package wrapper

import (
	"gitee.com/h79/goutils/dao/option"
	"strings"
)

var _ IFrom = (*From)(nil)

type From struct {
	child bool   //子源
	From  string `json:"from" yaml:"from"`
	As    string `json:"as" yaml:"as"`
}

func (f *From) Is() bool {
	return f.From != ""
}

func (f *From) SetChild(child bool) {
	f.child = child
}

func (f *From) SetAs(as string) {
	f.As = as
}

func (f *From) Build(opts ...option.Option) string {
	if !f.Is() {
		return ""
	}
	var builder = strings.Builder{}
	builder.WriteString(" FROM ")
	if f.child {
		builder.WriteByte('(')
	}
	f.from(&builder, f.From)
	if f.child {
		builder.WriteByte(')')
	}
	AddAlias(&builder, f.As)
	return builder.String()
}

func (f *From) from(builder *strings.Builder, v string) bool {
	if v == "" {
		return false
	}
	quo := true
	first := v[0]
	end := v[len(v)-1]
	if first == '`' {
		quo = false
	} else {
		l := len(v)
		if l > 9 {
			l = 9
		}
		up := strings.ToUpper(v[0:l])
		if strings.Contains(up, "DROP") || strings.Contains(up, "DELETE") {
			panic("may be illegal，lead to serious consequences")
		}
		quo = !strings.Contains(up, "SELECT")
	}
	if quo {
		builder.WriteByte('`')
		first = '`'
	}
	builder.WriteString(v)
	if first == '`' && end != '`' {
		builder.WriteByte('`')
	}
	return true
}