package messages

import (
	"errors"

	"forge.redroom.link/yves/meowlib"
	"forge.redroom.link/yves/meowlib/client"
	"google.golang.org/protobuf/proto"
)

// Step3InitiatorFinalizesInviteeAndCreatesContactCard is called by the initiator when a
// step-2 answer (invitee's encrypted ContactCard) arrives. It decrypts the card, upgrades
// the invitee's peer entry with the real keys, and returns the initiator's own ContactCard
// ready to be sent to the invitee via any transport.
func Step3InitiatorFinalizesInviteeAndCreatesContactCard(invitation *meowlib.Invitation) (*client.Peer, *meowlib.ContactCard, error) {
	var invitationAnswer meowlib.PackedUserMessage
	if err := proto.Unmarshal(invitation.Payload, &invitationAnswer); err != nil {
		return nil, nil, err
	}

	peer := client.GetConfig().GetIdentity().Peers.GetFromInvitationId(invitation.Uuid)
	if peer == nil {
		return nil, nil, errors.New("no peer for invitation uuid " + invitation.Uuid)
	}
	// Guard against duplicate delivery (e.g., same answer from multiple servers).
	if peer.InvitationKp == nil {
		return nil, nil, nil
	}

	usermsg, err := peer.ProcessInboundStep2UserMessage(&invitationAnswer, invitation.From)
	if err != nil {
		return nil, nil, err
	}

	var inviteeCC meowlib.ContactCard
	if err := proto.Unmarshal(usermsg.Invitation.Payload, &inviteeCC); err != nil {
		return nil, nil, err
	}

	myCC, peer, err := client.GetConfig().GetIdentity().InvitationStep3(&inviteeCC)
	if err != nil {
		return nil, nil, err
	}
	client.GetConfig().GetIdentity().Save()
	return peer, myCC, nil
}