//go:build linux

package logger

import (
	"fmt"
	"os"
	"syscall"
	"testing"
)

func TestParseJournalStream(t *testing.T) {
	tests := []struct {
		name    string
		input   string
		wantDev uint64
		wantIno uint64
		wantOK  bool
	}{
		{"empty", "", 0, 0, false},
		{"no separator", "12345", 0, 0, false},
		{"leading colon", ":12345", 0, 0, false},
		{"trailing colon", "8:", 0, 0, false},
		{"non-numeric dev", "x:12345", 0, 0, false},
		{"non-numeric ino", "8:x", 0, 0, false},
		{"valid small", "8:12345", 8, 12345, true},
		{"valid large", "18446744073709551615:1", 18446744073709551615, 1, true},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			dev, ino, ok := parseJournalStream(tt.input)
			if ok != tt.wantOK {
				t.Fatalf("ok=%v want %v (input=%q)", ok, tt.wantOK, tt.input)
			}
			if ok && (dev != tt.wantDev || ino != tt.wantIno) {
				t.Fatalf("dev=%d ino=%d want dev=%d ino=%d", dev, ino, tt.wantDev, tt.wantIno)
			}
		})
	}
}

func TestStderrIsJournal_Unset(t *testing.T) {
	t.Setenv("JOURNAL_STREAM", "")
	if stderrIsJournal() {
		t.Fatal("stderrIsJournal returned true with JOURNAL_STREAM unset")
	}
}

func TestStderrIsJournal_Bogus(t *testing.T) {
	t.Setenv("JOURNAL_STREAM", "not-a-valid-value")
	if stderrIsJournal() {
		t.Fatal("stderrIsJournal returned true with bogus JOURNAL_STREAM")
	}
}

func TestStderrIsJournal_Mismatch(t *testing.T) {
	// Pick impossibly high dev:inode that won't match real stderr.
	t.Setenv("JOURNAL_STREAM", "999999999:999999999")
	if stderrIsJournal() {
		t.Fatal("stderrIsJournal returned true for mismatching dev:ino")
	}
}

func TestStderrIsJournal_Match(t *testing.T) {
	// Point JOURNAL_STREAM at the real stderr's dev:inode and confirm
	// detection works. This exercises the fstat+compare path without
	// needing an actual journal socket.
	var st syscall.Stat_t
	if err := syscall.Fstat(int(os.Stderr.Fd()), &st); err != nil {
		t.Fatalf("fstat stderr: %v", err)
	}
	t.Setenv("JOURNAL_STREAM", fmt.Sprintf("%d:%d", uint64(st.Dev), uint64(st.Ino)))
	if !stderrIsJournal() {
		t.Fatal("stderrIsJournal returned false when JOURNAL_STREAM matches stderr dev:ino")
	}
}