<?php namespace SokoWeb\Session;

use DateTime;
use SokoWeb\Database\Query\Modify;
use SokoWeb\Database\Query\Select;
use SokoWeb\Interfaces\Database\IConnection;
use SokoWeb\Interfaces\Database\IResultSet;
use SokoWeb\Interfaces\Session\ISessionHandler;

class DatabaseSessionHandler implements ISessionHandler
{
    private IConnection $dbConnection;

    private string $table;

    private DateTime $shouldBeNewerThan;

    private bool $exists = false;

    private bool $written = false;

    public function __construct(IConnection $dbConnection, string $table, DateTime $shouldBeNewerThan)
    {
        $this->dbConnection = $dbConnection;
        $this->table = $table;
        $this->shouldBeNewerThan = $shouldBeNewerThan;
    }

    public function open($savePath, $sessionName): bool
    {
        return true;
    }

    public function close(): bool
    {
        return true;
    }

    public function read($id): string
    {
        $select = new Select($this->dbConnection, $this->table);
        $select->columns(['data', 'updated']);
        $select->whereId(substr($id, 0, 32));

        $result = $select->execute()->fetch(IResultSet::FETCH_ASSOC);
        if ($result === null) {
            return '';
        }

        $this->exists = true;

        if (new DateTime($result['updated']) < $this->shouldBeNewerThan) {
            return '';
        }

        return $result['data'];
    }

    public function write($id, $data): bool
    {
        $modify = new Modify($this->dbConnection, $this->table);

        if ($this->exists) {
            $modify->setId(substr($id, 0, 32));
        } else {
            $modify->setExternalId(substr($id, 0, 32));
        }

        $modify->set('data', $data);
        $modify->set('updated', (new DateTime())->format('Y-m-d H:i:s'));
        $modify->save();

        $this->written = true;

        return true;
    }

    public function destroy($id): bool
    {
        $modify = new Modify($this->dbConnection, $this->table);
        $modify->setId(substr($id, 0, 32));
        $modify->delete();

        $this->exists = false;

        return true;
    }

    public function gc($maxlifetime): bool
    {
        // empty on purpose
        // old sessions are deleted by MaintainDatabaseCommand

        return true;
    }

    public function create_sid(): string
    {
        return bin2hex(random_bytes(16));
    }

    public function validateId($id): bool
    {
        return preg_match('/^[a-f0-9]{32}$/', $id) === 1;
    }

    public function updateTimestamp($id, $data): bool
    {
        if ($this->written) {
            return true;
        }

        $modify = new Modify($this->dbConnection, $this->table);

        $modify->setId(substr($id, 0, 32));
        $modify->set('updated', (new DateTime())->format('Y-m-d H:i:s'));
        $modify->save();

        return true;
    }
}