package data

import (
	"context"
	"fmt"

	"github.com/go-kratos/kratos/v2/log"
	"gorm.io/gorm"
)

// ShareRepo implements share link persistence operations using GORM.
type ShareRepo struct {
	data *Data
	log  *log.Helper
}

// NewShareRepo creates a new ShareRepo.
func NewShareRepo(data *Data, logger log.Logger) *ShareRepo {
	return &ShareRepo{
		data: data,
		log:  log.NewHelper(logger),
	}
}

// Create inserts a new share link record.
func (r *ShareRepo) Create(ctx context.Context, share *ShareLinkPO) error {
	return r.data.DB(ctx).Create(share).Error
}

// GetByToken retrieves a share link by its token. Returns nil if not found.
func (r *ShareRepo) GetByToken(ctx context.Context, token string) (*ShareLinkPO, error) {
	return r.queryOne(ctx, "token = ?", token)
}

// GetByID retrieves a share link by its ID. Returns nil if not found.
func (r *ShareRepo) GetByID(ctx context.Context, id string) (*ShareLinkPO, error) {
	return r.queryOne(ctx, "id = ?", id)
}

// Delete removes a share link by ID and creator. Returns error if not found.
func (r *ShareRepo) Delete(ctx context.Context, id string, createdBy string) error {
	result := r.data.DB(ctx).
		Where("id = ? AND created_by = ?", id, createdBy).
		Delete(&ShareLinkPO{})
	if result.Error != nil {
		return fmt.Errorf("failed to delete share link: %w", result.Error)
	}
	if result.RowsAffected == 0 {
		return fmt.Errorf("share link not found or not owned by user")
	}
	return nil
}

// IncrementDownloadCount atomically increments the download count for the given token.
func (r *ShareRepo) IncrementDownloadCount(ctx context.Context, token string) error {
	result := r.data.DB(ctx).Model(&ShareLinkPO{}).
		Where("token = ?", token).
		UpdateColumn("download_count", gorm.Expr("download_count + 1"))
	if result.Error != nil {
		return fmt.Errorf("failed to increment download count: %w", result.Error)
	}
	return nil
}

// ListByResource retrieves all share links for a given resource, ordered by created_at descending.
func (r *ShareRepo) ListByResource(ctx context.Context, resourceType string, resourceID string) ([]ShareLinkPO, error) {
	var links []ShareLinkPO
	err := r.data.DB(ctx).
		Where("resource_type = ? AND resource_id = ?", resourceType, resourceID).
		Order("created_at DESC").
		Find(&links).Error
	if err != nil {
		return nil, fmt.Errorf("failed to list share links: %w", err)
	}
	return links, nil
}

func (r *ShareRepo) queryOne(ctx context.Context, query string, args ...interface{}) (*ShareLinkPO, error) {
	var share ShareLinkPO
	err := r.data.DB(ctx).Where(query, args...).First(&share).Error
	if err != nil {
		if isRecordNotFound(err) {
			return nil, nil
		}
		return nil, fmt.Errorf("failed to query share link: %w", err)
	}
	return &share, nil
}