package store

import (
	"sort"
	"time"
)

func (m *Memory) GetASNPrefixCache(asn int64) (*ASNPrefixCacheEntry, bool, error) {
	m.mu.RLock()
	defer m.mu.RUnlock()
	if m.asnPrefixCache == nil {
		return nil, false, nil
	}
	e, ok := m.asnPrefixCache[asn]
	if !ok || e == nil {
		return nil, false, nil
	}
	pfx := append([]string(nil), e.Prefixes...)
	return &ASNPrefixCacheEntry{
		ASN:       asn,
		Holder:    e.Holder,
		Prefixes:  pfx,
		FetchedAt: e.FetchedAt,
	}, true, nil
}

func (m *Memory) SetASNPrefixCache(asn int64, holder string, prefixes []string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.asnPrefixCache == nil {
		m.asnPrefixCache = make(map[int64]*ASNPrefixCacheEntry)
	}
	if cur := m.asnPrefixCache[asn]; cur != nil && sameStringSet(cur.Prefixes, prefixes) {
		cur.Holder = holder
		cur.FetchedAt = time.Now().UTC()
		return nil
	}
	cp := append([]string(nil), prefixes...)
	m.asnPrefixCache[asn] = &ASNPrefixCacheEntry{
		ASN:       asn,
		Holder:    holder,
		Prefixes:  cp,
		FetchedAt: time.Now().UTC(),
	}
	return nil
}

func sameStringSet(a, b []string) bool {
	if len(a) != len(b) {
		return false
	}
	aa := append([]string(nil), a...)
	bb := append([]string(nil), b...)
	sort.Strings(aa)
	sort.Strings(bb)
	for i := range aa {
		if aa[i] != bb[i] {
			return false
		}
	}
	return true
}