#!/usr/bin/env bash
# Helper for the sid.scheduled-jobs bar widget. Read-only throughout.
#   list-jobs --list           print all scheduled jobs as JSON for the panel
#   list-jobs peek SCOPE UNIT  show a unit's recent journal in the terminal
#   list-jobs full             plain systemctl list-timers for both scopes
set -euo pipefail

# Hard bounds imposed at the point of capture, before anything is held in a
# shell variable or handed to the panel: at most MAX_BYTES of systemctl JSON
# per scope, MAX_TIMERS timers per scope (and Result lookups), MAX_CRON_LINES
# crontab lines of at most MAX_CRON_LINE_LEN characters each.
MAX_BYTES=262144
MAX_TIMERS=150
MAX_CRON_LINES=100
MAX_CRON_LINE_LEN=300

timers_json() {
  local scope="$1"
  local flag=()
  [[ $scope == user ]] && flag=(--user)
  local raw
  raw=$(systemctl "${flag[@]}" list-timers --all --output=json 2>/dev/null | head -c "$MAX_BYTES") || raw="[]"
  # A byte-truncated capture is invalid JSON; treat it (and empty output) as
  # a bounded, well-formed list rather than passing garbage downstream.
  raw=$(jq --argjson n "$MAX_TIMERS" '.[0:$n]' <<<"$raw" 2>/dev/null) || raw="[]"
  [[ -n $raw ]] || raw="[]"

  # Attach each activated service's last Result (success/failed/…) so the
  # panel can show whether the last run worked. `systemctl show` is read-only;
  # the loop is bounded by MAX_TIMERS via the truncation above.
  local results="{}"
  local unit result
  while IFS= read -r unit; do
    [[ -n $unit ]] || continue
    result=$(systemctl "${flag[@]}" show -p Result --value "$unit" 2>/dev/null | head -c 64 || echo "")
    results=$(jq --arg u "$unit" --arg r "$result" '. + {($u): $r}' <<<"$results")
  done < <(jq -r '.[].activates // empty' <<<"$raw" | sort -u | head -n "$MAX_TIMERS")

  jq --arg scope "$scope" --argjson results "$results" '
    map(. + {scope: $scope, result: ($results[.activates // ""] // "")})' <<<"$raw"
}

case "${1:-}" in
--list)
  system=$(timers_json system)
  user=$(timers_json user)
  cron="[]"
  if command -v crontab >/dev/null 2>&1; then
    cron=$(crontab -l 2>/dev/null |
      grep -vE '^\s*(#|$)' |
      head -n "$MAX_CRON_LINES" | cut -c1-"$MAX_CRON_LINE_LEN" |
      jq -Rs 'split("\n") | map(select(length > 0) | {line: ., source: "crontab"})' || echo "[]")
  fi
  jq -n --argjson system "$system" --argjson user "$user" --argjson cron "$cron" \
    '{timers: ($system + $user), cron: $cron}'
  ;;
peek)
  scope="${2:-system}"
  unit="${3:-}"
  [[ -n $unit ]] || { echo "usage: list-jobs peek SCOPE UNIT" >&2; exit 1; }
  flag=()
  [[ $scope == user ]] && flag=(--user)
  systemctl "${flag[@]}" status "$unit" --no-pager -n 0 2>&1 | head -12 || true
  echo
  journalctl "${flag[@]}" -u "$unit" -n 40 --no-pager 2>&1 | tail -40 || true
  echo
  read -r -p "Press Enter to close..."
  ;;
full)
  echo "── system timers ──────────────────────────────"
  systemctl list-timers --all --no-pager 2>&1 || true
  echo
  echo "── user timers ────────────────────────────────"
  systemctl --user list-timers --all --no-pager 2>&1 || true
  echo
  read -r -p "Press Enter to close..."
  ;;
*)
  echo "usage: list-jobs --list | peek SCOPE UNIT | full" >&2
  exit 1
  ;;
esac