Show_test.go

// SPDX-License-Identifier: MIT
// Copyright (c) 2026 MaIII Themd

package dijkstra

import (
	"bytes"
	"strings"
	"testing"
)

func TestShowDefault(t *testing.T) {
	var g StGraph
	g.VertexAdd("A", 0, 0, 0)
	g.VertexAdd("B", 1, 0, 0)
	g.VertexAddEdge("A", "B", 2.5, true) // one-way

	var buf bytes.Buffer
	g.Show(&buf)
	out := buf.String()

	if !strings.Contains(out, "Vertex A") || !strings.Contains(out, "Vertex B") {
		t.Errorf("Show missing vertices:\n%s", out)
	}
	if !strings.Contains(out, "(B, 2.50") {
		t.Errorf("Show missing edge weight:\n%s", out)
	}
	if !strings.Contains(out, "one-way") {
		t.Errorf("Show should mark one-way edges:\n%s", out)
	}
}

func TestShowFuncCustom(t *testing.T) {
	var g StGraph
	g.VertexAdd("A", 0, 0, 0)
	g.VertexAdd("B", 1, 0, 0)

	var buf bytes.Buffer
	g.ShowFunc(&buf, func(v StVertex) string { return v.Name + "\n" })
	if got, want := buf.String(), "A\nB\n"; got != want {
		t.Errorf("ShowFunc custom = %q, want %q", got, want)
	}
}

func TestShowFuncNilUsesDefault(t *testing.T) {
	var g StGraph
	g.VertexAdd("A", 0, 0, 0)

	var a, b bytes.Buffer
	g.Show(&a)
	g.ShowFunc(&b, nil)
	if a.String() != b.String() {
		t.Errorf("ShowFunc(nil) should equal Show:\n%q\n%q", a.String(), b.String())
	}
}

func TestPathString(t *testing.T) {
	var g StGraph
	g.VertexAdd("A", 0, 0, 0)
	g.VertexAdd("B", 1, 0, 0)
	g.VertexAdd("C", 2, 0, 0)
	for _, e := range [][3]interface{}{{"A", "B", 1.0}, {"B", "C", 2.0}} {
		g.VertexAddEdge(e[0].(string), e[1].(string), e[2].(float64), false)
		g.VertexAddEdge(e[1].(string), e[0].(string), e[2].(float64), false)
	}

	ok, path := g.DijkstraSearch("A", "C")
	if !ok {
		t.Fatal("expected a path")
	}
	if got, want := PathString(path), "A -> B -> C (cost 3)"; got != want {
		t.Errorf("PathString = %q, want %q", got, want)
	}
	if got := PathString(nil); got != "(no path)" {
		t.Errorf("PathString(nil) = %q, want %q", got, "(no path)")
	}
}

func TestShowDijkstra(t *testing.T) {
	var g StGraph
	g.VertexAdd("A", 0, 0, 0)
	g.VertexAdd("B", 1, 0, 0)
	g.VertexAddEdge("A", "B", 1, false)
	g.VertexAddEdge("B", "A", 1, false)
	g.DijkstraSearch("A", "B")

	var buf bytes.Buffer
	g.ShowDijkstra(&buf)
	if !strings.Contains(buf.String(), "parent A") {
		t.Errorf("ShowDijkstra should report B's parent as A:\n%s", buf.String())
	}
}