/* Copyright (c) 2019 Marcelo Zimbres Silva (mzimbres@gmail.com)
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

#include <iostream>

#include <aedis/src.hpp>
#include <aedis/aedis.hpp>

#include "lib/client_base.hpp"
#include "lib/user_session.hpp"
#include "src.hpp"

namespace net = aedis::net;
using aedis::resp3::client_base;
using aedis::command;
using aedis::user_session;
using aedis::user_session_base;
using aedis::resp3::adapt;
using aedis::resp3::detail::response_traits;
using aedis::resp3::node;
using aedis::resp3::type;

// TODO: Use all necessary data types.
struct adapter_helper {
   using adapter_type = response_traits<std::vector<node>>::adapter_type;
   adapter_type adapter;

   void
   operator()(
      command,
      type t,
      std::size_t aggregate_size,
      std::size_t depth,
      char const* data,
      std::size_t size,
      std::error_code& ec)
   {
      adapter(t, aggregate_size, depth, data, size, ec);
   }
};

class my_redis_client : public client_base {
private:
   std::vector<node> resp_;
   std::queue<std::weak_ptr<user_session_base>> sessions_;

   void on_message(command cmd) override
   {
      switch (cmd) {
	 case command::ping:
	 {
	    if (auto session = sessions_.front().lock()) {
	       session->deliver(resp_.front().data);
	    } else {
	       std::cout << "Session expired." << std::endl;
	    }

	    sessions_.pop();
	    resp_.clear();
	 } break;
	 case command::incr:
	 {
	    std::cout << "Echos so far: " << resp_.front().data << std::endl;
	    resp_.clear();
	 } break;
         default:
         {
	    assert(false);
	 }
      }
   }

public:
   my_redis_client(net::any_io_executor ex)
   : client_base(ex, adapter_helper{adapt(resp_)})
   {}

   void add_user_session(std::shared_ptr<user_session_base> session)
      { sessions_.push(session); }
};

net::awaitable<void> listener()
{
   auto ex = co_await net::this_coro::executor;
   net::ip::tcp::acceptor acceptor(ex, {net::ip::tcp::v4(), 55555});
   
   auto client = std::make_shared<my_redis_client>(ex);
   client->start();

   for (;;) {
      auto socket = co_await acceptor.async_accept(net::use_awaitable);
      auto session = std::make_shared<user_session>(std::move(socket));

      auto on_msg = [client, session](std::string const& msg)
      {
	 client->send(command::ping, msg);
	 client->add_user_session(session);
	 client->send(command::incr, "echo-counter");
      };

      session->start(on_msg);
   }
}

int main()
{
   try {
      net::io_context ioc{1};
      net::signal_set signals(ioc, SIGINT, SIGTERM);
      signals.async_wait([&](auto, auto){ ioc.stop(); });
      co_spawn(ioc, listener(), net::detached);
      ioc.run();
   } catch (std::exception const& e) {
      std::cerr << e.what() << std::endl;
   }
}