<?php

class Genghis_Models_Collection implements ArrayAccess, Genghis_JsonEncodable
{
    public $database;
    public $collection;

    public function __construct(Genghis_Models_Database $database, MongoCollection $collection)
    {
        $this->database   = $database;
        $this->collection = $collection;
    }

    public function offsetExists($id)
    {
        try {
            $this->findDocument($id);
        } catch (Genghis_HttpException $e) {
            if ($e->getStatus() == 404) {
                return false;
            } else {
                // catch and release
                throw $e;
            }
        }

        return true;
    }

    public function offsetGet($id)
    {
        return $this->findDocument($id);
    }

    public function offsetSet($id, $doc)
    {
        $this->findDocument($id);

        $query = array('_id' => $this->thunkMongoId($id));
        $result = $this->collection->update($query, $doc, array('safe' => true));

        if (!(isset($result['ok']) && $result['ok'])) {
            throw new Genghis_HttpException;
        }
    }

    public function offsetUnset($id)
    {
        $this->findDocument($id);

        $query = array('_id' => $this->thunkMongoId($id));
        $result = $this->collection->remove($query, array('safe' => true));

        if (!(isset($result['ok']) && $result['ok'])) {
            throw new Genghis_HttpException;
        }
    }

    public function findDocuments($query = null, $page = 1)
    {
        try {
            $query = Genghis_Json::decode($query);
        } catch (Genghis_JsonException $e) {
            throw new Genghis_HttpException(400, 'Malformed document');
        }

        $offset = Genghis_Api::PAGE_LIMIT * ($page - 1);
        $cursor = $this->collection
            ->find($query ? $query : array())
            ->limit(Genghis_Api::PAGE_LIMIT)
            ->skip($offset);

        $count = $cursor->count();

        if (is_array($count) && isset($count['errmsg'])) {
            throw new Genghis_HttpException(400, $count['errmsg']);
        }

        // Can't use iterator_to_array because Mongo doesn't use sane keys.
        $documents = array();
        foreach ($cursor as $doc) {
            $documents[] = $doc;
        }

        return array(
            'count'     => $count,
            'page'      => $page,
            'pages'     => max(1, ceil($count / Genghis_Api::PAGE_LIMIT)),
            'per_page'  => Genghis_Api::PAGE_LIMIT,
            'offset'    => $offset,
            'documents' => $documents,
        );
    }

    public function insert($data)
    {
        $result = $this->collection->insert($data, array('safe' => true));

        if (!(isset($result['ok']) && $result['ok'])) {
            throw new Genghis_HttpException;
        }

        return $data;
    }

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

    public function asJson()
    {
        $name  = $this->collection->getName();
        $colls = $this->database->database->listCollections();
        foreach ($colls as $coll) {
            if ($coll->getName() == $name) {
                return array(
                    'id'      => $coll->getName(),
                    'name'    => $coll->getName(),
                    'count'   => $coll->count(),
                    'indexes' => $coll->getIndexInfo(),
                );
            }
        }

        throw new Genghis_HttpException(404, sprintf("Collection '%s' not found in '%s'", $name, $this->database->name));
    }

    private function thunkMongoId($id)
    {
        if ($id[0] == '~') {
            return Genghis_Json::decode(base64_decode(substr($id, 1)));
        }

        return preg_match('/^[a-f0-9]{24}$/i', $id) ? new MongoId($id) : $id;
    }

    private function findDocument($id)
    {
        $doc = $this->collection->findOne(array('_id' => $this->thunkMongoId($id)));
        if (!$doc) {
            throw new Genghis_HttpException(404, sprintf("Document '%s' not found in '%s'", $id, $this->collection->getName()));
        }

        return $doc;
    }

}