//go:build mxl_integration

package mxlfabrics_test

import (
	"errors"
	"sync"
	"testing"
	"time"

	"github.com/qvest-digital/go-mxl/fabrics"
	"github.com/qvest-digital/go-mxl/mxl"
)

const testAudioFlowID = "b3bb5be7-9fe9-4324-a5bb-4c70e1084449"

const testAudioFlow = `{
  "description": "MXL Player Fabrics SHM audio integration test",
  "id": "b3bb5be7-9fe9-4324-a5bb-4c70e1084449",
  "format": "urn:x-nmos:format:audio",
  "label": "Fabrics SHM test audio",
  "tags": {
    "urn:x-nmos:tag:grouphint/v1.0": [
      "mxl-player-fabrics-test:Audio"
    ]
  },
  "parents": [],
  "media_type": "audio/float32",
  "sample_rate": {
    "numerator": 48000
  },
  "channel_count": 2,
  "bit_depth": 32
}`

type sampleCompletion struct {
	head  uint64
	count int
}

func TestSampleTransferSHM(t *testing.T) {
	sourceInstance := newTestDomain(t)
	targetInstance := newTestDomain(t)

	sourceWriter, _, err := sourceInstance.NewWriter(testAudioFlow)
	if err != nil {
		t.Fatalf("create source writer: %v", err)
	}
	t.Cleanup(func() {
		if err := sourceWriter.Close(); err != nil {
			t.Errorf("close source writer: %v", err)
		}
	})

	sourceReader, err := sourceInstance.NewReader(testAudioFlowID)
	if err != nil {
		t.Fatalf("create source reader: %v", err)
	}
	t.Cleanup(func() {
		if err := sourceReader.Close(); err != nil {
			t.Errorf("close source reader: %v", err)
		}
	})

	targetWriter, _, err := targetInstance.NewWriter(testAudioFlow)
	if err != nil {
		t.Fatalf("create target writer: %v", err)
	}
	t.Cleanup(func() {
		if err := targetWriter.Close(); err != nil {
			t.Errorf("close target writer: %v", err)
		}
	})

	sourceFabrics, err := fabrics.NewInstance(sourceInstance)
	if err != nil {
		t.Fatalf("create source Fabrics instance: %v", err)
	}
	t.Cleanup(func() {
		if err := sourceFabrics.Close(); err != nil {
			t.Errorf("close source Fabrics instance: %v", err)
		}
	})

	targetFabrics, err := fabrics.NewInstance(targetInstance)
	if err != nil {
		t.Fatalf("create target Fabrics instance: %v", err)
	}
	t.Cleanup(func() {
		if err := targetFabrics.Close(); err != nil {
			t.Errorf("close target Fabrics instance: %v", err)
		}
	})

	target, err := targetFabrics.NewTarget()
	if err != nil {
		t.Fatalf("create target: %v", err)
	}
	t.Cleanup(func() {
		if err := target.Close(); err != nil {
			t.Errorf("close target: %v", err)
		}
	})

	targetInfo, err := target.Setup(fabrics.TargetConfig{
		Interface: requireSHMInterface(t, targetFabrics),
		Writer:    targetWriter,
	})
	if err != nil {
		t.Fatalf("set up target: %v", err)
	}
	t.Cleanup(func() {
		if err := targetInfo.Close(); err != nil {
			t.Errorf("close target info: %v", err)
		}
	})

	initiator, err := sourceFabrics.NewInitiator()
	if err != nil {
		t.Fatalf("create initiator: %v", err)
	}
	t.Cleanup(func() {
		if err := initiator.Close(); err != nil {
			t.Errorf("close initiator: %v", err)
		}
	})

	if err := initiator.Setup(fabrics.InitiatorConfig{
		Interface: requireSHMInterface(t, sourceFabrics),
		Reader:    sourceReader,
	}); err != nil {
		t.Fatalf("set up initiator: %v", err)
	}

	if err := initiator.AddTarget(targetInfo); err != nil {
		t.Fatalf("add target: %v", err)
	}

	connectDeadline := time.Now().Add(5 * time.Second)
	for {
		if time.Now().After(connectDeadline) {
			t.Fatal("SHM initiator did not become ready")
		}

		_, _, err := target.ReadSamplesNonBlocking()
		if err != nil && !errors.Is(err, fabrics.ErrNotReady) {
			t.Fatalf("progress target during setup: %v", err)
		}

		err = initiator.MakeProgressNonBlocking()
		if err == nil {
			break
		}
		if !errors.Is(err, fabrics.ErrNotReady) {
			t.Fatalf("progress initiator during setup: %v", err)
		}

		time.Sleep(time.Millisecond)
	}

	const sampleCount = 480
	head := mxl.CurrentIndex(sourceWriter.Config().Common.GrainRate)

	sourceSamples, err := sourceWriter.OpenSamples(head, sampleCount)
	if err != nil {
		t.Fatalf("open source samples: %v", err)
	}
	for channel := uint64(0); channel < sourceSamples.ChannelCount; channel++ {
		first, second, err := sourceSamples.ChannelFragments(channel)
		if err != nil {
			t.Fatalf("get source channel %d fragments: %v", channel, err)
		}
		var position uint64
		for _, fragment := range [][]byte{first, second} {
			for offset := range fragment {
				fragment[offset] = byte((position + head + channel) & 0xff)
				position++
			}
		}
	}
	if err := sourceSamples.Commit(); err != nil {
		t.Fatalf("commit source samples: %v", err)
	}

	deadline := time.Now().Add(5 * time.Second)
	received := make(chan sampleCompletion, 1)
	targetErrors := make(chan error, 1)
	stopTarget := make(chan struct{})
	var targetWG sync.WaitGroup

	targetWG.Add(1)
	go func() {
		defer targetWG.Done()
		for {
			select {
			case <-stopTarget:
				return
			default:
			}

			receivedHead, receivedCount, err := target.ReadSamplesNonBlocking()
			switch {
			case err == nil:
				received <- sampleCompletion{head: receivedHead, count: receivedCount}
				return
			case errors.Is(err, fabrics.ErrNotReady):
				time.Sleep(time.Millisecond)
			default:
				targetErrors <- err
				return
			}
		}
	}()
	defer func() {
		close(stopTarget)
		targetWG.Wait()
	}()

	for {
		err := initiator.TransferSamples(head, sampleCount)
		if err == nil {
			break
		}
		if !errors.Is(err, fabrics.ErrNotReady) {
			t.Fatalf("transfer samples: %v", err)
		}
		if time.Now().After(deadline) {
			t.Fatal("timed out enqueueing SHM sample transfer")
		}

		err = initiator.MakeProgressNonBlocking()
		if err != nil && !errors.Is(err, fabrics.ErrNotReady) {
			t.Fatalf("make initiator progress while enqueueing: %v", err)
		}
		time.Sleep(time.Millisecond)
	}

	var completion sampleCompletion
	for {
		if time.Now().After(deadline) {
			t.Fatal("SHM sample transfer timed out")
		}

		err := initiator.MakeProgressNonBlocking()
		if err != nil && !errors.Is(err, fabrics.ErrNotReady) {
			t.Fatalf("make initiator progress: %v", err)
		}

		select {
		case completion = <-received:
			goto receivedSamples
		case err := <-targetErrors:
			t.Fatalf("read target completion: %v", err)
		default:
			time.Sleep(time.Millisecond)
		}
	}

receivedSamples:
	if completion.head != head {
		t.Fatalf("received sample head = %d, want %d", completion.head, head)
	}
	if completion.count != sampleCount {
		t.Fatalf("received sample count = %d, want %d", completion.count, sampleCount)
	}

	targetSamples, err := targetWriter.OpenSamples(head, sampleCount)
	if err != nil {
		t.Fatalf("open transferred samples: %v", err)
	}
	defer func() {
		if err := targetSamples.Cancel(); err != nil {
			t.Errorf("cancel transferred samples: %v", err)
		}
	}()

	for channel := uint64(0); channel < targetSamples.ChannelCount; channel++ {
		first, second, err := targetSamples.ChannelFragments(channel)
		if err != nil {
			t.Fatalf("get target channel %d fragments: %v", channel, err)
		}
		var position uint64
		for _, fragment := range [][]byte{first, second} {
			for _, got := range fragment {
				want := byte((position + head + channel) & 0xff)
				if got != want {
					t.Fatalf("channel %d sample byte %d = %d, want %d", channel, position, got, want)
				}
				position++
			}
		}
	}
}