/*
NAME
  audio_test.go

AUTHOR
  Trek Hopton <trek@ausocean.org>

LICENSE
  This file 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 [GNU licenses](http://www.gnu.org/licenses).
*/

package audio

import (
	"bytes"
	"errors"
	"os"
	"testing"
	"time"

	"bitbucket.org/ausocean/av/codec/codecutil"
	"bitbucket.org/ausocean/utils/logger"
	"github.com/yobert/alsa"
)

// Check that a device exists with the given config parameters.
func checkDevice(ac *Config) error {
	cards, err := alsa.OpenCards()
	if err != nil {
		return errors.New("no audio cards found")
	}
	defer alsa.CloseCards(cards)
	var testDev *alsa.Device
	for _, card := range cards {
		devices, err := card.Devices()
		if err != nil {
			continue
		}
		for _, dev := range devices {
			if dev.Type != alsa.PCM || !dev.Record {
				continue
			}
			testDev = dev
			break
		}
	}
	if testDev == nil {
		return errors.New("no suitable device found")
	}
	err = testDev.Open()
	if err != nil {
		return err
	}
	_, err = testDev.NegotiateChannels(2)
	if err != nil {
		return err
	}
	foundRate := false
	for i := 0; i < len(Rates) && !foundRate; i++ {
		if Rates[i] < ac.SampleRate {
			continue
		}
		if Rates[i]%ac.SampleRate == 0 {
			_, err = testDev.NegotiateRate(Rates[i])
			if err == nil {
				foundRate = true
			}
		}
	}
	if !foundRate {
		_, err = testDev.NegotiateRate(defaultSampleRate)
		if err != nil {
			return err
		}
	}
	var aFmt alsa.FormatType
	switch ac.BitDepth {
	case 16:
		aFmt = alsa.S16_LE
	case 32:
		aFmt = alsa.S32_LE
	default:
		return errors.New("unsupported bitdepth")
	}
	_, err = testDev.NegotiateFormat(aFmt)
	if err != nil {
		return err
	}
	_, err = testDev.NegotiateBufferSize(8192, 16384)
	if err != nil {
		return err
	}
	if err = testDev.Prepare(); err != nil {
		return err
	}
	if testDev != nil {
		testDev.Close()
	}
	return nil
}

func TestDevice(t *testing.T) {
	// We want to open a device with a standard configuration.
	ac := &Config{
		SampleRate: 8000,
		Channels:   1,
		RecPeriod:  0.3,
		BitDepth:   16,
		Codec:      codecutil.ADPCM,
	}
	n := 2 // Number of periods to wait while recording.

	// Skip if there are no suitable devices to test with.
	err := checkDevice(ac)
	if err != nil {
		t.Skip(err)
	}

	// Create a new audio Device, start, read/lex, and then stop it.
	l := logger.New(logger.Debug, os.Stderr)
	ai, err := NewDevice(ac, l)
	if err != nil {
		t.Error(err)
	}
	dst := bytes.NewBuffer(make([]byte, 0))
	err = ai.Start()
	if err != nil {
		t.Error(err)
	}
	go codecutil.LexBytes(dst, ai, time.Duration(ac.RecPeriod*float64(time.Second)), ai.ChunkSize())
	time.Sleep(time.Duration(ac.RecPeriod*float64(time.Second)) * time.Duration(n))
	ai.Stop()
}

func TestNearestPowerOfTwo(t *testing.T) {
	testValues := []int{36, 47, 3, 46, 7, 2, 36, 757, 2464, 18980, 70000, 8192, 2048, 65536, -2048, -127, -1, 0, 1}
	testAnswers := []int{32, 32, 4, 32, 8, 2, 32, 512, 2048, 16384, 65536, 8192, 2048, 65536, 1, 1, 1, 1, 2}
	for i, v := range testValues {
		if r := nearestPowerOfTwo(v); testAnswers[i] != r {
			t.Errorf("test %v gave incorrect result: %v, should be %v", i, r, testAnswers[i])
		}
	}
}