package admin

import (
	"context"
	"server/internal/db"
	"server/internal/db/sqlc"
	"server/internal/model/common"
	"server/internal/model/request"
	"server/internal/pkg/dberr"
	"server/internal/pkg/errs"
)

type PostService struct {
	store *db.Store
}

func NewPostService(store *db.Store) *PostService {
	return &PostService{
		store: store,
	}
}

func (s *PostService) List(ctx context.Context, p *common.Pagination) (*common.PageResult[sqlc.ListPostsRow], error) {
	params := sqlc.ListPostsParams{
		Limit:  p.PageSize,
		Offset: (p.Page - 1) * p.PageSize,
	}

	total, err := s.store.CountPosts(ctx)
	if err != nil {
		return nil, err
	}

	list, err := s.store.ListPosts(ctx, params)
	if err != nil {
		return nil, err
	}

	return &common.PageResult[sqlc.ListPostsRow]{
		List:  list,
		Total: total,
	}, nil
}

func (s *PostService) FindByID(ctx context.Context, id int32) (*sqlc.GetPostByIDRow, error) {
	post, err := s.store.GetPostByID(ctx, id)
	if err != nil {
		return nil, dberr.MapNoRows(err, errs.ErrPostNotFound)
	}

	return &post, nil
}

func (s *PostService) Create(ctx context.Context, req request.CreatePostRequest) (int32, error) {
	postID, err := db.WithTxResult(ctx, s.store, func(q *sqlc.Queries) (int32, error) {
		params := sqlc.CreatePostParams{
			Title:       req.Title,
			CoverID:     req.CoverID,
			Slug:        req.Slug,
			Content:     req.Content,
			Summary:     req.Summary,
			Status:      *req.Status,
			Sort:        req.Sort,
			PublishedAt: req.PublishedAt,
		}

		// 创建博客
		postID, err := q.CreatePost(ctx, params)
		if err != nil {
			return 0, dberr.MapUniqueViolation(err, dberr.PostSlugKey, errs.ErrSlugAlreadyExists)
		}

		// 关联分类
		if err = q.CreatePostCategory(ctx, sqlc.CreatePostCategoryParams{
			PostID:     postID,
			CategoryID: *req.CategoryID,
		}); err != nil {
			return 0, err
		}

		var tagsParams []sqlc.CreatePostTagParams
		for _, tagID := range req.Tags {
			tagsParams = append(tagsParams, sqlc.CreatePostTagParams{
				PostID: postID,
				TagID:  tagID,
			})
		}

		if _, err = q.CreatePostTag(ctx, tagsParams); err != nil {
			return 0, err
		}

		return postID, nil
	})
	if err != nil {
		return 0, err
	}

	return postID, nil
}

func (s *PostService) Update(ctx context.Context, id int32, req request.UpdatePostRequest) error {
	return s.store.WithTx(ctx, func(q *sqlc.Queries) error {
		params := sqlc.UpdatePostParams{
			Title:       req.Title,
			Slug:        req.Slug,
			Content:     req.Content,
			Summary:     req.Summary,
			Status:      req.Status,
			Sort:        req.Sort,
			PublishedAt: req.PublishedAt,
			ID:          id,
		}

		if req.CoverID.Set {
			params.UpdateCoverID = true
			if req.CoverID.Valid {
				params.CoverID = &req.CoverID.Value
			}
		}

		rows, err := q.UpdatePost(ctx, params)
		if err != nil {
			return dberr.MapUniqueViolation(err, dberr.PostSlugKey, errs.ErrSlugAlreadyExists)
		}

		if err = dberr.MapRowsAffected(rows, nil, errs.ErrPostNotFound); err != nil {
			return err
		}

		// 先删除分类
		if err = q.DeletePostCategoryByPostID(ctx, id); err != nil {
			return err
		}

		if err = q.CreatePostCategory(ctx, sqlc.CreatePostCategoryParams{
			PostID:     id,
			CategoryID: *req.CategoryID,
		}); err != nil {
			return err
		}

		// 先删除标签
		if err = q.DeletePostTagByPostID(ctx, id); err != nil {
			return err
		}

		var tagsParams []sqlc.CreatePostTagParams
		for _, tagID := range req.Tags {
			tagsParams = append(tagsParams, sqlc.CreatePostTagParams{
				PostID: id,
				TagID:  tagID,
			})
		}

		if _, err = q.CreatePostTag(ctx, tagsParams); err != nil {
			return err
		}

		return nil
	})
}

func (s *PostService) Delete(ctx context.Context, id int32) error {
	return s.store.WithTx(ctx, func(q *sqlc.Queries) error {
		err := q.DeletePostCategoryByPostID(ctx, id)
		if err != nil {
			return err
		}

		rows, err := q.DeletePost(ctx, id)
		return dberr.MapRowsAffected(rows, err, errs.ErrPostNotFound)
	})
}