package lightpush

import (
	"context"

	"github.com/libp2p/go-libp2p/core/host"
	"github.com/libp2p/go-libp2p/core/peer"
	"github.com/waku-org/go-waku/waku/v2/peermanager"
	"github.com/waku-org/go-waku/waku/v2/protocol"
	"github.com/waku-org/go-waku/waku/v2/utils"
	"go.uber.org/zap"
)

type lightPushParameters struct {
	host         host.Host
	selectedPeer peer.ID
	requestID    []byte
	pm           *peermanager.PeerManager
	log          *zap.Logger
}

// Option is the type of options accepted when performing LightPush protocol requests
type Option func(*lightPushParameters)

// WithPeer is an option used to specify the peerID to push a waku message to
func WithPeer(p peer.ID) Option {
	return func(params *lightPushParameters) {
		params.selectedPeer = p
	}
}

// WithAutomaticPeerSelection is an option used to randomly select a peer from the peer store
// to push a waku message to. If a list of specific peers is passed, the peer will be chosen
// from that list assuming it supports the chosen protocol, otherwise it will chose a peer
// from the node peerstore
func WithAutomaticPeerSelection(fromThesePeers ...peer.ID) Option {
	return func(params *lightPushParameters) {
		var p peer.ID
		var err error
		if params.pm == nil {
			p, err = utils.SelectPeer(params.host, LightPushID_v20beta1, fromThesePeers, params.log)
		} else {
			p, err = params.pm.SelectPeer(LightPushID_v20beta1, fromThesePeers, params.log)
		}
		if err == nil {
			params.selectedPeer = p
		} else {
			params.log.Info("selecting peer", zap.Error(err))
		}
	}
}

// WithFastestPeerSelection is an option used to select a peer from the peer store
// with the lowest ping. If a list of specific peers is passed, the peer will be chosen
// from that list assuming it supports the chosen protocol, otherwise it will chose a peer
// from the node peerstore
func WithFastestPeerSelection(ctx context.Context, fromThesePeers ...peer.ID) Option {
	return func(params *lightPushParameters) {
		p, err := utils.SelectPeerWithLowestRTT(ctx, params.host, LightPushID_v20beta1, fromThesePeers, params.log)
		if err == nil {
			params.selectedPeer = p
		} else {
			params.log.Info("selecting peer", zap.Error(err))
		}
	}
}

// WithRequestID is an option to set a specific request ID to be used when
// publishing a message
func WithRequestID(requestID []byte) Option {
	return func(params *lightPushParameters) {
		params.requestID = requestID
	}
}

// WithAutomaticRequestID is an option to automatically generate a request ID
// when publishing a message
func WithAutomaticRequestID() Option {
	return func(params *lightPushParameters) {
		params.requestID = protocol.GenerateRequestId()
	}
}

// DefaultOptions are the default options to be used when using the lightpush protocol
func DefaultOptions(host host.Host) []Option {
	return []Option{
		WithAutomaticRequestID(),
		WithAutomaticPeerSelection(),
	}
}