feat(api): add POST /members

backend/db/member.go

@@ -5,10 +5,13 @@ import (
 
 	"emperror.dev/errors"
 	"github.com/georgysavva/scany/pgxscan"
+	"github.com/jackc/pgconn"
 	"github.com/jackc/pgx/v4"
 	"github.com/rs/xid"
 )
 
+const MaxMemberCount = 500
+
 type Member struct {
 	ID         xid.ID
 	UserID     xid.ID
@@ -18,7 +21,10 @@ type Member struct {
 	Links      []string
 }
 
-const ErrMemberNotFound = errors.Sentinel("member not found")
+const (
+	ErrMemberNotFound  = errors.Sentinel("member not found")
+	ErrMemberNameInUse = errors.Sentinel("member name already in use")
+)
 
 func (db *DB) Member(ctx context.Context, id xid.ID) (m Member, err error) {
 	sql, args, err := sq.Select("*").From("members").Where("id = ?", id).ToSql()
@@ -71,3 +77,43 @@ func (db *DB) UserMembers(ctx context.Context, userID xid.ID) (ms []Member, err
 	}
 	return ms, nil
 }
+
+// CreateMember creates a member.
+func (db *DB) CreateMember(ctx context.Context, tx pgx.Tx, userID xid.ID, name, bio string, links []string) (m Member, err error) {
+	sql, args, err := sq.Insert("members").
+		Columns("user_id", "id", "name", "bio", "links").
+		Values(userID, xid.New(), name, bio, links).
+		Suffix("RETURNING *").ToSql()
+	if err != nil {
+		return m, errors.Wrap(err, "building sql")
+	}
+
+	err = pgxscan.Get(ctx, db, &m, sql, args...)
+	if err != nil {
+		pge := &pgconn.PgError{}
+		if errors.As(err, &pge) {
+			if pge.Code == "23505" {
+				return m, ErrMemberNameInUse
+			}
+		}
+
+		return m, errors.Wrap(err, "executing query")
+	}
+
+	return m, nil
+}
+
+// MemberCount returns the number of members that the given user has.
+func (db *DB) MemberCount(ctx context.Context, userID xid.ID) (n int64, err error) {
+	sql, args, err := sq.Select("count(id)").From("members").Where("user_id = ?", userID).ToSql()
+	if err != nil {
+		return 0, errors.Wrap(err, "building sql")
+	}
+
+	err = db.QueryRow(ctx, sql, args...).Scan(&n)
+	if err != nil {
+		return 0, errors.Wrap(err, "executing query")
+	}
+
+	return n, nil
+}