clockins

#!/bin/bash
# usage: clockins [<since>]
#
# <since> defaults to "yesterday".
set -euo pipefail

since="${1:-yesterday}${1:+ ago}"

{
    journalctl \
      --unit smartcard.target \
      --output json \
      --reverse \
      --since "$since" \
      JOB_TYPE={start,stop} \
      JOB_RESULT=done \
  | recs xform '{{__REALTIME_TIMESTAMP}} /= 1e6' \
  | recs collate -k INVOCATION_ID -a ts=vk,JOB_TYPE,__REALTIME_TIMESTAMP \
  | jq --raw-output '
      def parse_ts:
        try {
          date: strflocaltime("%Y-%m-%d"),
          day:  strflocaltime("%d %b"),
          time: strflocaltime("%H:%M")
        }
        catch null
      ;

        .start = (.ts.start | parse_ts)
      | .stop  = (.ts.stop  | parse_ts)
      | if .start and .stop then
          if .start.date == .stop.date then
            "\(.start.time)–\(.stop.time)  \(.start.day)"
          else
            "\(.start.time)–\(.stop.time)  \(.start.day)–\(.stop.day)"
          end
        elif .start then
          "\(.start.time)–       \(.start.day)"
        elif .stop then
          "     –\(.stop.time)  \(.stop.day)"
        else
          .   # if here, then something weird is going on!
        end
  '
}