/*
NAME
  rtmp.go

DESCRIPTION
  See Readme.md

AUTHORS
  Saxon Nelson-Milton <saxon@ausocean.org>
  Dan Kortschak <dan@ausocean.org>

LICENSE
  rtmp.go is Copyright (C) 2017 the Australian Ocean Lab (AusOcean)

  It is free software: you can redistribute it and/or modify them
  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.

  It is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  for more details.

  You should have received a copy of the GNU General Public License
  along with revid in gpl.txt. If not, see http://www.gnu.org/licenses.

  Derived from librtmp under the GNU Lesser General Public License 2.1
  Copyright (C) 2005-2008 Team XBMC http://www.xbmc.org
  Copyright (C) 2008-2009 Andrej Stepanchuk
  Copyright (C) 2009-2010 Howard Chu
*/

package rtmp

/*
#include <stdlib.h>
#include <unistd.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <netdb.h>

typedef struct sockaddr_in sockaddr_in;
typedef struct sockaddr sockaddr;
*/
import "C"

import (
	"log"
	"syscall"
	"unsafe"

	"github.com/chamaken/cgolmnl/inet"
)

func bAddr(buf []byte) *byte {
	if len(buf) == 0 {
		return nil
	}
	return &buf[0]
}

// int add_addr_info(struct sockaddr_in *service, AVal *host, int port)
// rtmp.c +869
func C_add_addr_info(service *C.sockaddr_in, hostname string, port uint16) (ok bool) {
	h := C.CString(hostname)
	defer C.free(unsafe.Pointer(h))
	service.sin_addr.s_addr = C.inet_addr(h)
	if service.sin_addr.s_addr == C.INADDR_NONE {
		host := C.gethostbyname(h)
		if host == nil || *host.h_addr_list == nil {
			//RTMP_Log(RTMP_LOGERROR, "Problem accessing the DNS. (addr: %s)", hostname)
			return false
		}
		service.sin_addr = *(*C.struct_in_addr)(unsafe.Pointer(*host.h_addr_list))
	}

	service.sin_port = C.ushort(inet.Htons(port))
	return true
}

// int RTMP_Connect0(RTMP *r, struct sockaddr* service);
// rtmp.c +906
func C_RTMP_Connect0(r *C_RTMP, service *C.sockaddr) (ok bool) {
	r.m_sb.sb_timedout = false
	r.m_pausing = 0
	r.m_fDuration = 0

	r.m_sb.sb_socket = int32(C.socket(C.AF_INET, C.SOCK_STREAM, C.IPPROTO_TCP))

	if r.m_sb.sb_socket != -1 {
		if C.connect(C.int(r.m_sb.sb_socket), service, C.socklen_t(unsafe.Sizeof(*service))) < 0 {
			log.Println("C_RTMP_Connect0, failed to connect socket.")
		}

		if r.Link.socksport != 0 {
			if debugMode {
				log.Println("C_RTMP_Connect0: socks negotiation.")
			}

			if !C_SocksNegotiate(r) {
				log.Println("C_RTMP_Connect0: SOCKS negotiation failed.")
				return false
			}
		}
	} else {
		log.Println("C_RTMP_Connect0: failed to create socket.")
		return false
	}

	{
		var tv int32
		SET_RCVTIMEO(&tv, r.Link.timeout)

		if C.setsockopt(C.int(r.m_sb.sb_socket), C.SOL_SOCKET, C.SO_RCVTIMEO,
			unsafe.Pointer(&tv), C.socklen_t(unsafe.Sizeof(tv))) != 0 {
			log.Println("C_RTMP_Connect0: Setting socket timeout failed")
		}
	}

	on := C.int(1)
	C.setsockopt(C.int(r.m_sb.sb_socket), C.IPPROTO_TCP, C.TCP_NODELAY,
		unsafe.Pointer(&on), C.socklen_t(unsafe.Sizeof(on)))

	return true
}

// int RTMP_Connect(RTMP *r, RTMPPacket* cp);
// rtmp.c +1032
func C_RTMP_Connect(r *C_RTMP, cp *C_RTMPPacket) (ok bool) {
	// TODO: port this
	var service C.sockaddr_in

	if r.Link.hostname == "" {
		return false
	}

	// TODO: port this
	service.sin_family = C.AF_INET

	if r.Link.socksport != 0 {
		if !C_add_addr_info(&service, r.Link.sockshost, r.Link.socksport) {
			return false
		}
	} else {
		// connect directly
		if !C_add_addr_info(&service, r.Link.hostname, r.Link.port) {
			return false
		}
	}
	if !C_RTMP_Connect0(r, (*C.sockaddr)(unsafe.Pointer(&service))) {
		return false
	}

	r.m_bSendCounter = true

	return C_RTMP_Connect1(r, cp)
}

// int SocksNegotiate(RTMP* r);
// rtmp.c +1062
func C_SocksNegotiate(r *C_RTMP) (ok bool) {
	var addr int32
	var service C.sockaddr_in

	C_add_addr_info(&service, r.Link.hostname, r.Link.port)
	addr = int32(inet.Htonl(uint32(service.sin_addr.s_addr)))

	packet := []byte{
		4, 1,
		byte((r.Link.port >> 8) & 0xFF),
		byte((r.Link.port) & 0xFF),
		byte(addr>>24) & 0xFF, byte(addr>>16) & 0xFF,
		byte(addr>>8) & 0xFF, byte(addr) & 0xFF,
		0,
	}

	C_WriteN(r, packet)

	if C_ReadN(r, packet[:8]) != 8 {
		return false
	}

	if packet[0] == 0 && packet[1] == 90 {
		return true
	}
	// TODO: use new logger here
	log.Println("C_SocksNegotitate: SOCKS returned error code!")
	return false
}

// int RTMPSockBuf_Fill(RTMPSockBuf* sb);
// rtmp.c +4253
func C_RTMPSockBuf_Fill(sb *C_RTMPSockBuf) int {
	if sb.sb_size == 0 {
		sb.sb_start = 0
	}

	nBytes := C.ssize_t((len(sb.sb_buf) - 1) - (sb.sb_size + sb.sb_start))
	nBytes, err := C.recv(C.int(sb.sb_socket), unsafe.Pointer(&sb.sb_buf[sb.sb_start+sb.sb_size]), C.size_t(nBytes), 0)
	if nBytes == -1 {
		log.Printf("C_RTMPSockBuf_Fill: recv error: %v", err)
		if err == syscall.EWOULDBLOCK || err == syscall.EAGAIN {
			sb.sb_timedout = true
			nBytes = 0
		}
	} else {
		sb.sb_size += int(nBytes)
	}

	return int(nBytes)
}

// int RTMPSockBuf_Send(RTMPSockBuf* sb, const char* buf, int len);
// rtmp.c +4297
// TODO replace send with golang net connection send
func C_RTMPSockBuf_Send(sb *C_RTMPSockBuf, buf []byte) int32 {
	return int32(C.send(C.int(sb.sb_socket), unsafe.Pointer(bAddr(buf)), C.size_t(len(buf)), 0))
}

// int
// RTMPSockBuf_Close(RTMPSockBuf *sb)
// rtmp.c +4369
func C_RTMPSockBuf_Close(sb *C_RTMPSockBuf) int32 {
	if sb.sb_socket != -1 {
		return int32(C.close(C.int(sb.sb_socket)))
	}
	return 0
}