package dataext

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

func TestNewPubSub(t *testing.T) {
	ps := NewPubSub[string, string](10)
	if ps == nil {
		t.Fatal("NewPubSub returned nil")
	}
	if ps.masterLock == nil {
		t.Fatal("masterLock is nil")
	}
	if ps.subscriptions == nil {
		t.Fatal("subscriptions is nil")
	}
}

func TestPubSub_Namespaces(t *testing.T) {
	ps := NewPubSub[string, string](10)

	// Initially no namespaces
	namespaces := ps.Namespaces()
	if len(namespaces) != 0 {
		t.Fatalf("Expected 0 namespaces, got %d", len(namespaces))
	}

	// Add a subscription to create a namespace
	_, sub1 := ps.SubscribeByChan("test-ns1", 1)
	defer sub1.Unsubscribe()

	// Add another subscription to a different namespace
	_, sub2 := ps.SubscribeByChan("test-ns2", 1)
	defer sub2.Unsubscribe()

	// Check namespaces
	namespaces = ps.Namespaces()
	if len(namespaces) != 2 {
		t.Fatalf("Expected 2 namespaces, got %d", len(namespaces))
	}

	// Check if namespaces contain the expected values
	found1, found2 := false, false
	for _, ns := range namespaces {
		if ns == "test-ns1" {
			found1 = true
		}
		if ns == "test-ns2" {
			found2 = true
		}
	}

	if !found1 || !found2 {
		t.Fatalf("Expected to find both namespaces, found ns1: %v, ns2: %v", found1, found2)
	}
}

func TestPubSub_SubscribeByCallback(t *testing.T) {
	ps := NewPubSub[string, string](10)

	var received string
	var wg sync.WaitGroup
	wg.Add(1)

	callback := func(msg string) {
		received = msg
		wg.Done()
	}

	sub := ps.SubscribeByCallback("test-ns", callback)
	defer sub.Unsubscribe()

	// Publish a message
	subs, receivers := ps.Publish("test-ns", "hello")

	if subs != 1 {
		t.Fatalf("Expected 1 subscriber, got %d", subs)
	}

	if receivers != 1 {
		t.Fatalf("Expected 1 receiver, got %d", receivers)
	}

	// Wait for the callback to be executed
	wg.Wait()

	if received != "hello" {
		t.Fatalf("Expected to receive 'hello', got '%s'", received)
	}
}

func TestPubSub_SubscribeByChan(t *testing.T) {
	ps := NewPubSub[string, string](10)

	ch, sub := ps.SubscribeByChan("test-ns", 1)
	defer sub.Unsubscribe()

	// Publish a message
	subs, receivers := ps.Publish("test-ns", "hello")

	if subs != 1 {
		t.Fatalf("Expected 1 subscriber, got %d", subs)
	}

	if receivers != 1 {
		t.Fatalf("Expected 1 receiver, got %d", receivers)
	}

	// Read from the channel with a timeout to avoid blocking
	select {
	case msg := <-ch:
		if msg != "hello" {
			t.Fatalf("Expected to receive 'hello', got '%s'", msg)
		}
	case <-time.After(time.Second):
		t.Fatal("Timed out waiting for message")
	}
}

func TestPubSub_SubscribeByIter(t *testing.T) {
	ps := NewPubSub[string, string](10)

	iterSeq, sub := ps.SubscribeByIter("test-ns", 1)
	defer sub.Unsubscribe()

	// Channel to communicate when message is received
	done := make(chan bool)
	received := false

	// Start a goroutine to use the iterator
	go func() {
		for msg := range iterSeq {
			if msg == "hello" {
				received = true
				done <- true
				return // Stop iteration
			}
		}
	}()

	// Give time for the iterator to start
	time.Sleep(100 * time.Millisecond)

	// Publish a message
	ps.Publish("test-ns", "hello")

	// Wait for the message to be received or timeout
	select {
	case <-done:
		if !received {
			t.Fatal("Message was received but not 'hello'")
		}
	case <-time.After(time.Second):
		t.Fatal("Timed out waiting for message")
	}

	subCount := ps.SubscriberCount("test-ns")
	if subCount != 0 {
		t.Fatalf("Expected 0 receivers, got %d", subCount)
	}
}

func TestPubSub_Publish(t *testing.T) {
	ps := NewPubSub[string, string](10)

	// Test publishing to a namespace with no subscribers
	subs, receivers := ps.Publish("empty-ns", "hello")
	if subs != 0 {
		t.Fatalf("Expected 0 subscribers, got %d", subs)
	}
	if receivers != 0 {
		t.Fatalf("Expected 0 receivers, got %d", receivers)
	}

	// Add a subscriber
	ch, sub := ps.SubscribeByChan("test-ns", 1)
	defer sub.Unsubscribe()

	// Publish a message
	subs, receivers = ps.Publish("test-ns", "hello")
	if subs != 1 {
		t.Fatalf("Expected 1 subscriber, got %d", subs)
	}
	if receivers != 1 {
		t.Fatalf("Expected 1 receiver, got %d", receivers)
	}

	// Verify the message was received
	select {
	case msg := <-ch:
		if msg != "hello" {
			t.Fatalf("Expected to receive 'hello', got '%s'", msg)
		}
	case <-time.After(time.Second):
		t.Fatal("Timed out waiting for message")
	}

	// Test non-blocking behavior with a full channel
	// First fill the channel
	ps.Publish("test-ns", "fill")

	// Now publish again - this should not block but skip the receiver
	subs, receivers = ps.Publish("test-ns", "overflow")
	if subs != 1 {
		t.Fatalf("Expected 1 subscriber, got %d", subs)
	}
	// The receiver count might be 0 if the channel is full

	// Drain the channel
	<-ch
}

func TestPubSub_PublishWithTimeout(t *testing.T) {
	ps := NewPubSub[string, string](10)

	// Add a subscriber with a channel
	ch, sub := ps.SubscribeByChan("test-ns", 1)
	defer sub.Unsubscribe()

	// Publish with a timeout
	subs, receivers := ps.PublishWithTimeout("test-ns", "hello", 100*time.Millisecond)
	if subs != 1 {
		t.Fatalf("Expected 1 subscriber, got %d", subs)
	}
	if receivers != 1 {
		t.Fatalf("Expected 1 receiver, got %d", receivers)
	}

	// Verify the message was received
	select {
	case msg := <-ch:
		if msg != "hello" {
			t.Fatalf("Expected to receive 'hello', got '%s'", msg)
		}
	case <-time.After(time.Second):
		t.Fatal("Timed out waiting for message")
	}

	// Fill the channel
	ps.Publish("test-ns", "fill")

	// Test timeout behavior with a full channel
	start := time.Now()
	subs, receivers = ps.PublishWithTimeout("test-ns", "timeout-test", 50*time.Millisecond)
	elapsed := time.Since(start)

	if subs != 1 {
		t.Fatalf("Expected 1 subscriber, got %d", subs)
	}

	// The receiver count should be 0 if the timeout occurred
	if elapsed < 50*time.Millisecond {
		t.Fatalf("Expected to wait at least 50ms, only waited %v", elapsed)
	}

	// Drain the channel
	<-ch
}

func TestPubSub_PublishWithContext(t *testing.T) {
	ps := NewPubSub[string, string](10)

	// Add a subscriber with a channel
	ch, sub := ps.SubscribeByChan("test-ns", 1)
	defer sub.Unsubscribe()

	// Create a context
	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
	defer cancel()

	// Publish with context
	subs, receivers, err := ps.PublishWithContext(ctx, "test-ns", "hello")
	if err != nil {
		t.Fatalf("Unexpected error: %v", err)
	}
	if subs != 1 {
		t.Fatalf("Expected 1 subscriber, got %d", subs)
	}
	if receivers != 1 {
		t.Fatalf("Expected 1 receiver, got %d", receivers)
	}

	// Verify the message was received
	select {
	case msg := <-ch:
		if msg != "hello" {
			t.Fatalf("Expected to receive 'hello', got '%s'", msg)
		}
	case <-time.After(time.Second):
		t.Fatal("Timed out waiting for message")
	}

	// Fill the channel
	ps.Publish("test-ns", "fill")

	// Test context cancellation with a full channel
	ctx, cancel = context.WithCancel(context.Background())

	// Cancel the context after a short delay
	go func() {
		time.Sleep(50 * time.Millisecond)
		cancel()
	}()

	start := time.Now()
	subs, receivers, err = ps.PublishWithContext(ctx, "test-ns", "context-test")
	elapsed := time.Since(start)

	if subs != 1 {
		t.Fatalf("Expected 1 subscriber, got %d", subs)
	}

	// Should get a context canceled error
	if err == nil {
		t.Fatal("Expected context canceled error, got nil")
	}

	if elapsed < 50*time.Millisecond {
		t.Fatalf("Expected to wait at least 50ms, only waited %v", elapsed)
	}

	// Drain the channel
	<-ch
}

func TestPubSub_Unsubscribe(t *testing.T) {
	ps := NewPubSub[string, string](10)

	// Add a subscriber
	ch, sub := ps.SubscribeByChan("test-ns", 1)

	// Publish a message
	subs, receivers := ps.Publish("test-ns", "hello")
	if subs != 1 {
		t.Fatalf("Expected 1 subscriber, got %d", subs)
	}
	if receivers != 1 {
		t.Fatalf("Expected 1 receiver, got %d", receivers)
	}

	// Verify the message was received
	select {
	case msg := <-ch:
		if msg != "hello" {
			t.Fatalf("Expected to receive 'hello', got '%s'", msg)
		}
	case <-time.After(time.Second):
		t.Fatal("Timed out waiting for message")
	}

	// Unsubscribe
	sub.Unsubscribe()

	// Publish again
	subs, receivers = ps.Publish("test-ns", "after-unsub")
	if subs != 0 {
		t.Fatalf("Expected 0 subscribers after unsubscribe, got %d", subs)
	}
	if receivers != 0 {
		t.Fatalf("Expected 0 receivers after unsubscribe, got %d", receivers)
	}

	// Check that the namespace is removed
	namespaces := ps.Namespaces()
	if len(namespaces) != 0 {
		t.Fatalf("Expected 0 namespaces after unsubscribe, got %d", len(namespaces))
	}
}

func TestPubSub_MultipleSubscribers(t *testing.T) {
	ps := NewPubSub[string, string](10)

	// Add multiple subscribers
	ch1, sub1 := ps.SubscribeByChan("test-ns", 1)
	defer sub1.Unsubscribe()

	ch2, sub2 := ps.SubscribeByChan("test-ns", 1)
	defer sub2.Unsubscribe()

	var received string
	var wg sync.WaitGroup
	wg.Add(1)

	sub3 := ps.SubscribeByCallback("test-ns", func(msg string) {
		received = msg
		wg.Done()
	})
	defer sub3.Unsubscribe()

	// Publish a message
	subs, receivers := ps.Publish("test-ns", "hello")
	if subs != 3 {
		t.Fatalf("Expected 3 subscribers, got %d", subs)
	}
	if receivers != 3 {
		t.Fatalf("Expected 3 receivers, got %d", receivers)
	}

	// Verify the message was received by all subscribers
	select {
	case msg := <-ch1:
		if msg != "hello" {
			t.Fatalf("Expected ch1 to receive 'hello', got '%s'", msg)
		}
	case <-time.After(time.Second):
		t.Fatal("Timed out waiting for message on ch1")
	}

	select {
	case msg := <-ch2:
		if msg != "hello" {
			t.Fatalf("Expected ch2 to receive 'hello', got '%s'", msg)
		}
	case <-time.After(time.Second):
		t.Fatal("Timed out waiting for message on ch2")
	}

	// Wait for the callback
	wg.Wait()

	if received != "hello" {
		t.Fatalf("Expected callback to receive 'hello', got '%s'", received)
	}
}