package transcoder

import (
	"errors"
	"fmt"

	notificationfbs "galaxy/schema/fbs/notification"

	flatbuffers "github.com/google/flatbuffers/go"
)

// GameTurnReadyEvent is the independent Go representation of
// `notification.GameTurnReadyEvent`.
type GameTurnReadyEvent struct {
	GameID     string
	TurnNumber int64
}

// GameFinishedEvent is the independent Go representation of
// `notification.GameFinishedEvent`.
type GameFinishedEvent struct {
	GameID          string
	FinalTurnNumber int64
}

// LobbyApplicationSubmittedEvent is the independent Go representation of
// `notification.LobbyApplicationSubmittedEvent`.
type LobbyApplicationSubmittedEvent struct {
	GameID          string
	ApplicantUserID string
}

// LobbyMembershipApprovedEvent is the independent Go representation of
// `notification.LobbyMembershipApprovedEvent`.
type LobbyMembershipApprovedEvent struct {
	GameID string
}

// LobbyMembershipRejectedEvent is the independent Go representation of
// `notification.LobbyMembershipRejectedEvent`.
type LobbyMembershipRejectedEvent struct {
	GameID string
}

// LobbyInviteCreatedEvent is the independent Go representation of
// `notification.LobbyInviteCreatedEvent`.
type LobbyInviteCreatedEvent struct {
	GameID        string
	InviterUserID string
}

// LobbyInviteRedeemedEvent is the independent Go representation of
// `notification.LobbyInviteRedeemedEvent`.
type LobbyInviteRedeemedEvent struct {
	GameID        string
	InviteeUserID string
}

// GameTurnReadyEventToPayload converts GameTurnReadyEvent to FlatBuffers bytes
// suitable for the authenticated gateway push transport.
func GameTurnReadyEventToPayload(event *GameTurnReadyEvent) ([]byte, error) {
	if event == nil {
		return nil, errors.New("encode game turn ready payload: event is nil")
	}
	if event.GameID == "" {
		return nil, errors.New("encode game turn ready payload: game_id is empty")
	}

	builder := flatbuffers.NewBuilder(64)
	gameID := builder.CreateString(event.GameID)

	notificationfbs.GameTurnReadyEventStart(builder)
	notificationfbs.GameTurnReadyEventAddGameId(builder, gameID)
	notificationfbs.GameTurnReadyEventAddTurnNumber(builder, event.TurnNumber)
	offset := notificationfbs.GameTurnReadyEventEnd(builder)
	notificationfbs.FinishGameTurnReadyEventBuffer(builder, offset)

	return builder.FinishedBytes(), nil
}

// PayloadToGameTurnReadyEvent converts FlatBuffers payload bytes into
// GameTurnReadyEvent.
func PayloadToGameTurnReadyEvent(data []byte) (result *GameTurnReadyEvent, err error) {
	if len(data) == 0 {
		return nil, errors.New("decode game turn ready payload: data is empty")
	}

	defer recoverNotificationDecodePanic("decode game turn ready payload", &result, &err)

	event := notificationfbs.GetRootAsGameTurnReadyEvent(data, 0)
	gameID, err := requiredNotificationString(event.GameId(), "game_id")
	if err != nil {
		return nil, fmt.Errorf("decode game turn ready payload: %w", err)
	}

	return &GameTurnReadyEvent{
		GameID:     gameID,
		TurnNumber: event.TurnNumber(),
	}, nil
}

// GameFinishedEventToPayload converts GameFinishedEvent to FlatBuffers bytes
// suitable for the authenticated gateway push transport.
func GameFinishedEventToPayload(event *GameFinishedEvent) ([]byte, error) {
	if event == nil {
		return nil, errors.New("encode game finished payload: event is nil")
	}
	if event.GameID == "" {
		return nil, errors.New("encode game finished payload: game_id is empty")
	}

	builder := flatbuffers.NewBuilder(64)
	gameID := builder.CreateString(event.GameID)

	notificationfbs.GameFinishedEventStart(builder)
	notificationfbs.GameFinishedEventAddGameId(builder, gameID)
	notificationfbs.GameFinishedEventAddFinalTurnNumber(builder, event.FinalTurnNumber)
	offset := notificationfbs.GameFinishedEventEnd(builder)
	notificationfbs.FinishGameFinishedEventBuffer(builder, offset)

	return builder.FinishedBytes(), nil
}

// PayloadToGameFinishedEvent converts FlatBuffers payload bytes into
// GameFinishedEvent.
func PayloadToGameFinishedEvent(data []byte) (result *GameFinishedEvent, err error) {
	if len(data) == 0 {
		return nil, errors.New("decode game finished payload: data is empty")
	}

	defer recoverNotificationDecodePanic("decode game finished payload", &result, &err)

	event := notificationfbs.GetRootAsGameFinishedEvent(data, 0)
	gameID, err := requiredNotificationString(event.GameId(), "game_id")
	if err != nil {
		return nil, fmt.Errorf("decode game finished payload: %w", err)
	}

	return &GameFinishedEvent{
		GameID:          gameID,
		FinalTurnNumber: event.FinalTurnNumber(),
	}, nil
}

// LobbyApplicationSubmittedEventToPayload converts
// LobbyApplicationSubmittedEvent to FlatBuffers bytes suitable for the
// authenticated gateway push transport.
func LobbyApplicationSubmittedEventToPayload(event *LobbyApplicationSubmittedEvent) ([]byte, error) {
	if event == nil {
		return nil, errors.New("encode lobby application submitted payload: event is nil")
	}
	if event.GameID == "" {
		return nil, errors.New("encode lobby application submitted payload: game_id is empty")
	}
	if event.ApplicantUserID == "" {
		return nil, errors.New("encode lobby application submitted payload: applicant_user_id is empty")
	}

	builder := flatbuffers.NewBuilder(96)
	gameID := builder.CreateString(event.GameID)
	applicantUserID := builder.CreateString(event.ApplicantUserID)

	notificationfbs.LobbyApplicationSubmittedEventStart(builder)
	notificationfbs.LobbyApplicationSubmittedEventAddGameId(builder, gameID)
	notificationfbs.LobbyApplicationSubmittedEventAddApplicantUserId(builder, applicantUserID)
	offset := notificationfbs.LobbyApplicationSubmittedEventEnd(builder)
	notificationfbs.FinishLobbyApplicationSubmittedEventBuffer(builder, offset)

	return builder.FinishedBytes(), nil
}

// PayloadToLobbyApplicationSubmittedEvent converts FlatBuffers payload bytes
// into LobbyApplicationSubmittedEvent.
func PayloadToLobbyApplicationSubmittedEvent(data []byte) (result *LobbyApplicationSubmittedEvent, err error) {
	if len(data) == 0 {
		return nil, errors.New("decode lobby application submitted payload: data is empty")
	}

	defer recoverNotificationDecodePanic("decode lobby application submitted payload", &result, &err)

	event := notificationfbs.GetRootAsLobbyApplicationSubmittedEvent(data, 0)
	gameID, err := requiredNotificationString(event.GameId(), "game_id")
	if err != nil {
		return nil, fmt.Errorf("decode lobby application submitted payload: %w", err)
	}
	applicantUserID, err := requiredNotificationString(event.ApplicantUserId(), "applicant_user_id")
	if err != nil {
		return nil, fmt.Errorf("decode lobby application submitted payload: %w", err)
	}

	return &LobbyApplicationSubmittedEvent{
		GameID:          gameID,
		ApplicantUserID: applicantUserID,
	}, nil
}

// LobbyMembershipApprovedEventToPayload converts LobbyMembershipApprovedEvent
// to FlatBuffers bytes suitable for the authenticated gateway push transport.
func LobbyMembershipApprovedEventToPayload(event *LobbyMembershipApprovedEvent) ([]byte, error) {
	if event == nil {
		return nil, errors.New("encode lobby membership approved payload: event is nil")
	}
	if event.GameID == "" {
		return nil, errors.New("encode lobby membership approved payload: game_id is empty")
	}

	builder := flatbuffers.NewBuilder(48)
	gameID := builder.CreateString(event.GameID)

	notificationfbs.LobbyMembershipApprovedEventStart(builder)
	notificationfbs.LobbyMembershipApprovedEventAddGameId(builder, gameID)
	offset := notificationfbs.LobbyMembershipApprovedEventEnd(builder)
	notificationfbs.FinishLobbyMembershipApprovedEventBuffer(builder, offset)

	return builder.FinishedBytes(), nil
}

// PayloadToLobbyMembershipApprovedEvent converts FlatBuffers payload bytes
// into LobbyMembershipApprovedEvent.
func PayloadToLobbyMembershipApprovedEvent(data []byte) (result *LobbyMembershipApprovedEvent, err error) {
	if len(data) == 0 {
		return nil, errors.New("decode lobby membership approved payload: data is empty")
	}

	defer recoverNotificationDecodePanic("decode lobby membership approved payload", &result, &err)

	event := notificationfbs.GetRootAsLobbyMembershipApprovedEvent(data, 0)
	gameID, err := requiredNotificationString(event.GameId(), "game_id")
	if err != nil {
		return nil, fmt.Errorf("decode lobby membership approved payload: %w", err)
	}

	return &LobbyMembershipApprovedEvent{GameID: gameID}, nil
}

// LobbyMembershipRejectedEventToPayload converts LobbyMembershipRejectedEvent
// to FlatBuffers bytes suitable for the authenticated gateway push transport.
func LobbyMembershipRejectedEventToPayload(event *LobbyMembershipRejectedEvent) ([]byte, error) {
	if event == nil {
		return nil, errors.New("encode lobby membership rejected payload: event is nil")
	}
	if event.GameID == "" {
		return nil, errors.New("encode lobby membership rejected payload: game_id is empty")
	}

	builder := flatbuffers.NewBuilder(48)
	gameID := builder.CreateString(event.GameID)

	notificationfbs.LobbyMembershipRejectedEventStart(builder)
	notificationfbs.LobbyMembershipRejectedEventAddGameId(builder, gameID)
	offset := notificationfbs.LobbyMembershipRejectedEventEnd(builder)
	notificationfbs.FinishLobbyMembershipRejectedEventBuffer(builder, offset)

	return builder.FinishedBytes(), nil
}

// PayloadToLobbyMembershipRejectedEvent converts FlatBuffers payload bytes
// into LobbyMembershipRejectedEvent.
func PayloadToLobbyMembershipRejectedEvent(data []byte) (result *LobbyMembershipRejectedEvent, err error) {
	if len(data) == 0 {
		return nil, errors.New("decode lobby membership rejected payload: data is empty")
	}

	defer recoverNotificationDecodePanic("decode lobby membership rejected payload", &result, &err)

	event := notificationfbs.GetRootAsLobbyMembershipRejectedEvent(data, 0)
	gameID, err := requiredNotificationString(event.GameId(), "game_id")
	if err != nil {
		return nil, fmt.Errorf("decode lobby membership rejected payload: %w", err)
	}

	return &LobbyMembershipRejectedEvent{GameID: gameID}, nil
}

// LobbyInviteCreatedEventToPayload converts LobbyInviteCreatedEvent to
// FlatBuffers bytes suitable for the authenticated gateway push transport.
func LobbyInviteCreatedEventToPayload(event *LobbyInviteCreatedEvent) ([]byte, error) {
	if event == nil {
		return nil, errors.New("encode lobby invite created payload: event is nil")
	}
	if event.GameID == "" {
		return nil, errors.New("encode lobby invite created payload: game_id is empty")
	}
	if event.InviterUserID == "" {
		return nil, errors.New("encode lobby invite created payload: inviter_user_id is empty")
	}

	builder := flatbuffers.NewBuilder(96)
	gameID := builder.CreateString(event.GameID)
	inviterUserID := builder.CreateString(event.InviterUserID)

	notificationfbs.LobbyInviteCreatedEventStart(builder)
	notificationfbs.LobbyInviteCreatedEventAddGameId(builder, gameID)
	notificationfbs.LobbyInviteCreatedEventAddInviterUserId(builder, inviterUserID)
	offset := notificationfbs.LobbyInviteCreatedEventEnd(builder)
	notificationfbs.FinishLobbyInviteCreatedEventBuffer(builder, offset)

	return builder.FinishedBytes(), nil
}

// PayloadToLobbyInviteCreatedEvent converts FlatBuffers payload bytes into
// LobbyInviteCreatedEvent.
func PayloadToLobbyInviteCreatedEvent(data []byte) (result *LobbyInviteCreatedEvent, err error) {
	if len(data) == 0 {
		return nil, errors.New("decode lobby invite created payload: data is empty")
	}

	defer recoverNotificationDecodePanic("decode lobby invite created payload", &result, &err)

	event := notificationfbs.GetRootAsLobbyInviteCreatedEvent(data, 0)
	gameID, err := requiredNotificationString(event.GameId(), "game_id")
	if err != nil {
		return nil, fmt.Errorf("decode lobby invite created payload: %w", err)
	}
	inviterUserID, err := requiredNotificationString(event.InviterUserId(), "inviter_user_id")
	if err != nil {
		return nil, fmt.Errorf("decode lobby invite created payload: %w", err)
	}

	return &LobbyInviteCreatedEvent{
		GameID:        gameID,
		InviterUserID: inviterUserID,
	}, nil
}

// LobbyInviteRedeemedEventToPayload converts LobbyInviteRedeemedEvent to
// FlatBuffers bytes suitable for the authenticated gateway push transport.
func LobbyInviteRedeemedEventToPayload(event *LobbyInviteRedeemedEvent) ([]byte, error) {
	if event == nil {
		return nil, errors.New("encode lobby invite redeemed payload: event is nil")
	}
	if event.GameID == "" {
		return nil, errors.New("encode lobby invite redeemed payload: game_id is empty")
	}
	if event.InviteeUserID == "" {
		return nil, errors.New("encode lobby invite redeemed payload: invitee_user_id is empty")
	}

	builder := flatbuffers.NewBuilder(96)
	gameID := builder.CreateString(event.GameID)
	inviteeUserID := builder.CreateString(event.InviteeUserID)

	notificationfbs.LobbyInviteRedeemedEventStart(builder)
	notificationfbs.LobbyInviteRedeemedEventAddGameId(builder, gameID)
	notificationfbs.LobbyInviteRedeemedEventAddInviteeUserId(builder, inviteeUserID)
	offset := notificationfbs.LobbyInviteRedeemedEventEnd(builder)
	notificationfbs.FinishLobbyInviteRedeemedEventBuffer(builder, offset)

	return builder.FinishedBytes(), nil
}

// PayloadToLobbyInviteRedeemedEvent converts FlatBuffers payload bytes into
// LobbyInviteRedeemedEvent.
func PayloadToLobbyInviteRedeemedEvent(data []byte) (result *LobbyInviteRedeemedEvent, err error) {
	if len(data) == 0 {
		return nil, errors.New("decode lobby invite redeemed payload: data is empty")
	}

	defer recoverNotificationDecodePanic("decode lobby invite redeemed payload", &result, &err)

	event := notificationfbs.GetRootAsLobbyInviteRedeemedEvent(data, 0)
	gameID, err := requiredNotificationString(event.GameId(), "game_id")
	if err != nil {
		return nil, fmt.Errorf("decode lobby invite redeemed payload: %w", err)
	}
	inviteeUserID, err := requiredNotificationString(event.InviteeUserId(), "invitee_user_id")
	if err != nil {
		return nil, fmt.Errorf("decode lobby invite redeemed payload: %w", err)
	}

	return &LobbyInviteRedeemedEvent{
		GameID:        gameID,
		InviteeUserID: inviteeUserID,
	}, nil
}

func requiredNotificationString(value []byte, field string) (string, error) {
	if len(value) == 0 {
		return "", fmt.Errorf("%s is missing", field)
	}

	return string(value), nil
}

func recoverNotificationDecodePanic[T any](message string, result **T, err *error) {
	if recovered := recover(); recovered != nil {
		*result = nil
		*err = fmt.Errorf("%s: panic recovered: %v", message, recovered)
	}
}