/*
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"
	"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 _, op := range []func([]byte) ([]byte, error){nil, Payload} {
		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, op, (*dummyLogger)(t).log, 1*time.Millisecond)
			if err != nil {
				testErr <- fmt.Errorf("could not create client, failed with error: %v\n", err)
			}
			c.Start()
			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: %v\n", err)
				}

				// Create expected data and apply operation if there is one.
				expect := (&Pkt{V: rtpVer, Payload: []byte{byte(packetsReceived)}}).Bytes(nil)
				if op != nil {
					expect, err = op(expect)
					if err != nil {
						testErr <- fmt.Errorf("unexpected error when applying op: %v\n", err)
					}
				}

				// 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++
			}
			c.Stop()
			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: %v\n", err)
			}

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

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