package webhook

import (
	"context"
	"encoding/json"
	"io"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"sync"
	"sync/atomic"
	"testing"
	"time"

	"github.com/orchard9/rdev/internal/domain"
)

// discardLogger returns a logger that discards all output.
func discardLogger() *slog.Logger {
	return slog.New(slog.NewTextHandler(io.Discard, nil))
}

// mockWebhookRepo implements port.WebhookRepository for testing.
type mockWebhookRepo struct {
	webhooks   []*domain.Webhook
	mu         sync.RWMutex
	deliveries []*domain.WebhookDelivery
	err        error
}

func (m *mockWebhookRepo) Create(ctx context.Context, webhook *domain.Webhook) error {
	return m.err
}

func (m *mockWebhookRepo) Update(ctx context.Context, webhook *domain.Webhook) error {
	return m.err
}

func (m *mockWebhookRepo) Delete(ctx context.Context, id domain.WebhookID) error {
	return m.err
}

func (m *mockWebhookRepo) GetByID(ctx context.Context, id domain.WebhookID) (*domain.Webhook, error) {
	if m.err != nil {
		return nil, m.err
	}
	for _, w := range m.webhooks {
		if w.ID == id {
			return w, nil
		}
	}
	return nil, domain.ErrWebhookNotFound
}

func (m *mockWebhookRepo) ListByProject(ctx context.Context, projectID string) ([]*domain.Webhook, error) {
	if m.err != nil {
		return nil, m.err
	}
	var result []*domain.Webhook
	for _, w := range m.webhooks {
		if w.ProjectID == projectID {
			result = append(result, w)
		}
	}
	return result, nil
}

func (m *mockWebhookRepo) ListEnabledByProjectAndEvent(ctx context.Context, projectID string, eventType domain.WebhookEventType) ([]*domain.Webhook, error) {
	if m.err != nil {
		return nil, m.err
	}
	var result []*domain.Webhook
	for _, w := range m.webhooks {
		if w.ProjectID == projectID && w.Enabled {
			for _, e := range w.Events {
				if e == eventType {
					result = append(result, w)
					break
				}
			}
		}
	}
	return result, nil
}

func (m *mockWebhookRepo) RecordDelivery(ctx context.Context, delivery *domain.WebhookDelivery) error {
	if m.err != nil {
		return m.err
	}
	m.mu.Lock()
	m.deliveries = append(m.deliveries, delivery)
	m.mu.Unlock()
	return nil
}

func (m *mockWebhookRepo) GetDeliveries(ctx context.Context, webhookID domain.WebhookID, filters *domain.WebhookDeliveryFilters) ([]*domain.WebhookDelivery, error) {
	m.mu.RLock()
	defer m.mu.RUnlock()
	return m.deliveries, m.err
}

func (m *mockWebhookRepo) DeliveryCount() int {
	m.mu.RLock()
	defer m.mu.RUnlock()
	return len(m.deliveries)
}

func (m *mockWebhookRepo) CleanupOldDeliveries(ctx context.Context, olderThanDays int) (int64, error) {
	return 0, m.err
}

func TestDispatcher_NewDispatcher(t *testing.T) {
	repo := &mockWebhookRepo{}

	// With nil config, should use defaults
	d := NewDispatcher(repo, nil)
	if d == nil {
		t.Fatal("NewDispatcher returned nil")
	}
	if d.config.WorkerCount != 10 {
		t.Errorf("expected default WorkerCount of 10, got %d", d.config.WorkerCount)
	}

	// With custom config
	cfg := &DispatcherConfig{
		WorkerCount: 5,
		MaxRetries:  5,
		Timeout:     10 * time.Second,
	}
	d = NewDispatcher(repo, cfg)
	if d.config.WorkerCount != 5 {
		t.Errorf("expected WorkerCount of 5, got %d", d.config.WorkerCount)
	}
}

func TestDispatcher_StartStop(t *testing.T) {
	repo := &mockWebhookRepo{}
	d := NewDispatcher(repo, &DispatcherConfig{
		WorkerCount: 2,
		Logger:      discardLogger(),
	})

	if err := d.Start(); err != nil {
		t.Fatalf("Start() error = %v", err)
	}

	// Verify health
	if !d.Health() {
		t.Error("expected dispatcher to be healthy after start")
	}

	// Stop should complete without deadlock
	done := make(chan struct{})
	go func() {
		d.Stop()
		close(done)
	}()

	select {
	case <-done:
		// OK
	case <-time.After(5 * time.Second):
		t.Fatal("Stop() timed out")
	}

	// After stop, should not be healthy
	if d.Health() {
		t.Error("expected dispatcher to be unhealthy after stop")
	}
}

func TestDispatcher_Dispatch(t *testing.T) {
	// Create a test server to receive webhooks
	var receivedCount atomic.Int32
	var payloadMu sync.Mutex
	var receivedPayload []byte
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		receivedCount.Add(1)
		buf := make([]byte, 1024)
		n, _ := r.Body.Read(buf)
		payloadMu.Lock()
		receivedPayload = buf[:n]
		payloadMu.Unlock()
		w.WriteHeader(http.StatusOK)
	}))
	defer server.Close()

	repo := &mockWebhookRepo{
		webhooks: []*domain.Webhook{
			{
				ID:        "wh-1",
				ProjectID: "proj-1",
				URL:       server.URL,
				Secret:    "test-secret",
				Events:    []domain.WebhookEventType{domain.WebhookEventCommandStarted},
				Enabled:   true,
			},
		},
	}

	d := NewDispatcher(repo, &DispatcherConfig{
		WorkerCount:  2,
		MaxRetries:   0,
		Timeout:      5 * time.Second,
		RetryBackoff: time.Millisecond,
		Logger:       discardLogger(),
	})
	if err := d.Start(); err != nil {
		t.Fatalf("Start() error = %v", err)
	}
	defer d.Stop()

	// Dispatch an event
	event := &domain.WebhookEvent{
		Type:      domain.WebhookEventCommandStarted,
		ProjectID: "proj-1",
		Timestamp: time.Now(),
		Data: map[string]any{
			"command_id": "cmd-123",
		},
	}

	if err := d.Dispatch(context.Background(), "proj-1", event); err != nil {
		t.Fatalf("Dispatch() error = %v", err)
	}

	// Wait for delivery
	time.Sleep(100 * time.Millisecond)

	if receivedCount.Load() != 1 {
		t.Errorf("expected 1 webhook delivery, got %d", receivedCount.Load())
	}

	// Verify payload
	payloadMu.Lock()
	payloadCopy := receivedPayload
	payloadMu.Unlock()

	if len(payloadCopy) > 0 {
		var payload domain.WebhookPayload
		if err := json.Unmarshal(payloadCopy, &payload); err != nil {
			t.Errorf("failed to unmarshal payload: %v", err)
		}
		if payload.Event != domain.WebhookEventCommandStarted {
			t.Errorf("expected event type %s, got %s", domain.WebhookEventCommandStarted, payload.Event)
		}
	}
}

func TestDispatcher_DispatchNoWebhooks(t *testing.T) {
	repo := &mockWebhookRepo{
		webhooks: nil, // No webhooks configured
	}

	d := NewDispatcher(repo, &DispatcherConfig{
		WorkerCount: 1,
		Logger:      discardLogger(),
	})
	if err := d.Start(); err != nil {
		t.Fatalf("Start() error = %v", err)
	}
	defer d.Stop()

	event := &domain.WebhookEvent{
		Type:      domain.WebhookEventCommandStarted,
		ProjectID: "proj-1",
		Timestamp: time.Now(),
	}

	// Should not error when there are no webhooks
	if err := d.Dispatch(context.Background(), "proj-1", event); err != nil {
		t.Errorf("Dispatch() error = %v, want nil", err)
	}
}

func TestDispatcher_DeliveryFailure(t *testing.T) {
	// Create a test server that always fails
	var requestCount atomic.Int32
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		requestCount.Add(1)
		w.WriteHeader(http.StatusInternalServerError)
	}))
	defer server.Close()

	repo := &mockWebhookRepo{
		webhooks: []*domain.Webhook{
			{
				ID:        "wh-1",
				ProjectID: "proj-1",
				URL:       server.URL,
				Events:    []domain.WebhookEventType{domain.WebhookEventCommandStarted},
				Enabled:   true,
			},
		},
	}

	d := NewDispatcher(repo, &DispatcherConfig{
		WorkerCount:  1,
		MaxRetries:   2, // 2 retries = 3 total attempts
		Timeout:      5 * time.Second,
		RetryBackoff: 10 * time.Millisecond, // Fast retries for testing
		Logger:       discardLogger(),
	})
	if err := d.Start(); err != nil {
		t.Fatalf("Start() error = %v", err)
	}
	defer d.Stop()

	event := &domain.WebhookEvent{
		Type:      domain.WebhookEventCommandStarted,
		ProjectID: "proj-1",
		Timestamp: time.Now(),
	}

	if err := d.Dispatch(context.Background(), "proj-1", event); err != nil {
		t.Fatalf("Dispatch() error = %v", err)
	}

	// Wait for delivery and retries (initial + 2 retries with exponential backoff)
	// Backoff: 10ms, 20ms = ~30ms total + processing time
	time.Sleep(200 * time.Millisecond)

	// Should have attempted delivery 3 times (initial + 2 retries)
	count := requestCount.Load()
	if count != 3 {
		t.Errorf("expected 3 delivery attempts, got %d", count)
	}

	// Verify delivery was recorded
	if repo.DeliveryCount() == 0 {
		t.Error("expected delivery to be recorded")
	}
}

func TestDispatcher_QueueSize(t *testing.T) {
	repo := &mockWebhookRepo{}
	d := NewDispatcher(repo, &DispatcherConfig{
		WorkerCount: 1,
	})

	// Before start, queue should be empty
	if d.QueueSize() != 0 {
		t.Errorf("expected queue size 0, got %d", d.QueueSize())
	}
}

func TestDispatcher_SignPayload(t *testing.T) {
	d := &Dispatcher{}
	payload := []byte(`{"test": true}`)
	secret := "my-secret"

	signature := d.signPayload(payload, secret)

	// Should be sha256=<hex>
	if len(signature) < 10 || signature[:7] != "sha256=" {
		t.Errorf("invalid signature format: %s", signature)
	}

	// Same payload and secret should produce same signature
	signature2 := d.signPayload(payload, secret)
	if signature != signature2 {
		t.Error("signatures should be deterministic")
	}

	// Different secret should produce different signature
	signature3 := d.signPayload(payload, "different-secret")
	if signature == signature3 {
		t.Error("different secrets should produce different signatures")
	}
}

func TestDefaultDispatcherConfig(t *testing.T) {
	cfg := DefaultDispatcherConfig()

	if cfg.WorkerCount != 10 {
		t.Errorf("expected WorkerCount 10, got %d", cfg.WorkerCount)
	}
	if cfg.MaxRetries != 3 {
		t.Errorf("expected MaxRetries 3, got %d", cfg.MaxRetries)
	}
	if cfg.Timeout != 30*time.Second {
		t.Errorf("expected Timeout 30s, got %v", cfg.Timeout)
	}
	if cfg.RetryBackoff != 5*time.Second {
		t.Errorf("expected RetryBackoff 5s, got %v", cfg.RetryBackoff)
	}
	if cfg.MaxResponseBodySize != 1024 {
		t.Errorf("expected MaxResponseBodySize 1024, got %d", cfg.MaxResponseBodySize)
	}
}