package event

import (
	"context"
	"fmt"
	"sync"

	. "git.gorlug.de/code/ersteller"
	"git.gorlug.de/code/ersteller/schema/ent"
)

type Listener interface {
	OnEvent(ctx context.Context, userId int, name string, data any)
}

type Service struct {
	entClient *ent.Client
	listeners []Listener
	mu        sync.RWMutex
}

func NewService(entClient *ent.Client) *Service {
	return &Service{
		entClient: entClient,
		listeners: make([]Listener, 0),
	}
}

func (s *Service) AddListener(listener Listener) {
	s.mu.Lock()
	defer s.mu.Unlock()
	s.listeners = append(s.listeners, listener)
}

func (s *Service) RemoveListener(listener Listener) {
	s.mu.Lock()
	defer s.mu.Unlock()
	for i, l := range s.listeners {
		if l == listener {
			s.listeners = append(s.listeners[:i], s.listeners[i+1:]...)
			return
		}
	}
}

func (s *Service) notifyListeners(ctx context.Context, userId int, name string, data any) {
	s.mu.RLock()
	defer s.mu.RUnlock()
	for _, listener := range s.listeners {
		go listener.OnEvent(ctx, userId, name, data)
	}
}

func (s *Service) Create(htmxContext HtmxContext, name string, data any) error {
	err := Create(s.entClient, htmxContext, name, data)
	if err == nil {
		var userId int
		ok, authContext := htmxContext.GetAuthContext()
		if ok {
			userId = authContext.UserId
		} else {
			userId = -1
		}
		s.notifyListeners(htmxContext.GetGoContext(), userId, name, data)
	}
	return err
}

func Should(err error) {
	if err != nil {
		Error("should not happen: ", err)
	}
}

func Create(entClient *ent.Client, c HtmxContext, name string, data any) error {
	Debug("event", name, data)
	hasAuth, authContext := c.GetAuthContext()
	if !hasAuth {
		return fmt.Errorf("failed to get auth context")
	}
	return CreateWithSession(entClient, c.GetGoContext(), authContext, name, data)
}

func CreateWithSession(entClient *ent.Client, ctx context.Context,
	auth AuthContext, name string, data any) error {
	return CreateWithSessionAndNotify(entClient, ctx, auth, name, data, nil)
}

func CreateWithSessionAndNotify(entClient *ent.Client, ctx context.Context,
	auth AuthContext, name string, data any, service *Service) error {
	Debug("event", name, data)
	var mapData JSONB
	if data == nil {
		mapData = make(JSONB)
	} else {
		mappedStruct, err := StructToMap(data)
		if err != nil {
			return fmt.Errorf("failed to map data to map for event create: %w", err)
		}
		mapData = mappedStruct
	}
	_, err := entClient.Event.Create().
		SetUserID(auth.UserId).
		SetName(name).
		SetData(mapData).
		Save(ctx)
	if err != nil {
		return fmt.Errorf("failed to create event: %w", err)
	}
	if service != nil {
		service.notifyListeners(ctx, auth.UserId, name, data)
	}
	return nil
}