package types

import (
	"github.com/attic-labs/noms/chunks"
	"github.com/attic-labs/noms/ref"
)

type Ref struct {
	target ref.Ref
	t      Type
	ref    *ref.Ref
}

type RefBase interface {
	TargetRef() ref.Ref
}

func NewRef(target ref.Ref) Ref {
	return newRef(target, refType)
}

func newRef(target ref.Ref, t Type) Ref {
	return Ref{target, t, &ref.Ref{}}
}

func (r Ref) Equals(other Value) bool {
	return other != nil && r.t.Equals(other.Type()) && r.Ref() == other.Ref()
}

func (r Ref) Ref() ref.Ref {
	return EnsureRef(r.ref, r)
}

func (r Ref) Chunks() []ref.Ref {
	return []ref.Ref{r.target}
}

func (r Ref) ChildValues() []Value {
	return nil
}

func (r Ref) TargetRef() ref.Ref {
	return r.target
}

var refType = MakeCompoundType(RefKind, MakePrimitiveType(ValueKind))

func (r Ref) Type() Type {
	return r.t
}

func (r Ref) Less(other OrderedValue) bool {
	return r.target.Less(other.(Ref).target)
}

func (r Ref) TargetValue(cs chunks.ChunkStore) Value {
	return ReadValue(r.target, cs)
}

func (r Ref) SetTargetValue(val Value, cs chunks.ChunkSink) Ref {
	assertType(r.t.Desc.(CompoundDesc).ElemTypes[0], val)
	return newRef(WriteValue(val, cs), r.t)
}