package client

import (
	"context"
	"encoding/hex"
	"fmt"
	"strings"

	pb "github.com/prysmaticlabs/prysm/proto/beacon/rpc/v1"
	"github.com/prysmaticlabs/prysm/shared/params"
	"github.com/sirupsen/logrus"
)

// LogValidatorGainsAndLosses logs important metrics related to this validator client's
// responsibilities throughout the beacon chain's lifecycle. It logs absolute accrued rewards
// and penalties over time, percentage gain/loss, and gives the end user a better idea
// of how the validator performs with respect to the rest.
func (v *validator) LogValidatorGainsAndLosses(ctx context.Context, slot uint64) error {
	if slot%params.BeaconConfig().SlotsPerEpoch != 0 {
		// Do nothing if we are not at the start of a new epoch.
		return nil
	}
	epoch := slot / params.BeaconConfig().SlotsPerEpoch
	if epoch == params.BeaconConfig().GenesisEpoch {
		v.prevBalance = params.BeaconConfig().MaxDepositAmount
	}
	var totalPrevBalance uint64
	reported := false
	for _, pkey := range v.pubkeys {
		req := &pb.ValidatorPerformanceRequest{
			Slot:      slot,
			PublicKey: pkey,
		}
		resp, err := v.validatorClient.ValidatorPerformance(ctx, req)
		if err != nil {
			if strings.Contains(err.Error(), "could not get validator index") {
				continue
			}
			return err
		}
		tpk := hex.EncodeToString(pkey)[:12]
		if !reported {
			log.WithFields(logrus.Fields{
				"slot":  slot - params.BeaconConfig().GenesisSlot,
				"epoch": (slot / params.BeaconConfig().SlotsPerEpoch) - params.BeaconConfig().GenesisEpoch,
			}).Info("Start of a new epoch!")
			log.WithFields(logrus.Fields{
				"totalValidators":     resp.TotalValidators,
				"numActiveValidators": resp.TotalActiveValidators,
			}).Info("Validator registry information")
			log.Info("Generating validator performance report from the previous epoch...")
			avgBalance := resp.AverageValidatorBalance / float32(params.BeaconConfig().GweiPerEth)
			log.WithField(
				"averageEthBalance", fmt.Sprintf("%f", avgBalance),
			).Info("Average eth balance per validator in the beacon chain")
			reported = true
		}
		newBalance := float64(resp.Balance) / float64(params.BeaconConfig().GweiPerEth)

		if v.prevBalance > 0 {
			prevBalance := float64(v.prevBalance) / float64(params.BeaconConfig().GweiPerEth)
			percentNet := (newBalance - prevBalance) / prevBalance
			if v.logValidatorBalances {
				log.WithFields(logrus.Fields{
					"prevBalance":   prevBalance,
					"newBalance":    newBalance,
					"delta":         fmt.Sprintf("%f", newBalance-prevBalance),
					"percentChange": fmt.Sprintf("%.2f%%", percentNet*100),
					"pubKey":        tpk,
				}).Info("Net gains/losses in eth")
			}
		}
		totalPrevBalance += resp.Balance
	}

	v.prevBalance = totalPrevBalance
	return nil
}