package treeops

import (
	"container/list"

	"gopkg.in/yaml.v3"
)

func DeleteChildOperator(d *dataTreeNavigator, matchingNodes *list.List, pathNode *PathTreeNode) (*list.List, error) {
	lhs, err := d.GetMatchingNodes(matchingNodes, pathNode.Lhs)
	if err != nil {
		return nil, err
	}
	// for each lhs, splat the node,
	// the intersect it against the rhs expression
	// recreate the contents using only the intersection result.

	for el := lhs.Front(); el != nil; el = el.Next() {
		candidate := el.Value.(*CandidateNode)
		elMap := list.New()
		elMap.PushBack(candidate)
		nodesToDelete, err := d.GetMatchingNodes(elMap, pathNode.Rhs)
		log.Debug("nodesToDelete:\n%v", NodesToString(nodesToDelete))
		if err != nil {
			return nil, err
		}

		if candidate.Node.Kind == yaml.SequenceNode {
			deleteFromArray(candidate, nodesToDelete)
		} else if candidate.Node.Kind == yaml.MappingNode {
			deleteFromMap(candidate, nodesToDelete)
		} else {
			log.Debug("Cannot delete from node that's not a map or array %v", NodeToString(candidate))
		}
	}
	return lhs, nil
}

func deleteFromMap(candidate *CandidateNode, nodesToDelete *list.List) {
	log.Debug("deleteFromMap")
	node := candidate.Node
	contents := node.Content
	newContents := make([]*yaml.Node, 0)

	for index := 0; index < len(contents); index = index + 2 {
		key := contents[index]
		value := contents[index+1]

		childCandidate := &CandidateNode{
			Node:     value,
			Document: candidate.Document,
			Path:     append(candidate.Path, key.Value),
		}
		// _, shouldDelete := nodesToDelete.Get(childCandidate.GetKey())
		shouldDelete := true

		log.Debugf("shouldDelete %v ? %v", childCandidate.GetKey(), shouldDelete)

		if !shouldDelete {
			newContents = append(newContents, key, value)
		}
	}
	node.Content = newContents
}

func deleteFromArray(candidate *CandidateNode, nodesToDelete *list.List) {
	log.Debug("deleteFromArray")
	node := candidate.Node
	contents := node.Content
	newContents := make([]*yaml.Node, 0)

	for index := 0; index < len(contents); index = index + 1 {
		value := contents[index]

		// childCandidate := &CandidateNode{
		// 	Node:     value,
		// 	Document: candidate.Document,
		// 	Path:     append(candidate.Path, index),
		// }

		// _, shouldDelete := nodesToDelete.Get(childCandidate.GetKey())
		shouldDelete := true
		if !shouldDelete {
			newContents = append(newContents, value)
		}
	}
	node.Content = newContents
}