#include "wrap-string.hpp"
#include "wrap-vector.hpp"

#include "world.hpp"
#include "drivenengine.hpp"
#include "luaconsole.hpp"
#include "util.hpp"
#include "printbuffer.hpp"

#include <memory>

class Client : public eng::opnew {
public:
    int64_t actor_id_;
    SharedChannel channel_;
    UniqueWorld sync_;
    double last_diff_;
    bool async_diff_;
};
using UniqueClient = std::unique_ptr<Client>;
using ClientVector = eng::vector<UniqueClient>;

class LpxServer : public DrivenEngine {
public:
    using StringVec = LuaConsole::StringVec;
    UniqueWorld master_;
    LuaConsole console_;
    ClientVector clients_;
    PrintChanneler print_channeler_;
    HttpChannelMap http_client_channels_;
    HttpChannelVec http_server_channels_;
    int64_t admin_id_;
    Gui gui_;
    int next_diff_chan_;
    double next_tick_;

public:
    virtual void event_init(std::string_view srcpk, int argc, char *argv[]) override {
        // Create the master world model.
        master_.reset(new World(WORLD_TYPE_MASTER));

        // Update the source code of the master model.
        master_->update_source(srcpk);

        // Create an actor for administrative commands.
        admin_id_ = master_->create_login_actor(true);

        // TODO: initialize the admin actor.

        // Print out admin ID for debugging purposes.
        stdostream() << "Admin actor id = " << admin_id_ << std::endl;

        // Enable listening on port 8085 (client connections)
        listen_port(8085);

        // Enable listening on port 8080 (http server connections)
        listen_port(8080);

        // Set the console prompt.
        set_console_prompt(console_.get_prompt());

        // Export stuff to the graphics engine.
        set_visible_world_and_actor(master_.get(), admin_id_);

        // for ticking.
        next_tick_ = 0.0;
    }

    void do_luainvoke_command(const util::StringVec &words) {
        master_->invoke(Invocation(Invocation::KIND_LUA, admin_id_, admin_id_, words[1]));
    }

    void do_luaprobe_command(const util::StringVec &words) {
        master_->snapshot();
        stdostream() << master_->probe_lua(admin_id_, words[1]);;
        master_->rollback();
    }

    void do_syntax_command(const util::StringVec &words) {
        stdostream() << "Syntax Error: " << words[1] << std::endl;
    }

    void do_menu_command(const StringVec &cmd) {
        int64_t place = sv::to_int64(cmd[1], admin_id_);
        master_->update_gui(admin_id_, place, &gui_);
        stdostream() << gui_.menu_debug_string();
    }

    void do_choose_command(const StringVec &cmd) {
        stdostream() << "Chose menu item: " << cmd[1] << std::endl;
        eng::string action = gui_.get_action(sv::to_int64(cmd[1]));
        if (action == "") {
            stdostream() << "Invalid menu item #" << std::endl;
            return;
        }
        stdostream() << "Invoking plan: " << action << std::endl;
        master_->invoke(Invocation(Invocation::KIND_CHOOSE, admin_id_, gui_.place(), action));
    }

    void do_tick_command(const util::StringVec &words) {
        master_->invoke(Invocation(Invocation::KIND_TICK, admin_id_, admin_id_, ""));
    }

    void do_cpl_command(const util::StringVec &words) {
        rescan_lua_source();
    }

    void do_quit_command(const util::StringVec &words) {
        stop_driver();
    }

    void do_aborthttp_command(const util::StringVec &words) {
        master_->abort_all_http_requests(425, "http requests aborted from the server command line");
    }

    void do_command(const util::StringVec &words) {
        if (words.empty()) return;
        else if (words[0] == "luainvoke") do_luainvoke_command(words);
        else if (words[0] == "luaprobe") do_luaprobe_command(words);
        else if (words[0] == "syntax") do_syntax_command(words);
        else if (words[0] == "menu") do_menu_command(words);
        else if (words[0] == "choose") do_choose_command(words);
        else if (words[0] == "tick") do_tick_command(words);
        else if (words[0] == "cpl") do_cpl_command(words);
        else if (words[0] == "quit") do_quit_command(words);
        else if (words[0] == "aborthttp") do_aborthttp_command(words);
        else {
            stdostream() << "Unsupported command: " << words[0] << std::endl;
        }
    }

    void delete_client(UniqueClient &client) {
        stdostream() << "Client closed: actor id=" << client->actor_id_ << std::endl;
        client.reset();
    }

    void send_diffs(UniqueClient &client) {
        StreamBuffer *sb = client->channel_->out();
        sb->write_uint8(util::MSG_DIFF);
        sb->write_uint32(0);
        int64_t tw_1 = sb->total_writes();
        //stdostream() << "Sending diffs to client " << client->actor_id_ << std::endl;
        client->sync_->diff_everything(client->actor_id_, master_.get(), sb);
        int64_t tw_2 = sb->total_writes();
        sb->overwrite_int32(tw_1, tw_2 - tw_1);
    }

    bool handle_invocation(UniqueClient &client) {
        StreamBuffer *sb = client->channel_->in();
        int64_t tr_before = sb->total_reads();
        Invocation inv;
        try {
            uint8_t msg_type = sb->read_uint8();
            if (msg_type != util::MSG_INVOKE) {
                delete_client(client);
                return false;
            }
            inv.deserialize(sb);
        } catch (const StreamEofOnRead &seof) {
            sb->unread_to(tr_before);
            return false;
        } catch (const StreamException &sexcept) {
            delete_client(client);
            return false;
        }
        // Security check.
        if (inv.actor() != client->actor_id_) {
            delete_client(client);
            return false;
        }
        //stdostream() << "Invoking: " << inv.debug_string() << std::endl;
        master_->invoke(inv);
        client->channel_->out()->write_uint8(util::MSG_ACK);
        client->channel_->out()->write_uint32(0);
        client->sync_->invoke(inv);
        client->async_diff_ = true;
        return true;
    }
    
    virtual void event_update() override {
        // Get the clock.
        double clock = get_clock();

        // Execute any queued invocations.
        // We just feed these directly into the master model.
        eng::vector<UniqueInvocation> invocations = get_queued_invocations();
        for (const UniqueInvocation &inv : invocations) {
            master_->invoke(*inv);
        }

        // Check for keyboard input on stdin.
        while (true) {
            eng::string line = get_stdio_channel()->in()->readline();
            if (line == "") break;
            console_.add(line);
            set_console_prompt(console_.get_prompt());
            do_command(console_.get_command());
        }

        // Anything in the administrator printbuffer should go to stdostream.
        if (print_channeler_.channel(master_->get_printbuffer(admin_id_), stdostream())) {
            master_->invoke(print_channeler_.invocation(admin_id_));
        }

        // Check for new incoming channels, set up client structures.
        while (true) {
            SharedChannel chan = new_incoming_channel();
            if (chan == nullptr) break;
            if (chan->port() == 8085) {
                Client *client = new Client;
                client->actor_id_ = master_->create_login_actor(true);
                // TODO: initialize the login actor on the master.
                client->channel_ = std::move(chan);
                client->async_diff_ = true;
                client->last_diff_ = -100.0;
                client->sync_.reset(new World(WORLD_TYPE_PREDICTIVE));
                // This login actor is never used, it is just to preserve the invariant that
                // the client model and the server synchronous model are identical.
                client->sync_->create_login_actor(false);
                clients_.emplace_back(client);
                stdostream() << "New client: actor id=" << client->actor_id_ << std::endl;
            } else if (chan->port() == 8080) {
                HttpChannel htchan;
                htchan.channel_ = chan;
                http_server_channels_.push_back(htchan);
            }
        }

        // If the clock has advanced far enough, tick the master model.
        if (clock >= next_tick_) {
            master_->invoke(Invocation(Invocation::KIND_TICK, 0, 0, ""));
            for (UniqueClient &client : clients_) {
                client->async_diff_ = true;
            }
            next_tick_ += 1.0;
            if (next_tick_ < clock + 0.3) next_tick_ = clock + 0.3;
        }

        // Traverse all existing channels, process any communication.
        for (UniqueClient &client : clients_) {
            if (client->channel_->closed()) {
                delete_client(client);
                continue;
            }
            
            // Check for received invocations.
            while (handle_invocation(client));

            // Possibly send a diff.
            double diffdelay = 5.0;
            if (client->async_diff_) diffdelay = 0.1;
            if (clock >= client->last_diff_ + diffdelay) {
                send_diffs(client);
                client->last_diff_ = clock;
                client->async_diff_ = false;
            }
        }
        util::remove_nullptrs(clients_);

        // Look for new outgoing HTTP client requests.
        for (const auto &pair : master_->http_requests()) {
            const HttpClientRequest &request = pair.second;
            HttpChannel &channel = http_client_channels_[request.request_id()];
            if (channel.channel_ == nullptr) {
                channel.channel_ = new_outgoing_channel(request.target());
                channel.method_ = request.method();
                channel.parsed_bytes_ = 0;
                request.send(channel.channel_->out());
            }
        }

        // Maintain existing outgoing HTTP client requests.
        HttpParserVec http_responses;
        for (auto &pair : http_client_channels_) {
            HttpChannel &htchan = pair.second;
            Channel &channel = *htchan.channel_;
            if (channel.closed() || (channel.in()->fill() > htchan.parsed_bytes_)) {
                HttpParser response;
                if (!channel.error().empty()) {
                    response.fail(503, util::ss("Service Unavailable: ", channel.error()));
                } else {
                    htchan.parsed_bytes_ = channel.in()->fill();
                    response.parse_response(channel.in()->view(), channel.closed(), htchan.method_);
                }
                if (response.complete()) {
                    response.set_request_id(pair.first);
                    http_responses.push_back(response);
                }
            }
        }
        for (const HttpParser &response : http_responses) {
            http_client_channels_.erase(response.request_id());
        }
        master_->http_responses(http_responses);

        // Maintain incoming HTTP server channels.
        for (HttpChannel &htchan : http_server_channels_) {
            SharedChannel &chan = htchan.channel_;
            if (chan->in()->fill() > htchan.parsed_bytes_) {
                HttpParser parser;
                parser.parse_request(chan->in()->view(), chan->closed());
                htchan.parsed_bytes_ = chan->in()->fill();
                if (parser.complete()) {
                    StreamBuffer *sb = chan->out();
                    HttpServerResponse resp = master_->http_serve(parser);
                    resp.send(sb);
                    htchan.channel_ = nullptr;
                }
            }
        }
        util::remove_marked_items(http_server_channels_);
    }
};

DrivenEngineDefine("lpxserver", LpxServer);