package balance

import (
	"context"
	"errors"
	"fmt"

	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/innerring/metrics"
	frostfscontract "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/morph/client/frostfs"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/morph/event"
	balanceEvent "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/morph/event/balance"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/logger"
	"github.com/nspcc-dev/neo-go/pkg/util"
	"github.com/panjf2000/ants/v2"
)

type (
	// AlphabetState is a callback interface for inner ring global state.
	AlphabetState interface {
		IsAlphabet(context.Context) bool
	}

	// PrecisionConverter converts balance amount values.
	PrecisionConverter interface {
		ToFixed8(int64) int64
	}

	FrostFSClient interface {
		Cheque(ctx context.Context, p frostfscontract.ChequePrm) error
	}

	// Processor of events produced by balance contract in the morphchain.
	Processor struct {
		log           *logger.Logger
		metrics       metrics.Register
		pool          *ants.Pool
		frostfsClient FrostFSClient
		balanceSC     util.Uint160
		alphabetState AlphabetState
		converter     PrecisionConverter
	}

	// Params of the processor constructor.
	Params struct {
		Log           *logger.Logger
		Metrics       metrics.Register
		PoolSize      int
		FrostFSClient FrostFSClient
		BalanceSC     util.Uint160
		AlphabetState AlphabetState
		Converter     PrecisionConverter
	}
)

const (
	lockNotification = "Lock"
)

// New creates a balance contract processor instance.
func New(p *Params) (*Processor, error) {
	switch {
	case p.Log == nil:
		return nil, errors.New("ir/balance: logger is not set")
	case p.AlphabetState == nil:
		return nil, errors.New("ir/balance: global state is not set")
	case p.Converter == nil:
		return nil, errors.New("ir/balance: balance precision converter is not set")
	}

	pool, err := ants.NewPool(p.PoolSize, ants.WithNonblocking(true))
	if err != nil {
		return nil, fmt.Errorf("ir/balance: can't create worker pool: %w", err)
	}

	metricsRegister := p.Metrics
	if metricsRegister == nil {
		metricsRegister = metrics.DefaultRegister{}
	}

	return &Processor{
		log:           p.Log,
		metrics:       metricsRegister,
		pool:          pool,
		frostfsClient: p.FrostFSClient,
		balanceSC:     p.BalanceSC,
		alphabetState: p.AlphabetState,
		converter:     p.Converter,
	}, nil
}

// ListenerNotificationParsers for the 'event.Listener' event producer.
func (bp *Processor) ListenerNotificationParsers() []event.NotificationParserInfo {
	var parsers []event.NotificationParserInfo

	// new lock event
	lock := event.NotificationParserInfo{}
	lock.SetType(lockNotification)
	lock.SetScriptHash(bp.balanceSC)
	lock.SetParser(balanceEvent.ParseLock)
	parsers = append(parsers, lock)

	return parsers
}

// ListenerNotificationHandlers for the 'event.Listener' event producer.
func (bp *Processor) ListenerNotificationHandlers() []event.NotificationHandlerInfo {
	var handlers []event.NotificationHandlerInfo

	// lock handler
	lock := event.NotificationHandlerInfo{}
	lock.SetType(lockNotification)
	lock.SetScriptHash(bp.balanceSC)
	lock.SetHandler(bp.handleLock)
	handlers = append(handlers, lock)

	return handlers
}

// ListenerNotaryParsers for the 'event.Listener' event producer.
func (bp *Processor) ListenerNotaryParsers() []event.NotaryParserInfo {
	return nil
}

// ListenerNotaryHandlers for the 'event.Listener' event producer.
func (bp *Processor) ListenerNotaryHandlers() []event.NotaryHandlerInfo {
	return nil
}