#ifndef _PROTOCOL_
#define _PROTOCOL_

#include <protocol/token.hpp>

#include <string>
#include <map>
#include <functional>
#include <iostream>

namespace protocol {
    struct message_t {
        std::string input;
        token::pattern_t pattern;
    };

    class protocol_t;
    using handler_t = std::function<void(protocol_t&, const message_t&)>;
    using handler_map_t = std::map<token::pattern_t, handler_t>;

    using session_key_t = token::string_t;

    session_key_t session_key_from(const token::list_t& tokens);
    session_key_t session_key_from(const message_t& message);

    token::string_t session_token_from(const token::list_t& tokens);
    token::string_t session_token_from(const message_t& message);

    class protocol_t {
    public:
        void set_handlers(const handler_map_t handlers);

        void absorb(const std::string& input);
        void send(const token::list_t& tokens);

        // TODO: Move these methods to a separate session_t class!
        void send_result(const session_key_t& session_key, const token::string_t& session_token, token::list_t tokens);
        void proceed(const session_key_t& session_key, const token::string_t& session_token);
        void junk(const session_key_t& session_key, const token::string_t& session_token);
        void fail(const session_key_t& session_key, const token::string_t& session_token);
        void submit_message(const session_key_t& session_key, const token::string_t& session_token, const std::vector<std::string>& header, const std::vector<std::string>& body);

    protected:
        virtual void emit(const std::string& output) { };

    private:
        handler_map_t handlers;
        size_t max_pattern_length;
        std::string version;

        void send_data_line(const session_key_t& session_key, const token::string_t& session_token, const std::string& data_line);
    };

    class ios_protocol_t : public protocol_t {
    public:
        ios_protocol_t(std::istream& in, std::ostream& out);
        void run();

    protected:
        virtual void emit(const std::string& output);

    private:
        std::istream& in;
        std::ostream& out;
    };
}

#endif