package ops

import (
	"gitlink.org.cn/cloudream/common/pkgs/ioswitch/dag"
	"gitlink.org.cn/cloudream/common/pkgs/ioswitch/exec"
)

func init() {
	exec.UseOp[*ConstVar]()
}

type ConstVar struct {
	ID    exec.VarID    `json:"id"`
	Value exec.VarValue `json:"value"`
}

func (o *ConstVar) Execute(ctx *exec.ExecContext, e *exec.Executor) error {
	e.PutVar(o.ID, o.Value)
	return nil
}

func (o *ConstVar) String() string {
	return "ConstVar"
}

type ConstNode struct {
	dag.NodeBase
	Value exec.VarValue
}

func (b *GraphNodeBuilder) NewConst(val exec.VarValue) *ConstNode {
	node := &ConstNode{
		Value: val,
	}
	b.AddNode(node)

	node.OutputValues().Init(node, 1)
	return node
}

func (t *ConstNode) Output() dag.ValueOutputSlot {
	return dag.ValueOutputSlot{
		Node:  t,
		Index: 0,
	}
}

func (t *ConstNode) GenerateOp() (exec.Op, error) {
	return &DropStream{
		Input: t.Output().Var().VarID,
	}, nil
}