package automation

import "fmt"

// buildProxyGroups implements the "proxy-groups" ssm feature: for each rule,
// filter the merged proxy pool by rule.Match and append a new proxy-group
// containing the matched proxies' display names.
// Returns one error per rule with an invalid match.name-pattern; other rules
// still run.
func buildProxyGroups(finalConfig map[string]interface{}, rules []ProxyGroupRule, proxies []ProxyRef) []error {
	var errs []error

	for _, rule := range rules {
		matched, err := matchProxies(proxies, rule.Match)
		if err != nil {
			errs = append(errs, fmt.Errorf("proxy-group '%s': %w", rule.Name, err))
			continue
		}

		// Multiple ProxyRefs (e.g. each subscription's own default
		// selector) can share a DisplayName (e.g. once folded into a
		// combined "Proxy Selection" group) — dedupe so it's not listed
		// more than once.
		seen := make(map[string]bool, len(matched))
		names := make([]interface{}, 0, len(matched))
		for _, p := range matched {
			if seen[p.DisplayName] {
				continue
			}
			seen[p.DisplayName] = true
			names = append(names, p.DisplayName)
		}
		if len(matched) == 0 {
			fmt.Printf("ℹ️  ssm: proxy-group '%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 defaultString(v, fallback string) string {
	if v == "" {
		return fallback
	}
	return v
}

func appendProxyGroup(finalConfig map[string]interface{}, group map[string]interface{}) {
	existing, _ := finalConfig["proxy-groups"].([]interface{})
	finalConfig["proxy-groups"] = append(existing, group)
}