1 files changed, 187 insertions, 0 deletions
diff --git a/src/post/draft_post.go b/src/post/draft_post.go
new file mode 100644
index 0000000..61283c3
--- /dev/null
+++ b/src/post/draft_post.go
@@ -0,0 +1,187 @@
+package post
+
+import (
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"fmt"
+)
+
+type DraftStore interface {
+
+	// Set sets the draft Post's data into the storage, keyed by the draft
+	// Post's ID.
+	Set(post Post) error
+
+	// Get returns count draft Posts, sorted id descending, offset by the
+	// given page number. The returned boolean indicates if there are more pages
+	// or not.
+	Get(page, count int) ([]Post, bool, error)
+
+	// GetByID will return the draft Post with the given ID, or ErrPostNotFound.
+	GetByID(id string) (Post, error)
+
+	// Delete will delete the draft Post with the given ID.
+	Delete(id string) error
+}
+
+type draftStore struct {
+	db *SQLDB
+}
+
+// NewDraftStore initializes a new DraftStore using an existing SQLDB.
+func NewDraftStore(db *SQLDB) DraftStore {
+	return &draftStore{
+		db: db,
+	}
+}
+
+func (s *draftStore) Set(post Post) error {
+
+	if post.ID == "" {
+		return errors.New("post ID can't be empty")
+	}
+
+	tagsJSON, err := json.Marshal(post.Tags)
+	if err != nil {
+		return fmt.Errorf("json marshaling tags %#v: %w", post.Tags, err)
+	}
+
+	_, err = s.db.db.Exec(
+		`INSERT INTO post_drafts (
+				id, title, description, tags, series, body
+			)
+			VALUES
+			(?, ?, ?, ?, ?, ?)
+			ON CONFLICT (id) DO UPDATE SET
+				title=excluded.title,
+				description=excluded.description,
+				tags=excluded.tags,
+				series=excluded.series,
+				body=excluded.body`,
+		post.ID,
+		post.Title,
+		post.Description,
+		&sql.NullString{String: string(tagsJSON), Valid: len(post.Tags) > 0},
+		&sql.NullString{String: post.Series, Valid: post.Series != ""},
+		post.Body,
+	)
+
+	if err != nil {
+		return fmt.Errorf("inserting into post_drafts: %w", err)
+	}
+
+	return nil
+}
+
+func (s *draftStore) get(
+	querier interface {
+		Query(string, ...interface{}) (*sql.Rows, error)
+	},
+	limit, offset int,
+	where string, whereArgs ...interface{},
+) (
+	[]Post, error,
+) {
+
+	query := `
+		SELECT
+			p.id, p.title, p.description, p.tags, p.series, p.body
+		FROM post_drafts p
+		` + where + `
+		ORDER BY p.id ASC`
+
+	if limit > 0 {
+		query += fmt.Sprintf(" LIMIT %d", limit)
+	}
+
+	if offset > 0 {
+		query += fmt.Sprintf(" OFFSET %d", offset)
+	}
+
+	rows, err := querier.Query(query, whereArgs...)
+
+	if err != nil {
+		return nil, fmt.Errorf("selecting: %w", err)
+	}
+
+	defer rows.Close()
+
+	var posts []Post
+
+	for rows.Next() {
+
+		var (
+			post         Post
+			tags, series sql.NullString
+		)
+
+		err := rows.Scan(
+			&post.ID, &post.Title, &post.Description, &tags, &series,
+			&post.Body,
+		)
+
+		if err != nil {
+			return nil, fmt.Errorf("scanning row: %w", err)
+		}
+
+		post.Series = series.String
+
+		if tags.String != "" {
+
+			if err := json.Unmarshal([]byte(tags.String), &post.Tags); err != nil {
+				return nil, fmt.Errorf("json parsing %q: %w", tags.String, err)
+			}
+		}
+
+		posts = append(posts, post)
+	}
+
+	return posts, nil
+}
+
+func (s *draftStore) Get(page, count int) ([]Post, bool, error) {
+
+	posts, err := s.get(s.db.db, count+1, page*count, ``)
+
+	if err != nil {
+		return nil, false, fmt.Errorf("querying post_drafts: %w", err)
+	}
+
+	var hasMore bool
+
+	if len(posts) > count {
+		hasMore = true
+		posts = posts[:count]
+	}
+
+	return posts, hasMore, nil
+}
+
+func (s *draftStore) GetByID(id string) (Post, error) {
+
+	posts, err := s.get(s.db.db, 0, 0, `WHERE p.id=?`, id)
+
+	if err != nil {
+		return Post{}, fmt.Errorf("querying post_drafts: %w", err)
+	}
+
+	if len(posts) == 0 {
+		return Post{}, ErrPostNotFound
+	}
+
+	if len(posts) > 1 {
+		panic(fmt.Sprintf("got back multiple draft posts querying id %q: %+v", id, posts))
+	}
+
+	return posts[0], nil
+}
+
+func (s *draftStore) Delete(id string) error {
+
+	if _, err := s.db.db.Exec(`DELETE FROM post_drafts WHERE id = ?`, id); err != nil {
+		return fmt.Errorf("deleting from post_drafts: %w", err)
+	}
+
+	return nil
+}