#!/usr/bin/env bash
# process_check.sh — systemd service liveness.
set -euo pipefail

SERVICE="${1:-}"
if [ -z "$SERVICE" ]; then
  echo '{"health":"unknown","signalKind":"process-check","evidence":"no service name provided"}'
  exit 0
fi

if ! command -v systemctl >/dev/null 2>&1; then
  echo '{"health":"unknown","signalKind":"process-check","evidence":"systemctl not found"}'
  exit 0
fi

# `systemctl is-active` PRINTS the state and exits non-zero when the unit is
# not active, so `... || echo unknown` appended a second line and produced
# "paperless is inactive\nunknown" — a raw newline inside a JSON string, which
# the scheduler rejected as invalid output. head -1 keeps the first line and
# the fallback only fires when there was no output at all.
STATE=$(systemctl is-active "$SERVICE" 2>/dev/null | head -1 || true)
[ -z "$STATE" ] && STATE="unknown"
# Belt and braces: a unit name or state containing a quote would break the
# hand-built JSON below just as thoroughly.
STATE=${STATE//\"/}
SAFE_SERVICE=${SERVICE//\"/}

if [ "$STATE" = "active" ]; then
  echo "{\"health\":\"healthy\"}"
else
  # signalKind is a taxonomy, not a per-service label. Emitting "$SERVICE"
  # here minted a distinct signal kind for every service (kind=paperless,
  # kind=qbit, …), which no approval_rule can match and which makes
  # "how many process checks are failing?" unanswerable.
  echo "{\"health\":\"degraded\",\"signalKind\":\"process\",\"evidence\":\"$SAFE_SERVICE is $STATE\"}"
fi