/*
NAME
  client.go

DESCRIPTION
  client.go provides an RTP client.

AUTHOR
  Saxon A. Nelson-Milton <saxon@ausocean.org>

LICENSE
  This is Copyright (C) 2019 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
  in gpl.txt.  If not, see http://www.gnu.org/licenses.
*/

package rtp

import (
	"net"
)

// Client describes an RTP client that can receive an RTP stream and implements
// io.Reader.
type Client struct {
	r *PacketReader
}

// NewClient returns a pointer to a new Client.
//
// addr is the address of form <ip>:<port> that we expect to receive
// RTP at.
func NewClient(addr string) (*Client, error) {
	c := &Client{r: &PacketReader{}}

	a, err := net.ResolveUDPAddr("udp", addr)
	if err != nil {
		return nil, err
	}

	c.r.PacketConn, err = net.ListenUDP("udp", a)
	if err != nil {
		return nil, err
	}

	return c, nil
}

// Read implements io.Reader.
func (c *Client) Read(p []byte) (int, error) {
	return c.r.Read(p)
}

// PacketReader provides an io.Reader interface to an underlying UDP PacketConn.
type PacketReader struct {
	net.PacketConn
}

// Read implements io.Reader.
func (r PacketReader) Read(b []byte) (int, error) {
	n, _, err := r.PacketConn.ReadFrom(b)
	return n, err
}