package notify

import (
	"b612.me/stario"
	"context"
	"errors"
	netpkg "net"
	"sync/atomic"
	"testing"
	"time"
)

type gatedDedicatedReadConn struct {
	netpkg.Conn
	total   int
	read    int
	reached chan struct{}
	release chan struct{}
	closed  bool
}

func (c *gatedDedicatedReadConn) Read(p []byte) (int, error) {
	n, err := c.Conn.Read(p)
	c.read += n
	if !c.closed && c.read >= c.total {
		c.closed = true
		close(c.reached)
		<-c.release
	}
	return n, err
}

func TestControlMessageErrorPreservesTransportDetachedSentinel(t *testing.T) {
	for name, decode := range map[string]func(string) error{
		"bulk":   bulkControlMessageError,
		"stream": streamControlMessageError,
	} {
		t.Run(name, func(t *testing.T) {
			err := decode("transport detached: stale transport generation=7")
			if !errors.Is(err, errTransportDetached) {
				t.Fatalf("decoded error = %v, want transport detached sentinel", err)
			}
		})
	}
}

func TestSendDedicatedBulkAttachRequestRejectsNilDialResult(t *testing.T) {
	client := &ClientCommon{}
	bulk := newBulkHandle(context.Background(), newBulkRuntime("cblk"), clientFileScope(), BulkOpenRequest{
		BulkID: "nil-dial",
	}, 0, nil, nil, 0, nil, nil, nil, nil, nil)
	if _, err := client.sendDedicatedBulkAttachRequest(context.Background(), nil, bulk); !errors.Is(err, errTransportDetached) {
		t.Fatalf("nil dial result error = %v, want transport detached", err)
	}
}

func TestDedicatedSidecarCloseWaitsForAttachment(t *testing.T) {
	left, right := netpkg.Pipe()
	defer left.Close()
	defer right.Close()
	sidecar := newBulkDedicatedSidecar(left, 1)
	entered := make(chan struct{})
	release := make(chan struct{})
	attachDone := make(chan error, 1)
	go func() {
		attachDone <- sidecar.withConn(func(conn netpkg.Conn) error {
			close(entered)
			<-release
			return nil
		})
	}()
	select {
	case <-entered:
	case <-time.After(time.Second):
		t.Fatal("sidecar attachment did not start")
	}
	closeDone := make(chan struct{})
	go func() {
		sidecar.close()
		close(closeDone)
	}()
	select {
	case <-closeDone:
		t.Fatal("sidecar closed while attachment still held")
	case <-time.After(25 * time.Millisecond):
	}
	close(release)
	if err := <-attachDone; err != nil {
		t.Fatalf("sidecar attachment error = %v", err)
	}
	select {
	case <-closeDone:
	case <-time.After(time.Second):
		t.Fatal("sidecar close did not finish after attachment release")
	}
}

func TestBulkAcceptDispatchRejectsResetBeforeHandler(t *testing.T) {
	bulk := newBulkHandle(context.Background(), newBulkRuntime("sblk"), serverFileDomain+":test", BulkOpenRequest{
		BulkID: "stale-dispatch",
	}, 0, nil, nil, 0, nil, nil, nil, nil, nil)
	bulk.markReset(errTransportDetached)
	var calls atomic.Int32
	err := dispatchBulkAccept(func(BulkAcceptInfo) error {
		calls.Add(1)
		return nil
	}, bulk, BulkAcceptInfo{Bulk: bulk})
	if !errors.Is(err, errTransportDetached) {
		t.Fatalf("stale dispatch error = %v, want transport detached", err)
	}
	if got := calls.Load(); got != 0 {
		t.Fatalf("stale dispatch handler calls = %d, want 0", got)
	}
}

func TestClientDedicatedSidecarDropsFrameAfterTransportReattach(t *testing.T) {
	client := NewClient().(*ClientCommon)
	UseLegacySecurityClient(client)
	stopCtx, stopFn := context.WithCancel(context.Background())
	defer stopFn()
	queue := stario.NewQueueCtx(stopCtx, 4, ^uint32(0))
	oldLeft, oldRight := netpkg.Pipe()
	defer oldRight.Close()
	epoch := client.beginClientSessionEpoch()
	client.setClientSessionRuntime(newClientSessionRuntime(oldLeft, stopCtx, stopFn, queue, epoch))
	client.markSessionStarted()
	defer client.markSessionStopped("test done", nil)
	oldRoute := client.clientSessionRouteSnapshot()

	sidecarLeft, sidecarRight := netpkg.Pipe()
	defer sidecarRight.Close()
	payload, err := client.encodeDedicatedBulkBatchPayload(101, []bulkDedicatedSendRequest{{
		Type:    bulkFastPayloadTypeData,
		Seq:     1,
		Payload: []byte("stale"),
	}})
	if err != nil {
		t.Fatalf("encode stale sidecar payload: %v", err)
	}
	frameRead := make(chan struct{})
	releaseFrame := make(chan struct{})
	readConn := &gatedDedicatedReadConn{
		Conn:    sidecarLeft,
		total:   bulkDedicatedRecordHeaderLen + len(payload),
		reached: frameRead,
		release: releaseFrame,
	}
	sidecar := newBulkDedicatedSidecar(readConn, 1)
	loopDone := make(chan struct{})
	go func() {
		client.readDedicatedSidecarLoopAtRoute(sidecar, oldRoute)
		close(loopDone)
	}()

	writeDone := make(chan error, 1)
	go func() { writeDone <- writeBulkDedicatedRecord(sidecarRight, payload) }()
	select {
	case <-frameRead:
	case <-time.After(time.Second):
		t.Fatal("sidecar loop did not read the complete frame")
	}

	newLeft, newRight := netpkg.Pipe()
	defer newRight.Close()
	if err := client.attachClientSessionTransport(newLeft); err != nil {
		t.Fatalf("attach replacement client transport: %v", err)
	}

	runtime := client.getBulkRuntime()
	bulk := newBulkHandle(stopCtx, runtime, clientFileScope(), BulkOpenRequest{
		BulkID: "stale-sidecar-frame",
		DataID: 101,
		Range:  BulkRange{Length: 32},
	}, oldRoute.epoch, nil, nil, 0, nil, nil, nil, nil, nil)
	bulk.setClientSnapshotOwner(client)
	bulk.setClientSessionRoute(oldRoute)
	if err := runtime.registerInbound(clientFileScope(), bulk); err != nil {
		t.Fatalf("register stale-route bulk: %v", err)
	}
	defer bulk.markReset(errors.New("test cleanup"))

	close(releaseFrame)
	if err := <-writeDone; err != nil {
		t.Fatalf("write stale sidecar payload: %v", err)
	}
	select {
	case <-loopDone:
	case <-time.After(time.Second):
		t.Fatal("stale-route sidecar loop did not stop after reattach")
	}

	bulk.mu.Lock()
	defer bulk.mu.Unlock()
	if len(bulk.readQueue) != 0 || len(bulk.readBuf.data) != 0 || bulk.resetErr != nil {
		t.Fatalf("stale sidecar frame mutated bulk: queued=%d buffered=%d reset=%v", len(bulk.readQueue), len(bulk.readBuf.data), bulk.resetErr)
	}
}