package core

import "strings"

// Filter is an interface to filter SQL
type Filter interface {
	Do(sql string, dialect Dialect, table *Table) string
}

// QuoteFilter filter SQL replace ` to database's own quote character
type QuoteFilter struct {
}

func (s *QuoteFilter) Do(sql string, dialect Dialect, table *Table) string {
	return strings.Replace(sql, "`", dialect.QuoteStr(), -1)
}

// IdFilter filter SQL replace (id) to primary key column name
type IdFilter struct {
}

type Quoter struct {
	dialect Dialect
}

func NewQuoter(dialect Dialect) *Quoter {
	return &Quoter{dialect}
}

func (q *Quoter) Quote(content string) string {
	return q.dialect.QuoteStr() + content + q.dialect.QuoteStr()
}

func (i *IdFilter) Do(sql string, dialect Dialect, table *Table) string {
	quoter := NewQuoter(dialect)
	if table != nil && len(table.PrimaryKeys) == 1 {
		sql = strings.Replace(sql, "`(id)`", quoter.Quote(table.PrimaryKeys[0]), -1)
		sql = strings.Replace(sql, quoter.Quote("(id)"), quoter.Quote(table.PrimaryKeys[0]), -1)
		return strings.Replace(sql, "(id)", quoter.Quote(table.PrimaryKeys[0]), -1)
	}
	return sql
}