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<?php


namespace SAREhub\Commons\Misc;

/**
 * Simple implemntation of HashStorage, where hashes are store in sqlite3 database
 */
class SqliteHashStorage implements HashStorage
{

    /** @var string */
    private $filePath;

    /** @var string */
    private $tableName;

    /** @var bool */
    private $firstTime = false;

    /** @var \SQLite3 */
    private $storage = null;

    /**
     * @param $filePath Database file path
     * @param string $tableName table name in database for store hashes
     */
    public function __construct($filePath, $tableName = 'hashes')
    {
        $this->filePath = $filePath;
        $this->tableName = $tableName;
    }

    public function open()
    {
        if ($this->isOpened()) {
            return;
        }

        $this->firstTime = !file_exists($this->filePath);

        $this->storage = new \SQLite3($this->filePath);
        $this->storage->exec("PRAGMA journal_mode = OFF;");
        $this->storage->exec("PRAGMA synchronous = NORMAL;");
        $this->storage->exec("PRAGMA locking_mode = EXCLUSIVE;");
        $this->storage->exec("PRAGMA automatic_index = false;");

        if ($this->firstTime) {
            $createTableSql = "CREATE TABLE " . $this->tableName . "(id TEXT PRIMARY KEY, hash TEXT NOT NULL) WITHOUT ROWID;";
            $this->storage->exec($createTableSql);
        }
    }

    public function close()
    {
        if ($this->isOpened()) {
            $this->storage->close();
            $this->storage = null;
        }
    }

    /**
     * @return bool
     */
    public function isOpened()
    {
        return $this->storage !== null;
    }

    /**
     * @param string $id
     * @return string
     */
    public function findById($id)
    {
        return $this->storage->querySingle("SELECT hash FROM " . $this->tableName . " WHERE id='$id'");
    }

    /**
     * Inserts hashes in batch for better performance
     * @param array $hashes 'id' => 'hash'
     */
    public function insertMulti(array $hashes)
    {
        $valuesString = '';
        foreach ($hashes as $id => $hash) {
            $valuesString .= "('$id','$hash'),";
        }

        $this->storage->exec("INSERT INTO " . $this->tableName . "(id, hash) VALUES " . rtrim($valuesString, ','));
    }

    /**
     * Updating hashes in batch for better performance
     * @param array $hashes 'id' => 'hash'
     */
    public function updateMulti(array $hashes)
    {
        $startSql = "UPDATE " . $this->tableName;
        $this->storage->exec('BEGIN TRANSACTION');
        foreach ($hashes as $id => $hash) {
            $this->storage->exec($startSql . " SET hash='$hash' WHERE id='$id'");
        }
        $this->storage->exec('END TRANSACTION');
    }


}