<?php

class GenericCollectionManager {
	private $db;

//	public $dataFolder         = PATH.'/data/';
//	public $collectionsFile    = 'addressbooks/addressbooks.json';
//	public $collectionsFolder  = 'addressbooks/';
//	public $collectionType     = 'Addressbook';
//	public $datafield          = 'carddata';


//	public function newCollection ($username, $uri, array $properties) {}
//	public function newObject ($collectionId, $uri, $data, $extraData) {}
//	public function newObjectUpdate ($collectionId, $uri, $data, $extraData) {}

	public function __construct (JSONDB $database) {
		$this->db = $database;
	}

	//
	//  Collections
	//

	public function collectionExists ($collectionId) {
		return (!$this->getCollection($collectionId)) ? false : true;
	}

	public function getCollection ($collectionId) {
		$result = $this->db->select('*')
			->from($this->collectionsFile)
			->where(['id' => $collectionId])
			->get();

		if (!isset($result[0])) return false;

		return $result[0];
	}

	public function getCollections ($username) {
		$result = $this->db->select('*')
			->from($this->collectionsFile)
			->where(['principaluri' => $username])
			->get();

		return $result;
	}

	public function getHighestCollectionId () {
		$data = $this->db->select('id')
			->from($this->collectionsFile)
			->order_by('id', JSONDB::ASC)
			->get();
		
		return end($data)['id'];
	}


	public function createCollection ($username, $uri, array $properties) {
		if(!preg_match('/^[\w-]+$/', $uri)) throw new Exception('URI contains not allowed characters.');

		$collections = $this->getCollections($username);
		foreach ($collections as $collection) {
			if ($collection['uri'] == $uri) throw new Exception('An '.strtolower($this->collectionType).' with this URI already exist.');
		}

		$collection = $this->newCollection($username, $uri, $properties);
		$this->db->insert($this->collectionsFile, $collection);
		mkdir($this->dataFolder.$this->collectionsFolder.$collection['id']);
		mkdir($this->dataFolder.$this->collectionsFolder.$collection['id'].'/data');

		return $collection['id'];
	}

	public function updateCollection ($collectionId, $properties) {
		if (!$this->exists($id)) throw new Exception($this->collectionType.' doesn\'t exist!');

		$this->db->update($properties)
			->from($this->collectionsFile)
			->where(['id' => $collectionId])
			->trigger();

		$this->addChange($collectionId, '', 2);
	}

	public function deleteCollection ($collectionId) {
		$this->db->delete()
			->from($this->collectionsFile)
			->where(['id' => $collectionId])
			->trigger();

		Helpers::delete($this->dataFolder.$this->collectionsFolder.$id);
	}


	//
	// Objects
	//

	public function getHighestObjectId ($collectionId) {
		$data = $this->db->select('id')
			->from($this->collectionsFolder.$collectionId.'/objects.json')
			->order_by('id', JSONDB::ASC)
			->get();
		
		return end($data)['id'];
	}

	public function getObject ($collectionId, $uri) {
		$objects = $result = $this->db->select('*')
			->from($this->collectionsFolder.$collectionId.'/objects.json')
			->where(['uri' => $uri])
			->get();

		if (!isset($objects[0])) return false;

		$result = $objects[0];
		$result[$this->datafield] = file_get_contents($this->dataFolder.$this->collectionsFolder.$collectionId.'/data/'.$objects[0]['uri']);

		return $result;
	}

	public function getObjects ($collectionId) {
		$objects = $this->db->select('*')
			->from($this->collectionsFolder.$collectionId.'/objects.json')
			->get();

		$results = [];
		foreach ($objects as $object) {
			$results[] = get_object_vars($object);
		}

		return $results;
	}

	public function createObject ($collectionId, $uri, $data, $extraData = NULL) {
		$object = $this->newObject($collectionId, $uri, $data, $extraData);
		
		$this->db->insert($this->collectionsFolder.$collectionId.'/objects.json', $object);
		file_put_contents($this->dataFolder.$this->collectionsFolder.$collectionId.'/data/'.$uri, $data);
        $this->addChange($collectionId, $uri, 1);

		return $object['etag'];
	}

	public function updateObject ($collectionId, $uri, $data, $extraData = NULL) {
		$update = $this->newObjectUpdate($collectionId, $uri, $data, $extraData);

		$this->db->update($update)
			->from($this->collectionsFolder.$collectionId.'/objects.json')
			->where(['uri' => $uri])
			->trigger();

		file_put_contents($this->dataFolder.$this->collectionsFolder.$collectionId.'/data/'.$uri, $data);
        $this->addChange($collectionId, $uri, 2);

		return $update['etag'];
	}

	public function deleteObject ($collectionId, $uri) {
		$result = $this->db->delete()
			->from($this->collectionsFolder.$collectionId.'/objects.json')
			->where(['uri' => $uri])
			->trigger();

		unlink($this->dataFolder.$this->collectionsFolder.$collectionId.'/data/'.$uri);
		$this->addChange($collectionId, $uri, 3);

		return $result;
	}

	public function addChange ($collectionId, $uri, $operation) {
		$synctoken = $this->getCollection($collectionId)['synctoken'];

		$this->db->insert($this->collectionsFolder.$collectionId.'/changes.json', [
				'synctoken'     => $synctoken,
				'operation'     => $operation,
				'uri'           => $uri,
			]);

		$this->db->update(['synctoken' => $synctoken+1])
			->from($this->collectionsFile)
			->where(['id' => $collectionId])
			->trigger();
	}

	public function getChanges ($collectionId, $syncToken, $syncLevel) {
		$currentToken = $this->getCollection($collectionId)['synctoken'];

		if (is_null($currentToken)) {
			return null;
		}

        	$result = [
				'syncToken' => $currentToken,
				'added'     => [],
				'modified'  => [],
				'deleted'   => [],
			];
		
        if ($syncToken) {
			$query = $this->db->select('*')
				->from($this->collectionsFolder.$collectionId.'/changes.json')
				->order_by('synctoken', JSONDB::ASC)
				->get();

			$changes = [];

			foreach ($query as $data) {
				if ($data['synctoken'] >= $syncToken) $changes[$data['uri']] = $data['operation'];
				if ($data['synctoken'] < $currentToken) $changes[$data['uri']] = $data['operation'];
			}

            foreach ($changes as $uri => $operation) {
                switch ($operation) {
                    case 1:
                        $result['added'][] = $uri;
                        break;
                    case 2:
                        $result['modified'][] = $uri;
                        break;
                    case 3:
                        $result['deleted'][] = $uri;
                        break;
                }
            }
        } else {
		$objects = $this->getObjects($collectionId);

		foreach ($objects as $object) {
	            $result['added'][] = $object['uri'];
	        }
        }

        return $result;
	}
}