// Copyright 2014 beego Author. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package orm

import (
	"fmt"
	"strings"
)

type dbIndex struct {
	Table string
	Name  string
	SQL   string
}

// get database column type string.
func getColumnTyp(al *alias, fi *fieldInfo) (col string) {
	T := al.DbBaser.DbTypes()
	fieldType := fi.fieldType
	fieldSize := fi.size

checkColumn:
	switch fieldType {
	case TypeBooleanField:
		col = T["bool"]
	case TypeVarCharField:
		if al.Driver == DRPostgres && fi.toText {
			col = T["string-text"]
		} else {
			col = fmt.Sprintf(T["string"], fieldSize)
		}
	case TypeCharField:
		col = fmt.Sprintf(T["string-char"], fieldSize)
	case TypeTextField:
		col = T["string-text"]
	case TypeTimeField:
		col = T["time.Time-clock"]
	case TypeDateField:
		col = T["time.Time-date"]
	case TypeDateTimeField:
		// the precision of sqlite is not implemented
		if al.Driver == 2 || fi.timePrecision == nil {
			col = T["time.Time"]
		} else {
			s := T["time.Time-precision"]
			col = fmt.Sprintf(s, *fi.timePrecision)
		}

	case TypeBitField:
		col = T["int8"]
	case TypeSmallIntegerField:
		col = T["int16"]
	case TypeIntegerField:
		col = T["int32"]
	case TypeBigIntegerField:
		if al.Driver == DRSqlite {
			fieldType = TypeIntegerField
			goto checkColumn
		}
		col = T["int64"]
	case TypePositiveBitField:
		col = T["uint8"]
	case TypePositiveSmallIntegerField:
		col = T["uint16"]
	case TypePositiveIntegerField:
		col = T["uint32"]
	case TypePositiveBigIntegerField:
		col = T["uint64"]
	case TypeFloatField:
		col = T["float64"]
	case TypeDecimalField:
		s := T["float64-decimal"]
		if !strings.Contains(s, "%d") {
			col = s
		} else {
			col = fmt.Sprintf(s, fi.digits, fi.decimals)
		}
	case TypeJSONField:
		if al.Driver != DRPostgres {
			fieldType = TypeVarCharField
			goto checkColumn
		}
		col = T["json"]
	case TypeJsonbField:
		if al.Driver != DRPostgres {
			fieldType = TypeVarCharField
			goto checkColumn
		}
		col = T["jsonb"]
	case RelForeignKey, RelOneToOne:
		fieldType = fi.relModelInfo.fields.pk.fieldType
		fieldSize = fi.relModelInfo.fields.pk.size
		goto checkColumn
	}

	return
}

// create alter sql string.
func getColumnAddQuery(al *alias, fi *fieldInfo) string {
	Q := al.DbBaser.TableQuote()
	typ := getColumnTyp(al, fi)

	if !fi.null {
		typ += " " + "NOT NULL"
	}

	return fmt.Sprintf("ALTER TABLE %s%s%s ADD COLUMN %s%s%s %s %s",
		Q, fi.mi.table, Q,
		Q, fi.column, Q,
		typ, getColumnDefault(fi),
	)
}

// Get string value for the attribute "DEFAULT" for the CREATE, ALTER commands
func getColumnDefault(fi *fieldInfo) string {
	var v, t, d string

	// Skip default attribute if field is in relations
	if fi.rel || fi.reverse {
		return v
	}

	t = " DEFAULT '%s' "

	// These defaults will be useful if there no config value orm:"default" and NOT NULL is on
	switch fi.fieldType {
	case TypeTimeField, TypeDateField, TypeDateTimeField, TypeTextField:
		return v

	case TypeBitField, TypeSmallIntegerField, TypeIntegerField,
		TypeBigIntegerField, TypePositiveBitField, TypePositiveSmallIntegerField,
		TypePositiveIntegerField, TypePositiveBigIntegerField, TypeFloatField,
		TypeDecimalField:
		t = " DEFAULT %s "
		d = "0"
	case TypeBooleanField:
		t = " DEFAULT %s "
		d = "FALSE"
	case TypeJSONField, TypeJsonbField:
		d = "{}"
	}

	if fi.colDefault {
		if !fi.initial.Exist() {
			v = fmt.Sprintf(t, "")
		} else {
			v = fmt.Sprintf(t, fi.initial.String())
		}
	} else {
		if !fi.null {
			v = fmt.Sprintf(t, d)
		}
	}

	return v
}