#include "common/Email.h"

#include <drogon/drogon.h>

#include <array>
#include <cstring>
#include <string>

#include <netdb.h>
#include <sys/socket.h>
#include <unistd.h>

namespace visione::email
{
namespace
{
std::string configString(const std::string &key, const std::string &fallback)
{
    const auto &mail = drogon::app().getCustomConfig()["mail"];
    return mail.get(key, fallback).asString();
}

int configInt(const std::string &key, int fallback)
{
    const auto &mail = drogon::app().getCustomConfig()["mail"];
    return mail.get(key, fallback).asInt();
}

bool readResponse(int socket)
{
    std::array<char, 512> buffer{};
    const auto count = recv(socket, buffer.data(), buffer.size() - 1, 0);
    return count > 0 && buffer[0] >= '2' && buffer[0] <= '3';
}

bool sendLine(int socket, const std::string &line)
{
    const auto payload = line + "\r\n";
    return send(socket, payload.data(), payload.size(), 0) ==
           static_cast<ssize_t>(payload.size());
}

bool sendCommand(int socket, const std::string &line)
{
    return sendLine(socket, line) && readResponse(socket);
}
}  // namespace

bool EmailService::sendOtp(const std::string &to, const std::string &code) const
{
    const auto host = configString("smtp_host", "127.0.0.1");
    const auto port = std::to_string(configInt("smtp_port", 1025));
    const auto from = configString("from", "noreply@visione.local");

    addrinfo hints{};
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;

    addrinfo *addresses = nullptr;
    if (getaddrinfo(host.c_str(), port.c_str(), &hints, &addresses) != 0)
    {
        return false;
    }

    int smtp = -1;
    for (auto *address = addresses; address != nullptr; address = address->ai_next)
    {
        smtp = socket(address->ai_family, address->ai_socktype, address->ai_protocol);
        if (smtp < 0)
        {
            continue;
        }
        if (connect(smtp, address->ai_addr, address->ai_addrlen) == 0)
        {
            break;
        }
        close(smtp);
        smtp = -1;
    }
    freeaddrinfo(addresses);

    if (smtp < 0)
    {
        return false;
    }

    const auto closeSocket = [&smtp]() {
        if (smtp >= 0)
        {
            close(smtp);
            smtp = -1;
        }
    };

    if (!readResponse(smtp) || !sendCommand(smtp, "HELO visione.local") ||
        !sendCommand(smtp, "MAIL FROM:<" + from + ">") ||
        !sendCommand(smtp, "RCPT TO:<" + to + ">") ||
        !sendCommand(smtp, "DATA"))
    {
        closeSocket();
        return false;
    }

    const std::string body =
        "From: Visione <" + from + ">\r\n"
        "To: " + to + "\r\n"
        "Subject: Codice OTP Visione\r\n"
        "Content-Type: text/plain; charset=UTF-8\r\n"
        "\r\n"
        "Il tuo codice OTP per Visione e': " + code + "\r\n"
        "Scade tra 10 minuti.\r\n"
        ".";

    const auto ok = sendCommand(smtp, body) && sendCommand(smtp, "QUIT");
    closeSocket();
    return ok;
}
}  // namespace visione::email