package dns

import (
	"fmt"
	"net/netip"
	"sort"
	"time"

	"darvaza.org/core"
	"github.com/libdns/libdns"
)

// SortAddrSlice ...
func SortAddrSlice(s []netip.Addr) []netip.Addr {
	sort.Slice(s, func(i, j int) bool {
		return s[i].Less(s[j])
	})
	return s
}

// AddrRecord represents an A or AAAA record
type AddrRecord struct {
	Name string
	Addr []netip.Addr
}

// Sort sorts the addresses of the record
func (rr *AddrRecord) Sort() {
	SortAddrSlice(rr.Addr)
}

// Export converts the record into libdns.Record
func (rr *AddrRecord) Export() []libdns.Record {
	out := make([]libdns.Record, len(rr.Addr))
	for i, addr := range rr.Addr {
		out[i] = libdns.Record{
			Name:  rr.Name,
			TTL:   time.Second * 1,
			Type:  core.IIf(addr.Is6(), "AAAA", "A"),
			Value: addr.String(),
		}
	}

	return out
}

func (mgr *Manager) genAllAddrRecords() []AddrRecord {
	var out []AddrRecord

	cache := make(map[string][]netip.Addr)

	// zones
	for _, z := range mgr.zones {
		// machines
		s := mgr.genZoneMachineRecords(z)
		out = append(out, s...)

		// zone alias
		addrs := mgr.genZoneAddresses(z)
		name := z.Name

		out = append(out, AddrRecord{
			Name: name + mgr.suffix,
			Addr: addrs,
		})

		// and cache for regions
		cache[name] = addrs
	}

	// regions
	for name, zones := range mgr.regions {
		var addrs []netip.Addr

		for _, z := range zones {
			addrs = append(addrs, cache[z]...)
		}

		rec := AddrRecord{
			Name: name + mgr.suffix,
			Addr: addrs,
		}
		rec.Sort()

		out = append(out, rec)
	}

	// sort
	sort.Slice(out, func(i, j int) bool {
		return out[i].Name < out[j].Name
	})

	return out
}

func (*Manager) genZoneAddresses(z *Zone) []netip.Addr {
	var out []netip.Addr

	for _, p := range z.Machines {
		if p.Active {
			out = append(out, p.Addrs...)
		}
	}

	SortAddrSlice(out)
	return out
}

func (mgr *Manager) genZoneMachineRecords(z *Zone) []AddrRecord {
	out := make([]AddrRecord, 0, len(z.Machines))

	for _, p := range z.Machines {
		rec := AddrRecord{
			Name: fmt.Sprintf("%s-%v%s", z.Name, p.ID, mgr.suffix),
			Addr: p.Addrs,
		}
		out = append(out, rec)
	}

	return out
}