package service

import (
	"errors"
	"go_redis_learn2/domain"
	"go_redis_learn2/internal/repository"
)

// IPostService 定义文章服务的业务接口
type IPostService interface {
	CreatePost(post domain.Post) error
	DeletePost(id uint) error
	UpdatePost(post domain.Post) error
	GetAllPosts() ([]domain.Post, error)
}

// PostService 实现 IPostService 接口
type PostService struct {
	repo *repository.PostRepository
}

var _ IPostService = (*PostService)(nil)

// NewPostService 创建 PostService 实例
func NewPostService(repo *repository.PostRepository) IPostService {
	return &PostService{
		repo: repo,
	}
}

// CreatePost 创建新文章
func (s *PostService) CreatePost(post domain.Post) error {
	if err := s.validatePost(post); err != nil {
		return err
	}
	return s.repo.Create(post)
}

// DeletePost 根据ID删除文章
func (s *PostService) DeletePost(id uint) error {
	if id == 0 {
		return errors.New("invalid post id")
	}
	return s.repo.DeleteByID(id)
}

// UpdatePost 更新文章
func (s *PostService) UpdatePost(post domain.Post) error {
	if post.ID == 0 {
		return errors.New("invalid post id")
	}
	if err := s.validatePost(post); err != nil {
		return err
	}
	return s.repo.Update(post)
}

// GetAllPosts 获取所有文章
func (s *PostService) GetAllPosts() ([]domain.Post, error) {
	return s.repo.FindAll()
}

// validatePost 验证文章数据
func (s *PostService) validatePost(post domain.Post) error {
	if post.Title == "" {
		return errors.New("标题不能为空")
	}
	if len(post.Title) > 100 {
		return errors.New("标题长度不能超过100个字符")
	}
	if post.Text == "" {
		return errors.New("文章内容不能为空")
	}
	return nil
}