feat: implement circuit breaker, fix auth vulnerability

internal/providers/circuit_breaker.go

@@ -0,0 +1,44 @@
+package providers
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/sony/gobreaker"
+	"gophergate/internal/models"
+)
+
+type CircuitBreakerProvider struct {
+	provider Provider
+	cb       *gobreaker.CircuitBreaker
+}
+
+func NewCircuitBreakerProvider(p Provider) Provider {
+	settings := gobreaker.Settings{
+		Name: p.Name(),
+	}
+	return &CircuitBreakerProvider{
+		provider: p,
+		cb:       gobreaker.NewCircuitBreaker(settings),
+	}
+}
+
+func (cbp *CircuitBreakerProvider) Name() string {
+	return cbp.provider.Name()
+}
+
+func (cbp *CircuitBreakerProvider) ChatCompletion(ctx context.Context, req *models.UnifiedRequest) (*models.ChatCompletionResponse, error) {
+	result, err := cbp.cb.Execute(func() (interface{}, error) {
+		return cbp.provider.ChatCompletion(ctx, req)
+	})
+	if err != nil {
+		return nil, err
+	}
+	return result.(*models.ChatCompletionResponse), nil
+}
+
+func (cbp *CircuitBreakerProvider) ChatCompletionStream(ctx context.Context, req *models.UnifiedRequest) (<-chan *models.ChatCompletionStreamResponse, error) {
+	// Circuit breaker for streaming is tricky. We'll just call the provider directly.
+	// Future: Implement a way to track stream failures in the circuit breaker.
+	return cbp.provider.ChatCompletionStream(ctx, req)
+}