package gsb

import "database/sql"

//
// Author: 陈永佳 chenyongjia@parkingwang.com, yoojiachen@gmail.com
//

type SQLPrepare interface {
	Prepare(query string) (*sql.Stmt, error)
}

type Executor struct {
	query     string
	DBPrepare SQLPrepare
	logger    func(sql string, args []interface{})
}

func newExecute(query string, prepare SQLPrepare) *Executor {
	return &Executor{
		query:     query,
		DBPrepare: prepare,
	}
}

func (slf *Executor) Logger(logger func(string, []interface{})) *Executor {
	slf.logger = logger
	return slf
}

func (slf *Executor) Exec(args ...interface{}) (sql.Result, error) {
	if nil != slf.logger {
		slf.logger(slf.query, args)
	}

	stmt, pErr := slf.DBPrepare.Prepare(slf.query)
	if nil != pErr {
		return nil, pErr
	}
	defer stmt.Close()

	return stmt.Exec(args...)
}

func (slf *Executor) Query(args ...interface{}) (*sql.Rows, error) {
	if nil != slf.logger {
		slf.logger(slf.query, args)
	}

	stmt, pErr := slf.DBPrepare.Prepare(slf.query)
	if nil != pErr {
		return nil, pErr
	}
	defer stmt.Close()

	return stmt.Query(args...)
}

func (slf *Executor) Exists(args ...interface{}) (bool, error) {
	if nil != slf.logger {
		slf.logger(slf.query, args)
	}

	stmt, pErr := slf.DBPrepare.Prepare(slf.query)
	if nil != pErr {
		return false, pErr
	}
	defer stmt.Close()

	rs, qErr := stmt.Query(args...)
	if nil != qErr {
		return false, qErr
	}
	defer rs.Close()

	return rs.Next(), nil
}