#!/usr/bin/env bash
#
# qdb-logprune.sh --- trim ii's append-only `out` logs to a recent
# window. ii has no built-in rotation: it appends every channel line
# to one `out` file per channel, forever. ii lines are epoch-prefixed,
# so "keep the last N days" is a one-line awk filter.
#
# ii holds `out` open for writing, so rewriting it underneath a
# running ii is racy. This script stops qdb-ii and qdb-watch for the
# few seconds the rewrite takes, then starts them again --- ii
# reconnects and re-joins the channel. (BindsTo propagates the stop
# but not the start, so both units are managed explicitly here.)
#
# Wired up as qdb-logprune.timer (weekly). Config via environment:
#   QDB_LOG_KEEP_DAYS  days of log to keep   (14)
#   QDB_IRC_BASE       ii's base dir         ($HOME/irc)
#
# qdb snapshots in quotes/ are NEVER touched --- they are permanent,
# which is the whole point of qdb.

set -u

KEEP_DAYS="${QDB_LOG_KEEP_DAYS:-14}"
IRC_BASE="${QDB_IRC_BASE:-$HOME/irc}"
cutoff=$(date -d "${KEEP_DAYS} days ago" +%s)

export XDG_RUNTIME_DIR="${XDG_RUNTIME_DIR:-/run/user/$(id -u)}"

# Pause the capture pipeline only if it is actually running, and only
# restart it if so. Stop watch before ii, start ii before watch.
was_active=$(systemctl --user is-active qdb-ii 2>/dev/null || true)
[ "$was_active" = active ] && systemctl --user stop qdb-watch qdb-ii

shopt -s nullglob
for f in "$IRC_BASE"/*/*/out "$IRC_BASE"/*/out; do
  [ -f "$f" ] || continue
  # Keep lines newer than the cutoff; keep any non-epoch line verbatim
  # (defensive --- never silently drop content we don't understand).
  if awk -v c="$cutoff" '!/^[0-9]+ / || $1 + 0 >= c' "$f" > "$f.prune.$$"; then
    mv "$f.prune.$$" "$f"
  else
    rm -f "$f.prune.$$"
  fi
done

[ "$was_active" = active ] && systemctl --user start qdb-ii qdb-watch