<?php

declare(strict_types=1);

namespace Laminas\Paginator\Adapter\LaminasDb;

use Laminas\Db\Adapter\Adapter;
use Laminas\Db\ResultSet\ResultSet;
use Laminas\Db\ResultSet\ResultSetInterface;
use Laminas\Db\Sql\Expression;
use Laminas\Db\Sql\Select;
use Laminas\Db\Sql\Sql;
use Laminas\Paginator\Adapter\AdapterInterface;
use Laminas\Paginator\Adapter\Exception\MissingRowCountColumnException;
use Laminas\Paginator\Exception;
use ReturnTypeWillChange;

use function array_key_exists;
use function iterator_to_array;
use function strtolower;

class DbSelect implements AdapterInterface
{
    public const ROW_COUNT_COLUMN_NAME = 'C';

    /** @var Sql */
    protected $sql;

    /**
     * Database query
     *
     * @var Select
     */
    protected $select;

    /**
     * Database count query
     *
     * @var Select|null
     */
    protected $countSelect;

    /** @var ResultSetInterface */
    protected $resultSetPrototype;

    /**
     * Total item count
     *
     * @var int|null
     */
    protected $rowCount;

    /**
     * @param Select $select The select query
     * @param Adapter|Sql $adapterOrSqlObject DB adapter or Sql object
     * @throws Exception\InvalidArgumentException
     */
    public function __construct(
        Select $select,
        $adapterOrSqlObject,
        ?ResultSetInterface $resultSetPrototype = null,
        ?Select $countSelect = null
    ) {
        $this->select      = $select;
        $this->countSelect = $countSelect;

        if ($adapterOrSqlObject instanceof Adapter) {
            $adapterOrSqlObject = new Sql($adapterOrSqlObject);
        }

        if (! $adapterOrSqlObject instanceof Sql) {
            throw new Exception\InvalidArgumentException(
                '$adapterOrSqlObject must be an instance of Laminas\Db\Adapter\Adapter or Laminas\Db\Sql\Sql'
            );
        }

        $this->sql                = $adapterOrSqlObject;
        $this->resultSetPrototype = $resultSetPrototype ?: new ResultSet();
    }

    /**
     * Returns an array of items for a page.
     *
     * @param  int $offset           Page offset
     * @param  int $itemCountPerPage Number of items per page
     * @return array
     */
    public function getItems($offset, $itemCountPerPage)
    {
        $select = clone $this->select;
        $select->offset($offset);
        $select->limit($itemCountPerPage);

        $statement = $this->sql->prepareStatementForSqlObject($select);
        $result    = $statement->execute();

        $resultSet = clone $this->resultSetPrototype;
        $resultSet->initialize($result);

        return iterator_to_array($resultSet);
    }

    /**
     * Returns the total number of rows in the result set.
     *
     * @return int
     * @throws MissingRowCountColumnException
     */
    #[ReturnTypeWillChange]
    public function count()
    {
        if ($this->rowCount !== null) {
            return $this->rowCount;
        }

        $select         = $this->getSelectCount();
        $statement      = $this->sql->prepareStatementForSqlObject($select);
        $result         = $statement->execute();
        $row            = $result->current();
        $this->rowCount = $this->locateRowCount($row);

        return $this->rowCount;
    }

    /**
     * Returns select query for count
     *
     * @return Select
     */
    protected function getSelectCount()
    {
        if ($this->countSelect) {
            return $this->countSelect;
        }

        $select = clone $this->select;
        $select->reset(Select::LIMIT);
        $select->reset(Select::OFFSET);
        $select->reset(Select::ORDER);

        $countSelect = new Select();

        $countSelect->columns([self::ROW_COUNT_COLUMN_NAME => new Expression('COUNT(1)')]);
        $countSelect->from(['original_select' => $select]);

        return $countSelect;
    }

    /**
     * @internal
     *
     * @see https://github.com/laminas/laminas-paginator/issues/3 Reference for creating an internal cache ID
     *
     * @todo The next major version should rework the entire caching of a paginator.
     * @return array
     */
    public function getArrayCopy()
    {
        return [
            'select'       => $this->sql->buildSqlString($this->select),
            'count_select' => $this->sql->buildSqlString(
                $this->getSelectCount()
            ),
        ];
    }

    /**
     * @throws MissingRowCountColumnException
     */
    private function locateRowCount(array $row): int
    {
        if (array_key_exists(self::ROW_COUNT_COLUMN_NAME, $row)) {
            return (int) $row[self::ROW_COUNT_COLUMN_NAME];
        }

        $lowerCaseColumnName = strtolower(self::ROW_COUNT_COLUMN_NAME);
        if (array_key_exists($lowerCaseColumnName, $row)) {
            return (int) $row[$lowerCaseColumnName];
        }

        throw MissingRowCountColumnException::forColumn(self::ROW_COUNT_COLUMN_NAME);
    }
}