\IndexDoesNotExist;
use Doctrine\DBAL\Schema\Schema;
use OCA\Polls\Migration\TableSchema;
use OCP\IConfig;

class IndexManager {
	
	private string $dbPrefix;
	
	/**
	 * @psalm-suppress PossiblyUnusedMethod
	 */
	public function __construct(
		private IConfig $config,
		private Schema $schema,
	) {
		$this->setUp();
	}
	
	private function setUp(): void {
		$this->dbPrefix = $this->config->getSystemValue('dbtableprefix', 'oc_');
	}

	public function setSchema(Schema &$schema): void {
		$this->schema = $schema;
	}

	/**
	 * Create all indices
	 *
	 * @return string[] logged messages
	 */
	public function createIndices(): array {
		$messages = [];

		foreach (TableSchema::UNIQUE_INDICES as $tableName => $values) {
			$messages[] = $this->createIndex($tableName, $values['name'], $values['columns'], $values['unique']);
		}

		foreach (TableSchema::COMMON_INDICES as $index) {
			$messages[] = $this->createIndex($index['table'], $index['name'], $index['columns'], $index['unique']);
		}

		return $messages;
	}

	/**
	 * add on delete fk contraints to all tables referencing the main polls table
	 *
	 * @return string[] logged messages
	 */
	public function createForeignKeyConstraints(): array {
		$messages = [];
		
		foreach (TableSchema::FK_CHILD_TABLES as $childTable) {
			$messages[] = $this->createForeignKeyConstraint(TableSchema::FK_PARENT_TABLE, $childTable);
		}
		
		return $messages;
	}

	/**
	 * add an on delete fk contraint
	 *
	 * @param string $parentTableName name of reffered table
	 * @param string $childTableName name of referring table
	 * @return string log message
	 */
	public function createForeignKeyConstraint(string $parentTableName, string $childTableName): string {
		$parentTableName = $this->dbPrefix . $parentTableName;
		$childTableName = $this->dbPrefix . $childTableName;
		$parentTable = $this->schema->getTable($parentTableName);
		$childTable = $this->schema->getTable($childTableName);

		$childTable->addForeignKeyConstraint($parentTable, ['poll_id'], ['id'], ['onDelete' => 'CASCADE']);
		return 'Added ' . $parentTableName . '[\'poll_id\'] <- ' . $childTableName . '[\'id\']';
	}

	/**
	 * Create named index for table
	 *
	 * @param string $tableName name of table to add the index to
	 * @param string $indexName index name
	 * @param string[] $columns columns to inclue to the index
	 * @param bool $unique create a unique index
	 * @return string log message
	 */
	public function createIndex(string $tableName, string $indexName, array $columns, bool $unique = false): string {
		$tableName = $this->dbPrefix . $tableName;

		if ($this->schema->hasTable($tableName)) {

			$table = $this->schema->getTable($tableName);

			if (!$table->hasIndex($indexName)) {
				if ($unique) {
					$table->addUniqueIndex($columns, $indexName);
					return 'Added unique index ' . $indexName . ' for ' . json_encode($columns) . ' to ' . $tableName;
				} else {
					$table->addIndex($columns, $indexName);
					return 'Added index ' . $indexName . ' for ' . json_encode($columns) . ' to ' . $tableName;
				}
			}
			return 'Index ' . $indexName . ' already exists in ' . $tableName;
		}
		return 'Table ' . $tableName . ' does not exist';
	}

	/**
	 * remove all foreign keys
	 *
	 * @return string[] logged messages
	 */
	public function removeAllForeignKeyConstraints(): array {
		$messages = [];

		foreach (TableSchema::FK_CHILD_TABLES as $tableName) {
			$messages = array_merge($messages, $this->removeForeignKeysFromTable($tableName));
		}

		return $messages;
	}

	/**
	 * remove all generic indices
	 *
	 * @return string[] logged messages
	 */
	public function removeAllGenericIndices(): array {
		$messages = [];

		foreach (TableSchema::FK_CHILD_TABLES as $tableName) {
			$messages = array_merge($messages, $this->removeGenericIndicesFromTable($tableName));
		}

		return $messages;
	}
	/**
	 * remove all generic indices
	 *
	 * @return string[] logged messages
	 */
	public function removeNamedIndices(): array {
		$messages = [];

		foreach (TableSchema::COMMON_INDICES as $index) {
			$message = $this->removeNamedIndexFromTable($index['table'], $index['name']);
			if ($message !== null && $message !== '') {
				$messages[] = $message;
			}
		}

		return $messages;
	}

	/**
	 * remove all unique indices
	 *
	 * @return string[] logged messages
	 */
	public function removeAllUniqueIndices(): array {
		$messages = [];

		foreach (array_keys(TableSchema::UNIQUE_INDICES) as $tableName) {
			$messages = array_merge($messages, $this->removeUniqueIndicesFromTable($tableName));
		}

		return $messages;
	}

	/**
	 * remove all foreign keys from $tableName
	 *
	 * @param string $tableName name of table to remove fk from
	 * @return string[] logged messages
	 */
	public function removeForeignKeysFromTable(string $tableName): array {
		$messages = [];
		$tableName = $this->dbPrefix . $tableName;

		if ($this->schema->hasTable($tableName)) {

			$table = $this->schema->getTable($tableName);

			foreach ($table->getForeignKeys() as $foreignKey) {
				$table->removeForeignKey($foreignKey->getName());
				$messages[] = 'Removed ' . $foreignKey->getName() . ' from ' . $tableName;
			}
		}

		return $messages;
	}

	/**
	 * remove all UNIQUE indices from $table
	 *
	 * @param string $tableName table name of table to remove unique incices from
	 * @return string[] logged messages
	 */
	public function removeUniqueIndicesFromTable(string $tableName): array {
		$messages = [];
		$tableName = $this->dbPrefix . $tableName;

		if ($this->schema->hasTable($tableName)) {

			$table = $this->schema->getTable($tableName);

			foreach ($table->getIndexes() as $index) {
				if (strpos($index->getName(), 'UNIQ_') === 0) {
					$table->dropIndex($index->getName());
					$messages[] = 'Removed ' . $index->getName() . ' from ' . $tableName;
				}
			}
		}
		return $messages;
	}

	/**
	 * remove all generic indices from $table
	 *
	 * @param string $tableName table name of table to remove incices from
	 * @return string[] logged messages
	 */
	public function removeGenericIndicesFromTable(string $tableName): array {
		$messages = [];
		$tableName = $this->dbPrefix . $tableName;

		if ($this->schema->hasTable($tableName)) {

			$table = $this->schema->getTable($tableName);

			foreach ($table->getIndexes() as $index) {
				if (strpos($index->getName(), 'IDX_') === 0) {
					$table->dropIndex($index->getName());
					$messages[] = 'Removes ' . $index->getName() . ' from ' . $tableName;
				}
			}
		}
		return $messages;
	}
	/**
	 * remove all generic indices from $table
	 *
	 * @param string $tableName table name of table to remove the index from
	 * @param string $indexName name of index to remove
	 *
	 * @return null|string
	 */
	public function removeNamedIndexFromTable(string $tableName, string $indexName): string|null {
		$tableName = $this->dbPrefix . $tableName;
		$message = null;
		try {
			if ($this->schema->hasTable($tableName)) {
				$table = $this->schema->getTable($tableName);
				$table->dropIndex($indexName);
				$message = 'Removed ' . $indexName . ' from ' . $tableName;
			}
		} catch (IndexDoesNotExist $e) {
			// common index does not exist, skip it
		}
		return $message;
	}
}