package migrator

import (
	"strconv"
	"strings"
)

type Mysql struct {
	BaseDialect
}

func NewMysqlDialect() *Mysql {
	d := Mysql{}
	d.BaseDialect.dialect = &d
	d.BaseDialect.driverName = MYSQL
	return &d
}

func (db *Mysql) SupportEngine() bool {
	return true
}

func (db *Mysql) Quote(name string) string {
	return "`" + name + "`"
}

func (db *Mysql) QuoteStr() string {
	return "`"
}

func (db *Mysql) AutoIncrStr() string {
	return "AUTO_INCREMENT"
}

func (db *Mysql) BooleanStr(value bool) string {
	if value {
		return "1"
	}
	return "0"
}

func (db *Mysql) SqlType(c *Column) string {
	var res string
	switch c.Type {
	case DB_Bool:
		res = DB_TinyInt
		c.Length = 1
	case DB_Serial:
		c.IsAutoIncrement = true
		c.IsPrimaryKey = true
		c.Nullable = false
		res = DB_Int
	case DB_BigSerial:
		c.IsAutoIncrement = true
		c.IsPrimaryKey = true
		c.Nullable = false
		res = DB_BigInt
	case DB_Bytea:
		res = DB_Blob
	case DB_TimeStampz:
		res = DB_Char
		c.Length = 64
	case DB_NVarchar:
		res = DB_Varchar
	default:
		res = c.Type
	}

	var hasLen1 bool = (c.Length > 0)
	var hasLen2 bool = (c.Length2 > 0)

	if res == DB_BigInt && !hasLen1 && !hasLen2 {
		c.Length = 20
		hasLen1 = true
	}

	if hasLen2 {
		res += "(" + strconv.Itoa(c.Length) + "," + strconv.Itoa(c.Length2) + ")"
	} else if hasLen1 {
		res += "(" + strconv.Itoa(c.Length) + ")"
	}

	switch c.Type {
	case DB_Char, DB_Varchar, DB_NVarchar, DB_TinyText, DB_Text, DB_MediumText, DB_LongText:
		res += " CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci"
	}

	return res
}

func (db *Mysql) TableCheckSql(tableName string) (string, []interface{}) {
	args := []interface{}{"grafana", tableName}
	sql := "SELECT `TABLE_NAME` from `INFORMATION_SCHEMA`.`TABLES` WHERE `TABLE_SCHEMA`=? and `TABLE_NAME`=?"
	return sql, args
}

func (db *Mysql) UpdateTableSql(tableName string, columns []*Column) string {
	var statements = []string{}

	statements = append(statements, "DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci")

	for _, col := range columns {
		statements = append(statements, "MODIFY "+col.StringNoPk(db))
	}

	return "ALTER TABLE " + db.Quote(tableName) + " " + strings.Join(statements, ", ") + ";"
}