package notify

import (
	"b612.me/stario"
	"context"
	"io"
	"math"
	"net"
	"sync/atomic"
	"testing"
	"time"
)

func TestClientWriteToTransportUsesRuntimeConn(t *testing.T) {
	client := NewClient().(*ClientCommon)
	fallbackLeft, fallbackRight := net.Pipe()
	defer fallbackLeft.Close()
	defer fallbackRight.Close()
	runtimeLeft, runtimeRight := net.Pipe()
	defer runtimeLeft.Close()
	defer runtimeRight.Close()

	client.conn = fallbackLeft
	runtimeCtx, runtimeCancel := context.WithCancel(context.Background())
	defer runtimeCancel()
	client.setClientSessionRuntime(&clientSessionRuntime{
		conn:    runtimeLeft,
		stopCtx: runtimeCtx,
		stopFn:  runtimeCancel,
		epoch:   1,
	})

	payload := []byte("runtime-conn")
	recvCh := make(chan []byte, 1)
	errCh := make(chan error, 1)
	go func() {
		buf := make([]byte, len(payload))
		_, err := io.ReadFull(runtimeRight, buf)
		if err != nil {
			errCh <- err
			return
		}
		recvCh <- buf
	}()

	if err := client.writeToTransport(payload); err != nil {
		t.Fatalf("writeToTransport failed: %v", err)
	}

	select {
	case err := <-errCh:
		t.Fatalf("runtime conn read failed: %v", err)
	case got := <-recvCh:
		if string(got) != string(payload) {
			t.Fatalf("runtime payload mismatch: got %q want %q", string(got), string(payload))
		}
	case <-time.After(time.Second):
		t.Fatal("runtime conn did not receive payload")
	}

	_ = fallbackRight.SetReadDeadline(time.Now().Add(20 * time.Millisecond))
	buf := make([]byte, 1)
	if _, err := fallbackRight.Read(buf); err == nil {
		t.Fatal("fallback conn should not receive payload when runtime conn is active")
	}
}

func TestClientMarkSessionStoppedUsesRuntimeStopFn(t *testing.T) {
	client := NewClient().(*ClientCommon)
	if !client.beginClientSessionStart() {
		t.Fatal("beginClientSessionStart should succeed")
	}
	client.markSessionStarted()

	runtimeCtx, runtimeCancel := context.WithCancel(context.Background())
	defer runtimeCancel()
	client.setClientSessionRuntime(&clientSessionRuntime{
		stopCtx: runtimeCtx,
		stopFn:  runtimeCancel,
		epoch:   1,
	})

	fallbackCtx, fallbackCancel := context.WithCancel(context.Background())
	defer fallbackCancel()
	client.stopCtx = fallbackCtx
	client.stopFn = fallbackCancel

	client.markSessionStopped("runtime stop", nil)

	select {
	case <-runtimeCtx.Done():
	case <-time.After(time.Second):
		t.Fatal("runtime stop context should be canceled by markSessionStopped")
	}
	select {
	case <-fallbackCtx.Done():
		t.Fatal("fallback owner stop context should not be canceled when runtime stopFn is active")
	default:
	}
	rt := client.clientSessionRuntimeSnapshot()
	if rt == nil {
		t.Fatal("runtime snapshot should remain available after stop")
	}
	if rt.conn != nil || rt.queue != nil {
		t.Fatalf("runtime transport should be cleared after stop: %+v", rt)
	}
	if rt.stopCtx == nil {
		t.Fatalf("runtime stop context should be preserved after stop: %+v", rt)
	}
}

func TestClientClearSessionRuntimeTransportPreservesStopState(t *testing.T) {
	client := NewClient().(*ClientCommon)
	left, right := net.Pipe()
	defer left.Close()
	defer right.Close()

	stopCtx, stopFn := context.WithCancel(context.Background())
	defer stopFn()
	queue := stario.NewQueueCtx(stopCtx, 4, math.MaxUint32)
	client.setClientSessionRuntime(&clientSessionRuntime{
		conn:    left,
		stopCtx: stopCtx,
		stopFn:  stopFn,
		queue:   queue,
		epoch:   7,
	})

	client.clearClientSessionRuntimeTransport()

	rt := client.clientSessionRuntimeSnapshot()
	if rt == nil {
		t.Fatal("runtime snapshot should remain after transport clear")
	}
	if rt.conn != nil {
		t.Fatalf("runtime conn should be cleared: %+v", rt)
	}
	if rt.queue != queue {
		t.Fatalf("runtime queue should be preserved across pure transport clear: got %v want %v", rt.queue, queue)
	}
	if rt.stopCtx != stopCtx || rt.stopFn == nil || rt.epoch != 7 {
		t.Fatalf("runtime control state should be preserved: %+v", rt)
	}
	if client.clientTransportAttachedSnapshot() {
		t.Fatal("client transport should be marked detached after runtime clear")
	}
	if got := client.clientQueueSnapshot(); got != queue {
		t.Fatalf("client queue snapshot should be preserved after transport clear: got %v want %v", got, queue)
	}
}

func TestClientTransportBindingSnapshotUsesRuntimeBinding(t *testing.T) {
	client := NewClient().(*ClientCommon)
	left, right := net.Pipe()
	defer left.Close()
	defer right.Close()

	stopCtx, stopFn := context.WithCancel(context.Background())
	defer stopFn()
	queue := stario.NewQueueCtx(stopCtx, 4, math.MaxUint32)
	client.setClientSessionRuntime(&clientSessionRuntime{
		transport: newTransportBinding(left, queue),
		conn:      left,
		stopCtx:   stopCtx,
		stopFn:    stopFn,
		queue:     queue,
		epoch:     9,
	})

	binding := client.clientTransportBindingSnapshot()
	if binding == nil {
		t.Fatal("runtime transport binding should exist")
	}
	if got := binding.connSnapshot(); got != left {
		t.Fatal("runtime transport binding conn should match runtime conn")
	}
	if got := binding.queueSnapshot(); got != queue {
		t.Fatal("runtime transport binding queue should match runtime queue")
	}
}

func TestRetireClientSessionRuntimeCancelsTransportOnly(t *testing.T) {
	client := NewClient().(*ClientCommon)
	stopCtx, stopFn := context.WithCancel(context.Background())
	defer stopFn()
	queue := stario.NewQueueCtx(stopCtx, 4, math.MaxUint32)
	left, right := net.Pipe()
	defer left.Close()
	defer right.Close()

	rt := newClientSessionRuntime(left, stopCtx, stopFn, queue, 3)
	client.setClientSessionRuntime(rt)
	client.retireClientSessionRuntime(rt, true)

	transportStopCtx := client.clientTransportStopContextSnapshot()
	if transportStopCtx == nil {
		t.Fatal("transport stop context should exist")
	}
	select {
	case <-transportStopCtx.Done():
	case <-time.After(time.Second):
		t.Fatal("transport stop context should be canceled by retireClientSessionRuntime")
	}
	select {
	case <-client.clientStopContextSnapshot().Done():
		t.Fatal("logical stop context should remain active when only retiring transport")
	default:
	}
}

func TestClientClearSessionRuntimeTransportPreservesQueueForEncoding(t *testing.T) {
	client := NewClient().(*ClientCommon)
	UseLegacySecurityClient(client)

	left, right := net.Pipe()
	defer left.Close()
	defer right.Close()

	stopCtx, stopFn := context.WithCancel(context.Background())
	defer stopFn()
	queue := stario.NewQueueCtx(stopCtx, 4, math.MaxUint32)
	client.setClientSessionRuntime(&clientSessionRuntime{
		conn:    left,
		stopCtx: stopCtx,
		stopFn:  stopFn,
		queue:   queue,
		epoch:   8,
	})
	client.markSessionStarted()
	defer client.markSessionStopped("test done", nil)

	client.clearClientSessionRuntimeTransport()

	data, err := client.encodeEnvelope(newSignalAckEnvelope(1003))
	if err != nil {
		t.Fatalf("encodeEnvelope failed after pure transport clear: %v", err)
	}
	if len(data) == 0 {
		t.Fatal("encodeEnvelope should still return framed payload after pure transport clear")
	}
}

func TestAttachClientSessionTransportRebindsRuntimeAndDispatchesOnNewConn(t *testing.T) {
	client := NewClient().(*ClientCommon)
	UseLegacySecurityClient(client)

	stopCtx, stopFn := context.WithCancel(context.Background())
	defer stopFn()
	queue := stario.NewQueueCtx(stopCtx, 4, math.MaxUint32)
	oldLeft, oldRight := net.Pipe()
	defer oldRight.Close()
	client.setClientSessionRuntime(&clientSessionRuntime{
		conn:                  oldLeft,
		stopCtx:               stopCtx,
		stopFn:                stopFn,
		queue:                 queue,
		epoch:                 11,
		suppressGoodByeOnStop: &atomic.Bool{},
	})
	client.markSessionStarted()
	defer client.markSessionStopped("test done", nil)

	recvCh := make(chan Message, 1)
	client.SetLink("reattach", func(message *Message) {
		recvCh <- *message
	})

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

	rt := client.clientSessionRuntimeSnapshot()
	if rt == nil {
		t.Fatal("runtime snapshot should exist after attach")
	}
	if rt.conn != newLeft || !rt.transportAttached || rt.queue != queue || rt.epoch != 11 {
		t.Fatalf("attached runtime mismatch: %+v", rt)
	}

	env, err := wrapTransferMsgEnvelope(TransferMsg{
		ID:    42,
		Key:   "reattach",
		Value: []byte("ok"),
		Type:  MSG_ASYNC,
	}, client.sequenceEn)
	if err != nil {
		t.Fatalf("wrapTransferMsgEnvelope failed: %v", err)
	}
	wire, err := client.encodeEnvelope(env)
	if err != nil {
		t.Fatalf("encodeEnvelope failed: %v", err)
	}
	if _, err := newRight.Write(wire); err != nil {
		t.Fatalf("new transport write failed: %v", err)
	}

	select {
	case message := <-recvCh:
		if got, want := message.Key, "reattach"; got != want {
			t.Fatalf("message key mismatch: got %q want %q", got, want)
		}
		if got, want := string(message.Value), "ok"; got != want {
			t.Fatalf("message value mismatch: got %q want %q", got, want)
		}
	case <-time.After(time.Second):
		t.Fatal("reattached transport did not dispatch message")
	}
}

func TestSetClientSessionRuntimeStopsOldBindingWorkersOnReattach(t *testing.T) {
	client := NewClient().(*ClientCommon)

	stopCtx, stopFn := context.WithCancel(context.Background())
	defer stopFn()
	queue := stario.NewQueueCtx(stopCtx, 4, math.MaxUint32)

	oldLeft, oldRight := net.Pipe()
	defer oldLeft.Close()
	defer oldRight.Close()
	oldBinding := newTransportBinding(oldLeft, queue)
	oldSender := oldBinding.bulkBatchSenderSnapshot()

	client.setClientSessionRuntime(&clientSessionRuntime{
		transport: oldBinding,
		conn:      oldLeft,
		stopCtx:   stopCtx,
		stopFn:    stopFn,
		queue:     queue,
		epoch:     1,
	})

	newLeft, newRight := net.Pipe()
	defer newLeft.Close()
	defer newRight.Close()
	newBinding := newTransportBinding(newLeft, queue)

	client.setClientSessionRuntime(&clientSessionRuntime{
		transport: newBinding,
		conn:      newLeft,
		stopCtx:   stopCtx,
		stopFn:    stopFn,
		queue:     queue,
		epoch:     2,
	})

	err := oldSender.submit(context.Background(), []byte("payload"))
	if err != errTransportDetached {
		t.Fatalf("old sender submit after reattach = %v, want %v", err, errTransportDetached)
	}
}