#include "lpxclient.hpp"

#include "drivenengine.hpp"
#include "world.hpp"
#include "luaconsole.hpp"
#include "invocation.hpp"
#include "util.hpp"
#include "printbuffer.hpp"
#include <memory>

class LpxClient : public DrivenEngine {
public:
    using StringVec = LuaConsole::StringVec;
    UniqueWorld world_;
    int64_t actor_id_;
    InvocationQueue unack_;
    UniqueChannel channel_;
    LuaConsole console_;
    PrintChanneler print_channeler_;
    Gui gui_;

public:
    void set_initial_state() {
        // Create the world model.
        world_.reset(new World(util::WORLD_TYPE_C_SYNC));

        // Snapshot the initial state.
        world_->snapshot();

        // Clear the unack command queue.
        unack_.clear();

        // This is a temporary actor that will be used only until the server sends
        // us the first difference transmission.  We do this only to establish
        // the invariant that there's always an actor.  When the first difference
        // transmission arrives, this actor may be deleted, or it may just be
        // ignored, at the server's discretion.
        actor_id_ = world_->create_login_actor();
    }


    // When the world is in synchronous mode, there's no
    // snapshot, and the commands in the unack queue are not
    // reflected in the world.  In asynchronous mode, there is
    // a snapshot that allows return to the synchronous mode,
    // and the unack commands are in the world model.

    void world_to_synchronous() {
        if (!world_->snapshot_empty()) {
            world_->rollback();
        }
    }

    void world_to_asynchronous() {
        if (world_->snapshot_empty()) {
            world_->snapshot();
            for (const Invocation &inv : unack_) {
                world_->invoke(inv);
            }
        }
    }

    void abandon_server() {
        stdostream() << "Abandoning server." << std::endl;

        // Put the world model back into a known-good state.
        set_initial_state();

        // Disconnect from the server.
        channel_.reset();
    }

    virtual void event_init(int argc, char *argv[]) {
        // Put the world into the starting state.
        set_initial_state();

        // Establish a connection to the server.
        channel_ = new_outgoing_channel("localhost:8085");

        // Set the console prompt
        get_stdio_channel()->set_prompt(console_.get_prompt());
    }

    void send_invocation(const Invocation &inv) {
        if (channel_ == nullptr) {
            stdostream() << "Cannot invoke any actions, not connected." << std::endl;
            return;
        }
        world_to_asynchronous();
        world_->invoke(inv);
        unack_.push_back(inv);
        StreamBuffer *sb = channel_->out();
        sb->write_uint8(util::MSG_INVOKE);
        inv.serialize(sb);
    }

    void do_luainvoke_command(const StringVec &words) {
        send_invocation(Invocation(Invocation::KIND_LUA, actor_id_, actor_id_, words[1]));
    }

    void do_luaprobe_command(const StringVec &words) {
        world_to_asynchronous();
        stdostream() << world_->probe_lua(actor_id_, words[1]);
        world_to_synchronous();
    }

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

    void do_view_command(const StringVec &cmd) {
        stdostream() << world_->tangibles_near_debug_string(actor_id_, 100);
    }

    void do_menu_command(const StringVec &cmd) {
        world_to_asynchronous();
        int64_t place = util::strtoint(cmd[1], actor_id_);
        world_->update_gui(actor_id_, place, &gui_);
        stdostream() << gui_.menu_debug_string();
    }

    void do_choose_command(const StringVec &cmd) {
        std::string action = gui_.get_action(util::strtoint(cmd[1], -1));
        if (action == "") {
            stdostream() << "Invalid menu item #" << std::endl;
            return;
        }
        stdostream() << "Invoking plan: " << action << std::endl;
        Invocation inv(Invocation::KIND_PLAN, actor_id_, gui_.place(), action);
        send_invocation(inv);
    }

    void do_tick_command(const util::StringVec &words) {
        send_invocation(Invocation(Invocation::KIND_TICK, actor_id_, actor_id_, ""));
    }

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

    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] == "view") do_view_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] == "quit") do_quit_command(words);
        else {
            stdostream() << "Unsupported command: " << words[0] << std::endl;
        }
    }

    void change_actor_id(int64_t actor_id) {
        stdostream() << "Actor ID changing: " << actor_id << std::endl;
        print_channeler_.reset();
        actor_id_ = actor_id;
    }

    void receive_ack_from_server(StreamBuffer *sb) {
        // An ack is just a single byte, so there's nothing left to read.
        if (unack_.empty()) {
            // Invalid acknowledgement when theres' nothing in the unack queue.
            abandon_server();
            return;
        }
        world_to_synchronous();
        world_->invoke(unack_.front());
        unack_.pop_front();
    }

    void receive_diff_from_server(StreamBuffer *sb) {
        world_to_synchronous();
        try {
            DebugCollector dbc("patch_everything");
            int64_t nactor = world_->patch_everything(sb, &dbc);
            if (nactor != actor_id_) change_actor_id(nactor);
            dbc.dump(stdostream());
        } catch (const StreamEof &seof) {
            abandon_server();
            return;
        } catch (const StreamCorruption &scorr) {
            abandon_server();
            return;
        }
    }

    bool receive_message_from_server(StreamBuffer *sb) {
        if (sb->fill() < 5) return false;
        int64_t tr_before = sb->total_reads();
        uint8_t message_type = sb->read_uint8();
        uint32_t message_body_len = sb->read_uint32();
        if (sb->fill() < message_body_len) {
            sb->unread_to(tr_before);
            return false;
        }
        StreamBuffer body(sb->read_bytes(message_body_len), message_body_len);
        if (message_type == util::MSG_ACK) {
            receive_ack_from_server(&body);
        } else if (message_type == util::MSG_DIFF) {
            receive_diff_from_server(&body);
        } else {
            abandon_server();
            return false;
        }
        if (!body.empty()) {
            abandon_server();
            return false;
        }
        return true;
    }

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

        // Check for communication from server..
        if (channel_ != nullptr) {
            if (channel_->closed()) {
                stdostream() << "Server closed connection " << channel_->error() << std::endl;
                abandon_server();
            } else {
                while (true) {
                    if (!receive_message_from_server(channel_->in())) break;
                    if (channel_ == nullptr) break;
                }
                world_to_asynchronous();
            }
        }

        // Channel print statements.
        if (print_channeler_.channel(world_->get_printbuffer(actor_id_), stdostream())) {
            send_invocation(print_channeler_.invocation(actor_id_));
        }
    }
};

UniqueDrivenEngine make_LpxClient() {
    return UniqueDrivenEngine(new LpxClient);
}