package opt

import (
	"gitlink.org.cn/cloudream/common/pkgs/ioswitch/dag"
	"gitlink.org.cn/cloudream/jcs-pub/common/pkgs/ioswitch2/ops2"
	"gitlink.org.cn/cloudream/jcs-pub/common/pkgs/ioswitch2/parser/state"
	"gitlink.org.cn/cloudream/jcs-pub/common/pkgs/storage/factory"
)

// 将直接从一个存储服务传到另一个存储服务的过程换成S2S传输
func UseS2STransfer(ctx *state.GenerateState) {
	// S2S传输暂不支持只传文件的一部分
	if ctx.StreamRange.Offset != 0 || ctx.StreamRange.Length != nil {
		return
	}

	dag.WalkOnlyType[*ops2.BaseWriteNode](ctx.DAG.Graph, func(node *ops2.BaseWriteNode) bool {
		inputVar := node.Input().Var()
		if inputVar == nil {
			return true
		}

		s2s, err := factory.GetBuilder(&node.UserSpace).CreateS2STransfer(true)
		if err != nil {
			return true
		}

		// 只有BaseRead->BaseWrite的情况才可以进行S2S传输
		switch inputNode := inputVar.Src.(type) {
		case *ops2.BaseReadNode:
			if !s2s.CanTransfer(&inputNode.UserSpace, &node.UserSpace) {
				return true
			}

			s2sNode := ctx.DAG.NewS2STransfer(inputNode.UserSpace, inputNode.Path, node.UserSpace, node.Path)
			// 直传指令在目的地Hub上执行
			s2sNode.Env().CopyFrom(node.Env())

			// 原本BaseWriteNode的FileInfoVar被替换成S2SNode的FileInfoVar
			for _, dstSlot := range node.FileInfoVar().ListDstSlots() {
				s2sNode.FileInfoVar().ToSlot(dstSlot)
			}

		case *ops2.BaseReadDynNode:
			if !s2s.CanTransfer(&inputNode.UserSpace, &node.UserSpace) {
				return true
			}

			s2sNode := ctx.DAG.NewS2STransferDyn(inputNode.UserSpace, node.UserSpace, node.Path)
			// 直传指令在目的地Hub上执行
			s2sNode.Env().CopyFrom(node.Env())

			// 原本BaseWriteNode的FileInfoVar被替换成S2SNode的FileInfoVar
			for _, dstSlot := range node.FileInfoVar().ListDstSlots() {
				s2sNode.FileInfoVar().ToSlot(dstSlot)
			}

			// 传递给BaseReadDyn的FileInfo也给S2S一份
			srcFileInfoVar := inputNode.FileInfoSlot().Var()
			if srcFileInfoVar != nil {
				srcFileInfoVar.ToSlot(s2sNode.SrcFileInfoSlot())
			}

		default:
			return true
		}

		// 中断srcVar的流向
		inputVar.NotTo(node)

		// 从计划中删除目标节点
		ctx.DAG.RemoveNode(node)
		return true
	})
}