package notify

import (
	"context"
	"errors"
	"net"
	"testing"
	"time"
)

func TestBulkDedicatedBatchPlainRoundTrip(t *testing.T) {
	releasePayload, err := encodeBulkDedicatedReleasePayload(4096, 2)
	if err != nil {
		t.Fatalf("encodeBulkDedicatedReleasePayload failed: %v", err)
	}
	items := []bulkDedicatedSendRequest{
		{
			Type:    bulkFastPayloadTypeData,
			Seq:     7,
			Payload: []byte("hello"),
		},
		{
			Type:  bulkFastPayloadTypeClose,
			Flags: bulkFastPayloadFlagFullClose,
		},
		{
			Type:    bulkFastPayloadTypeReset,
			Payload: []byte("boom"),
		},
		{
			Type:    bulkFastPayloadTypeRelease,
			Payload: releasePayload,
		},
	}

	plain, err := encodeBulkDedicatedBatchPlain(42, items)
	if err != nil {
		t.Fatalf("encodeBulkDedicatedBatchPlain failed: %v", err)
	}

	dataID, decoded, matched, err := decodeBulkDedicatedBatchPlain(plain)
	if err != nil {
		t.Fatalf("decodeBulkDedicatedBatchPlain failed: %v", err)
	}
	if !matched {
		t.Fatal("decodeBulkDedicatedBatchPlain should match dedicated batch")
	}
	if dataID != 42 {
		t.Fatalf("decoded data id = %d, want 42", dataID)
	}
	if len(decoded) != len(items) {
		t.Fatalf("decoded item count = %d, want %d", len(decoded), len(items))
	}

	for i := range items {
		if decoded[i].Type != items[i].Type {
			t.Fatalf("item %d type = %d, want %d", i, decoded[i].Type, items[i].Type)
		}
		if decoded[i].Flags != items[i].Flags {
			t.Fatalf("item %d flags = %d, want %d", i, decoded[i].Flags, items[i].Flags)
		}
		if decoded[i].Seq != items[i].Seq {
			t.Fatalf("item %d seq = %d, want %d", i, decoded[i].Seq, items[i].Seq)
		}
		if got, want := string(decoded[i].Payload), string(items[i].Payload); got != want {
			t.Fatalf("item %d payload = %q, want %q", i, got, want)
		}
	}
}

func TestBulkOpenRoundTripDedicatedMultiWriteTCP(t *testing.T) {
	server := NewServer().(*ServerCommon)
	if err := UseModernPSKServer(server, integrationSharedSecret, integrationModernPSKOptions()); err != nil {
		t.Fatalf("UseModernPSKServer failed: %v", err)
	}

	acceptCh := make(chan BulkAcceptInfo, 1)
	server.SetBulkHandler(func(info BulkAcceptInfo) error {
		acceptCh <- info
		return nil
	})

	if err := server.Listen("tcp", "127.0.0.1:0"); err != nil {
		t.Fatalf("server Listen failed: %v", err)
	}
	defer func() {
		_ = server.Stop()
	}()

	client := NewClient().(*ClientCommon)
	if err := UseModernPSKClient(client, integrationSharedSecret, integrationModernPSKOptions()); err != nil {
		t.Fatalf("UseModernPSKClient failed: %v", err)
	}
	if err := client.Connect("tcp", server.listener.Addr().String()); err != nil {
		t.Fatalf("client Connect failed: %v", err)
	}
	defer func() {
		_ = client.Stop()
	}()

	bulk, err := client.OpenBulk(context.Background(), BulkOpenOptions{
		Range: BulkRange{
			Offset: 0,
			Length: 1024,
		},
		Dedicated: true,
		ChunkSize: 4,
	})
	if err != nil {
		t.Fatalf("client OpenBulk dedicated failed: %v", err)
	}

	accepted := waitAcceptedBulk(t, acceptCh, 2*time.Second)

	clientParts := []string{"aa", "bb", "cc", "dd", "ee", "ff"}
	for _, part := range clientParts {
		if _, err := bulk.Write([]byte(part)); err != nil {
			t.Fatalf("client dedicated bulk Write(%q) failed: %v", part, err)
		}
	}
	readBulkExactly(t, accepted.Bulk, "aabbccddeeff", 2*time.Second)

	serverParts := []string{"11", "22", "33", "44", "55", "66"}
	for _, part := range serverParts {
		if _, err := accepted.Bulk.Write([]byte(part)); err != nil {
			t.Fatalf("server dedicated bulk Write(%q) failed: %v", part, err)
		}
	}
	readBulkExactly(t, bulk, "112233445566", 2*time.Second)

	if err := bulk.CloseWrite(); err != nil {
		t.Fatalf("client dedicated bulk CloseWrite failed: %v", err)
	}
	waitForBulkReadEOF(t, accepted.Bulk, 2*time.Second)

	if err := accepted.Bulk.Close(); err != nil {
		t.Fatalf("server dedicated bulk Close failed: %v", err)
	}
	waitForBulkReadEOF(t, bulk, 2*time.Second)
	waitForBulkContextDone(t, bulk.Context(), 2*time.Second)
}

func TestBulkDedicatedSenderRespectsWriteDeadlineWhenReceiverStalls(t *testing.T) {
	left, right := net.Pipe()
	defer left.Close()
	defer right.Close()

	sender := newBulkDedicatedSender(left, 1, func(plain []byte) ([]byte, error) {
		return plain, nil
	}, nil, nil)
	defer sender.stop()

	ctx, cancel := context.WithTimeout(context.Background(), 50*time.Millisecond)
	defer cancel()

	errCh := make(chan error, 1)
	go func() {
		errCh <- sender.submitControl(ctx, bulkFastPayloadTypeClose, 0, 0, nil)
	}()

	select {
	case err := <-errCh:
		if err == nil {
			t.Fatal("sender.submitControl should fail when receiver stalls")
		}
		if !isTimeoutLikeError(err) {
			t.Fatalf("sender.submitControl error = %v, want timeout-like error", err)
		}
	case <-time.After(time.Second):
		t.Fatal("sender.submitControl should not hang when receiver stalls")
	}
}

func TestBulkDedicatedSenderSubmitWriteDirectPathRespectsWriteDeadlineWhenReceiverStalls(t *testing.T) {
	left, right := net.Pipe()
	defer left.Close()
	defer right.Close()

	sender := newBulkDedicatedSender(left, 1, func(plain []byte) ([]byte, error) {
		return plain, nil
	}, nil, nil)
	defer sender.stop()

	ctx, cancel := context.WithTimeout(context.Background(), 50*time.Millisecond)
	defer cancel()

	payload := make([]byte, 256*1024)
	errCh := make(chan error, 1)
	go func() {
		_, err := sender.submitWrite(ctx, 1, payload, len(payload))
		errCh <- err
	}()

	select {
	case err := <-errCh:
		if err == nil {
			t.Fatal("sender.submitWrite should fail when receiver stalls")
		}
		if !isTimeoutLikeError(err) {
			t.Fatalf("sender.submitWrite error = %v, want timeout-like error", err)
		}
	case <-time.After(time.Second):
		t.Fatal("sender.submitWrite should not hang when receiver stalls")
	}
}

func TestBulkDedicatedSenderSkipsQueuedCanceledRequest(t *testing.T) {
	conn := newBlockingPacketWriteConn()
	sender := newBulkDedicatedSender(conn, 1, func(plain []byte) ([]byte, error) {
		return plain, nil
	}, nil, nil)
	defer sender.stop()

	firstErrCh := make(chan error, 1)
	go func() {
		firstErrCh <- sender.submitControl(context.Background(), bulkFastPayloadTypeClose, 0, 1, nil)
	}()

	select {
	case <-conn.startCh:
	case <-time.After(time.Second):
		t.Fatal("first dedicated bulk write did not start")
	}

	ctx, cancel := context.WithCancel(context.Background())
	secondErrCh := make(chan error, 1)
	go func() {
		secondErrCh <- sender.submitControl(ctx, bulkFastPayloadTypeReset, 0, 2, nil)
	}()
	time.Sleep(20 * time.Millisecond)
	cancel()

	select {
	case err := <-secondErrCh:
		if !errors.Is(err, context.Canceled) {
			t.Fatalf("second dedicated bulk submit error = %v, want %v", err, context.Canceled)
		}
	case <-time.After(time.Second):
		t.Fatal("second dedicated bulk submit did not return after cancel")
	}

	close(conn.unblockCh)

	select {
	case err := <-firstErrCh:
		if err != nil {
			t.Fatalf("first dedicated bulk submit failed: %v", err)
		}
	case <-time.After(time.Second):
		t.Fatal("first dedicated bulk submit did not finish")
	}

	time.Sleep(50 * time.Millisecond)
	if got, want := conn.writeCount.Load(), int32(2); got != want {
		t.Fatalf("dedicated bulk write count = %d, want %d", got, want)
	}
}

func TestBulkDedicatedSenderReturnsFlushResultAfterStartedContextCancel(t *testing.T) {
	conn := newBlockingPacketWriteConn()
	sender := newBulkDedicatedSender(conn, 1, func(plain []byte) ([]byte, error) {
		return plain, nil
	}, nil, nil)
	defer sender.stop()

	ctx, cancel := context.WithCancel(context.Background())
	errCh := make(chan error, 1)
	go func() {
		errCh <- sender.submitControl(ctx, bulkFastPayloadTypeClose, 0, 1, nil)
	}()

	select {
	case <-conn.startCh:
	case <-time.After(time.Second):
		t.Fatal("dedicated bulk write did not start")
	}

	cancel()

	select {
	case err := <-errCh:
		t.Fatalf("sender.submitControl returned before flush completed: %v", err)
	case <-time.After(50 * time.Millisecond):
	}

	close(conn.unblockCh)

	select {
	case err := <-errCh:
		if err != nil {
			t.Fatalf("sender.submitControl failed after started flush: %v", err)
		}
	case <-time.After(time.Second):
		t.Fatal("sender.submitControl did not return after started flush completed")
	}
}