package orm

type TableReference interface {
	table()
}

// 普通表
type Table struct {
	entity any
	alias  string
}

func (t Table) As(alias string) Table {
	return Table{
		entity: t.entity,
		alias:  alias,
	}
}

func (t Table) C(name string) Column {
	return Column{
		Name:  name,
		Table: t,
	}
}

func (t Table) table() {}

func (t Table) Join(target TableReference) *JoinBuilder {
	return &JoinBuilder{
		left:  t,
		right: target,
		typ:   " JOIN ",
	}
}

func (t Table) LeftJoin(target TableReference) *JoinBuilder {
	return &JoinBuilder{
		left:  t,
		right: target,
		typ:   " LEFT JOIN ",
	}
}

func (t Table) RightJoin(target TableReference) *JoinBuilder {
	return &JoinBuilder{
		left:  t,
		right: target,
		typ:   " RIGHT JOIN ",
	}
}

// join
type Join struct {
	left  TableReference
	right TableReference
	typ   string
	on    []Predicate
}

func (j Join) table() {}

func (j Join) Join(target TableReference) *JoinBuilder {
	return &JoinBuilder{
		left:  j,
		right: target,
		typ:   " JOIN ",
	}
}

func (j Join) LeftJoin(target TableReference) *JoinBuilder {
	return &JoinBuilder{
		left:  j,
		right: target,
		typ:   " LEFT JOIN ",
	}
}

func (j Join) RightJoin(target TableReference) *JoinBuilder {
	return &JoinBuilder{
		left:  j,
		right: target,
		typ:   " RIGHT JOIN ",
	}
}

// /=====================================
func TableOf(entity any) Table {
	return Table{entity: entity}
}

type JoinBuilder struct {
	left  TableReference
	right TableReference
	typ   string
}

func (j *JoinBuilder) On(ps ...Predicate) Join {
	return Join{
		left:  j.left,
		right: j.right,
		typ:   j.typ,
		on:    ps,
	}
}