#include <iostream>
#include <functional>
#include <unordered_map>

#include "crow.h"

#define NULL_STRING std::string("null")
#define EMPTY_STRING std::string("")
#define NO_SUCH_COMMAND std::string("no_such_command")

typedef std::function<std::string(std::string const &arguments, std::string const &session,
                                  void *payload)> handler_func;

struct CommandHandler {
    [[nodiscard]] std::string exec(std::string const &arguments, std::string const &session) const {
        return func(arguments, session, payload);
    }

    handler_func func;
    void *payload{nullptr};
};

std::string stopHandler(std::string const &arguments, std::string const &session, void *payload);
std::string klingerHandler(std::string const &arguments, std::string const &session, void *payload);

[[maybe_unused]] void decl_me_daddy(int not_an_int) { (void) not_an_int; }

int main() {
    crow::SimpleApp app;

    // command --> handler
    static std::unordered_map<std::string, CommandHandler> const commands{
            {"stop", {stopHandler, &app}},
            {"klinger", {klingerHandler}}
    };

    CROW_ROUTE(app, "/")
            .methods("POST"_method)
                    ([&app](crow::request const &request) {
                        auto data = crow::json::load(request.body);

                        if (!data)
                            return crow::response(400);

                        if (!data.count("command"))
                            return crow::response(400, "malformed request: missing `command` field\n");

                        std::string command = (data.count("command") ? data["command"].s() : NO_SUCH_COMMAND);
                        std::string arguments = (data.count("arguments") ? data["arguments"].s() : EMPTY_STRING);
                        std::string session = (data.count("session") ? data["session"].s() : NULL_STRING);

                        if (auto itor = commands.find(command); itor != commands.end()) {
                            auto handler = itor->second;
                            return crow::response{handler.exec(arguments, session)};
                        }

                        return crow::response{"no such command!\n"};
                    });

    app.port(18080).multithreaded().run();

    std::cout << "Stopped successfully" << std::endl;
}

std::string klingerHandler(std::string const &arguments, std::string const &session, void *payload) {
    return "Bonjour!";
}

std::string stopHandler(std::string const &arguments, std::string const &session, void *payload) {
    auto app = (crow::SimpleApp*) payload;
    app->stop();
    return "stopped";
}

// curl -d '{"command":"klinger", "b":"12"}' -H "Content-Type: application/json" -X POST http://localhost:18080/