gv2adj/cmd/internal/graph/dot/graph.go

/*
Copyright © 2025 filifa

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package dot

import (
	"math"

	igraph "scm.dairydemon.net/filifa/gv2adj/cmd/internal/graph"

	"gonum.org/v1/gonum/graph"
	"gonum.org/v1/gonum/graph/multi"
)

// DOTDirectedGraph is a graph to unmarshal DOT graphs.
type DOTDirectedGraph struct {
	*igraph.DirectedGraph
	WeightAttribute string
}

// NewDOTDirectedGraph returns a graph with no nodes or edges.
func NewDOTDirectedGraph(weightAttr string) *DOTDirectedGraph {
	return &DOTDirectedGraph{DirectedGraph: igraph.NewDirectedGraph(), WeightAttribute: weightAttr}
}

// NewLine returns a DOT-aware weighted line.
func (g *DOTDirectedGraph) NewLine(from, to graph.Node) graph.Line {
	var defaultWeight float64
	if g.WeightAttribute == "" {
		defaultWeight = 1
	} else {
		defaultWeight = math.NaN()
	}

	e := g.DirectedGraph.NewWeightedLine(from, to, defaultWeight).(multi.WeightedLine)
	return &weightedLine{WeightedLine: e, weightAttribute: g.WeightAttribute}
}

// NewNode returns a DOT-aware Node.
func (g *DOTDirectedGraph) NewNode() graph.Node {
	return &Node{Node: g.DirectedGraph.NewNode()}
}

// SetLine adds a DOT-aware weighted line to the graph.
func (g *DOTDirectedGraph) SetLine(e graph.Line) {
	g.DirectedGraph.SetWeightedLine(e.(*weightedLine))
}