package platform

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

func TestGetDistroFamily(t *testing.T) {
	tests := []struct {
		name   string
		id     string
		idLike string
		want   string
	}{
		{"fedora", "fedora", "", "rhel"},
		{"rocky via ID_LIKE", "rocky", "rhel centos fedora", "rhel"},
		{"arch", "arch", "", "arch"},
		{"manjaro via ID_LIKE", "manjaro", "arch", "arch"},
		{"unknown derivative via ID_LIKE arch", "myarchdistro", "arch", "arch"},
		{"elementary", "elementary", "ubuntu debian", "debian"},
		{"opensuse tumbleweed", "opensuse-tumbleweed", "opensuse suse", "suse"},
		{"opensuse leap", "opensuse-leap", "suse opensuse", "suse"},
		{"debian", "debian", "", "debian"},
		{"ubuntu", "ubuntu", "debian", "debian"},
		{"unknown id returned unchanged", "void", "", "void"},
		{"empty input", "", "", ""},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if got := GetDistroFamily(tt.id, tt.idLike); got != tt.want {
				t.Errorf("GetDistroFamily(%q, %q) = %q, want %q", tt.id, tt.idLike, got, tt.want)
			}
		})
	}
}

// withOSRelease writes content to a temp file and points osReleasePaths at it
// for the duration of the test.
func withOSRelease(t *testing.T, content string) {
	t.Helper()
	path := filepath.Join(t.TempDir(), "os-release")
	if err := os.WriteFile(path, []byte(content), 0644); err != nil {
		t.Fatalf("failed to write temp os-release: %v", err)
	}
	orig := osReleasePaths
	osReleasePaths = []string{path}
	t.Cleanup(func() { osReleasePaths = orig })
}

func TestIsImmutableDistro(t *testing.T) {
	tests := []struct {
		name      string
		distro    string
		osRelease string
		want      bool
	}{
		{
			name:      "fedora silverblue via VARIANT_ID",
			distro:    "fedora",
			osRelease: "ID=fedora\nVARIANT_ID=silverblue\n",
			want:      true,
		},
		{
			name:      "fedora kinoite via VARIANT_ID",
			distro:    "fedora",
			osRelease: "ID=fedora\nVARIANT_ID=kinoite\n",
			want:      true,
		},
		{
			name:      "plain fedora workstation",
			distro:    "fedora",
			osRelease: "ID=fedora\nVARIANT_ID=workstation\n",
			want:      false,
		},
		{
			name:      "bluefin via distro name",
			distro:    "bluefin",
			osRelease: "ID=bluefin\nID_LIKE=\"fedora\"\n",
			want:      true,
		},
		{
			name:      "plain arch",
			distro:    "arch",
			osRelease: "ID=arch\n",
			want:      false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			withOSRelease(t, tt.osRelease)
			p := &Platform{OSType: Linux, Distro: tt.distro}
			if got := p.IsImmutableDistro(); got != tt.want {
				t.Errorf("IsImmutableDistro() = %v, want %v", got, tt.want)
			}
		})
	}

	t.Run("non-linux is never immutable", func(t *testing.T) {
		p := &Platform{OSType: Windows, Distro: "fedora"}
		if p.IsImmutableDistro() {
			t.Errorf("IsImmutableDistro() on Windows = true, want false")
		}
	})
}

func TestReadOSReleaseFallback(t *testing.T) {
	dir := t.TempDir()
	fallback := filepath.Join(dir, "usr-lib-os-release")
	content := "ID=opensuse-tumbleweed\nID_LIKE=\"opensuse suse\"\nVARIANT_ID=tumbleweed\n"
	if err := os.WriteFile(fallback, []byte(content), 0644); err != nil {
		t.Fatalf("failed to write temp os-release: %v", err)
	}

	orig := osReleasePaths
	osReleasePaths = []string{filepath.Join(dir, "missing"), fallback}
	t.Cleanup(func() { osReleasePaths = orig })

	id, idLike, variantID := readOSRelease()
	if id != "opensuse-tumbleweed" {
		t.Errorf("readOSRelease() id = %q, want %q", id, "opensuse-tumbleweed")
	}
	if idLike != "opensuse suse" {
		t.Errorf("readOSRelease() idLike = %q, want %q", idLike, "opensuse suse")
	}
	if variantID != "tumbleweed" {
		t.Errorf("readOSRelease() variantID = %q, want %q", variantID, "tumbleweed")
	}
	if family := GetDistroFamily(id, idLike); family != "suse" {
		t.Errorf("GetDistroFamily(%q, %q) = %q, want %q", id, idLike, family, "suse")
	}
}

func TestReadOSReleaseMissing(t *testing.T) {
	orig := osReleasePaths
	osReleasePaths = []string{filepath.Join(t.TempDir(), "missing")}
	t.Cleanup(func() { osReleasePaths = orig })

	id, idLike, variantID := readOSRelease()
	if id != "" || idLike != "" || variantID != "" {
		t.Errorf("readOSRelease() = (%q, %q, %q), want all empty", id, idLike, variantID)
	}
}