package service

import (
	"context"
	"errors"

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

// BannerService implements business logic for Banner operations.
// Reference: Chatwoot Platform::Api::V1::BannersController — super-admin CRUD,
// and api/v1/accounts/:account_id/banners — read-only list of active banners.
type BannerService struct {
	repo *repository.BannerRepo
}

// NewBannerService creates a new BannerService.
func NewBannerService(repo *repository.BannerRepo) *BannerService {
	return &BannerService{repo: repo}
}

// List retrieves all banners with pagination (platform admin).
func (s *BannerService) List(ctx context.Context, offset, limit int) ([]model.Banner, int64, error) {
	banners, total, err := s.repo.List(ctx, offset, limit)
	if err != nil {
		applogger.L().Errorf("BannerService.List error: %v", err)
		return nil, 0, err
	}
	return banners, total, nil
}

// Get retrieves a single banner by ID.
func (s *BannerService) Get(ctx context.Context, id uint) (*model.Banner, error) {
	banner, err := s.repo.FindByID(ctx, id)
	if err != nil {
		applogger.L().Errorf("BannerService.Get error: %v", err)
		return nil, err
	}
	return banner, nil
}

// Create creates a new banner.
func (s *BannerService) Create(ctx context.Context, banner *model.Banner) error {
	if banner.Title == "" {
		return errors.New("title is required")
	}
	if banner.Content == "" {
		return errors.New("content is required")
	}
	if banner.BannerType == "" {
		return errors.New("banner_type is required")
	}
	if err := s.repo.Create(ctx, banner); err != nil {
		applogger.L().Errorf("BannerService.Create error: %v", err)
		return err
	}
	return nil
}

// Update patches an existing banner.
func (s *BannerService) Update(ctx context.Context, id uint, updates map[string]interface{}) error {
	if id == 0 {
		return errors.New("invalid banner ID")
	}
	if err := s.repo.Update(ctx, id, updates); err != nil {
		applogger.L().Errorf("BannerService.Update error: %v", err)
		return err
	}
	return nil
}

// Delete soft-deletes a banner by ID.
func (s *BannerService) Delete(ctx context.Context, id uint) error {
	if id == 0 {
		return errors.New("invalid banner ID")
	}
	if err := s.repo.Delete(ctx, id); err != nil {
		applogger.L().Errorf("BannerService.Delete error: %v", err)
		return err
	}
	return nil
}

// ListActive returns all active banners (for account-scoped read-only endpoint).
func (s *BannerService) ListActive(ctx context.Context) ([]model.Banner, error) {
	banners, err := s.repo.FindActive(ctx)
	if err != nil {
		applogger.L().Errorf("BannerService.ListActive error: %v", err)
		return nil, err
	}
	return banners, nil
}