<?php
/*
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the MIT license. For more information, see
 * <http://www.doctrine-project.org>.
 */

namespace Doctrine\ODM\MongoDB\Id;

use Doctrine\ODM\MongoDB\DocumentManager;

/**
 * IncrementGenerator is responsible for generating auto increment identifiers. It uses
 * a collection and generates the next id by using $inc on a field named "current_id".
 *
 * The 'collection' property determines which collection name is used to store the
 * id values. If not specified it defaults to 'doctrine_increment_ids'.
 *
 * The 'key' property determines the document ID used to store the id values in the
 * collection. If not specified it defaults to the name of the collection for the
 * document.
 *
 * @final
 * @since       1.0
 */
class IncrementGenerator extends AbstractIdGenerator
{
    protected $collection = null;
    protected $key = null;
    protected $startingId = 1;

    public function __construct()
    {
        if (self::class !== static::class) {
            @trigger_error(sprintf('The class "%s" extends "%s" which will be final in doctrine/mongodb-odm 2.0.', static::class, self::class), E_USER_DEPRECATED);
        }
    }

    public function setCollection($collection)
    {
        $this->collection = $collection;
    }

    public function setKey($key)
    {
        $this->key = $key;
    }

    public function setStartingId($startingId)
    {
        $this->startingId = $startingId;
    }

    /** @inheritDoc */
    public function generate(DocumentManager $dm, $document)
    {
        $className = get_class($document);
        $db = $dm->getDocumentDatabase($className);

        $coll = $this->collection ?: 'doctrine_increment_ids';
        $key = $this->key ?: $dm->getDocumentCollection($className)->getName();

        /*
         * Unable to use '$inc' and '$setOnInsert' together due to known bug.
         * @see https://jira.mongodb.org/browse/SERVER-10711
         * Results in error: Cannot update 'current_id' and 'current_id' at the same time
         */
        $command = [
            'findAndModify' => $coll,
            'query' => ['_id' => $key, 'current_id' => ['$exists' => true]],
            'update' => ['$inc' => ['current_id' => 1]],
            'upsert' => false,
            'new' => true,
        ];
        $result = $db->command($command);

        /*
         * Updated nothing - counter doesn't exist, creating new counter.
         * Not bothering with {$exists: false} in the criteria as that won't avoid
         * an exception during a possible race condition.
         */
        if (array_key_exists('value', $result) && ! isset($result['value'])) {
            $command = [
                'findAndModify' => $coll,
                'query' => ['_id' => $key],
                'update' => ['$inc' => ['current_id' => $this->startingId]],
                'upsert' => true,
                'new' => true,
            ];
            $db->command($command);
            return $this->startingId;
        }

        return $result['value']['current_id'];
    }
}