package internal

import (
	"errors"
)

type Graph struct {
	Name  string  `hcl:"name"`
	Nodes []*Node `hcl:"nodes,block"`
	Links []*Link `hcl:"links,block"`
}

func (g *Graph) GetStartingNode() (Node, error) {
	for i := 0; i < len(g.Nodes); i++ {
		n := (*g.Nodes[i])
		if n.IsStart == true {
			return n, nil
		}
	}
	return Node{}, errors.New("No start node found")
}

func (g *Graph) GetNeighbour(n Node) []Node {
	var neighbourNodeName []string
	for i := 0; i < len(g.Links); i++ {
		if g.Links[i].From == n.Name {
			neighbourNodeName = append(neighbourNodeName, g.Links[i].To)
		}
	}

	// create temporary map of node by here name for direct future access
	var nodeByName = make(map[string]Node)
	for i := 0; i < len(g.Nodes); i++ {
		nodeByName[g.Nodes[i].Name] = (*g.Nodes[i])
	}

	var neighbourNode = make([]Node, len(neighbourNodeName))
	for i := 0; i < len(neighbourNodeName); i++ {
		neighbourNode[i] = nodeByName[neighbourNodeName[i]]
	}
	return neighbourNode
}