package photos

import (
	"context"
	"encoding/json"
	"errors"

	"galo/internal/httpx"
	"galo/internal/models"
	"galo/internal/roles"
)

// editablePhoto loads a photo and checks that the user may change its
// editing parameters: the uploader of the photo or an album owner/admin.
func (s *Service) editablePhoto(ctx context.Context, photoID, userID string) (*models.Photo, error) {
	p, err := s.store.GetByID(ctx, photoID, userID)
	if err != nil {
		if errors.Is(err, ErrNotFound) {
			return nil, httpx.NotFound("photo_not_found", "photo not found")
		}
		return nil, err
	}
	if p.DeletedAt != nil {
		return nil, httpx.NotFound("photo_not_found", "photo not found")
	}
	_, role, err := s.albums.Access(ctx, p.AlbumID, userID)
	if err != nil {
		return nil, err
	}
	own := p.UploaderID == userID
	if !(roles.CanDeleteAnyPhoto(role) || (own && roles.CanDeleteOwnPhoto(role))) {
		return nil, httpx.Forbidden("forbidden", "you cannot edit this photo")
	}
	return p, nil
}

// EditPhoto stores new editing parameters for a photo and schedules the
// render of the edited version. The original object is never modified, so the
// edit can always be reset.
func (s *Service) EditPhoto(ctx context.Context, photoID, userID string, params EditParams) (*models.Photo, error) {
	p, err := s.editablePhoto(ctx, photoID, userID)
	if err != nil {
		return nil, err
	}
	if p.Kind != KindImage {
		return nil, httpx.BadRequest("invalid_request", "only images can be edited")
	}
	params = params.Normalized()
	if params.IsEmpty() {
		return s.ResetEdit(ctx, photoID, userID)
	}
	if err := s.store.SetEditParams(ctx, photoID, params.JSON()); err != nil {
		return nil, err
	}
	if err := s.store.EnqueueEditJob(ctx, photoID); err != nil {
		return nil, err
	}
	// Рендер начинается сразу, а не в конце цикла воркера.
	if s.wakeEdit != nil {
		s.wakeEdit()
	}
	return s.publishEdit(ctx, photoID, userID)
}

// ResetEdit removes the editing parameters of a photo together with the
// edited version, returning the photo to its original look.
func (s *Service) ResetEdit(ctx context.Context, photoID, userID string) (*models.Photo, error) {
	if _, err := s.editablePhoto(ctx, photoID, userID); err != nil {
		return nil, err
	}
	if err := s.store.ClearEditParams(ctx, photoID); err != nil {
		return nil, err
	}
	if err := s.store.DeleteEditJob(ctx, photoID); err != nil {
		return nil, err
	}
	if err := s.store.DeleteObjectBindings(ctx, photoID, EditRoles()...); err != nil {
		return nil, err
	}
	return s.publishEdit(ctx, photoID, userID)
}

// publishEdit reloads a photo with its current editing state and notifies the
// album subscribers.
func (s *Service) publishEdit(ctx context.Context, photoID, userID string) (*models.Photo, error) {
	p, err := s.store.GetByID(ctx, photoID, userID)
	if err != nil {
		if errors.Is(err, ErrNotFound) {
			return nil, httpx.NotFound("photo_not_found", "photo not found")
		}
		return nil, err
	}
	if err := s.attachURLs(ctx, p); err != nil {
		return nil, err
	}
	s.hub.Publish(p.AlbumID, "photo.updated", p)
	return p, nil
}

// EditParamsOf returns the editing parameters stored on a photo.
func EditParamsOf(p *models.Photo) EditParams {
	if p == nil || len(p.EditParams) == 0 {
		return EditParams{}
	}
	data, err := json.Marshal(p.EditParams)
	if err != nil {
		return EditParams{}
	}
	params, err := ParseEditParams(data)
	if err != nil {
		return EditParams{}
	}
	return params
}