// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
//
// Copyright 2017 The Go-MySQL-Driver Authors. All rights reserved.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at http://mozilla.org/MPL/2.0/.

package mysql

import (
	"database/sql"
	"reflect"
)

var typeDatabaseName = map[fieldType]string{
	fieldTypeBit:        "BIT",
	fieldTypeBLOB:       "BLOB",
	fieldTypeDate:       "DATE",
	fieldTypeDateTime:   "DATETIME",
	fieldTypeDecimal:    "DECIMAL",
	fieldTypeDouble:     "DOUBLE",
	fieldTypeEnum:       "ENUM",
	fieldTypeFloat:      "FLOAT",
	fieldTypeGeometry:   "GEOMETRY",
	fieldTypeInt24:      "MEDIUMINT",
	fieldTypeJSON:       "JSON",
	fieldTypeLong:       "INT",
	fieldTypeLongBLOB:   "LONGBLOB",
	fieldTypeLongLong:   "BIGINT",
	fieldTypeMediumBLOB: "MEDIUMBLOB",
	fieldTypeNewDate:    "DATE",
	fieldTypeNewDecimal: "DECIMAL",
	fieldTypeNULL:       "NULL",
	fieldTypeSet:        "SET",
	fieldTypeShort:      "SMALLINT",
	fieldTypeString:     "CHAR",
	fieldTypeTime:       "TIME",
	fieldTypeTimestamp:  "TIMESTAMP",
	fieldTypeTiny:       "TINYINT",
	fieldTypeTinyBLOB:   "TINYBLOB",
	fieldTypeVarChar:    "VARCHAR",
	fieldTypeVarString:  "VARCHAR",
	fieldTypeYear:       "YEAR",
}

var (
	scanTypeFloat32   = reflect.TypeOf(float32(0))
	scanTypeFloat64   = reflect.TypeOf(float64(0))
	scanTypeInt8      = reflect.TypeOf(int8(0))
	scanTypeInt16     = reflect.TypeOf(int16(0))
	scanTypeInt32     = reflect.TypeOf(int32(0))
	scanTypeInt64     = reflect.TypeOf(int64(0))
	scanTypeNullFloat = reflect.TypeOf(sql.NullFloat64{})
	scanTypeNullInt   = reflect.TypeOf(sql.NullInt64{})
	scanTypeNullTime  = reflect.TypeOf(NullTime{})
	scanTypeUint8     = reflect.TypeOf(uint8(0))
	scanTypeUint16    = reflect.TypeOf(uint16(0))
	scanTypeUint32    = reflect.TypeOf(uint32(0))
	scanTypeUint64    = reflect.TypeOf(uint64(0))
	scanTypeRawBytes  = reflect.TypeOf(sql.RawBytes{})
	scanTypeUnknown   = reflect.TypeOf(new(interface{}))
)

type mysqlField struct {
	tableName string
	name      string
	length    uint32
	flags     fieldFlag
	fieldType fieldType
	decimals  byte
}

func (mf *mysqlField) scanType() reflect.Type {
	switch mf.fieldType {
	case fieldTypeTiny:
		if mf.flags&flagNotNULL != 0 {
			if mf.flags&flagUnsigned != 0 {
				return scanTypeUint8
			}
			return scanTypeInt8
		}
		return scanTypeNullInt

	case fieldTypeShort, fieldTypeYear:
		if mf.flags&flagNotNULL != 0 {
			if mf.flags&flagUnsigned != 0 {
				return scanTypeUint16
			}
			return scanTypeInt16
		}
		return scanTypeNullInt

	case fieldTypeInt24, fieldTypeLong:
		if mf.flags&flagNotNULL != 0 {
			if mf.flags&flagUnsigned != 0 {
				return scanTypeUint32
			}
			return scanTypeInt32
		}
		return scanTypeNullInt

	case fieldTypeLongLong:
		if mf.flags&flagNotNULL != 0 {
			if mf.flags&flagUnsigned != 0 {
				return scanTypeUint64
			}
			return scanTypeInt64
		}
		return scanTypeNullInt

	case fieldTypeFloat:
		if mf.flags&flagNotNULL != 0 {
			return scanTypeFloat32
		}
		return scanTypeNullFloat

	case fieldTypeDouble:
		if mf.flags&flagNotNULL != 0 {
			return scanTypeFloat64
		}
		return scanTypeNullFloat

	case fieldTypeDecimal, fieldTypeNewDecimal, fieldTypeVarChar,
		fieldTypeBit, fieldTypeEnum, fieldTypeSet, fieldTypeTinyBLOB,
		fieldTypeMediumBLOB, fieldTypeLongBLOB, fieldTypeBLOB,
		fieldTypeVarString, fieldTypeString, fieldTypeGeometry, fieldTypeJSON,
		fieldTypeTime:
		return scanTypeRawBytes

	case fieldTypeDate, fieldTypeNewDate,
		fieldTypeTimestamp, fieldTypeDateTime:
		// NullTime is always returned for more consistent behavior as it can
		// handle both cases of parseTime regardless if the field is nullable.
		return scanTypeNullTime

	default:
		return scanTypeUnknown
	}
}