#!/bin/sh -eu

directory="$XDG_DATA_HOME/bash"
persist="$directory/history"
default="$HOME/.bash_history"
current="$HISTFILE"
lockfile='/tmp/bashhistory_Ri5ki9ei.lock'

_prune() {
 sed --in-place '/^#/d;/^ /d;/^\t/d;/.........../!d' "$1" && # Remove all timestamps, lines beginning with tabs/spaces, and commands less than 11 characters
 sort --unique "$1" > "$1.tmp" &&                            # Remove all duplicate entries.
  mv --force "$1.tmp" "$1" > /dev/null 2>&1
}

_migrate() {
 [ -f "$default" ] &&
  cat "$default" >>"$persist" &&
  _prune "$persist" &&
  rm "$default"
}

_store() {
 cat "$current" >> "$persist" &&
 cat "$current" >> "$persist.bak" &&
 _prune "$persist" &&
 true > "$current"
}

[ -f "$lockfile" ] && exit;

mkdir --parents "$directory"
touch "$current" "$lockfile"

trap 'rm "$lockfile" > /dev/null 2>&1; trap - EXIT; exit' EXIT INT HUP

_migrate || true
_store