/*
 *	C++ ICAP library
 *	Copyright (C) 2012	Uditha Atukorala
 *
 *	This program is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU General Public License as published by
 *	the Free Software Foundation; either version 3 of the License, or
 *	(at your option) any later version.
 *
 *	This program is distributed in the hope that it will be useful,
 *	but WITHOUT ANY WARRANTY; without even the implied warranty of
 *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *	GNU General Public License for more details.
 *
 *	You should have received a copy of the GNU General Public License
 *	along with this program; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#ifndef ICAP_HEADER_H
#define ICAP_HEADER_H

#include "common.h"

#include <string>
#include <map>
#include <vector>
#include <functional>


namespace icap {

	class Header {
	public:

		/* headers data type */
		typedef std::map<std::string, std::string> headers_t;

		/* headers iterator type */
		typedef headers_t::iterator headers_index_t;

		/* encapsulated header type */
		typedef std::map<std::string, int> encapsulated_header_t;

		/* encapsulated header iterator type */
		typedef encapsulated_header_t::iterator encapsulated_header_index_t;

		/* encapsulated header data type */
		typedef std::pair<std::string, int> encapsulated_header_data_t;

		/**
		*   Binary compare structure to compare two encapsulated header
		*   entity (data) values. Used for sorting.
		*/
		struct encapsulated_header_compare
			: std::binary_function<icap::Header::encapsulated_header_data_t, icap::Header::encapsulated_header_data_t, bool> {
			inline bool operator()( const icap::Header::encapsulated_header_data_t &lhs, const icap::Header::encapsulated_header_data_t &rhs ) {
				return lhs.second < rhs.second;
			}
		};


		Header();
		virtual ~Header();

		/**
		*   Return headers
		*   @return headers
		*/
		const headers_t &headers() const throw();

		/**
		*   Returns the header value for the given header key or an empty string
		*   if the header is not found.
		*
		*   @param key header key
		*   @return header value 
		*/
		const std::string value( const std::string &key ) throw();

		/**
		*   Return Encapsulated header value for the given entity
		*   or -1 if the given entity is invalid.
		*
		*   @param entity encapsulated header entity
		*   @return -1 | encapsulated header value
		*/
		const int encapsulated_header( const std::string &entity ) throw();

		/**
		*   Attach header data into the header
		*
		*   <pre>
		*   e.g.
		*   Host: icap-server.net
		*   Encapsulated: req-hdr=0, null-body=170
		*   [key]: [value]
		*   </pre>
		*
		*   @param key header key
		*   @param value header value
		*/
		virtual void attach( std::string key, std::string value ) throw();

		/**
		*   Attach Encapsulated header data. This method should only be used
		*   when reading a raw request / response. Consider using update_encapsulated()
		*   method for other scenarios.
		*
		*   <pre>
		*   e.g.
		*   Encapsulated: req-hdr=0, req-body=412
		*   Encapsulated: req-hdr=0, res-hdr=822, res-body=1655
		*   Encapsulated: [header_value]
		*   </pre>
		*
		*   @param header_value Encapsulated header value
		*   @return boolean to denote success or failure
		*/
		virtual bool attach_encapsulated( std::string header_value ) throw();


		/**
		*   Update Encapsulated header data using the passed in (icap::payload_t) payload.
		*   When the request / response has been populated with the payload, calling this
		*   method will update the encapsulated header entities with appropriate values.
		*
		*   This methos will always succeed.
		*
		*   @param payload request or response payload
		*/
		virtual void update_encapsulated( const payload_t &payload ) throw();

		/**
		*   Remove header data from the header instance with the given key
		*
		*   @param key header key
		*   @return boolean to denote success or failure
		*/
		virtual bool remove( std::string key ) throw();

		/**
		*   Return Encapsulated header as a std::string value.
		*   @return encapsulated header value (e.g. res-hdr=0, res-body=213)
		*/
		virtual const std::string encapsulated_header_str() throw();

		/**
		*   Sort the encapsulated header data and return a std::vector of
		*   encapsulated_header_data_t. The actual header data won't be changed.
		*
		*   @return sorted encapsulated header
		*/
		virtual std::vector<encapsulated_header_data_t> sort_encapsulated_header();


	protected:
		headers_t _headers;
		encapsulated_header_t _encapsulated;

	private:

	};

} /* end of namespace icap */

#endif /* !ICAP_HEADER_H */