/*
NAME
  client_test.go

DESCRIPTION
  client_test.go provides testing utilities to check RTP client functionality
  provided in client.go.

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 (
	"bytes"
	"fmt"
	"io"
	"net"
	"testing"
)

// TestReceive checks that the Client can correctly receive RTP packets and
// perform a specificed operation on the packets before storing in the ringBuffer.
func TestReceive(t *testing.T) {
	const (
		clientAddr    = "localhost:8000"
		packetsToSend = 20
	)

	testErr := make(chan error)
	serverErr := make(chan error)
	done := make(chan struct{})
	clientReady := make(chan struct{})
	var c *Client

	// Start routine to read from client.
	go func() {
		// Create and start the client.
		var err error
		c, err = NewClient(clientAddr)
		if err != nil {
			testErr <- fmt.Errorf("could not create client, failed with error: %w\n", err)
		}
		close(clientReady)

		// Read packets using the client and check them with expected.
		var packetsReceived int
		buf := make([]byte, 4096)
		for packetsReceived != packetsToSend {
			n, err := c.Read(buf)
			switch err {
			case nil:
			case io.EOF:
				continue
			default:
				testErr <- fmt.Errorf("unexpected error from c.Read: %w\n", err)
			}

			// Create expected data and apply operation if there is one.
			expect := (&Packet{Version: rtpVer, Payload: []byte{byte(packetsReceived)}}).Bytes(nil)

			// Compare.
			got := buf[:n]
			if !bytes.Equal(got, expect) {
				testErr <- fmt.Errorf("did not get expected result. \nGot: %v\n Want: %v\n", got, expect)
			}
			packetsReceived++
		}
		close(done)
	}()

	// Start the RTP server.
	go func() {
		<-clientReady
		cAddr, err := net.ResolveUDPAddr("udp", clientAddr)
		if err != nil {
			serverErr <- fmt.Errorf("could not resolve server address, failed with err: %w\n", err)
		}

		conn, err := net.DialUDP("udp", nil, cAddr)
		if err != nil {
			serverErr <- fmt.Errorf("could not dial udp, failed with err: %w\n", err)
		}

		// Send packets to the client.
		for i := 0; i < packetsToSend; i++ {
			p := (&Packet{Version: rtpVer, Payload: []byte{byte(i)}}).Bytes(nil)
			_, err := conn.Write(p)
			if err != nil {
				serverErr <- fmt.Errorf("could not write packet to conn, failed with err: %w\n", err)
			}
		}
	}()

	<-clientReady
loop:
	for {
		select {
		case err := <-testErr:
			t.Fatal(err)
		case err := <-serverErr:
			t.Fatal(err)
		case <-done:
			break loop
		default:
		}
	}
}