var (
	// ErrVersionNotFound must be returned by [GetMigration] when a migration version is not found.
	ErrVersionNotFound = errors.New("version not found")
)

type DBTxConn interface {
	ExecContext(ctx context.Context, query string, args ...any) (sql.Result, error)
	QueryContext(ctx context.Context, query string, args ...any) (*sql.Rows, error)
	QueryRowContext(ctx context.Context, query string, args ...any) *sql.Row
}

type Dialect string

const (
	DialectClickHouse Dialect = "clickhouse"
	DialectMSSQL      Dialect = "mssql"
	DialectMySQL      Dialect = "mysql"
	DialectPostgres   Dialect = "postgres"
	DialectRedshift   Dialect = "redshift"
	DialectSQLite3    Dialect = "sqlite3"
	DialectTiDB       Dialect = "tidb"
	DialectVertica    Dialect = "vertica"
	DialectYdB        Dialect = "ydb"
)

type GetMigrationResult struct {
	Timestamp time.Time
	IsApplied bool
}

type InsertRequest struct {
	Version int64
}

type ListMigrationsResult struct {
	Version   int64
	IsApplied bool
}

type Store interface {
	// Tablename is the version table used to record applied migrations. Must not be empty.
	Tablename() string

	// CreateVersionTable creates the version table. This table is used to record applied
	// migrations. When creating the table, the implementation must also insert a row for the
	// initial version (0).
	CreateVersionTable(ctx context.Context, db DBTxConn) error

	// Insert inserts a version id into the version table.
	Insert(ctx context.Context, db DBTxConn, req InsertRequest) error

	// Delete deletes a version id from the version table.
	Delete(ctx context.Context, db DBTxConn, version int64) error

	// GetMigration retrieves a single migration by version id. If the query succeeds, but the
	// version is not found, this method must return [ErrVersionNotFound].
	GetMigration(ctx context.Context, db DBTxConn, version int64) (*GetMigrationResult, error)

	// ListMigrations retrieves all migrations sorted in descending order by id or timestamp. If
	// there are no migrations, return empty slice with no error. Typically this method will return
	// at least one migration, because the initial version (0) is always inserted into the version
	// table when it is created.
	ListMigrations(ctx context.Context, db DBTxConn) ([]*ListMigrationsResult, error)
	// contains filtered or unexported methods
}