package cli

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

func TestParseOSReleaseID_Ubuntu(t *testing.T) {
	content := `NAME="Ubuntu"
VERSION="24.04.4 LTS (Noble Numbat)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 24.04.4 LTS"`
	if got := parseOSReleaseID([]byte(content)); got != "ubuntu" {
		t.Errorf("got %q, want ubuntu", got)
	}
}

func TestParseOSReleaseID_Debian(t *testing.T) {
	content := `PRETTY_NAME="Debian GNU/Linux 12 (bookworm)"
NAME="Debian GNU/Linux"
VERSION_ID="12"
VERSION="12 (bookworm)"
ID=debian`
	if got := parseOSReleaseID([]byte(content)); got != "debian" {
		t.Errorf("got %q, want debian", got)
	}
}

func TestParseOSReleaseID_Alpine(t *testing.T) {
	content := `NAME="Alpine Linux"
ID=alpine
VERSION_ID=3.20.3
PRETTY_NAME="Alpine Linux v3.20"`
	if got := parseOSReleaseID([]byte(content)); got != "alpine" {
		t.Errorf("got %q, want alpine", got)
	}
}

func TestParseOSReleaseID_PVE(t *testing.T) {
	content := `NAME="Proxmox Virtual Environment"
VERSION="9.2.3"
ID=pve
ID_LIKE=debian`
	if got := parseOSReleaseID([]byte(content)); got != "pve" {
		t.Errorf("got %q, want pve", got)
	}
}

func TestParseOSReleaseID_QuotedValue(t *testing.T) {
	content := `ID="ubuntu"`
	if got := parseOSReleaseID([]byte(content)); got != "ubuntu" {
		t.Errorf("got %q, want ubuntu", got)
	}
}

func TestParseOSReleaseID_UnquotedValue(t *testing.T) {
	content := `ID=alpine`
	if got := parseOSReleaseID([]byte(content)); got != "alpine" {
		t.Errorf("got %q, want alpine", got)
	}
}

func TestParseOSReleaseID_MissingID(t *testing.T) {
	content := `NAME="Some Distro"
VERSION="1.0"`
	if got := parseOSReleaseID([]byte(content)); got != "" {
		t.Errorf("got %q, want empty", got)
	}
}

func TestParseOSReleaseID_EmptyContent(t *testing.T) {
	if got := parseOSReleaseID([]byte("")); got != "" {
		t.Errorf("got %q, want empty", got)
	}
}

func TestParseOSReleaseID_CommentsAndBlankLines(t *testing.T) {
	content := `# This is a comment

NAME="Test"
# ID is set below
ID=arch
PRETTY_NAME="Test Arch"`
	if got := parseOSReleaseID([]byte(content)); got != "arch" {
		t.Errorf("got %q, want arch", got)
	}
}

func TestParseOSReleaseID_UnknownIDReturnedVerbatim(t *testing.T) {
	content := `ID=fedora`
	if got := parseOSReleaseID([]byte(content)); got != "fedora" {
		t.Errorf("got %q, want fedora (unknown IDs returned verbatim)", got)
	}
}

func TestDetectOS_FallbackToLinux(t *testing.T) {
	// Temporarily point osReleasePaths at non-existent files.
	orig := osReleasePaths
	defer func() { osReleasePaths = orig }()
	osReleasePaths = []string{
		filepath.Join(t.TempDir(), "nonexistent-os-release"),
	}
	if got := detectOS(); got != "linux" {
		t.Errorf("got %q, want linux (fallback)", got)
	}
}

func TestDetectOS_ReadsEtcOSRelease(t *testing.T) {
	dir := t.TempDir()
	orig := osReleasePaths
	defer func() { osReleasePaths = orig }()
	osReleasePaths = []string{filepath.Join(dir, "os-release")}
	if err := os.WriteFile(osReleasePaths[0], []byte("ID=ubuntu\n"), 0o644); err != nil {
		t.Fatalf("write: %v", err)
	}
	if got := detectOS(); got != "ubuntu" {
		t.Errorf("got %q, want ubuntu", got)
	}
}

func TestDetectOS_FallbackToUsrLib(t *testing.T) {
	dir := t.TempDir()
	orig := osReleasePaths
	defer func() { osReleasePaths = orig }()
	osReleasePaths = []string{
		filepath.Join(dir, "etc-os-release"),     // missing
		filepath.Join(dir, "usr-lib-os-release"), // fallback
	}
	if err := os.WriteFile(osReleasePaths[1], []byte("ID=alpine\n"), 0o644); err != nil {
		t.Fatalf("write: %v", err)
	}
	if got := detectOS(); got != "alpine" {
		t.Errorf("got %q, want alpine (from fallback path)", got)
	}
}