/*
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"
	"io"
	"net"
	"testing"
	"time"

	"bitbucket.org/ausocean/utils/logger"
)

// dummyLogger will allow logging to be done by the testing pkg.
type dummyLogger testing.T

func (dl *dummyLogger) log(lvl int8, msg string, args ...interface{}) {
	var l string
	switch lvl {
	case logger.Warning:
		l = "warning"
	case logger.Debug:
		l = "debug"
	case logger.Info:
		l = "info"
	case logger.Error:
		l = "error"
	case logger.Fatal:
		l = "fatal"
	}
	msg = l + ": " + msg
	for i := 0; i < len(args); i++ {
		msg += " %v"
	}
	if len(args) == 0 {
		dl.Log(msg + "\n")
		return
	}
	dl.Logf(msg+"\n", args...)
}

// 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
	)

	for i, op := range []func([]byte) ([]byte, error){nil, Payload} {
		t.Logf("running op: %v", i)
		// Create new client and give current operation we are testing.
		c, err := NewClient(clientAddr, op, (*dummyLogger)(t).log, 1*time.Millisecond)
		if err != nil {
			t.Fatalf("could not create client, failed with error: %v", err)
		}
		c.Start()

		// Log any errors from client.
		go func() {
			for {
				err := <-c.Err()
				t.Logf("unexpected error from client: %v", err)
			}
		}()

		// Start the RTP 'server'.
		go func() {
			cAddr, err := net.ResolveUDPAddr("udp", clientAddr)
			if err != nil {
				t.Fatalf("could not resolve server address, failed with err: %v", err)
			}

			conn, err := net.DialUDP("udp", nil, cAddr)
			if err != nil {
				t.Fatalf("could not dial udp, failed with err: %v", err)
			}

			// Send packets to the client.
			for i := 0; i < packetsToSend; i++ {
				p := (&Pkt{V: rtpVer, Payload: []byte{byte(i)}}).Bytes(nil)
				_, err := conn.Write(p)
				if err != nil {
					t.Errorf("could not write packet to conn, failed with err: %v", err)
				}
			}
		}()

		// Read packets using the client and check them with expected.
		var packetsReceived int
		buf := make([]byte, 4096)
		for {
			if packetsReceived == packetsToSend {
				break
			}

			n, err := c.Read(buf)
			switch err {
			case nil:
			case io.EOF:
				continue
			default:
				t.Fatalf("unexpected error: %v", err)
			}

			expect := (&Pkt{V: rtpVer, Payload: []byte{byte(packetsReceived)}}).Bytes(nil)
			if op != nil {
				expect, err = op(expect)
				if err != nil {
					t.Fatalf("unexpected error when applying op: %v", err)
				}
			}

			got := buf[:n]
			if !bytes.Equal(got, expect) {
				t.Errorf("did not get expected result. \nGot: %v\n Want: %v\n", got, expect)
			}
			packetsReceived++
		}
		c.Stop()
	}
}