// Package testpg opens throwaway Postgres schemas for integration tests.
// Imported only from _test.go files, so it never reaches the server binary.
package testpg

import (
	"regexp"
	"testing"

	"gorm.io/driver/postgres"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
)

var schemaName = regexp.MustCompile(`^[a-z_][a-z0-9_]{0,62}$`)

// Open connects to a THROWAWAY Postgres (the DSN from REGISTRY_TEST_DSN)
// inside a schema of its own, created if missing.
//
// Each test package passes a different schema: `go test ./...` runs packages
// in parallel, and two packages dropping and recreating the same tables in the
// same schema at once fail each other at random.
func Open(t testing.TB, dsn, schema string) *gorm.DB {
	t.Helper()
	if !schemaName.MatchString(schema) {
		t.Fatalf("bad test schema name %q", schema)
	}
	cfg := &gorm.Config{Logger: logger.Default.LogMode(logger.Silent)}
	base, err := gorm.Open(postgres.Open(dsn), cfg)
	if err != nil {
		t.Fatalf("connect: %v", err)
	}
	if err := base.Exec("CREATE SCHEMA IF NOT EXISTS " + schema).Error; err != nil {
		t.Fatalf("create schema %s: %v", schema, err)
	}
	if sqlDB, err := base.DB(); err == nil {
		_ = sqlDB.Close()
	}
	db, err := gorm.Open(postgres.Open(dsn+" search_path="+schema), cfg)
	if err != nil {
		t.Fatalf("connect to schema %s: %v", schema, err)
	}
	t.Cleanup(func() {
		if sqlDB, err := db.DB(); err == nil {
			_ = sqlDB.Close()
		}
	})
	return db
}