feat: first commit

backend/internal/adapter/postgres/user_repo.go

@@ -0,0 +1,58 @@
+package postgres
+
+import (
+	"context"
+	"crypto/rand"
+	"errors"
+
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+
+	"github.com/snip/backend/internal/domain"
+)
+
+type UserRepo struct{ pool *pgxpool.Pool }
+
+func NewUserRepo(pool *pgxpool.Pool) *UserRepo { return &UserRepo{pool: pool} }
+
+func (r *UserRepo) Upsert(ctx context.Context, u *domain.User) (*domain.User, error) {
+	id := newUserID()
+	var out domain.User
+	err := r.pool.QueryRow(ctx,
+		`INSERT INTO users (id, email, name, provider, subject)
+		 VALUES ($1,$2,$3,$4,$5)
+		 ON CONFLICT (provider, subject)
+		 DO UPDATE SET email = EXCLUDED.email, name = EXCLUDED.name
+		 RETURNING id, email, name, provider, subject`,
+		id, u.Email, u.Name, u.Provider, u.Subject).
+		Scan(&out.ID, &out.Email, &out.Name, &out.Provider, &out.Subject)
+	if err != nil {
+		return nil, err
+	}
+	return &out, nil
+}
+
+func (r *UserRepo) GetByID(ctx context.Context, id string) (*domain.User, error) {
+	var u domain.User
+	err := r.pool.QueryRow(ctx,
+		`SELECT id, email, name, provider, subject FROM users WHERE id=$1`, id).
+		Scan(&u.ID, &u.Email, &u.Name, &u.Provider, &u.Subject)
+	if errors.Is(err, pgx.ErrNoRows) {
+		return nil, domain.ErrNotFound
+	}
+	if err != nil {
+		return nil, err
+	}
+	return &u, nil
+}
+
+func newUserID() string {
+	const hex = "0123456789abcdef"
+	b := make([]byte, 16)
+	_, _ = rand.Read(b)
+	out := make([]byte, 16)
+	for i := range out {
+		out[i] = hex[int(b[i])%16]
+	}
+	return "u_" + string(out)
+}