// Copyright 2015 The Xorm Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package xorm

import (
	"database/sql/driver"
	"fmt"
	"reflect"
	"strings"
	"time"

	"xorm.io/builder"
	"xorm.io/core"
)

// Statement save all the sql info for executing SQL
type Statement struct {
	RefTable        *core.Table
	Engine          *Engine
	Start           int
	LimitN          *int
	idParam         *core.PK
	OrderStr        string
	JoinStr         string
	joinArgs        []interface{}
	GroupByStr      string
	HavingStr       string
	ColumnStr       string
	selectStr       string
	useAllCols      bool
	OmitStr         string
	AltTableName    string
	tableName       string
	RawSQL          string
	RawParams       []interface{}
	UseAutoJoin     bool
	StoreEngine     string
	Charset         string
	UseCache        bool
	UseAutoTime     bool
	noAutoCondition bool
	IsDistinct      bool
	IsForUpdate     bool
	TableAlias      string
	allUseBool      bool
	checkVersion    bool
	unscoped        bool
	columnMap       columnMap
	omitColumnMap   columnMap
	mustColumnMap   map[string]bool
	nullableMap     map[string]bool
	incrColumns     exprParams
	decrColumns     exprParams
	exprColumns     exprParams
	cond            builder.Cond
	bufferSize      int
	lastError       error
}

// Init reset all the statement's fields
func (statement *Statement) Init() {
	statement.RefTable = nil
	statement.Start = 0
	statement.LimitN = nil
	statement.OrderStr = ""
	statement.JoinStr = ""
	statement.joinArgs = make([]interface{}, 0)
	statement.GroupByStr = ""
	statement.HavingStr = ""
	statement.ColumnStr = ""
	statement.OmitStr = ""
	statement.columnMap = columnMap{}
	statement.omitColumnMap = columnMap{}
	statement.AltTableName = ""
	statement.tableName = ""
	statement.idParam = nil
	statement.RawSQL = ""
	statement.RawParams = make([]interface{}, 0)
	statement.UseCache = true
	statement.UseAutoTime = true
	statement.noAutoCondition = false
	statement.IsDistinct = false
	statement.IsForUpdate = false
	statement.TableAlias = ""
	statement.selectStr = ""
	statement.allUseBool = false
	statement.useAllCols = false
	statement.mustColumnMap = make(map[string]bool)
	statement.nullableMap = make(map[string]bool)
	statement.checkVersion = true
	statement.unscoped = false
	statement.incrColumns = exprParams{}
	statement.decrColumns = exprParams{}
	statement.exprColumns = exprParams{}
	statement.cond = builder.NewCond()
	statement.bufferSize = 0
	statement.lastError = nil
}

var (
	ptrPkType = reflect.TypeOf(&core.PK{})
	pkType    = reflect.TypeOf(core.PK{})
)

// NoAutoCondition if you do not want convert bean's field as query condition, then use this function
func (statement *Statement) NoAutoCondition(no ...bool) *Statement {
	statement.noAutoCondition = true
	if len(no) > 0 {
		statement.noAutoCondition = no[0]
	}
	return statement
}

// Alias set the table alias
func (statement *Statement) Alias(alias string) *Statement {
	statement.TableAlias = alias
	return statement
}

// SQL adds raw sql statement
func (statement *Statement) SQL(query interface{}, args ...interface{}) *Statement {
	switch query.(type) {
	case (*builder.Builder):
		var err error
		statement.RawSQL, statement.RawParams, err = query.(*builder.Builder).ToSQL()
		if err != nil {
			statement.lastError = err
		}
	case string:
		statement.RawSQL = query.(string)
		statement.RawParams = args
	default:
		statement.lastError = ErrUnSupportedSQLType
	}

	return statement
}

// Where add Where statement
func (statement *Statement) Where(query interface{}, args ...interface{}) *Statement {
	return statement.And(query, args...)
}

// And add Where & and statement
func (statement *Statement) And(query interface{}, args ...interface{}) *Statement {
	switch query.(type) {
	case string:
		cond := builder.Expr(query.(string), args...)
		statement.cond = statement.cond.And(cond)
	case map[string]interface{}:
		queryMap := query.(map[string]interface{})
		newMap := make(map[string]interface{})
		for k, v := range queryMap {
			newMap[statement.Engine.Quote(k)] = v
		}
		statement.cond = statement.cond.And(builder.Eq(newMap))
	case builder.Cond:
		cond := query.(builder.Cond)
		statement.cond = statement.cond.And(cond)
		for _, v := range args {
			if vv, ok := v.(builder.Cond); ok {
				statement.cond = statement.cond.And(vv)
			}
		}
	default:
		statement.lastError = ErrConditionType
	}

	return statement
}

// Or add Where & Or statement
func (statement *Statement) Or(query interface{}, args ...interface{}) *Statement {
	switch query.(type) {
	case string:
		cond := builder.Expr(query.(string), args...)
		statement.cond = statement.cond.Or(cond)
	case map[string]interface{}:
		cond := builder.Eq(query.(map[string]interface{}))
		statement.cond = statement.cond.Or(cond)
	case builder.Cond:
		cond := query.(builder.Cond)
		statement.cond = statement.cond.Or(cond)
		for _, v := range args {
			if vv, ok := v.(builder.Cond); ok {
				statement.cond = statement.cond.Or(vv)
			}
		}
	default:
		// TODO: not support condition type
	}
	return statement
}

// In generate "Where column IN (?) " statement
func (statement *Statement) In(column string, args ...interface{}) *Statement {
	in := builder.In(statement.Engine.Quote(column), args...)
	statement.cond = statement.cond.And(in)
	return statement
}

// NotIn generate "Where column NOT IN (?) " statement
func (statement *Statement) NotIn(column string, args ...interface{}) *Statement {
	notIn := builder.NotIn(statement.Engine.Quote(column), args...)
	statement.cond = statement.cond.And(notIn)
	return statement
}

func (statement *Statement) setRefValue(v reflect.Value) error {
	var err error
	statement.RefTable, err = statement.Engine.autoMapType(reflect.Indirect(v))
	if err != nil {
		return err
	}
	statement.tableName = statement.Engine.TableName(v, true)
	return nil
}

func (statement *Statement) setRefBean(bean interface{}) error {
	var err error
	statement.RefTable, err = statement.Engine.autoMapType(rValue(bean))
	if err != nil {
		return err
	}
	statement.tableName = statement.Engine.TableName(bean, true)
	return nil
}

// Auto generating update columnes and values according a struct
func (statement *Statement) buildUpdates(bean interface{},
	includeVersion, includeUpdated, includeNil,
	includeAutoIncr, update bool) ([]string, []interface{}) {
	engine := statement.Engine
	table := statement.RefTable
	allUseBool := statement.allUseBool
	useAllCols := statement.useAllCols
	mustColumnMap := statement.mustColumnMap
	nullableMap := statement.nullableMap
	columnMap := statement.columnMap
	omitColumnMap := statement.omitColumnMap
	unscoped := statement.unscoped

	var colNames = make([]string, 0)
	var args = make([]interface{}, 0)
	for _, col := range table.Columns() {
		if !includeVersion && col.IsVersion {
			continue
		}
		if col.IsCreated && !columnMap.contain(col.Name) {
			continue
		}
		if !includeUpdated && col.IsUpdated {
			continue
		}
		if !includeAutoIncr && col.IsAutoIncrement {
			continue
		}
		if col.IsDeleted && !unscoped {
			continue
		}
		if omitColumnMap.contain(col.Name) {
			continue
		}
		if len(columnMap) > 0 && !columnMap.contain(col.Name) {
			continue
		}

		if col.MapType == core.ONLYFROMDB {
			continue
		}

		if statement.incrColumns.isColExist(col.Name) {
			continue
		} else if statement.decrColumns.isColExist(col.Name) {
			continue
		} else if statement.exprColumns.isColExist(col.Name) {
			continue
		}

		fieldValuePtr, err := col.ValueOf(bean)
		if err != nil {
			engine.logger.Error(err)
			continue
		}

		fieldValue := *fieldValuePtr
		fieldType := reflect.TypeOf(fieldValue.Interface())
		if fieldType == nil {
			continue
		}

		requiredField := useAllCols
		includeNil := useAllCols

		if b, ok := getFlagForColumn(mustColumnMap, col); ok {
			if b {
				requiredField = true
			} else {
				continue
			}
		}

		// !evalphobia! set fieldValue as nil when column is nullable and zero-value
		if b, ok := getFlagForColumn(nullableMap, col); ok {
			if b && col.Nullable && isZero(fieldValue.Interface()) {
				var nilValue *int
				fieldValue = reflect.ValueOf(nilValue)
				fieldType = reflect.TypeOf(fieldValue.Interface())
				includeNil = true
			}
		}

		var val interface{}

		if fieldValue.CanAddr() {
			if structConvert, ok := fieldValue.Addr().Interface().(core.Conversion); ok {
				data, err := structConvert.ToDB()
				if err != nil {
					engine.logger.Error(err)
				} else {
					val = data
				}
				goto APPEND
			}
		}

		if structConvert, ok := fieldValue.Interface().(core.Conversion); ok {
			data, err := structConvert.ToDB()
			if err != nil {
				engine.logger.Error(err)
			} else {
				val = data
			}
			goto APPEND
		}

		if fieldType.Kind() == reflect.Ptr {
			if fieldValue.IsNil() {
				if includeNil {
					args = append(args, nil)
					colNames = append(colNames, fmt.Sprintf("%v=?", engine.Quote(col.Name)))
				}
				continue
			} else if !fieldValue.IsValid() {
				continue
			} else {
				// dereference ptr type to instance type
				fieldValue = fieldValue.Elem()
				fieldType = reflect.TypeOf(fieldValue.Interface())
				requiredField = true
			}
		}

		switch fieldType.Kind() {
		case reflect.Bool:
			if allUseBool || requiredField {
				val = fieldValue.Interface()
			} else {
				// if a bool in a struct, it will not be as a condition because it default is false,
				// please use Where() instead
				continue
			}
		case reflect.String:
			if !requiredField && fieldValue.String() == "" {
				continue
			}
			// for MyString, should convert to string or panic
			if fieldType.String() != reflect.String.String() {
				val = fieldValue.String()
			} else {
				val = fieldValue.Interface()
			}
		case reflect.Int8, reflect.Int16, reflect.Int, reflect.Int32, reflect.Int64:
			if !requiredField && fieldValue.Int() == 0 {
				continue
			}
			val = fieldValue.Interface()
		case reflect.Float32, reflect.Float64:
			if !requiredField && fieldValue.Float() == 0.0 {
				continue
			}
			val = fieldValue.Interface()
		case reflect.Uint8, reflect.Uint16, reflect.Uint, reflect.Uint32, reflect.Uint64:
			if !requiredField && fieldValue.Uint() == 0 {
				continue
			}
			t := int64(fieldValue.Uint())
			val = reflect.ValueOf(&t).Interface()
		case reflect.Struct:
			if fieldType.ConvertibleTo(core.TimeType) {
				t := fieldValue.Convert(core.TimeType).Interface().(time.Time)
				if !requiredField && (t.IsZero() || !fieldValue.IsValid()) {
					continue
				}
				val = engine.formatColTime(col, t)
			} else if nulType, ok := fieldValue.Interface().(driver.Valuer); ok {
				val, _ = nulType.Value()
			} else {
				if !col.SQLType.IsJson() {
					engine.autoMapType(fieldValue)
					if table, ok := engine.Tables[fieldValue.Type()]; ok {
						if len(table.PrimaryKeys) == 1 {
							pkField := reflect.Indirect(fieldValue).FieldByName(table.PKColumns()[0].FieldName)
							// fix non-int pk issues
							if pkField.IsValid() && (!requiredField && !isZero(pkField.Interface())) {
								val = pkField.Interface()
							} else {
								continue
							}
						} else {
							// TODO: how to handler?
							panic("not supported")
						}
					} else {
						val = fieldValue.Interface()
					}
				} else {
					// Blank struct could not be as update data
					if requiredField || !isStructZero(fieldValue) {
						bytes, err := DefaultJSONHandler.Marshal(fieldValue.Interface())
						if err != nil {
							panic(fmt.Sprintf("mashal %v failed", fieldValue.Interface()))
						}
						if col.SQLType.IsText() {
							val = string(bytes)
						} else if col.SQLType.IsBlob() {
							val = bytes
						}
					} else {
						continue
					}
				}
			}
		case reflect.Array, reflect.Slice, reflect.Map:
			if !requiredField {
				if fieldValue == reflect.Zero(fieldType) {
					continue
				}
				if fieldType.Kind() == reflect.Array {
					if isArrayValueZero(fieldValue) {
						continue
					}
				} else if fieldValue.IsNil() || !fieldValue.IsValid() || fieldValue.Len() == 0 {
					continue
				}
			}

			if col.SQLType.IsText() {
				bytes, err := DefaultJSONHandler.Marshal(fieldValue.Interface())
				if err != nil {
					engine.logger.Error(err)
					continue
				}
				val = string(bytes)
			} else if col.SQLType.IsBlob() {
				var bytes []byte
				var err error
				if fieldType.Kind() == reflect.Slice &&
					fieldType.Elem().Kind() == reflect.Uint8 {
					if fieldValue.Len() > 0 {
						val = fieldValue.Bytes()
					} else {
						continue
					}
				} else if fieldType.Kind() == reflect.Array &&
					fieldType.Elem().Kind() == reflect.Uint8 {
					val = fieldValue.Slice(0, 0).Interface()
				} else {
					bytes, err = DefaultJSONHandler.Marshal(fieldValue.Interface())
					if err != nil {
						engine.logger.Error(err)
						continue
					}
					val = bytes
				}
			} else {
				continue
			}
		default:
			val = fieldValue.Interface()
		}

	APPEND:
		args = append(args, val)
		if col.IsPrimaryKey && engine.dialect.DBType() == "ql" {
			continue
		}
		colNames = append(colNames, fmt.Sprintf("%v = ?", engine.Quote(col.Name)))
	}

	return colNames, args
}

func (statement *Statement) needTableName() bool {
	return len(statement.JoinStr) > 0
}

func (statement *Statement) colName(col *core.Column, tableName string) string {
	if statement.needTableName() {
		var nm = tableName
		if len(statement.TableAlias) > 0 {
			nm = statement.TableAlias
		}
		return statement.Engine.Quote(nm) + "." + statement.Engine.Quote(col.Name)
	}
	return statement.Engine.Quote(col.Name)
}

// TableName return current tableName
func (statement *Statement) TableName() string {
	if statement.AltTableName != "" {
		return statement.AltTableName
	}

	return statement.tableName
}

// ID generate "where id = ? " statement or for composite key "where key1 = ? and key2 = ?"
func (statement *Statement) ID(id interface{}) *Statement {
	idValue := reflect.ValueOf(id)
	idType := reflect.TypeOf(idValue.Interface())

	switch idType {
	case ptrPkType:
		if pkPtr, ok := (id).(*core.PK); ok {
			statement.idParam = pkPtr
			return statement
		}
	case pkType:
		if pk, ok := (id).(core.PK); ok {
			statement.idParam = &pk
			return statement
		}
	}

	switch idType.Kind() {
	case reflect.String:
		statement.idParam = &core.PK{idValue.Convert(reflect.TypeOf("")).Interface()}
		return statement
	}

	statement.idParam = &core.PK{id}
	return statement
}

// Incr Generate  "Update ... Set column = column + arg" statement
func (statement *Statement) Incr(column string, arg ...interface{}) *Statement {
	if len(arg) > 0 {
		statement.incrColumns.addParam(column, arg[0])
	} else {
		statement.incrColumns.addParam(column, 1)
	}
	return statement
}

// Decr Generate  "Update ... Set column = column - arg" statement
func (statement *Statement) Decr(column string, arg ...interface{}) *Statement {
	if len(arg) > 0 {
		statement.decrColumns.addParam(column, arg[0])
	} else {
		statement.decrColumns.addParam(column, 1)
	}
	return statement
}

// SetExpr Generate  "Update ... Set column = {expression}" statement
func (statement *Statement) SetExpr(column string, expression interface{}) *Statement {
	statement.exprColumns.addParam(column, expression)
	return statement
}

func (statement *Statement) col2NewColsWithQuote(columns ...string) []string {
	newColumns := make([]string, 0)
	quotes := append(strings.Split(statement.Engine.Quote(""), ""), "`")
	for _, col := range columns {
		newColumns = append(newColumns, statement.Engine.Quote(eraseAny(col, quotes...)))
	}
	return newColumns
}

func (statement *Statement) colmap2NewColsWithQuote() []string {
	newColumns := make([]string, len(statement.columnMap))
	copy(newColumns, statement.columnMap)
	for i := 0; i < len(statement.columnMap); i++ {
		newColumns[i] = statement.Engine.Quote(newColumns[i])
	}
	return newColumns
}

// Distinct generates "DISTINCT col1, col2 " statement
func (statement *Statement) Distinct(columns ...string) *Statement {
	statement.IsDistinct = true
	statement.Cols(columns...)
	return statement
}

// ForUpdate generates "SELECT ... FOR UPDATE" statement
func (statement *Statement) ForUpdate() *Statement {
	statement.IsForUpdate = true
	return statement
}

// Select replace select
func (statement *Statement) Select(str string) *Statement {
	statement.selectStr = str
	return statement
}

// Cols generate "col1, col2" statement
func (statement *Statement) Cols(columns ...string) *Statement {
	cols := col2NewCols(columns...)
	for _, nc := range cols {
		statement.columnMap.add(nc)
	}

	newColumns := statement.colmap2NewColsWithQuote()

	statement.ColumnStr = strings.Join(newColumns, ", ")
	statement.ColumnStr = strings.Replace(statement.ColumnStr, statement.Engine.quote("*"), "*", -1)
	return statement
}

// AllCols update use only: update all columns
func (statement *Statement) AllCols() *Statement {
	statement.useAllCols = true
	return statement
}

// MustCols update use only: must update columns
func (statement *Statement) MustCols(columns ...string) *Statement {
	newColumns := col2NewCols(columns...)
	for _, nc := range newColumns {
		statement.mustColumnMap[strings.ToLower(nc)] = true
	}
	return statement
}

// UseBool indicates that use bool fields as update contents and query contiditions
func (statement *Statement) UseBool(columns ...string) *Statement {
	if len(columns) > 0 {
		statement.MustCols(columns...)
	} else {
		statement.allUseBool = true
	}
	return statement
}

// Omit do not use the columns
func (statement *Statement) Omit(columns ...string) {
	newColumns := col2NewCols(columns...)
	for _, nc := range newColumns {
		statement.omitColumnMap = append(statement.omitColumnMap, nc)
	}
	statement.OmitStr = statement.Engine.Quote(strings.Join(newColumns, statement.Engine.Quote(", ")))
}

// Nullable Update use only: update columns to null when value is nullable and zero-value
func (statement *Statement) Nullable(columns ...string) {
	newColumns := col2NewCols(columns...)
	for _, nc := range newColumns {
		statement.nullableMap[strings.ToLower(nc)] = true
	}
}

// Top generate LIMIT limit statement
func (statement *Statement) Top(limit int) *Statement {
	statement.Limit(limit)
	return statement
}

// Limit generate LIMIT start, limit statement
func (statement *Statement) Limit(limit int, start ...int) *Statement {
	statement.LimitN = &limit
	if len(start) > 0 {
		statement.Start = start[0]
	}
	return statement
}

// OrderBy generate "Order By order" statement
func (statement *Statement) OrderBy(order string) *Statement {
	if len(statement.OrderStr) > 0 {
		statement.OrderStr += ", "
	}
	statement.OrderStr += order
	return statement
}

// Desc generate `ORDER BY xx DESC`
func (statement *Statement) Desc(colNames ...string) *Statement {
	var buf strings.Builder
	if len(statement.OrderStr) > 0 {
		fmt.Fprint(&buf, statement.OrderStr, ", ")
	}
	newColNames := statement.col2NewColsWithQuote(colNames...)
	fmt.Fprintf(&buf, "%v DESC", strings.Join(newColNames, " DESC, "))
	statement.OrderStr = buf.String()
	return statement
}

// Asc provide asc order by query condition, the input parameters are columns.
func (statement *Statement) Asc(colNames ...string) *Statement {
	var buf strings.Builder
	if len(statement.OrderStr) > 0 {
		fmt.Fprint(&buf, statement.OrderStr, ", ")
	}
	newColNames := statement.col2NewColsWithQuote(colNames...)
	fmt.Fprintf(&buf, "%v ASC", strings.Join(newColNames, " ASC, "))
	statement.OrderStr = buf.String()
	return statement
}

// Table tempororily set table name, the parameter could be a string or a pointer of struct
func (statement *Statement) Table(tableNameOrBean interface{}) *Statement {
	v := rValue(tableNameOrBean)
	t := v.Type()
	if t.Kind() == reflect.Struct {
		var err error
		statement.RefTable, err = statement.Engine.autoMapType(v)
		if err != nil {
			statement.Engine.logger.Error(err)
			return statement
		}
	}

	statement.AltTableName = statement.Engine.TableName(tableNameOrBean, true)
	return statement
}

// Join The joinOP should be one of INNER, LEFT OUTER, CROSS etc - this will be prepended to JOIN
func (statement *Statement) Join(joinOP string, tablename interface{}, condition string, args ...interface{}) *Statement {
	var buf strings.Builder
	if len(statement.JoinStr) > 0 {
		fmt.Fprintf(&buf, "%v %v JOIN ", statement.JoinStr, joinOP)
	} else {
		fmt.Fprintf(&buf, "%v JOIN ", joinOP)
	}

	switch tp := tablename.(type) {
	case builder.Builder:
		subSQL, subQueryArgs, err := tp.ToSQL()
		if err != nil {
			statement.lastError = err
			return statement
		}
		tbs := strings.Split(tp.TableName(), ".")
		quotes := append(strings.Split(statement.Engine.Quote(""), ""), "`")

		var aliasName = strings.Trim(tbs[len(tbs)-1], strings.Join(quotes, ""))
		fmt.Fprintf(&buf, "(%s) %s ON %v", subSQL, aliasName, condition)
		statement.joinArgs = append(statement.joinArgs, subQueryArgs...)
	case *builder.Builder:
		subSQL, subQueryArgs, err := tp.ToSQL()
		if err != nil {
			statement.lastError = err
			return statement
		}
		tbs := strings.Split(tp.TableName(), ".")
		quotes := append(strings.Split(statement.Engine.Quote(""), ""), "`")

		var aliasName = strings.Trim(tbs[len(tbs)-1], strings.Join(quotes, ""))
		fmt.Fprintf(&buf, "(%s) %s ON %v", subSQL, aliasName, condition)
		statement.joinArgs = append(statement.joinArgs, subQueryArgs...)
	default:
		tbName := statement.Engine.TableName(tablename, true)
		fmt.Fprintf(&buf, "%s ON %v", tbName, condition)
	}

	statement.JoinStr = buf.String()
	statement.joinArgs = append(statement.joinArgs, args...)
	return statement
}

// GroupBy generate "Group By keys" statement
func (statement *Statement) GroupBy(keys string) *Statement {
	statement.GroupByStr = keys
	return statement
}

// Having generate "Having conditions" statement
func (statement *Statement) Having(conditions string) *Statement {
	statement.HavingStr = fmt.Sprintf("HAVING %v", conditions)
	return statement
}

// Unscoped always disable struct tag "deleted"
func (statement *Statement) Unscoped() *Statement {
	statement.unscoped = true
	return statement
}

func (statement *Statement) genColumnStr() string {
	if statement.RefTable == nil {
		return ""
	}

	var buf strings.Builder
	columns := statement.RefTable.Columns()

	for _, col := range columns {
		if statement.omitColumnMap.contain(col.Name) {
			continue
		}

		if len(statement.columnMap) > 0 && !statement.columnMap.contain(col.Name) {
			continue
		}

		if col.MapType == core.ONLYTODB {
			continue
		}

		if buf.Len() != 0 {
			buf.WriteString(", ")
		}

		if statement.JoinStr != "" {
			if statement.TableAlias != "" {
				buf.WriteString(statement.TableAlias)
			} else {
				buf.WriteString(statement.TableName())
			}

			buf.WriteString(".")
		}

		statement.Engine.QuoteTo(&buf, col.Name)
	}

	return buf.String()
}

func (statement *Statement) genCreateTableSQL() string {
	return statement.Engine.dialect.CreateTableSql(statement.RefTable, statement.TableName(),
		statement.StoreEngine, statement.Charset)
}

func (statement *Statement) genIndexSQL() []string {
	var sqls []string
	tbName := statement.TableName()
	for _, index := range statement.RefTable.Indexes {
		if index.Type == core.IndexType {
			sql := statement.Engine.dialect.CreateIndexSql(tbName, index)
			sqls = append(sqls, sql)
		}
	}
	return sqls
}

func uniqueName(tableName, uqeName string) string {
	return fmt.Sprintf("UQE_%v_%v", tableName, uqeName)
}

func (statement *Statement) genUniqueSQL() []string {
	var sqls []string
	tbName := statement.TableName()
	for _, index := range statement.RefTable.Indexes {
		if index.Type == core.UniqueType {
			sql := statement.Engine.dialect.CreateIndexSql(tbName, index)
			sqls = append(sqls, sql)
		}
	}
	return sqls
}

func (statement *Statement) genDelIndexSQL() []string {
	var sqls []string
	tbName := statement.TableName()
	idxPrefixName := strings.Replace(tbName, `"`, "", -1)
	idxPrefixName = strings.Replace(idxPrefixName, `.`, "_", -1)
	for idxName, index := range statement.RefTable.Indexes {
		var rIdxName string
		if index.Type == core.UniqueType {
			rIdxName = uniqueName(idxPrefixName, idxName)
		} else if index.Type == core.IndexType {
			rIdxName = indexName(idxPrefixName, idxName)
		}
		sql := fmt.Sprintf("DROP INDEX %v", statement.Engine.Quote(statement.Engine.TableName(rIdxName, true)))
		if statement.Engine.dialect.IndexOnTable() {
			sql += fmt.Sprintf(" ON %v", statement.Engine.Quote(tbName))
		}
		sqls = append(sqls, sql)
	}
	return sqls
}

func (statement *Statement) genAddColumnStr(col *core.Column) (string, []interface{}) {
	quote := statement.Engine.Quote
	sql := fmt.Sprintf("ALTER TABLE %v ADD %v", quote(statement.TableName()),
		col.String(statement.Engine.dialect))
	if statement.Engine.dialect.DBType() == core.MYSQL && len(col.Comment) > 0 {
		sql += " COMMENT '" + col.Comment + "'"
	}
	sql += ";"
	return sql, []interface{}{}
}

func (statement *Statement) buildConds(table *core.Table, bean interface{}, includeVersion bool, includeUpdated bool, includeNil bool, includeAutoIncr bool, addedTableName bool) (builder.Cond, error) {
	return statement.Engine.buildConds(table, bean, includeVersion, includeUpdated, includeNil, includeAutoIncr, statement.allUseBool, statement.useAllCols,
		statement.unscoped, statement.mustColumnMap, statement.TableName(), statement.TableAlias, addedTableName)
}

func (statement *Statement) mergeConds(bean interface{}) error {
	if !statement.noAutoCondition {
		var addedTableName = (len(statement.JoinStr) > 0)
		autoCond, err := statement.buildConds(statement.RefTable, bean, true, true, false, true, addedTableName)
		if err != nil {
			return err
		}
		statement.cond = statement.cond.And(autoCond)
	}

	if err := statement.processIDParam(); err != nil {
		return err
	}
	return nil
}

func (statement *Statement) genConds(bean interface{}) (string, []interface{}, error) {
	if err := statement.mergeConds(bean); err != nil {
		return "", nil, err
	}

	return builder.ToSQL(statement.cond)
}

func (statement *Statement) genGetSQL(bean interface{}) (string, []interface{}, error) {
	v := rValue(bean)
	isStruct := v.Kind() == reflect.Struct
	if isStruct {
		statement.setRefBean(bean)
	}

	var columnStr = statement.ColumnStr
	if len(statement.selectStr) > 0 {
		columnStr = statement.selectStr
	} else {
		// TODO: always generate column names, not use * even if join
		if len(statement.JoinStr) == 0 {
			if len(columnStr) == 0 {
				if len(statement.GroupByStr) > 0 {
					columnStr = statement.Engine.quoteColumns(statement.GroupByStr)
				} else {
					columnStr = statement.genColumnStr()
				}
			}
		} else {
			if len(columnStr) == 0 {
				if len(statement.GroupByStr) > 0 {
					columnStr = statement.Engine.quoteColumns(statement.GroupByStr)
				}
			}
		}
	}

	if len(columnStr) == 0 {
		columnStr = "*"
	}

	if isStruct {
		if err := statement.mergeConds(bean); err != nil {
			return "", nil, err
		}
	} else {
		if err := statement.processIDParam(); err != nil {
			return "", nil, err
		}
	}
	condSQL, condArgs, err := builder.ToSQL(statement.cond)
	if err != nil {
		return "", nil, err
	}

	sqlStr, err := statement.genSelectSQL(columnStr, condSQL, true, true)
	if err != nil {
		return "", nil, err
	}

	return sqlStr, append(statement.joinArgs, condArgs...), nil
}

func (statement *Statement) genCountSQL(beans ...interface{}) (string, []interface{}, error) {
	var condSQL string
	var condArgs []interface{}
	var err error
	if len(beans) > 0 {
		statement.setRefBean(beans[0])
		condSQL, condArgs, err = statement.genConds(beans[0])
	} else {
		condSQL, condArgs, err = builder.ToSQL(statement.cond)
	}
	if err != nil {
		return "", nil, err
	}

	var selectSQL = statement.selectStr
	if len(selectSQL) <= 0 {
		if statement.IsDistinct {
			selectSQL = fmt.Sprintf("count(DISTINCT %s)", statement.ColumnStr)
		} else {
			selectSQL = "count(*)"
		}
	}
	sqlStr, err := statement.genSelectSQL(selectSQL, condSQL, false, false)
	if err != nil {
		return "", nil, err
	}

	return sqlStr, append(statement.joinArgs, condArgs...), nil
}

func (statement *Statement) genSumSQL(bean interface{}, columns ...string) (string, []interface{}, error) {
	statement.setRefBean(bean)

	var sumStrs = make([]string, 0, len(columns))
	for _, colName := range columns {
		if !strings.Contains(colName, " ") && !strings.Contains(colName, "(") {
			colName = statement.Engine.Quote(colName)
		}
		sumStrs = append(sumStrs, fmt.Sprintf("COALESCE(sum(%s),0)", colName))
	}
	sumSelect := strings.Join(sumStrs, ", ")

	condSQL, condArgs, err := statement.genConds(bean)
	if err != nil {
		return "", nil, err
	}

	sqlStr, err := statement.genSelectSQL(sumSelect, condSQL, true, true)
	if err != nil {
		return "", nil, err
	}

	return sqlStr, append(statement.joinArgs, condArgs...), nil
}

func (statement *Statement) genSelectSQL(columnStr, condSQL string, needLimit, needOrderBy bool) (string, error) {
	var (
		distinct                  string
		dialect                   = statement.Engine.Dialect()
		quote                     = statement.Engine.Quote
		fromStr                   = " FROM "
		top, mssqlCondi, whereStr string
	)
	if statement.IsDistinct && !strings.HasPrefix(columnStr, "count") {
		distinct = "DISTINCT "
	}
	if len(condSQL) > 0 {
		whereStr = " WHERE " + condSQL
	}

	fromStr += quote(statement.TableName())

	if statement.TableAlias != "" {
		if dialect.DBType() == core.ORACLE {
			fromStr += " " + quote(statement.TableAlias)
		} else {
			fromStr += " AS " + quote(statement.TableAlias)
		}
	}
	if statement.JoinStr != "" {
		fromStr = fmt.Sprintf("%v %v", fromStr, statement.JoinStr)
	}

	pLimitN := statement.LimitN

	var buf strings.Builder
	fmt.Fprintf(&buf, "SELECT %v%v%v%v%v", distinct, top, columnStr, fromStr, whereStr)
	if len(mssqlCondi) > 0 {
		if len(whereStr) > 0 {
			fmt.Fprint(&buf, " AND ", mssqlCondi)
		} else {
			fmt.Fprint(&buf, " WHERE ", mssqlCondi)
		}
	}

	if statement.GroupByStr != "" {
		fmt.Fprint(&buf, " GROUP BY ", statement.GroupByStr)
	}
	if statement.HavingStr != "" {
		fmt.Fprint(&buf, " ", statement.HavingStr)
	}
	if needOrderBy && statement.OrderStr != "" {
		fmt.Fprint(&buf, " ORDER BY ", statement.OrderStr)
	}
	if needLimit {
		if dialect.DBType() != core.ORACLE {
			if statement.Start > 0 {
				if pLimitN != nil {
					fmt.Fprintf(&buf, " LIMIT %v OFFSET %v", *pLimitN, statement.Start)
				} else {
					fmt.Fprintf(&buf, "LIMIT 0 OFFSET %v", statement.Start)
				}
			} else if pLimitN != nil {
				fmt.Fprint(&buf, " LIMIT ", *pLimitN)
			}
		} else {
			if statement.Start != 0 || pLimitN != nil {
				oldString := buf.String()
				buf.Reset()
				rawColStr := columnStr
				if rawColStr == "*" {
					rawColStr = "at.*"
				}
				fmt.Fprintf(&buf, "SELECT %v FROM (SELECT %v,ROWNUM RN FROM (%v) at WHERE ROWNUM <= %d) aat WHERE RN > %d",
					columnStr, rawColStr, oldString, statement.Start+*pLimitN, statement.Start)
			}
		}
	}
	if statement.IsForUpdate {
		return dialect.ForUpdateSql(buf.String()), nil
	}

	return buf.String(), nil
}

func (statement *Statement) processIDParam() error {
	if statement.idParam == nil || statement.RefTable == nil {
		return nil
	}

	if len(statement.RefTable.PrimaryKeys) != len(*statement.idParam) {
		return fmt.Errorf("ID condition is error, expect %d primarykeys, there are %d",
			len(statement.RefTable.PrimaryKeys),
			len(*statement.idParam),
		)
	}

	for i, col := range statement.RefTable.PKColumns() {
		var colName = statement.colName(col, statement.TableName())
		statement.cond = statement.cond.And(builder.Eq{colName: (*(statement.idParam))[i]})
	}
	return nil
}