package channelbridge

import (
	"context"
	"sync"
	"testing"
	"time"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/channel/adapter"
)

// deadSessionAdapter mimics a channel whose session dies while the bridge is
// running — today the iLink session rejection (errcode=-14): Connect
// reports success, the read loop then returns on its own (nothing cancelled it)
// and IsConnected reports false from that point on.
type deadSessionAdapter struct {
	name string
	mu   sync.Mutex
	up   bool
}

func (a *deadSessionAdapter) Name() string           { return a.name }
func (a *deadSessionAdapter) Config() map[string]any { return map[string]any{"bot_token": "tok"} }
func (a *deadSessionAdapter) Connect(context.Context) error {
	a.mu.Lock()
	a.up = true
	a.mu.Unlock()
	return nil
}
func (a *deadSessionAdapter) Disconnect(context.Context) error {
	a.mu.Lock()
	a.up = false
	a.mu.Unlock()
	return nil
}
func (a *deadSessionAdapter) IsConnected() bool {
	a.mu.Lock()
	defer a.mu.Unlock()
	return a.up
}
func (a *deadSessionAdapter) HealthCheck(context.Context) error { return adapter.ErrNotConnected }
func (a *deadSessionAdapter) ReadMessages(context.Context, func(adapter.UnifiedMessage)) {
	// The session died: the read loop ends by itself, no cancellation involved.
	a.mu.Lock()
	a.up = false
	a.mu.Unlock()
}
func (a *deadSessionAdapter) SendMessage(context.Context, adapter.UnifiedResponse) error {
	return adapter.ErrNotConnected
}
func (a *deadSessionAdapter) SendProactive(context.Context, adapter.UnifiedMessage) error {
	return adapter.ErrNotConnected
}
func (a *deadSessionAdapter) SetMessageHandler(adapter.MessageHandler) {}
func (a *deadSessionAdapter) Capabilities() adapter.Capabilities {
	return adapter.DefaultCapabilities()
}
func (a *deadSessionAdapter) ListChannels(context.Context) ([]adapter.ChannelInfo, error) {
	return nil, nil
}

// signaledAdapter is a fakeAdapter whose read loop reports when it has returned,
// so a test can wait for a replaced adapter's exit deterministically.
type signaledAdapter struct {
	*fakeAdapter
	exited chan struct{}
}

func (a *signaledAdapter) ReadMessages(ctx context.Context, _ func(adapter.UnifiedMessage)) {
	<-ctx.Done()
	close(a.exited)
}

// TestReadLoopExitClearsConnectedFlag is the regression for "the adapter goes mute
// while the bridge still claims it is connected": the read loop ends with the
// session down and nothing cancelled it, so IsConnected/ConnectedCount must stop
// reporting a live channel.
func TestReadLoopExitClearsConnectedFlag(t *testing.T) {
	t.Parallel()
	b := newReloadBridge(t, nil)
	ad := &deadSessionAdapter{name: "weixin-ilink"}
	b.Add(ad)
	b.Start()

	waitDeadline := time.Now().Add(2 * time.Second)
	for time.Now().Before(waitDeadline) {
		if !b.IsConnected("weixin-ilink") {
			if n := b.ConnectedCount(); n != 0 {
				t.Fatalf("ConnectedCount() = %d, want 0 after the only read loop died", n)
			}
			return
		}
		time.Sleep(time.Millisecond)
	}
	t.Fatal("bridge still reports weixin-ilink as connected after its read loop ended")
}

// TestReplacedAdapterExitKeepsReplacementConnected guards the other direction: the
// read-loop exit accounting must not undo a replacement installed by a hot reload.
// The replaced adapter's loop is cancelled by Reload (a deliberate stop), so its
// exit says nothing about the adapter that now owns the name.
func TestReplacedAdapterExitKeepsReplacementConnected(t *testing.T) {
	t.Parallel()
	old := &signaledAdapter{
		fakeAdapter: &fakeAdapter{name: "kook:conf0", cfg: map[string]any{"bot_token": "old"}},
		exited:      make(chan struct{}),
	}
	factory := &stubFactory{adpts: []adapter.PlatformAdapter{
		&fakeAdapter{name: "kook:conf0", cfg: map[string]any{"bot_token": "new"}},
	}}
	b := newReloadBridge(t, factory)
	b.Add(old)
	b.Start()

	if err := b.Reload("kook"); err != nil {
		t.Fatalf("Reload: %v", err)
	}
	<-old.exited
	// The exit accounting runs immediately after the read path returns; a short
	// settle window catches it without relying on a specific interleaving.
	settle := time.Now().Add(50 * time.Millisecond)
	for time.Now().Before(settle) {
		if !b.IsConnected("kook:conf0") {
			t.Fatal("the replaced adapter's read-loop exit cleared the replacement's connected flag")
		}
		time.Sleep(time.Millisecond)
	}
}