package graph

import (
	"errors"

	"edge-infra.dev/pkg/lib/text/drawing"
)

var errUnsupportedDotNodeType = errors.New("unsupported type for dot node")

// Creates a dot graph representation of the graph from its root node
func (g *graph) toDot() (*drawing.Digraph, error) {
	// as nodes are traversed depth-first, the last node is the root
	root := g.keys[len(g.keys)-1]
	rootNode := g.nodes[root]

	rootDotNode, dotNodes, err := rootNode.toDot()
	if err != nil {
		return nil, err
	}

	dt := &drawing.DotTree{
		Root:  rootDotNode,
		Nodes: dotNodes,
		Attributes: map[string]string{
			"rankdir": "TB",
		},
	}

	return &drawing.Digraph{
		Title: rootNode.name,
		Subgraphs: []drawing.Subgraph{
			&palletLegend{},
			dt,
		},
	}, nil
}

// Creates a dot representation of the node and its dependencies, returning the root node and a map of all nodes
func (n *node) toDot() (rootNode *drawing.DotNode, nodes map[string]*drawing.DotNode, err error) {
	children := []*drawing.DotNode{}
	for _, dep := range n.deps {
		var child *drawing.DotNode
		child, nodes, err = dep.toDot()
		if err != nil {
			return nil, nil, err
		}
		children = append(children, child)
	}

	rootNode, err = dotNodeByType(n.label(), n.nodeType)
	if err != nil {
		return nil, nil, err
	}

	rootNode.Children = children
	if n.nodeType == objectsNode {
		rootNode.Data = n.data
	}

	if nodes == nil {
		nodes = map[string]*drawing.DotNode{}
	}
	nodes[n.digest.String()] = rootNode

	return rootNode, nodes, err
}