package viz

import (
	"bytes"
	"os"
	"path/filepath"
	"testing"

	"bspviz/internal/bsp"
	"bspviz/internal/geom"
	"bspviz/internal/mapfmt"
)

func TestEmitDOT(t *testing.T) {
	root := &bsp.Node{
		O: geom.V(0, 0),
		D: geom.V(1, 0),
		Left: &bsp.Node{
			Leaf: &bsp.Leaf{Segs: []geom.Seg{{A: geom.V(0, 0), B: geom.V(1, 1)}}},
		},
		Right: &bsp.Node{
			Leaf: &bsp.Leaf{},
		},
	}
	out := filepath.Join(t.TempDir(), "tree.dot")
	if err := EmitDOT(root, out); err != nil {
		t.Fatalf("EmitDOT error: %v", err)
	}
	got, err := os.ReadFile(out)
	if err != nil {
		t.Fatalf("ReadFile: %v", err)
	}
	expect := "digraph BSP {\n" +
		"  node [fontname=\"Helvetica\"];\n" +
		"  n0 [label=\"Split\\nO=(0,0) D=(1,0)\"];\n" +
		"  n1 [label=\"Leaf\\nSegs=1\", shape=ellipse, style=filled, fillcolor=lightgray];\n" +
		"  n2 [label=\"Leaf\\nSegs=0\", shape=ellipse, style=filled, fillcolor=lightgray];\n" +
		"  n0 -> n1 [label=\"L\"];\n" +
		"  n0 -> n2 [label=\"R\"];\n" +
		"}\n"
	if string(got) != expect {
		t.Fatalf("unexpected DOT output:\n%s", got)
	}
}

func TestRenderPNGProducesFile(t *testing.T) {
	m := &mapfmt.MapData{
		Vertices: []mapfmt.Vertex{{X: 0, Y: 0}, {X: 64, Y: 0}, {X: 64, Y: 64}},
		Linedefs: []mapfmt.Linedef{
			{V1: 0, V2: 1},
			{V1: 1, V2: 2},
			{V1: 2, V2: 0},
		},
	}
	root := &bsp.Node{
		O:     geom.V(0, 0),
		D:     geom.V(1, 0),
		Left:  &bsp.Node{Leaf: &bsp.Leaf{Segs: []geom.Seg{{A: geom.V(0, 0), B: geom.V(64, 64)}}}},
		Right: &bsp.Node{Leaf: &bsp.Leaf{}},
	}
	out := filepath.Join(t.TempDir(), "render.png")
	if err := RenderPNG(m, root, out); err != nil {
		t.Fatalf("RenderPNG error: %v", err)
	}
	data, err := os.ReadFile(out)
	if err != nil {
		t.Fatalf("ReadFile: %v", err)
	}
	pngMagic := []byte{0x89, 'P', 'N', 'G', '\r', '\n', 0x1a, '\n'}
	if len(data) < len(pngMagic) || !bytes.Equal(data[:len(pngMagic)], pngMagic) {
		t.Fatalf("output is not a PNG")
	}
}