// This file is part of Timmi.
//
// Timmi is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

#include <string>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <poll.h>
#include <errno.h>
#include <unistd.h>
#include <tcpsocket.hh>
#include <utils.hh>

const int RECVBUF = 1024; // Amount of data to receive at one go
const int LINELENGTH = 4096; // Maximum line length

TCPSocket::TCPSocket(int fd, std::string addr):
    fd_(fd), addr_(addr), buf_(""), good_(true) {
}

TCPSocket::~TCPSocket() {
    shutdown(fd_, SHUT_RDWR);
    close(fd_);
}

int TCPSocket::getfd() const {
    return fd_;
}

std::string TCPSocket::getaddr() const {
    return addr_;
}

bool TCPSocket::good() const {
    return good_;
}

bool TCPSocket::wait_for_event(int timeout) const {
    pollfd fds[1] = {{fd_, POLLIN, 0}};
    int status = poll(fds, 1, timeout);
    
    if (status < 0) {
        debug_with_errno(WARNING, "Poll error");
    }
    
    return status != 0; // 0 == timeout
}

bool TCPSocket::getline(std::string &line) {
    int pos = buf_.find("\n");
    if (pos == std::string::npos) {
        receive_();
        pos = buf_.find("\n");
        if (pos == std::string::npos) {
            return false;
        }
    }
    
    line = buf_.substr(0, pos);
    buf_ = buf_.substr(pos + 1); // Skip \n
    return true;
}

void TCPSocket::putline(std::string line) {
    int status;
    line += "\n";
    status = send(fd_, line.c_str(), line.size(), MSG_NOSIGNAL);
    if (status != line.size()) {
        good_ = false;
        debug_with_errno(INFO, "Writing to socket");
    }
}

void TCPSocket::receive_() {
    if (!good()) {
        return;
    }

    char rawbuf[RECVBUF + 1] = {0};
    int status = 0;
    status = recv(fd_, rawbuf, RECVBUF, MSG_DONTWAIT | MSG_NOSIGNAL);
    
    if (status < 0 && errno == EAGAIN) {
        // Normal in non-blocking mode
        return;
    }
    
    if (status <= 0) {
        if (status != 0) {
            // 0 = Orderly shutdown connection
            debug_with_errno(INFO, "Socket read failed");
        }
        good_ = false;
        return;
    }
    
    buf_ += std::string(rawbuf);
    
    if (buf_.length() > LINELENGTH &&
        buf_.find('\n') == std::string::npos) {
        // Buffer grew too large
        // Disconnect to avoid denial of service attacks
        good_ = false;
    }
}