#include "instance.hpp"
#include "config.hpp"
#include "uid.hpp"

#include <fmt/format.h>
#include <string>
#include <string_view>
#include <ctime>

using fmt::operator""_format;



inline std::string_view operator ""_sv(const char *str, unsigned long len) {
    return {str, static_cast<std::string_view::size_type>(len)};
}

static std::vector<std::string> strsplit(std::string_view s, char delimiter, std::vector<std::string>::size_type times = 0) {
    std::vector<std::string> to_return;
    decltype(s.size()) start = 0, finish = 0;
    while ((finish = s.find_first_of(delimiter, start)) != std::string_view::npos) {
        to_return.emplace_back(s.substr(start, finish - start));
        start = finish + 1;
        if (to_return.size() == times) { break; }
    }
    to_return.emplace_back(s.substr(start));
    return to_return;
}


void Event::parse(std::string_view str) {
    auto split = strsplit(str, ' ', 2);
    // Check split size
    if (split.size() < 2) {
        throw ParseError("In event parser: Events are expected to have both a sender and name");
    }
    // Move values
    split[0].erase(0, 1); // Erase leading ':'
    auto id_len = split[0].size();
    if (id_len == SUID_len) {
        sender = SUID(std::move(split[0]));
    } else if (id_len == UUID_len) {
        sender = UUID(std::move(split[0]));
    } else {
        sender = std::move(split[0]);
    }
    name = std::move(split[1]);
    if (split.size() == 3) {
        // Get args and text
        split = strsplit(std::move(split[2]), ':', 1);
        if (split.size() == 2) {
            text = std::move(split[1]);
        }
        if (!split.empty()) {
            args = std::move(split[0]);
        }
    }
}


void Command::parse(std::string_view str) {
    auto split = strsplit(str, ' ', 1);
    name = std::move(split[0]);
    // Get text from args
    split = strsplit(std::move(split[1]), ':', 1);
    if (split.size() == 2) {
        text = std::move(split[1]);
    }
    if (!split.empty()) {
        args = std::move(split[0]);
    }
}


void User::parse(Event event) {
    this->server = std::get<SUID>(event.sender.id);
    auto split = strsplit(event.args, ' ', 8);
    // Check size
    if (split.size() != 9) {
        throw ParseError("In euid parser: This euid event does not have enough arguments");
    }
    // Move values
    nick = std::move(split[0]);
    hops = std::stoull(std::move(split[1]));
    ts = std::stoull(std::move(split[2]));
    umode = std::move(split[3]);
    ident = std::move(split[4]);
    host = std::move(split[5]);
    realhost = std::move(split[6]);
    id = UUID(std::move(split[7]));
    // Get realname
    realname = std::move(event.text);
}


async::result<void> Instance::run() {
    // Create connection
    socket = new uvpp::tcp{s};
    co_await socket->connect(addr);
    socket->recv_start();

    // Login
    co_await login();

    // Mainloop
    while (true) {
        // Read
        auto data = co_await socket->recv();
        // Check for general error
        if (data->error()) {
            continue;
        }
        // Check for broken connection
        if (data->broken()) {
            break;
        }
        // Make string
        auto dataStr = std::string_view{
                data->data.get(),
                static_cast<std::string_view::size_type>(data->nread)
        };
        // Split by newlines
        for (auto& line : strsplit(dataStr, '\n')) {
            if (line.size() < 2) {
                continue; // Empty line
            }
            // Remove \r
            if (line.back() == '\r') {
                line.pop_back();
            }
            // Check if server sent an event or command, then parse and process it
            if (line[0] == ':') {
                Event event;
                event.parse(std::move(line));
                std::clog << event.dump() << std::flush;
                async::detach(process(std::move(event)));
            } else {
                Command command;
                command.parse(std::move(line));
                std::clog << command.dump() << std::flush;
                async::detach(process(std::move(command)));
            }
        }
    }
}

async::result<void> Instance::login() {
    co_await socket->send("PASS {} TS 6 :{}\n"_format(config.auth.send_password, config.server.uid.str()));
    co_await socket->send("CAPAB :QS EX IE KLN UNKLN ENCAP TB SERVICES EUID EOPMOD MLOCK\n"_sv);
    co_await socket->send("SERVER {} 1 :{}{}\n"_format(config.server.name, config.server.hidden ? "(H) " : "", config.server.description));
    co_await socket->send("SVINFO 6 3 0 :{}\n"_format(time(nullptr)));
}

async::result<void> Instance::burst() {
    // End burst
    co_await send_ping();
    client_bursting = false;
    std::cout << "I'm done bursting too. Ready." << std::endl;
}

async::result<void> Instance::process(const Command command) {
    if (command.name == "PASS") {
        // Check password
        {
            auto given_password = strsplit(command.args, ' ', 1)[0];
            if (given_password != config.auth.accept_password) {
                throw ConnectionError("Server supplied wrong password during authentication");
            }
            authed = true;
        }
        // Get server ID
        connected_server.uid = SUID(command.text);
    } if (!authed) {
        throw ConnectionError("Server tried to execute a command before authenticating");
    } else if (command.name == "SERVER") {
        // Get name and description of connected server
        connected_server.name = strsplit(command.args, ' ', 1)[0];
        connected_server.description = command.text;
    } else if (command.name == "PING") {
        // End of burst
        if (server_bursting) {
            server_bursting = false;
            std::cout << "Server burst is over. It's my turn." << std::endl;
            co_await burst();
        }
        // Reply
        co_await socket->send(":{} PONG {} {} :{}\n"_format(config.server.uid.str(), config.server.name, command.args, command.text));
    }
}

async::result<void> Instance::process(const Event event) {
    if (event.name == "NOTICE") {
        // Don't do anything special
    } else if (!authed) {
        throw ConnectionError("Server tried to send an event before authenticating");
    } else if (event.name == "EUID") {
        User user;
        user.parse(event);
        std::cout << "User registered: " << user.dump().dump() << std::flush;
        users[user.id.str()] = std::move(user);
    }
    co_return;
}

async::result<void> Instance::send_ping() {
    co_await socket->send("PING :{}\n"_format(connected_server.uid.str()));
}