package util

import (
	"fmt"
	"math"
	"strings"
	"time"

	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/netmap"
	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/ns"
	"github.com/nspcc-dev/neo-go/pkg/util"
)

// ResolveContractHash determine contract hash by resolving NNS name.
func ResolveContractHash(contractHash, rpcAddress string) (util.Uint160, error) {
	if hash, err := util.Uint160DecodeStringLE(contractHash); err == nil {
		return hash, nil
	}

	splitName := strings.Split(contractHash, ".")
	if len(splitName) != 2 {
		return util.Uint160{}, fmt.Errorf("invalid contract name: '%s'", contractHash)
	}

	var domain container.Domain
	domain.SetName(splitName[0])
	domain.SetZone(splitName[1])

	var nns ns.NNS
	if err := nns.Dial(rpcAddress); err != nil {
		return util.Uint160{}, fmt.Errorf("dial nns %s: %w", rpcAddress, err)
	}
	defer nns.Close()

	return nns.ResolveContractHash(domain)
}

func TimeToEpoch(ni *netmap.NetworkInfo, now, t time.Time) (uint64, error) {
	duration := t.Sub(now)
	durationAbs := duration.Abs()

	durEpoch := ni.EpochDuration()
	if durEpoch == 0 {
		return 0, fmt.Errorf("epoch duration is missing or zero")
	}

	msPerEpoch := durEpoch * uint64(ni.MsPerBlock())
	epochLifetime := uint64(durationAbs.Milliseconds()) / msPerEpoch

	if uint64(durationAbs.Milliseconds())%msPerEpoch != 0 {
		epochLifetime++
	}

	curr := ni.CurrentEpoch()

	var epoch uint64
	if duration > 0 {
		if epochLifetime >= math.MaxUint64-curr {
			epoch = math.MaxUint64
		} else {
			epoch = curr + epochLifetime
		}
	} else {
		if epochLifetime >= curr {
			epoch = 0
		} else {
			epoch = curr - epochLifetime
		}
	}

	return epoch, nil
}