#!/usr/bin/env bash
# log-gate.sh: refuse to close a run unless its correction log grew.
#   log-gate.sh begin <log>   record the current row count in <log>.baseline
#   log-gate.sh close <log>   exit 0 only if the log now has more rows than the baseline
# A row is a table line that starts with a date: "| YYYY-MM-DD |".
# Exit: 0 ok · 1 log did not grow · 2 could not measure (missing log or baseline) · 3 usage.
set -u

count_rows() { grep -cE '^\|[[:space:]]*[0-9]{4}-[0-9]{2}-[0-9]{2}[[:space:]]*\|' "$1"; }

[ $# -eq 2 ] || { echo "usage: log-gate.sh begin|close <log>" >&2; exit 3; }
cmd="$1"; log="$2"; base="$log.baseline"
[ -f "$log" ] || { echo "could not measure: log not found: $log" >&2; exit 2; }
now="$(count_rows "$log")"

case "$cmd" in
  begin)
    echo "$now" > "$base" || { echo "could not measure: cannot write $base" >&2; exit 2; }
    echo "begin: $now rows recorded in $base"
    ;;
  close)
    [ -f "$base" ] || { echo "could not measure: no baseline, run 'begin' first" >&2; exit 2; }
    was="$(cat "$base")"
    case "$was" in ''|*[!0-9]*) echo "could not measure: bad baseline in $base" >&2; exit 2;; esac
    if [ "$now" -gt "$was" ]; then
      echo "close: log grew from $was to $now rows"
      rm -f "$base"
    else
      echo "close refused: log has $now rows, baseline $was. Append this run's corrections first." >&2
      exit 1
    fi
    ;;
  *) echo "usage: log-gate.sh begin|close <log>" >&2; exit 3 ;;
esac