copy

func copyFile(src, dst string) error

{
	in, err := os.Open(src)
	if err != nil {
		return err
	}
	defer in.Close()

	out, err := os.Create(dst)
	if err != nil {
		return err
	}
	if _, err := io.Copy(out, in); err != nil {
		out.Close()
		return err
	}
	return out.Close()
}

func TestBuildAndShouldRebuild(t *testing.T)

{
	p := &plugin{}
	tmp := t.TempDir()

	cwd, _ := os.Getwd()
	defer os.Chdir(cwd)
	if err := os.Chdir(tmp); err != nil {
		t.Fatalf("chdir: %v", err)
	}

	srcRoot := filepath.Join("examples", "components")
	if err := os.MkdirAll(filepath.Join(srcRoot, "templates"), 0o755); err != nil {
		t.Fatalf("mkdir: %v", err)
	}
	fileA := filepath.Join(srcRoot, "comp.txt")
	if err := os.WriteFile(fileA, []byte("a"), 0o644); err != nil {
		t.Fatalf("write: %v", err)
	}
	fileB := filepath.Join(srcRoot, "templates", "tpl.txt")
	if err := os.WriteFile(fileB, []byte("b"), 0o644); err != nil {
		t.Fatalf("write: %v", err)
	}

	destRoot := filepath.Join("build", "static", "examples", "components")
	cfg := struct {
		Files []struct {
			From string `json:"from"`
			To   string `json:"to"`
		} `json:"files"`
	}{
		Files: []struct {
			From string `json:"from"`
			To   string `json:"to"`
		}{{
			From: filepath.Join(srcRoot, "**", "*"),
			To:   destRoot,
		}},
	}
	raw, _ := json.Marshal(cfg)
	if err := p.Build(raw); err != nil {
		t.Fatalf("Build: %v", err)
	}

	absDest := filepath.Join(tmp, destRoot)
	if data, err := os.ReadFile(filepath.Join(absDest, "comp.txt")); err != nil || string(data) != "a" {
		t.Fatalf("comp.txt not copied: %v %s", err, data)
	}
	if data, err := os.ReadFile(filepath.Join(absDest, "templates", "tpl.txt")); err != nil || string(data) != "b" {
		t.Fatalf("tpl.txt not copied: %v %s", err, data)
	}

	if !p.ShouldRebuild(fileA) {
		t.Fatalf("expected ShouldRebuild true for %s", fileA)
	}
	if p.ShouldRebuild(filepath.Join("other.txt")) {
		t.Fatalf("unexpected rebuild for unrelated file")
	}
}