package rabbitmq

import (
	"context"
	"reflect"
	"sync"
	"testing"
)

type fakeChannel struct {
	mu          sync.Mutex
	cancelCalls int
	closeCalls  int
	closed      bool
}

func (f *fakeChannel) Cancel(string, bool) error {
	f.mu.Lock()
	defer f.mu.Unlock()
	f.cancelCalls++
	return nil
}

func (f *fakeChannel) Close() error {
	f.mu.Lock()
	defer f.mu.Unlock()
	f.closeCalls++
	f.closed = true
	return nil
}

func (f *fakeChannel) IsClosed() bool {
	f.mu.Lock()
	defer f.mu.Unlock()
	return f.closed
}

func TestCloseIsIdempotent(t *testing.T) {
	resetRabbitMQState(t)

	channel := &fakeChannel{}
	done := make(chan struct{})
	close(done)
	registerConsumer(&managedConsumer{
		channel: channel,
		tag:     "test-consumer",
		done:    done,
	})

	if err := Close(context.Background()); err != nil {
		t.Fatalf("first Close() error = %v", err)
	}
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	if err := Close(ctx); err != nil {
		t.Fatalf("second Close() error = %v", err)
	}

	channel.mu.Lock()
	defer channel.mu.Unlock()
	if channel.cancelCalls != 1 {
		t.Fatalf("Cancel() calls = %d, want 1", channel.cancelCalls)
	}
	if channel.closeCalls != 1 {
		t.Fatalf("Close() calls = %d, want 1", channel.closeCalls)
	}
}

func TestCloseSkipsAlreadyClosedChannel(t *testing.T) {
	resetRabbitMQState(t)

	channel := &fakeChannel{closed: true}
	done := make(chan struct{})
	close(done)
	registerConsumer(&managedConsumer{
		channel: channel,
		tag:     "closed-consumer",
		done:    done,
	})

	if err := Close(context.Background()); err != nil {
		t.Fatalf("Close() error = %v", err)
	}

	channel.mu.Lock()
	defer channel.mu.Unlock()
	if channel.cancelCalls != 0 || channel.closeCalls != 0 {
		t.Fatalf("closed channel calls: Cancel=%d Close=%d, want 0", channel.cancelCalls, channel.closeCalls)
	}
}

func TestCloseHonorsContextWhileWaiting(t *testing.T) {
	resetRabbitMQState(t)

	channel := &fakeChannel{}
	registerConsumer(&managedConsumer{
		channel: channel,
		tag:     "blocked-consumer",
		done:    make(chan struct{}),
	})

	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	if err := Close(ctx); err == nil {
		t.Fatal("Close() error = nil, want context cancellation error")
	}

	channel.mu.Lock()
	defer channel.mu.Unlock()
	if channel.closeCalls != 1 {
		t.Fatalf("Close() calls = %d, want forced cleanup", channel.closeCalls)
	}
}

func TestDeliveryMetadataContext(t *testing.T) {
	expected := DeliveryMetadata{
		DeliveryTag: 42,
		Redelivered: true,
		Consumer:    "batch-consumer",
		Queue:       "iotlcm.batch.execute",
	}
	ctx := WithDeliveryMetadata(context.Background(), expected)
	actual, ok := DeliveryMetadataFromContext(ctx)
	if !ok {
		t.Fatal("delivery metadata not found in context")
	}
	if !reflect.DeepEqual(actual, expected) {
		t.Fatalf("delivery metadata = %+v, want %+v", actual, expected)
	}
	if _, ok = DeliveryMetadataFromContext(context.Background()); ok {
		t.Fatal("unexpected delivery metadata in empty context")
	}
}

func resetRabbitMQState(t *testing.T) {
	t.Helper()
	consumerMu.Lock()
	consumers = nil
	consumerMu.Unlock()
	connMu.Lock()
	conn = nil
	connMu.Unlock()
	t.Cleanup(func() {
		consumerMu.Lock()
		consumers = nil
		consumerMu.Unlock()
		connMu.Lock()
		conn = nil
		connMu.Unlock()
	})
}