implement DraftStore

4 files changed, 372 insertions, 56 deletions

diff --git a/srv/src/post/draft_post.go b/srv/src/post/draft_post.go
new file mode 100644
index 0000000..af52965
--- /dev/null
+++ b/srv/src/post/draft_post.go
@@ -0,0 +1,186 @@
+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
+		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
+}
diff --git a/srv/src/post/draft_post_test.go b/srv/src/post/draft_post_test.go
new file mode 100644
index 0000000..f404bb0
--- /dev/null
+++ b/srv/src/post/draft_post_test.go
@@ -0,0 +1,130 @@
+package post
+
+import (
+	"sort"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type draftStoreTestHarness struct {
+	store DraftStore
+}
+
+func newDraftStoreTestHarness(t *testing.T) draftStoreTestHarness {
+
+	db := NewInMemSQLDB()
+	t.Cleanup(func() { db.Close() })
+
+	store := NewDraftStore(db)
+
+	return draftStoreTestHarness{
+		store: store,
+	}
+}
+
+func TestDraftStore(t *testing.T) {
+
+	assertPostEqual := func(t *testing.T, exp, got Post) {
+		t.Helper()
+		sort.Strings(exp.Tags)
+		sort.Strings(got.Tags)
+		assert.Equal(t, exp, got)
+	}
+
+	assertPostsEqual := func(t *testing.T, exp, got []Post) {
+		t.Helper()
+
+		if !assert.Len(t, got, len(exp), "exp:%+v\ngot: %+v", exp, got) {
+			return
+		}
+
+		for i := range exp {
+			assertPostEqual(t, exp[i], got[i])
+		}
+	}
+
+	t.Run("not_found", func(t *testing.T) {
+		h := newDraftStoreTestHarness(t)
+
+		_, err := h.store.GetByID("foo")
+		assert.ErrorIs(t, err, ErrPostNotFound)
+	})
+
+	t.Run("set_get_delete", func(t *testing.T) {
+		h := newDraftStoreTestHarness(t)
+
+		post := testPost(0)
+		post.Tags = []string{"foo", "bar"}
+
+		err := h.store.Set(post)
+		assert.NoError(t, err)
+
+		gotPost, err := h.store.GetByID(post.ID)
+		assert.NoError(t, err)
+
+		assertPostEqual(t, post, gotPost)
+
+		// we will now try updating the post, and ensure it updates properly
+
+		post.Title = "something else"
+		post.Series = "whatever"
+		post.Body = "anything"
+		post.Tags = []string{"bar", "baz"}
+
+		err = h.store.Set(post)
+		assert.NoError(t, err)
+
+		gotPost, err = h.store.GetByID(post.ID)
+		assert.NoError(t, err)
+
+		assertPostEqual(t, post, gotPost)
+
+		// delete the post, it should go away
+		assert.NoError(t, h.store.Delete(post.ID))
+
+		_, err = h.store.GetByID(post.ID)
+		assert.ErrorIs(t, err, ErrPostNotFound)
+	})
+
+	t.Run("get", func(t *testing.T) {
+		h := newDraftStoreTestHarness(t)
+
+		posts := []Post{
+			testPost(0),
+			testPost(1),
+			testPost(2),
+			testPost(3),
+		}
+
+		for _, post := range posts {
+			err := h.store.Set(post)
+			assert.NoError(t, err)
+		}
+
+		gotPosts, hasMore, err := h.store.Get(0, 2)
+		assert.NoError(t, err)
+		assert.True(t, hasMore)
+		assertPostsEqual(t, posts[:2], gotPosts)
+
+		gotPosts, hasMore, err = h.store.Get(1, 2)
+		assert.NoError(t, err)
+		assert.False(t, hasMore)
+		assertPostsEqual(t, posts[2:4], gotPosts)
+
+		posts = append(posts, testPost(4))
+		err = h.store.Set(posts[4])
+		assert.NoError(t, err)
+
+		gotPosts, hasMore, err = h.store.Get(1, 2)
+		assert.NoError(t, err)
+		assert.True(t, hasMore)
+		assertPostsEqual(t, posts[2:4], gotPosts)
+
+		gotPosts, hasMore, err = h.store.Get(2, 2)
+		assert.NoError(t, err)
+		assert.False(t, hasMore)
+		assertPostsEqual(t, posts[4:], gotPosts)
+	})
+
+}
diff --git a/srv/src/post/post.go b/srv/src/post/post.go
index a39af61..03bce6c 100644
--- a/srv/src/post/post.go
+++ b/srv/src/post/post.go
@@ -77,44 +77,16 @@ type Store interface {
 }
 
 type store struct {
-	db *sql.DB
+	db *SQLDB
 }
 
 // NewStore initializes a new Store using an existing SQLDB.
 func NewStore(db *SQLDB) Store {
 	return &store{
-		db: db.db,
+		db: db,
 	}
 }
 
-// if the callback returns an error then the transaction is aborted.
-func (s *store) withTx(cb func(*sql.Tx) error) error {
-
-	tx, err := s.db.Begin()
-
-	if err != nil {
-		return fmt.Errorf("starting transaction: %w", err)
-	}
-
-	if err := cb(tx); err != nil {
-
-		if rollbackErr := tx.Rollback(); rollbackErr != nil {
-			return fmt.Errorf(
-				"rolling back transaction: %w (original error: %v)",
-				rollbackErr, err,
-			)
-		}
-
-		return fmt.Errorf("performing transaction: %w (rolled back)", err)
-	}
-
-	if err := tx.Commit(); err != nil {
-		return fmt.Errorf("committing transaction: %w", err)
-	}
-
-	return nil
-}
-
 func (s *store) Set(post Post, now time.Time) (bool, error) {
 
 	if post.ID == "" {
@@ -123,7 +95,7 @@ func (s *store) Set(post Post, now time.Time) (bool, error) {
 
 	var first bool
 
-	err := s.withTx(func(tx *sql.Tx) error {
+	err := s.db.withTx(func(tx *sql.Tx) error {
 
 		nowTS := now.Unix()
 
@@ -270,7 +242,7 @@ func (s *store) get(
 
 func (s *store) Get(page, count int) ([]StoredPost, bool, error) {
 
-	posts, err := s.get(s.db, count+1, page*count, ``)
+	posts, err := s.get(s.db.db, count+1, page*count, ``)
 
 	if err != nil {
 		return nil, false, fmt.Errorf("querying posts: %w", err)
@@ -288,7 +260,7 @@ func (s *store) Get(page, count int) ([]StoredPost, bool, error) {
 
 func (s *store) GetByID(id string) (StoredPost, error) {
 
-	posts, err := s.get(s.db, 0, 0, `WHERE p.id=?`, id)
+	posts, err := s.get(s.db.db, 0, 0, `WHERE p.id=?`, id)
 
 	if err != nil {
 		return StoredPost{}, fmt.Errorf("querying posts: %w", err)
@@ -306,14 +278,14 @@ func (s *store) GetByID(id string) (StoredPost, error) {
 }
 
 func (s *store) GetBySeries(series string) ([]StoredPost, error) {
-	return s.get(s.db, 0, 0, `WHERE p.series=?`, series)
+	return s.get(s.db.db, 0, 0, `WHERE p.series=?`, series)
 }
 
 func (s *store) GetByTag(tag string) ([]StoredPost, error) {
 
 	var posts []StoredPost
 
-	err := s.withTx(func(tx *sql.Tx) error {
+	err := s.db.withTx(func(tx *sql.Tx) error {
 
 		rows, err := tx.Query(`SELECT post_id FROM post_tags WHERE tag = ?`, tag)
 
@@ -357,7 +329,7 @@ func (s *store) GetByTag(tag string) ([]StoredPost, error) {
 
 func (s *store) GetTags() ([]string, error) {
 
-	rows, err := s.db.Query(`SELECT tag FROM post_tags GROUP BY tag`)
+	rows, err := s.db.db.Query(`SELECT tag FROM post_tags GROUP BY tag`)
 	if err != nil {
 		return nil, fmt.Errorf("querying all tags: %w", err)
 	}
@@ -381,23 +353,16 @@ func (s *store) GetTags() ([]string, error) {
 
 func (s *store) Delete(id string) error {
 
-	tx, err := s.db.Begin()
-
-	if err != nil {
-		return fmt.Errorf("starting transaction: %w", err)
-	}
-
-	if _, err := tx.Exec(`DELETE FROM post_tags WHERE post_id = ?`, id); err != nil {
-		return fmt.Errorf("deleting from post_tags: %w", err)
-	}
+	return s.db.withTx(func(tx *sql.Tx) error {
 
-	if _, err := tx.Exec(`DELETE FROM posts WHERE id = ?`, id); err != nil {
-		return fmt.Errorf("deleting from posts: %w", err)
-	}
+		if _, err := tx.Exec(`DELETE FROM post_tags WHERE post_id = ?`, id); err != nil {
+			return fmt.Errorf("deleting from post_tags: %w", err)
+		}
 
-	if err := tx.Commit(); err != nil {
-		return fmt.Errorf("committing transaction: %w", err)
-	}
+		if _, err := tx.Exec(`DELETE FROM posts WHERE id = ?`, id); err != nil {
+			return fmt.Errorf("deleting from posts: %w", err)
+		}
 
-	return nil
+		return nil
+	})
 }
diff --git a/srv/src/post/sql.go b/srv/src/post/sql.go
index 16cdc95..c768c9a 100644
--- a/srv/src/post/sql.go
+++ b/srv/src/post/sql.go
@@ -38,10 +38,18 @@ var migrations = &migrate.MemoryMigrationSource{Migrations: []*migrate.Migration
 				body BLOB NOT NULL
 			)`,
 		},
-		Down: []string{
-			"DROP TABLE assets",
-			"DROP TABLE post_tags",
-			"DROP TABLE posts",
+	},
+	{
+		Id: "2",
+		Up: []string{
+			`CREATE TABLE post_drafts (
+				id          TEXT NOT NULL PRIMARY KEY,
+				title       TEXT NOT NULL,
+				description TEXT NOT NULL,
+				tags        TEXT,
+				series      TEXT,
+				body        TEXT NOT NULL
+			)`,
 		},
 	},
 }}
@@ -89,3 +97,30 @@ func NewInMemSQLDB() *SQLDB {
 func (db *SQLDB) Close() error {
 	return db.db.Close()
 }
+
+func (db *SQLDB) withTx(cb func(*sql.Tx) error) error {
+
+	tx, err := db.db.Begin()
+
+	if err != nil {
+		return fmt.Errorf("starting transaction: %w", err)
+	}
+
+	if err := cb(tx); err != nil {
+
+		if rollbackErr := tx.Rollback(); rollbackErr != nil {
+			return fmt.Errorf(
+				"rolling back transaction: %w (original error: %v)",
+				rollbackErr, err,
+			)
+		}
+
+		return fmt.Errorf("performing transaction: %w (rolled back)", err)
+	}
+
+	if err := tx.Commit(); err != nil {
+		return fmt.Errorf("committing transaction: %w", err)
+	}
+
+	return nil
+}