package wrapper

import "strings"

type FField string

func (ff FField) Equal(des FField) bool {
	return ff == des
}

type Flag struct {
	FInt int `form:"flag" json:"flag"`
}

type Column struct {
	Flag
	Column string `form:"col" json:"col"`
	As     string `form:"-" json:"-"`
	Desc   bool   `form:"desc" json:"desc"` //（降序（大=>小）desc, 升序（小=>大）asc
}

func WithColumn(column string) *Column {
	return &Column{
		Column: column,
	}
}

func WithColumns(cols []string) *Column {
	c := &Column{}
	c.SetColumn(cols)
	return c
}

func (col *Column) GetColumn() []string {
	return strings.SplitN(col.Column, ",", maxColumns)
}

func (col *Column) SetColumn(cols []string) {
	if len(cols) <= 0 {
		col.Column = ""
		return
	}
	col.Column = strings.Join(cols, ",")
}

func (col *Column) With(column string) *Column {
	col.Column = column
	return col
}

func (col *Column) AS(newCol string) *Column {
	if newCol == "" {
		col.As = col.Column
	} else {
		col.As = newCol
	}
	return col
}

func (col *Column) WithFunc(fg int) *Column {
	col.FInt = fg
	return col
}

func (col *Column) Check(filters []FField) *Column {
	var (
		filter = func(col string) bool {
			for i := range filters {
				if filters[i].Equal(FField(col)) {
					return true
				}
			}
			return false
		}
		newCol []string
	)
	cols := col.GetColumn()
	for i := range cols {
		if filter(cols[i]) {
			newCol = append(newCol, cols[i])
		}
	}
	col.SetColumn(newCol)
	return col
}

func defColumnConvert(col string) string {
	return col
}

type ColumnConvert func(col string) string

func (col *Column) Sql(convert ColumnConvert) string {
	if convert == nil {
		convert = defColumnConvert
	}
	builder := strings.Builder{}
	fn := SQLFunc(col.FInt)
	if len(fn) > 0 {
		builder.WriteString(fn)
		builder.WriteByte('(')
	}
	builder.WriteString(convert(col.Column))
	if len(fn) > 0 {
		builder.WriteByte(')')
	}
	if len(col.As) > 0 {
		builder.WriteString(" AS ")
		builder.WriteString(col.As)
	}
	return builder.String()
}