server_main.cpp

//
// Created by ilya on 12.05.18.
//

#include "dict_socket.h"
#include "utils.h"
#include "fill_db.h"
#include <stdexcept>
#include <vector>
#include <iostream>
#include <signal.h>
#include <algorithm>
#include <sstream>
#include <map>

using std::string;
using std::vector;
using std::cout;
using std::cin;
using std::cerr;
using std::pair;
using std::endl;
using std::map;

// dicts: dictionary name -> dictionary
// dictionary: word -> word
map<string, map<string, string>> dicts;

dict_socket listener{};
bool need_to_terminate = false;

void sigint_handler(int signum)
{
    cout << "SIGINT catched, exiting...";
    listener.close();
    need_to_terminate = true;
}

string get_connection_message()
{
    return "220 connected successfully\r\n";
}

void process_show_db(dict_socket &socket)
{
    if (dicts.empty())
    {
        socket.send("554 No databases present\r\n");
        return;
    }
    string res = "110 ";
    res += (std::to_string(dicts.size()) + string(" databases present -"));
    for (auto const& p: dicts)
    {
        res += " " + p.first + ",";
    }
    res.pop_back();
    res += "\r\n";
    socket.send(res);
}

void process_show_info(dict_socket& socket, string const& name)
{
    if (dicts.count(name) == 0)
    {
        socket.send("550 Invalid database, use \"SHOW DB\" for list of databases\r\n");
        return;
    }
    string res = "112 name: " + name + ", size: " +
                 std::to_string(dicts[name].size()) + "\r\n";
    socket.send(res);
}

void process_define_request(dict_socket& socket, vector<string>& parts)
{
    string database = parts[1];
    string word = parts[2];
    if (database != "*" && database != "!")
    {
        if (dicts.count(database) == 0)
        {
            socket.send("550 Invalid database, use \"SHOW DB\" for list of databases\r\n");
            return;
        }
        map<string, string> cur_dict = dicts[database];
        if (cur_dict.count(word) == 0)
        {
            socket.send("552 No match\r\n");
            return;
        }
        socket.send("150 1 definitions retrieved - definitions follow\r\n");
        socket.send("151 " + cur_dict[word] + " " + database + "\r\n");
        socket.send("250 ok\r\n");
        return;
    }
    if (database == "!")
    {
        vector <pair<string, string>> answers;
        for (auto const& dict: dicts)
        {
            if (dict.second.count(word) > 0)
            {
                answers.emplace_back(dict.second.at(word), dict.first);
            }
        }
        if (answers.empty())
        {
            socket.send("552 No match\r\n");
            return;
        }
        socket.send("150 " +
                    std::to_string(answers.size()) +
                    " definitions retrieved - definitions follow\r\n");
        for (auto const& answer: answers)
        {
            socket.send("151 "  + answer.first + " " + answer.second + "\r\n");
        }
        socket.send("250 ok\r\n");
        return;
    }
    if (database == "*")
    {
        for (auto const& dict: dicts)
        {
            if (dict.second.count(word) > 0)
            {
                socket.send("150 1 definitions retrieved - definitions follow\r\n");
                socket.send("151 " + dict.second.at(word) + " " + dict.first + "\r\n");
                socket.send("250 ok\r\n");
                return;
            }
        }
        socket.send("552 No match\r\n");
        return;
    }
}

bool process_request(dict_socket& socket, string const& request, bool first)
{

    cout << "Request received: " + request << endl;
    vector<string> parts = parse_querry(request);
    for (size_t i = 0; i < parts.size(); ++i)
    {
        cout << "Part № " << i << " - " << parts[i] << endl;
    }
    if (first)
    {
        if (!parts.empty() && parts[0] == "client")
        {
            cout << "CLIENT request: " << endl;
            socket.send("250 ok client information received\r\n");
            return false;
        }
        else
        {
            socket.send("500 Error, CLIENT request should be first\r\n");
            return true;
        }
    }


    if (parts.size() == 2 && parts[0] == "show" &&
            (parts[1] == "db" || parts[1] == "databases"))
    {
        cout << "SHOW DB request: " << endl;
        process_show_db(socket);
    }
    else if (parts.size() == 2 && parts[0] == "show" &&
             (parts[1] == "strat" || parts[1] == "strategies"))
    {
        cout << "SHOW STRAT request: " << endl;
        socket.send("555 No strategies available\r\n");
    }
    else if (parts.size() == 2 && parts[0] == "show" &&
             parts[1] == "server")
    {
        cout << "SHOW SERVER request: " << endl;
        socket.send("114 my dictionary server for OS Course\r\n");
    }
    else if (parts.size() == 3 && parts[0] == "show" &&
             parts[1] == "info")
    {
        cout << "SHOW INFO request: " << endl;
        process_show_info(socket, parts[2]);
    }
    else if (parts.size() == 4 && parts[0] == "match")
    {
        cout << "MATCH request: " << endl;
        socket.send("551 Invalid strategy, use \"SHOW STRAT\" for a list of strategies\r\n");
    }
    else if (parts.size() == 1 && parts[0] == "status")
    {
        cout << "STATUS request: " << endl;
        socket.send("210 server working properly\r\n");
    }
    else if (parts.size() == 1 && parts[0] == "help")
    {
        cout << "HELP request: " << endl;
        socket.send("113 read https://tools.ietf.org/html/rfc2229 for help\r\n");
    }
    else if (parts.size() == 1 && parts[0] == "quit")
    {
        cout << "QUIT request: " << endl;
        socket.send("221 Closing Connection\r\n");
        return true;
    }
    else if (!parts.empty() && parts[0] == "client")
    {
        cout << "CLIENT request: " << endl;
        socket.send("250 ok client information received\r\n");
    }
    else if (parts.size() == 3 && parts[0] == "define")
    {
        cout << "DEFINE request: " << endl;
        process_define_request(socket, parts);
    }
    else
    {
        socket.send("502 Command not implemented\r\n");
    }
    return false;

}

int main(int argc, char* argv[])
{
    fill_databases(dicts);

    cout << "Dictionary initialization finished: " << endl;
    for (const auto& dict: dicts)
    {
        cout << "Dictionary: " << dict.first << endl;
        for (const auto& p: dict.second)
        {
            cout << p.first << " - " << p.second << endl;
        }
        cout << "Dictionary finished" << endl;
    }

    try
    {
        listener.create();
        signal(SIGINT, &sigint_handler);
        listener.bind();
        listener.listen();

        while (!need_to_terminate)
        {
            dict_socket socket = listener.accept();

            socket.send(get_connection_message());

            read_result res {"", "", false};
            string request;
            string rem;

            bool first = true;

            do
            {
                //cout << "Reading" << endl;
                res = read_until_crlf(socket, rem);
                request = res.querry;
                rem = res.remainder;

                std::replace(request.begin(), request.end(), '\t', ' ');
                std::transform(request.begin(), request.end(), request.begin(), ::tolower);
                if(process_request(socket, request, first))
                {
                    break;
                }
                first = false;
            } while (!res.empty_input);

        }


    }
    catch (std::runtime_error& e)
    {
        cout << e.what();
        return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;
}