Added "create list" handler, service + repository

internal/repository/list.go

@@ -0,0 +1,64 @@
+package repository
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"log/slog"
+
+	"github.com/robindittmar/dttmr-api/internal/domain"
+)
+
+type ListRepo struct {
+	db *sql.DB
+}
+
+func NewListRepo(db *sql.DB) *ListRepo {
+	return &ListRepo{db: db}
+}
+
+func (r *ListRepo) CreateList(ctx context.Context, name string, userIDs []string) (*domain.List, error) {
+	tx, err := r.db.BeginTx(ctx, nil)
+	if err != nil {
+		return nil, fmt.Errorf("begin transaction: %w", err)
+	}
+	defer func() {
+		err := tx.Rollback()
+		if err != nil {
+			slog.Error("Failed to rollback transaction", slog.Any("error", err))
+		}
+	}()
+
+	list := &domain.List{Name: name}
+
+	err = tx.QueryRowContext(ctx,
+		"INSERT INTO lists (name) VALUES ($1) RETURNING id, created_at",
+		name,
+	).Scan(&list.ID, &list.CreatedAt)
+	if err != nil {
+		return nil, fmt.Errorf("failed to insert list: %w", err)
+	}
+
+	stmt, err := tx.PrepareContext(ctx, "INSERT INTO list_users (list_id, user_id) VALUES ($1, $2)")
+	if err != nil {
+		return nil, fmt.Errorf("failed to prepare user/list association statement: %w", err)
+	}
+	defer func() {
+		err := stmt.Close()
+		if err != nil {
+
+		}
+	}()
+
+	for _, userID := range userIDs {
+		if _, err = stmt.ExecContext(ctx, list.ID, userID); err != nil {
+			return nil, fmt.Errorf("failed to insert user/list association: %w", err)
+		}
+	}
+
+	if err := tx.Commit(); err != nil {
+		return nil, fmt.Errorf("commit transaction: %w", err)
+	}
+
+	return list, err
+}