feat: Claude Sonnet 429 仅限模型限流

backend/internal/service/model_rate_limit.go

@@ -0,0 +1,56 @@
+package service
+
+import (
+	"strings"
+	"time"
+)
+
+const modelRateLimitsKey = "model_rate_limits"
+const modelRateLimitScopeClaudeSonnet = "claude_sonnet"
+
+func resolveModelRateLimitScope(requestedModel string) (string, bool) {
+	model := strings.ToLower(strings.TrimSpace(requestedModel))
+	if model == "" {
+		return "", false
+	}
+	model = strings.TrimPrefix(model, "models/")
+	if strings.Contains(model, "sonnet") {
+		return modelRateLimitScopeClaudeSonnet, true
+	}
+	return "", false
+}
+
+func (a *Account) isModelRateLimited(requestedModel string) bool {
+	scope, ok := resolveModelRateLimitScope(requestedModel)
+	if !ok {
+		return false
+	}
+	resetAt := a.modelRateLimitResetAt(scope)
+	if resetAt == nil {
+		return false
+	}
+	return time.Now().Before(*resetAt)
+}
+
+func (a *Account) modelRateLimitResetAt(scope string) *time.Time {
+	if a == nil || a.Extra == nil || scope == "" {
+		return nil
+	}
+	rawLimits, ok := a.Extra[modelRateLimitsKey].(map[string]any)
+	if !ok {
+		return nil
+	}
+	rawLimit, ok := rawLimits[scope].(map[string]any)
+	if !ok {
+		return nil
+	}
+	resetAtRaw, ok := rawLimit["rate_limit_reset_at"].(string)
+	if !ok || strings.TrimSpace(resetAtRaw) == "" {
+		return nil
+	}
+	resetAt, err := time.Parse(time.RFC3339, resetAtRaw)
+	if err != nil {
+		return nil
+	}
+	return &resetAt
+}