<?php

/**
 * This abstract class defines an interface for metadata storage sources.
 *
 * It also contains the overview of the different metadata storage sources.
 * A metadata storage source can be loaded by passing the configuration of it
 * to the getSource static function.
 *
 * @author Olav Morken, UNINETT AS.
 * @author Andreas Aakre Solberg, UNINETT AS.
 * @package simpleSAMLphp
 */
abstract class SimpleSAML_Metadata_MetaDataStorageSource {


	/**
	 * Parse array with metadata sources.
	 *
	 * This function accepts an array with metadata sources, and returns an array with
	 * each metadata source as an object.
	 *
	 * @param array $sourcesConfig  Array with metadata source configuration.
	 * @return array  Parsed metadata configuration.
	 */
	public static function parseSources($sourcesConfig) {
		assert('is_array($sourcesConfig)');

		$sources = array();

		foreach ($sourcesConfig as $sourceConfig) {
			if (!is_array($sourceConfig)) {
				throw new Exception('Found an element in metadata source' .
					' configuration which wasn\'t an array.');
			}

			$sources[] = self::getSource($sourceConfig);
		}

		return $sources;
	}


	/**
	 * This function creates a metadata source based on the given configuration.
	 * The type of source is based on the 'type' parameter in the configuration.
	 * The default type is 'flatfile'.
	 *
	 * @param array $sourceConfig  Associative array with the configuration for this metadata source.
	 * @return SimpleSAML_Metadata_MetaDataStorageHandlerFlatFile|
	 * SimpleSAML_Metadata_MetaDataStorageHandlerXML|
	 * SimpleSAML_Metadata_MetaDataStorageHandlerSerialize|
	 * SimpleSAML_Metadata_MetaDataStorageHandlerMDX|
	 * SimpleSAML_Metadata_MetaDataStorageHandlerPdo An instance of a metadata source with the given configuration.
	 */
	public static function getSource($sourceConfig) {

		assert(is_array($sourceConfig));

		if(array_key_exists('type', $sourceConfig)) {
			$type = $sourceConfig['type'];
		} else {
			$type = 'flatfile';
		}

		switch($type) {
			case 'flatfile':
				return new SimpleSAML_Metadata_MetaDataStorageHandlerFlatFile($sourceConfig);
			case 'xml':
				return new SimpleSAML_Metadata_MetaDataStorageHandlerXML($sourceConfig);
			case 'serialize':
				return new SimpleSAML_Metadata_MetaDataStorageHandlerSerialize($sourceConfig);
			case 'mdx':
				return new SimpleSAML_Metadata_MetaDataStorageHandlerMDX($sourceConfig);
			case 'pdo':
				return new SimpleSAML_Metadata_MetaDataStorageHandlerPdo($sourceConfig);
			default:
				throw new Exception('Invalid metadata source type: "' . $type . '".');
		}
	}


	/**
	 * This function attempts to generate an associative array with metadata for all entities in the
	 * given set. The key of the array is the entity id.
	 *
	 * A subclass should override this function if it is able to easily generate this list.
	 *
	 * @param string $set  The set we want to list metadata for.
	 * @return array An associative array with all entities in the given set, or an empty array if we are
	 *         unable to generate this list.
	 */
	public function getMetadataSet($set) {
		return array();
	}


	/**
	 * This function resolves an host/path combination to an entity id.
	 *
	 * This class implements this function using the getMetadataSet-function. A subclass should
	 * override this function if it doesn't implement the getMetadataSet function, or if the
	 * implementation of getMetadataSet is slow.
	 *
	 * @param string $hostPath  The host/path combination we are looking up.
	 * @param string $set  Which set of metadata we are looking it up in.
	 * @param string $type Do you want to return the metaindex or the entityID. [entityid|metaindex]

	 * @return array|null An entity id which matches the given host/path combination, or NULL if
	 *         we are unable to locate one which matches.
	 */
	public function getEntityIdFromHostPath($hostPath, $set, $type = 'entityid') {

		$metadataSet = $this->getMetadataSet($set);
		if ($metadataSet === NULL) {
			/* This metadata source does not have this metadata set. */
			return NULL;
		}

		foreach($metadataSet AS $index => $entry) {

			if(!array_key_exists('host', $entry)) {
				continue;
			}

			if($hostPath === $entry['host']) {
				if ($type === 'entityid') {
					return $entry['entityid'];
				} else {
					return $index;
				}	
			}
		}

		/* No entries matched - we should return NULL. */
		return NULL;
	}
	
	/**
	 * This function will go through all the metadata, and check the hint.cidr
	 * parameter, which defines a network space (ip range) for each remote entry.
	 * This function returns the entityID for any of the entities that have an 
	 * IP range which the IP falls within.
	 *
	 * @param string $set  Which set of metadata we are looking it up in.
	 * @param string $ip	IP address
	 * @param string $type Do you want to return the metaindex or the entityID. [entityid|metaindex]
	 * @return string The entity id of a entity which have a CIDR hint where the provided
	 * 		IP address match.
	 */
	public function getPreferredEntityIdFromCIDRhint($set, $ip, $type = 'entityid') {
		
		$metadataSet = $this->getMetadataSet($set);

		foreach($metadataSet AS $index => $entry) {

			if(!array_key_exists('hint.cidr', $entry)) continue;
			if(!is_array($entry['hint.cidr'])) continue;
			
			foreach ($entry['hint.cidr'] AS $hint_entry) {
				if (SimpleSAML\Utils\Net::ipCIDRcheck($hint_entry, $ip)) {
					if ($type === 'entityid') {
						return $entry['entityid'];
					} else {
						return $index;
					}		
				}
			}

		}

		/* No entries matched - we should return NULL. */
		return NULL;
	}

	/*
	 *
	 */
	private function lookupIndexFromEntityId($entityId, $set) {

		assert('is_string($entityId)');
		assert('isset($set)');

		$metadataSet = $this->getMetadataSet($set);

		/* Check for hostname. */
		$currenthost = \SimpleSAML\Utils\HTTP::getSelfHost(); // sp.example.org
		if(strpos($currenthost, ":") !== FALSE) {
			$currenthostdecomposed = explode(":", $currenthost);
			$currenthost = $currenthostdecomposed[0];
		}
		
		foreach($metadataSet AS $index => $entry) {
			if ($index === $entityId) return $index;
			if ($entry['entityid'] === $entityId) {
				if ($entry['host'] === '__DEFAULT__' || $entry['host'] === $currenthost) return $index;
			}
		}
		
		return NULL;
	}

	/**
	 * This function retrieves metadata for the given entity id in the given set of metadata.
	 * It will return NULL if it is unable to locate the metadata.
	 *
	 * This class implements this function using the getMetadataSet-function. A subclass should
	 * override this function if it doesn't implement the getMetadataSet function, or if the
	 * implementation of getMetadataSet is slow.
	 *
	 * @param string $index  The entityId or metaindex we are looking up.
	 * @param string $set  The set we are looking for metadata in.
	 * @return array An associative array with metadata for the given entity, or NULL if we are unable to
	 *         locate the entity.
	 */
	public function getMetaData($index, $set) {

		assert('is_string($index)');
		assert('isset($set)');

		$metadataSet = $this->getMetadataSet($set);

		if(array_key_exists($index, $metadataSet))
			return $metadataSet[$index];

		$indexlookup = $this->lookupIndexFromEntityId($index, $set);
		if (isset($indexlookup) && array_key_exists($indexlookup, $metadataSet)) 
			return $metadataSet[$indexlookup];

		return NULL;
	}

}