package orm

import (
	"context"
	"io"

	"github.com/go-pg/pg/types"
)

// ColumnScanner is used to scan column values.
type ColumnScanner interface {
	// Scan assigns a column value from a row.
	//
	// An error should be returned if the value can not be stored
	// without loss of information.
	ScanColumn(colIdx int, colName string, rd types.Reader, n int) error
}

type QueryAppender interface {
	Copy() QueryAppender
	Query() *Query
	AppendQuery(dst []byte) ([]byte, error)
}

type QueryFormatter interface {
	FormatQuery(b []byte, query string, params ...interface{}) []byte
}

// DB is a common interface for pg.DB and pg.Tx types.
type DB interface {
	Model(model ...interface{}) *Query
	Select(model interface{}) error
	Insert(model ...interface{}) error
	Update(model interface{}) error
	Delete(model interface{}) error
	ForceDelete(model interface{}) error

	Exec(query interface{}, params ...interface{}) (Result, error)
	ExecOne(query interface{}, params ...interface{}) (Result, error)
	Query(coll, query interface{}, params ...interface{}) (Result, error)
	QueryOne(model, query interface{}, params ...interface{}) (Result, error)

	CopyFrom(r io.Reader, query interface{}, params ...interface{}) (Result, error)
	CopyTo(w io.Writer, query interface{}, params ...interface{}) (Result, error)

	Context() context.Context
	QueryFormatter
}