package app

import dnscfgpkg "selective-vpn-api/app/dnscfg"

func dnscfgPoolItemsFromApp(items []DNSUpstreamPoolItem) []dnscfgpkg.UpstreamPoolItem {
	out := make([]dnscfgpkg.UpstreamPoolItem, 0, len(items))
	for _, item := range items {
		out = append(out, dnscfgpkg.UpstreamPoolItem{
			Addr:    item.Addr,
			Enabled: item.Enabled,
		})
	}
	return out
}

func dnscfgPoolItemsToApp(items []dnscfgpkg.UpstreamPoolItem) []DNSUpstreamPoolItem {
	out := make([]DNSUpstreamPoolItem, 0, len(items))
	for _, item := range items {
		out = append(out, DNSUpstreamPoolItem{
			Addr:    item.Addr,
			Enabled: item.Enabled,
		})
	}
	return out
}

func dnscfgUpstreamsFromApp(cfg DNSUpstreams) dnscfgpkg.Upstreams {
	return dnscfgpkg.Upstreams{
		Default1: cfg.Default1,
		Default2: cfg.Default2,
		Meta1:    cfg.Meta1,
		Meta2:    cfg.Meta2,
	}
}

func dnscfgUpstreamsToApp(cfg dnscfgpkg.Upstreams) DNSUpstreams {
	return DNSUpstreams{
		Default1: cfg.Default1,
		Default2: cfg.Default2,
		Meta1:    cfg.Meta1,
		Meta2:    cfg.Meta2,
	}
}

func dnscfgLegacyDefaults() dnscfgpkg.Upstreams {
	return dnscfgpkg.Upstreams{
		Default1: defaultDNS1,
		Default2: defaultDNS2,
		Meta1:    defaultMeta1,
		Meta2:    defaultMeta2,
	}
}

func normalizeDNSUpstreamPoolItems(items []DNSUpstreamPoolItem) []DNSUpstreamPoolItem {
	return dnscfgPoolItemsToApp(
		dnscfgpkg.NormalizeUpstreamPoolItems(dnscfgPoolItemsFromApp(items), normalizeDNSUpstream),
	)
}

func dnsUpstreamPoolFromLegacy(cfg DNSUpstreams) []DNSUpstreamPoolItem {
	return dnscfgPoolItemsToApp(
		dnscfgpkg.UpstreamPoolFromLegacy(dnscfgUpstreamsFromApp(cfg), normalizeDNSUpstream),
	)
}

func dnsUpstreamPoolToLegacy(items []DNSUpstreamPoolItem) DNSUpstreams {
	return dnscfgUpstreamsToApp(
		dnscfgpkg.UpstreamPoolToLegacy(
			dnscfgPoolItemsFromApp(items),
			dnscfgLegacyDefaults(),
			normalizeDNSUpstream,
		),
	)
}

func loadEnabledDNSUpstreamPool() []string {
	items := loadDNSUpstreamPoolState()
	return uniqueStrings(
		dnscfgpkg.EnabledPool(dnscfgPoolItemsFromApp(items), normalizeDNSUpstream),
	)
}

// ---------------------------------------------------------------------
// EN: `loadDNSUpstreamsConf` loads dns upstreams conf from storage or config.
// RU: `loadDNSUpstreamsConf` - загружает dns upstreams conf из хранилища или конфига.
// ---------------------------------------------------------------------
func loadDNSUpstreamsConf() DNSUpstreams {
	pool := loadDNSUpstreamPoolState()
	if len(pool) > 0 {
		return dnsUpstreamPoolToLegacy(pool)
	}
	return loadDNSUpstreamsConfFile()
}

// ---------------------------------------------------------------------
// EN: `saveDNSUpstreamsConf` saves dns upstreams conf to persistent storage.
// RU: `saveDNSUpstreamsConf` - сохраняет dns upstreams conf в постоянное хранилище.
// ---------------------------------------------------------------------
func saveDNSUpstreamsConf(cfg DNSUpstreams) error {
	if err := saveDNSUpstreamsConfFile(cfg); err != nil {
		return err
	}
	return saveDNSUpstreamPoolFile(dnsUpstreamPoolFromLegacy(cfg))
}