package dag

import (
	"fmt"
	"strings"
	"testing"
)

func TestGraph_empty(t *testing.T) {
	var g Graph
	g.Add(1)
	g.Add(2)
	g.Add(3)

	actual := strings.TrimSpace(g.String())
	expected := strings.TrimSpace(testGraphEmptyStr)
	if actual != expected {
		t.Fatalf("bad: %s", actual)
	}
}

func TestGraph_basic(t *testing.T) {
	var g Graph
	g.Add(1)
	g.Add(2)
	g.Add(3)
	g.Connect(BasicEdge(1, 3))

	actual := strings.TrimSpace(g.String())
	expected := strings.TrimSpace(testGraphBasicStr)
	if actual != expected {
		t.Fatalf("bad: %s", actual)
	}
}

func TestGraph_remove(t *testing.T) {
	var g Graph
	g.Add(1)
	g.Add(2)
	g.Add(3)
	g.Connect(BasicEdge(1, 3))
	g.Remove(3)

	actual := strings.TrimSpace(g.String())
	expected := strings.TrimSpace(testGraphRemoveStr)
	if actual != expected {
		t.Fatalf("bad: %s", actual)
	}
}

func TestGraph_replace(t *testing.T) {
	var g Graph
	g.Add(1)
	g.Add(2)
	g.Add(3)
	g.Connect(BasicEdge(1, 2))
	g.Connect(BasicEdge(2, 3))
	g.Replace(2, 42)

	actual := strings.TrimSpace(g.String())
	expected := strings.TrimSpace(testGraphReplaceStr)
	if actual != expected {
		t.Fatalf("bad: %s", actual)
	}
}

func TestGraph_replaceSelf(t *testing.T) {
	var g Graph
	g.Add(1)
	g.Add(2)
	g.Add(3)
	g.Connect(BasicEdge(1, 2))
	g.Connect(BasicEdge(2, 3))
	g.Replace(2, 2)

	actual := strings.TrimSpace(g.String())
	expected := strings.TrimSpace(testGraphReplaceSelfStr)
	if actual != expected {
		t.Fatalf("bad: %s", actual)
	}
}

// This tests that connecting edges works based on custom Hashcode
// implementations for uniqueness.
func TestGraph_hashcode(t *testing.T) {
	var g Graph
	g.Add(&hashVertex{code: 1})
	g.Add(&hashVertex{code: 2})
	g.Add(&hashVertex{code: 3})
	g.Connect(BasicEdge(
		&hashVertex{code: 1},
		&hashVertex{code: 3}))

	actual := strings.TrimSpace(g.String())
	expected := strings.TrimSpace(testGraphBasicStr)
	if actual != expected {
		t.Fatalf("bad: %s", actual)
	}
}

type hashVertex struct {
	code interface{}
}

func (v *hashVertex) Hashcode() interface{} {
	return v.code
}

func (v *hashVertex) Name() string {
	return fmt.Sprintf("%#v", v.code)
}

const testGraphBasicStr = `
1
  3
2
3
`

const testGraphEmptyStr = `
1
2
3
`

const testGraphRemoveStr = `
1
2
`

const testGraphReplaceStr = `
1
  42
3
42
  3
`

const testGraphReplaceSelfStr = `
1
  2
2
  3
3
`