///////////////////////////////////////////////////////////////////////////////
//
// Copyright (c) Crossbar.io Technologies GmbH and contributors
//
// Boost Software License - Version 1.0 - August 17th, 2003
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
//
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
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///////////////////////////////////////////////////////////////////////////////

#ifndef AUTOBAHN_SESSION_HPP
#define AUTOBAHN_SESSION_HPP

#include "wamp_call_options.hpp"
#include "wamp_call_result.hpp"
#include "wamp_event_handler.hpp"
#include "wamp_message.hpp"
#include "wamp_procedure.hpp"
#include "wamp_subscribe_options.hpp"
#include "wamp_transport_handler.hpp"
#include "boost_config.hpp"

#include <boost/asio.hpp>
#include <cstdint>
#include <functional>
#include <istream>
#include <ostream>
#include <map>
#include <memory>
#include <msgpack.hpp>
#include <stdexcept>
#include <string>
#include <utility>
#include <vector>

#if defined(_WIN32) || defined(WIN32)
#define WIN32_LEAN_AND_MEAN
#endif

#ifdef ERROR
#undef ERROR
#endif

namespace autobahn {

class wamp_call;
class wamp_message;
class wamp_register_request;
class wamp_registration;
class wamp_subscribe_request;
class wamp_subscription;
class wamp_transport;
class wamp_unregister_request;
class wamp_unsubscribe_request;
class wamp_authenticate;
class wamp_challenge;

/// Representation of a WAMP session.
class wamp_session :
        public wamp_transport_handler,
        public std::enable_shared_from_this<wamp_session>
{
public:

    /*!
     * Create a new WAMP session.
     *
     * \param io_service The io service to drive event dispatching.
     * \param debug_enabled Whether or not to run in debug mode.
     */
    wamp_session(
            boost::asio::io_service& io_service,
            bool debug_enabled = false);

    ~wamp_session();

    /*!
     * Establishes a session with the router.
     *
     * \return A future that indicates if the session was successfully started.
     */
    boost::future<void> start();

    /*!
     * Stops the session with the router.
     *
     * \return A future that indicates if the session was successfully stopped.
     */
    boost::future<void> stop();

    /*!
     * Join a realm with the session.
     *
     * \param realm The realm to join on the application router.
     * \param authmethods The authentication methods this instance support e.g. "wampcra","ticket"
     * \param authid The username or maybe an other identifier for the user to join.
     * \return A future that resolves with the session ID when the realm was joined.
     */
    boost::future<uint64_t> join(
            const std::string& realm,
            const std::vector<std::string>& authmethods = std::vector<std::string>(),
            const std::string& authid = "");

    /*!
     * Leave the realm.
     *
     * \param reason An optional WAMP URI providing a reason for leaving.
     * \return A future that resolves with the reason sent by the peer.
     */
    boost::future<std::string> leave(
            const std::string& reason = std::string("wamp.error.close_realm"));

    /*!
     * Publish an event with empty payload to a topic.
     *
     * \param topic The URI of the topic to publish to.
     * \return A future that resolves once the the topic has been published to.
     */
    boost::future<void> publish(const std::string& topic);

    /*!
     * Publish an event with positional payload to a topic.
     *
     * \param topic The URI of the topic to publish to.
     * \param arguments The positional payload for the event.
     * \return A future that resolves once the the topic has been published to.
     */
    template <typename List>
    boost::future<void> publish(const std::string& topic, const List& arguments);

    /*!
     * Publish an event with both positional and keyword payload to a topic.
     *
     * \param topic The URI of the topic to publish to.
     * \param arguments The positional payload for the event.
     * \param kw_arguments The keyword payload for the event.
     * \return A future that resolves once the the topic has been published to.
     */
    template <typename List, typename Map>
    boost::future<void> publish(
            const std::string& topic,
            const List& arguments,
            const Map& kw_arguments);

    /*!
     * Subscribe a handler to a topic to receive events.
     *
     * \param topic The URI of the topic to subscribe to.
     * \param handler The handler that will receive events under the subscription.
     * \param options The options to pass in the subscribe request to the router.
     * \return A future that resolves to the autobahn::subscription.
     */
    boost::future<wamp_subscription> subscribe(
            const std::string& topic,
            const wamp_event_handler& handler,
            const wamp_subscribe_options& options = wamp_subscribe_options());

    /*!
     * Unubscribe a handler to previously subscribed topic.
     *
     * \param subscription The subscription to unsubscribe from.
     * \return A future that resolves to the unsubscribed response.
     */
    boost::future<void> unsubscribe(const wamp_subscription& subscription);

    /*!
     * Calls a remote procedure with no arguments.
     *
     * \param procedure The URI of the remote procedure to call.
     * \param options The options to pass in the call to the router.
     * \return A future that resolves to the result of the remote procedure call.
     */
    boost::future<wamp_call_result> call(
            const std::string& procedure,
            const wamp_call_options& options = wamp_call_options());

    /*!
     * Calls a remote procedure with positional arguments.
     *
     * \param procedure The URI of the remote procedure to call.
     * \param arguments The positional arguments for the call.
     * \param options The options to pass in the call to the router.
     * \return A future that resolves to the result of the remote procedure call.
     */
    template <typename List>
    boost::future<wamp_call_result> call(
            const std::string& procedure,
            const List& arguments,
            const wamp_call_options& options = wamp_call_options());

    /*!
     * Calls a remote procedure with positional and keyword arguments.
     *
     * \param procedure The URI of the remote procedure to call.
     * \param arguments The positional arguments for the call.
     * \param kw_arguments The keyword arguments for the call.
     * \param options The options to pass in the call to the router.
     * \return A future that resolves to the result of the remote procedure call.
     */
    template<typename List, typename Map>
    boost::future<wamp_call_result> call(
            const std::string& procedure,
            const List& arguments, const Map& kw_arguments,
            const wamp_call_options& options = wamp_call_options());

    /*!
     * Register a procedure that can be called remotely.
     *
     * \param uri The URI associated with the procedure.
     * \param procedure The procedure to be exposed as a remotely callable procedure.
     * \param options Options for registering the procedure.
     * \return A future that resolves to a autobahn::registration
     */
    boost::future<wamp_registration> provide(
            const std::string& uri,
            const wamp_procedure& procedure,
            const provide_options& options = provide_options());

    /*!
    * Unregister a handler to previosly registered service.
    *
    * \param registration The registration to unregister.
    * \return A future that resolves to the unregistered response.
    */
    boost::future<void> unprovide(const wamp_registration& registration);

    /*!
     * Function called by the session when authenticating. It always has to be
     * re-implemented (if authentication is part of the system).
     *
     * \param challenge The challenge from the router containing enough information
     *        for the system to prove membership.
     * \return A future that resolves to an authentication response.
     */
    virtual boost::future<wamp_authenticate> on_challenge(const wamp_challenge& challenge);

    /*!
    * Accessor method to WELCOME DETAILS dictionary containing router roles 
    * and corresponding features, authid, authrole, ...)
    *
    *
    * \return A dictionary of objects received with WELCOME message upon joining.
    * i.e.
    * {
    *   "realm": "<string>",
    *   "authprovider": "dynamic",
    *   "roles": {
    *     "broker": {
    *       "features": {
    *         "publisher_identification": true,
    *         "pattern_based_subscription": true,
    *         ...
    *       }
    *     },
    *     "dealer": {
    *       "features": {
    *         "pattern_based_registration": true,
    *         "progressive_call_results": true,
    *          ...
    *       }
    *     }
    *   },
    * "authid": "<assigned authid>",
    * "authrole": "<assigned auth role>",
    * "authmethod": "wampcra",
    *  ...
    * }
    */
    const std::unordered_map<std::string, msgpack::object>& welcome_details();

private:
    // Implements the wamp transport handler interface.
    virtual void on_attach(const std::shared_ptr<wamp_transport>& transport) override;
    virtual void on_detach(bool was_clean, const std::string& reason) override;
    virtual void on_message(wamp_message&& message) override;

    // WAMP message processing
    void process_error(wamp_message&& message);
    void process_welcome(wamp_message&& message);
    void process_abort(wamp_message&& message);
    void process_challenge(wamp_message&& message);
    void process_call_result(wamp_message&& message);
    void process_subscribed(wamp_message&& message);
    void process_unsubscribed(wamp_message&& message);
    void process_event(wamp_message&& message);
    void process_registered(wamp_message&& message);
    void process_unregistered(wamp_message&& message);
    void process_invocation(wamp_message&& message);
    void process_goodbye(wamp_message&& message);

    // Transmitting/receiving messages
    void send_message(wamp_message&& message, bool session_established = true);
    void receive_message();

    void got_handshake_reply(const boost::system::error_code& error);
    void got_message_header(const boost::system::error_code& error);
    void got_message_body(const boost::system::error_code& error);
    void got_message(wamp_message&& message);

    bool m_debug_enabled;

    boost::asio::io_service& m_io_service;

    // The transport this session runs on.
    std::shared_ptr<wamp_transport> m_transport;

    // Last request ID of outgoing WAMP requests.
    std::atomic<uint64_t> m_request_id;

    // WAMP session ID (if the session is joined to a realm).
    uint64_t m_session_id;

    // Synchronization for dealing with starting the session.
    boost::promise<void> m_session_start;

    // Future to be fired when session was joined.
    boost::promise<uint64_t> m_session_join;

    // Whether or not we have already sent a goodbye when leaving the session.
    bool m_goodbye_sent;

    boost::promise<std::string> m_session_leave;

    // Set to true when the session is stopped.
    bool m_running;

    // Synchronization for dealing with stopping the session
    boost::promise<void> m_session_stop;

    //////////////////////////////////////////////////////////////////////////////////////
    // Caller

    // Track pending calls by request id.
    std::map<uint64_t /*request id*/, std::shared_ptr<wamp_call>> m_calls;

    //////////////////////////////////////////////////////////////////////////////////////
    // Subscriber

    // Pending subscribe requests by request id.
    std::map<uint64_t /*request id*/, std::shared_ptr<wamp_subscribe_request>> m_subscribe_requests;

    // Pending unsubscribe requests by request id.
    std::map<uint64_t /*request id*/, std::shared_ptr<wamp_unsubscribe_request>> m_unsubscribe_requests;

    // Event handlers by subscription id.
    std::multimap<uint64_t /*subscription id*/, wamp_event_handler> m_subscription_handlers;

    //////////////////////////////////////////////////////////////////////////////////////
    // Callee

    // Map of outstanding WAMP register requests (request ID -> register request).
    std::map<uint64_t, std::shared_ptr<wamp_register_request>> m_register_requests;

    // Map of outstanding WAMP unregister requests (request ID -> unregister request).
    std::map<uint64_t, std::shared_ptr<wamp_unregister_request>> m_unregister_requests;

    // Map of registered procedures (registration ID -> procedure)
    std::map<uint64_t, wamp_procedure> m_procedures;

    // Welcome details
    std::unordered_map<std::string, msgpack::object> m_welcome_details;

};

} // namespace autobahn

#include "wamp_session.ipp"

#endif // AUTOBAHN_SESSION_HPP
