package pipeline

import (
	"context"
	"net/http"
	"net/netip"
	"os"
	"strconv"
	"strings"
	"time"

	"evobgp/internal/store"
)

func domainCacheTTL() time.Duration {
	sec := 300
	if s := strings.TrimSpace(os.Getenv("EVOBGP_DOMAIN_CACHE_TTL_SEC")); s != "" {
		if v, err := strconv.Atoi(s); err == nil && v > 0 {
			sec = v
		}
	}
	return time.Duration(sec) * time.Second
}

func resolveDomainIPsCached(ctx context.Context, st store.Backend, hc *http.Client, profiles []*store.DohProfile, policy, fqdn string) ([]netip.Addr, error) {
	key := strings.TrimSpace(fqdn)
	ttl := domainCacheTTL()
	if st != nil && ttl > 0 {
		if ent, ok, err := st.GetDomainResolveCache(key); err == nil && ok && ent != nil {
			if time.Since(ent.ResolvedAt) < ttl {
				if addrs := parseCachedDomainAddrs(ent.Addrs); len(addrs) > 0 {
					return addrs, nil
				}
			}
		}
	}
	addrs, err := resolveDomainIPsWithPolicy(ctx, hc, profiles, policy, key)
	if err != nil {
		return nil, err
	}
	if st != nil {
		_ = st.SetDomainResolveCache(key, domainAddrsToStrings(addrs))
	}
	return addrs, nil
}

func parseCachedDomainAddrs(raw []string) []netip.Addr {
	out := make([]netip.Addr, 0, len(raw))
	for _, s := range raw {
		a, err := netip.ParseAddr(strings.TrimSpace(s))
		if err != nil {
			continue
		}
		out = append(out, a)
	}
	return out
}

func domainAddrsToStrings(addrs []netip.Addr) []string {
	out := make([]string, 0, len(addrs))
	for _, a := range addrs {
		if a.IsValid() {
			out = append(out, a.String())
		}
	}
	return out
}