feat: support merging multiple subscriptions

internal/automation/ratefilter.go

@@ -0,0 +1,82 @@
+package automation
+
+import (
+	"fmt"
+	"regexp"
+	"strconv"
+)
+
+// buildRateFilterGroups implements the "rate-filters" ssm feature: for each
+// rule, extract a rate from each candidate proxy's original name via
+// rule.Pattern's first capture group, keep those satisfying
+// "rate rule.Operator rule.Value", and append a new proxy-group containing
+// them. Proxies whose name doesn't match Pattern at all are excluded.
+// Returns one error per rule with an invalid pattern/operator; other rules
+// still run.
+func buildRateFilterGroups(finalConfig map[string]interface{}, rules []RateFilterRule, proxies []ProxyRef) []error {
+	var errs []error
+
+	for _, rule := range rules {
+		re, err := regexp.Compile(rule.Pattern)
+		if err != nil {
+			errs = append(errs, fmt.Errorf("rate-filter '%s': invalid pattern %q: %w", rule.Name, rule.Pattern, err))
+			continue
+		}
+
+		cmp, err := comparator(rule.Operator)
+		if err != nil {
+			errs = append(errs, fmt.Errorf("rate-filter '%s': %w", rule.Name, err))
+			continue
+		}
+
+		candidates := matchProxies(proxies, rule.Match)
+		names := make([]interface{}, 0, len(candidates))
+		for _, p := range candidates {
+			m := re.FindStringSubmatch(p.OriginalName)
+			if len(m) < 2 {
+				continue
+			}
+			rate, err := strconv.ParseFloat(m[1], 64)
+			if err != nil {
+				continue
+			}
+			if cmp(rate, rule.Value) {
+				names = append(names, p.DisplayName)
+			}
+		}
+		if len(names) == 0 {
+			fmt.Printf("ℹ️  ssm: rate-filter '%s' matched 0 proxies\n", rule.Name)
+		}
+
+		group := map[string]interface{}{
+			"name":    rule.Name,
+			"type":    defaultString(rule.Type, "select"),
+			"proxies": names,
+		}
+		for k, v := range rule.Extra {
+			group[k] = v
+		}
+		appendProxyGroup(finalConfig, group)
+	}
+
+	return errs
+}
+
+func comparator(op string) (func(a, b float64) bool, error) {
+	switch op {
+	case "<":
+		return func(a, b float64) bool { return a < b }, nil
+	case "<=":
+		return func(a, b float64) bool { return a <= b }, nil
+	case ">":
+		return func(a, b float64) bool { return a > b }, nil
+	case ">=":
+		return func(a, b float64) bool { return a >= b }, nil
+	case "==", "=":
+		return func(a, b float64) bool { return a == b }, nil
+	case "!=":
+		return func(a, b float64) bool { return a != b }, nil
+	default:
+		return nil, fmt.Errorf("unknown operator %q (expected <, <=, >, >=, ==, !=)", op)
+	}
+}