#!/bin/sh
# Pulse agent installer.  Usage:  curl -fsSL https://visionstack.space/install.sh | sudo sh -s -- <SERVER_TOKEN>
# Installs a read-only agent that runs once a minute via a systemd timer.
# Remove with:  sudo sh -c 'systemctl disable --now pulse-agent.timer; rm -rf /etc/pulse /var/lib/pulse /usr/local/bin/pulse-agent /etc/systemd/system/pulse-agent.*'
set -eu

TOKEN="${1:-}"
URL="${PULSE_URL:-https://visionstack.space}"

[ -n "$TOKEN" ] || { echo "Usage: curl -fsSL $URL/install.sh | sudo sh -s -- <SERVER_TOKEN>" >&2; exit 1; }
[ "$(id -u)" = 0 ] || { echo "Please run as root (sudo)." >&2; exit 1; }
command -v python3 >/dev/null || { echo "python3 is required." >&2; exit 1; }
command -v systemctl >/dev/null || { echo "systemd is required." >&2; exit 1; }

echo "Installing Pulse agent..."
curl -fsSL "$URL/agent/pulse-agent.py" -o /usr/local/bin/pulse-agent
chmod 755 /usr/local/bin/pulse-agent

mkdir -p /etc/pulse /var/lib/pulse
umask 077
printf 'PULSE_URL=%s\nPULSE_TOKEN=%s\n' "$URL" "$TOKEN" > /etc/pulse/config

# Certificate checks: start from the hostnames nginx serves, if any. Edit freely.
if [ ! -f /etc/pulse/domains ]; then
  { echo "# One hostname per line; Pulse checks TLS certificate expiry hourly."
    grep -RhoE '^\s*server_name\s+[^;]+' /etc/nginx 2>/dev/null \
      | sed -E 's/^\s*server_name\s+//' | tr ' ' '\n' \
      | grep -E '^[A-Za-z0-9.-]+\.[A-Za-z]{2,}$' | grep -v '^www\.' | sort -u | head -40
  } > /etc/pulse/domains || true
fi

cat > /etc/systemd/system/pulse-agent.service <<'EOF'
[Unit]
Description=Pulse health snapshot (read-only)
After=network-online.target

[Service]
Type=oneshot
ExecStart=/usr/bin/python3 /usr/local/bin/pulse-agent
Nice=10
IOSchedulingClass=idle
TimeoutStartSec=120
EOF

cat > /etc/systemd/system/pulse-agent.timer <<'EOF'
[Unit]
Description=Run the Pulse agent every minute

[Timer]
OnBootSec=30s
OnUnitActiveSec=60s
AccuracySec=5s

[Install]
WantedBy=timers.target
EOF

systemctl daemon-reload
systemctl enable --now pulse-agent.timer >/dev/null
systemctl start pulse-agent.service || true
echo "Done. Your server should appear in the Pulse dashboard within a minute."