package service

import (
	"context"

	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/repository"
	applogger "github.com/gochat/gochat/pkg/logger"
)

// FolderService implements business logic for Folder CRUD.
type FolderService struct {
	repo *repository.FolderRepo
}

func NewFolderService(repo *repository.FolderRepo) *FolderService {
	return &FolderService{repo: repo}
}

// CreateFolderRequest is the DTO for creating a folder.
type CreateFolderRequest struct {
	Name     string `json:"name" validate:"required,min=2"`
	Slug     string `json:"slug" validate:"required"`
	Position int    `json:"position"`
}

// UpdateFolderRequest is the DTO for updating a folder.
type UpdateFolderRequest struct {
	Name     string `json:"name"`
	Position *int   `json:"position"`
}

func (s *FolderService) Create(ctx context.Context, portalID uint, req *CreateFolderRequest) (*model.Folder, error) {
	folder := &model.Folder{
		PortalID: portalID,
		Name:     req.Name,
	}
	if err := s.repo.Create(ctx, folder); err != nil {
		applogger.L().Errorf("Create folder: %v", err)
		return nil, err
	}
	return folder, nil
}

func (s *FolderService) GetByID(ctx context.Context, id uint) (*model.Folder, error) {
	folder, err := s.repo.GetByID(ctx, id)
	if err != nil {
		applogger.L().Errorf("Get folder by ID: %v", err)
		return nil, err
	}
	return folder, nil
}

func (s *FolderService) Update(ctx context.Context, id uint, req *UpdateFolderRequest) (*model.Folder, error) {
	folder, err := s.repo.GetByID(ctx, id)
	if err != nil {
		applogger.L().Errorf("Get folder for update: %v", err)
		return nil, err
	}
	if req.Name != "" {
		folder.Name = req.Name
	}
	if err := s.repo.Update(ctx, folder); err != nil {
		applogger.L().Errorf("Update folder: %v", err)
		return nil, err
	}
	return folder, nil
}

func (s *FolderService) Delete(ctx context.Context, id uint) error {
	// Check existence first — GORM Delete() returns nil even for non-existent IDs
	if _, err := s.repo.GetByID(ctx, id); err != nil {
		applogger.L().Errorf("Find folder for delete: %v", err)
		return err
	}
	if err := s.repo.Delete(ctx, id); err != nil {
		applogger.L().Errorf("Delete folder: %v", err)
		return err
	}
	return nil
}

func (s *FolderService) ListByPortalID(ctx context.Context, portalID uint, offset, limit int) ([]model.Folder, int64, error) {
	folders, count, err := s.repo.FindByPortalID(ctx, portalID, offset, limit)
	if err != nil {
		applogger.L().Errorf("List folders by portal: %v", err)
		return nil, 0, err
	}
	return folders, count, nil
}