CPP Lesson 2 Homework

// Skillbox chat day 2.cpp : Этот файл содержит функцию "main". Здесь начинается и заканчивается выполнение программы.
//

#include <iostream>
#include <uwebsockets/App.h>

using namespace std;

// START OF DAY 1

#include <regex>
#include <algorithm>

map<string, string> knowledge = {
    {"hello", "oh,. hello, human"},
    {"what", "ChatBot ewfgwegwthth"},
    {"how", "fine qgkqogk wffw"},
    {"do", "Coding gqokgoqgkq"}
};

string to_lower(string text) {
    transform(text.begin(), text.end(), text.begin(), ::tolower);

    return text;
}

string botAnswer(string question) {
    string answer;

    question = to_lower(question);

    for (auto entry : knowledge) {
        regex expression = regex(".*" + entry.first + ".*");

        if (answer.empty() && regex_match(question, expression)) {
            // отвечаем на первый попавшийся знакомый вопрос
            // пока не умею создавать массивы неизвестной длины, чтобы выдать N ответов
            answer = entry.second;
        }
    }

    if (answer.empty()) {
        answer = "Unknown command";
    }

    return answer;
}

// END OF DAY 1


const string SET_NAME = "SET_NAME::";
const string DIRECT = "DIRECT::";

bool isSetNameCommand(string_view message) {
    return message.find(SET_NAME) == 0;
}

bool isInvalidName(string_view message) {
    const string name = string(message.substr(SET_NAME.length() + 2));

    if (name.find("::") != string::npos) {
        return true;
    }

    if (name.length() > 255) {
        return true;
    }

    return false;
}

string parseName(string_view message) {
    return string(message.substr(SET_NAME.length()));
}

string parseReceiverId(string_view message) {
    string_view rest = message.substr(DIRECT.length());
    int pos = rest.find("::");
    string_view id = rest.substr(0, pos);

    return string(id);
}

string parseDirectMessage(string_view message) {
    string_view rest = message.substr(DIRECT.length());
    int pos = rest.find("::");
    string_view text = rest.substr(pos + 2);

    return string(text);
}

bool isDirectCommand(string_view message) {
    return message.find(DIRECT) == 0;
}

/* This is a simple WebSocket echo server example.
 * You may compile it with "WITH_OPENSSL=1 make" or with "make" */

int main() {
    /* ws->getUserData returns one of these */
    struct PerSocketData {
        /* Fill with user data */
        int user_id;
        string name;
    };

    int last_user_id = 2;

    /* Keep in mind that uWS::SSLApp({options}) is the same as uWS::App() when compiled without SSL support.
     * You may swap to using uWS:App() if you don't need SSL */
    //uWS::SSLApp({
    //    /* There are example certificates in uWebSockets.js repo */
    //    .key_file_name = "../misc/key.pem",
    //    .cert_file_name = "../misc/cert.pem",
    //    .passphrase = "1234"
    //})
    uWS::App()
    .ws<PerSocketData>("/*", {
        /* Settings */
        .compression = uWS::SHARED_COMPRESSOR,
        .maxPayloadLength = 16 * 1024,
        .idleTimeout = 600,
        .maxBackpressure = 1 * 1024 * 1024,
        /* Handlers */
        .upgrade = nullptr,
        .open = [&last_user_id](auto* connection) {
            /* Open event here, you may access ws->getUserData() which points to a PerSocketData struct */
            cout << "New connection created" << endl;

            PerSocketData* userData = (PerSocketData*)connection->getUserData();

            userData->user_id = last_user_id++;
            userData->name = "Unnamed";

            connection->subscribe("broadcast");
            connection->subscribe("user#" + to_string(userData->user_id));

            connection->publish("broadcast", "Total users connected: " + to_string(last_user_id - 2));
        },
        .message = [&last_user_id](auto* connection, std::string_view message, uWS::OpCode opCode) {
            cout << "New message received: " << message << endl;

            PerSocketData* userData = (PerSocketData*)connection->getUserData();

            if (isSetNameCommand(message)) {
                if (isInvalidName(message)) {
                    cout << "ERROR: Trying to set invalid name\n";
                    connection->publish("user#" + to_string(userData->user_id), "Name is invalid (contain :: or too long)");
                }
                else {
                    cout << "User set their name\n";
                    userData->name = parseName(message);
                }
            }

            if (isDirectCommand(message)) {
                string receiver = parseReceiverId(message);
                string text = parseDirectMessage(message);
                int id = stoi(receiver);

                const string selfChannel = "user#" + to_string(userData->user_id);

                if (id > last_user_id || id < 1) {
                    cout << "ERROR: User trying to send message to wrong id \n";

                    connection->publish(selfChannel, "Error, there is no user with ID = " + receiver);
                }
                else if (id == 1) {
                    cout << "User sent direct message to BOT\n";

                    connection->publish(selfChannel, botAnswer(text));
                }
                else {
                    cout << "User sent direct message\n";

                    connection->publish("user#" + receiver, text);
                }
            }
        },
        .close = [](auto*/*ws*/, int /*code*/, std::string_view /*message*/) {
            /* You may access ws->getUserData() here */
            cout << "Connection closed" << endl;
        }
        //.drain = [](auto*/*ws*/) {
        //    /* Check ws->getBufferedAmount() here */
        //},
        //.ping = [](auto*/*ws*/) {
        //    /* Not implemented yet */
        //},
        //.pong = [](auto*/*ws*/) {
        //    /* Not implemented yet */
        //},
    })
    .listen(9001, [](auto* listen_socket) {
        if (listen_socket) {
            cout << "Listening on port " << 9001 << endl;
        }
    })
    .run();
}