#!/usr/bin/env bash
# Run executables in ~/.config/anacron.<period>/<state> when the period is due
# and the state's AC/online conditions hold.
# Periods and due-specs: $XDG_CONFIG_HOME/anacron.periods

set -o errexit -o nounset -o pipefail
[[ "${TRACE:-0}" == "1" ]] && set -o xtrace

SECONDS_PER_HOUR=3600
ONLINE_HOST=github.com
ONLINE_PORT=22
NM_ONLINE_TIMEOUT_SEC=10
NC_CONNECT_TIMEOUT_SEC=3

: "${HOME:=$(getent passwd "${USER:-$(id -un)}" | cut -d: -f6)}"
: "${XDG_CONFIG_HOME:=$HOME/.config}"
: "${XDG_STATE_HOME:=$HOME/.local/state}"

PERIODS_FILE="$XDG_CONFIG_HOME/anacron.periods"
declare -A PERIOD_DUE=()

load_periods() {
  local period spec
  if [[ ! -f $PERIODS_FILE ]]; then
    echo "missing periods file ${PERIODS_FILE}" >&2
    exit 2
  fi
  while read -r period spec _; do
    [[ -z ${period:-} || $period == \#* ]] && continue
    if [[ ! $period =~ ^[a-z][a-z0-9]*$ ]]; then
      echo "invalid period name: ${period}" >&2
      exit 2
    fi
    if [[ $spec != calendar-day && $spec != calendar-month && ! $spec =~ ^[0-9]+[dh]$ ]]; then
      echo "invalid due spec for ${period}: ${spec}" >&2
      exit 2
    fi
    PERIOD_DUE[$period]=$spec
  done <"$PERIODS_FILE"
  if [[ ${#PERIOD_DUE[@]} -eq 0 ]]; then
    echo "no periods in ${PERIODS_FILE}" >&2
    exit 2
  fi
}

usage() {
  local p
  echo "usage: $0 <period>-{on|on_ac|on_line|on_line_ac}" >&2
  echo "periods:" >&2
  for p in "${!PERIOD_DUE[@]}"; do
    echo "  ${p}  ${PERIOD_DUE[$p]}" >&2
  done
  exit 2
}

load_periods

INSTANCE="${1-}"
if [[ $INSTANCE != *-* ]]; then
  usage
fi
PERIOD="${INSTANCE%%-*}"
STATE="${INSTANCE#*-}"
if [[ -z ${PERIOD_DUE[$PERIOD]+x} ]]; then
  usage
fi
case "$STATE" in
  on | on_ac | on_line | on_line_ac) ;;
  *)
    usage
    ;;
esac
DUE_SPEC="${PERIOD_DUE[$PERIOD]}"

FOLDER="$XDG_CONFIG_HOME/anacron.${PERIOD}/${STATE}"
STAMP_DIR="$XDG_STATE_HOME/anacron"
STAMP_FILE="$STAMP_DIR/${PERIOD}.${STATE}"

if [[ ! -d $FOLDER ]]; then
  echo "skip ${INSTANCE}: missing folder ${FOLDER}" >&2
  exit 0
fi

if [[ $STATE == on_ac || $STATE == on_line_ac ]] && ! systemd-ac-power; then
  echo "skip ${INSTANCE}: on battery" >&2
  exit 0
fi

if [[ $STATE == on_line || $STATE == on_line_ac ]]; then
  if ! nm-online --timeout="$NM_ONLINE_TIMEOUT_SEC" --quiet; then
    echo "skip ${INSTANCE}: offline (nm-online)" >&2
    exit 0
  fi
  if ! nc -zw"$NC_CONNECT_TIMEOUT_SEC" "$ONLINE_HOST" "$ONLINE_PORT"; then
    echo "skip ${INSTANCE}: offline (${ONLINE_HOST}:${ONLINE_PORT})" >&2
    exit 0
  fi
fi

stamp_date_iso() {
  local last=$1
  [[ ${#last} -ge 8 ]] || return 1
  echo "${last:0:4}-${last:4:2}-${last:6:2}"
}

stamp_to_epoch() {
  local last=$1 iso
  case ${#last} in
    8)
      iso="$(stamp_date_iso "$last")"
      date -d "$iso" +%s
      ;;
    14)
      iso="$(stamp_date_iso "$last") ${last:8:2}:${last:10:2}:${last:12:2}"
      date -d "$iso" +%s
      ;;
    *)
      return 1
      ;;
  esac
}

period_is_due() {
  local last=$1 spec=$2
  local today last_iso due_on n last_epoch now
  today=$(date +%Y%m%d)
  case "$spec" in
    calendar-day)
      [[ ${#last} -ge 8 && ${last:0:8} < $today ]]
      ;;
    calendar-month)
      [[ ${#last} -ge 6 && ${last:0:6} < $(date +%Y%m) ]]
      ;;
    *d)
      n=${spec%d}
      last_iso=$(stamp_date_iso "$last") || return 0
      date -d "$last_iso" >/dev/null 2>&1 || return 0
      due_on=$(date -d "${last_iso} +${n} days" +%Y%m%d)
      [[ $today -ge $due_on ]]
      ;;
    *h)
      n=${spec%h}
      last_epoch=$(stamp_to_epoch "$last") || return 0
      now=$(date +%s)
      [[ $now -ge $((last_epoch + n * SECONDS_PER_HOUR)) ]]
      ;;
  esac
}

stamp_now() {
  case "$DUE_SPEC" in
    *h) date +%Y%m%d%H%M%S ;;
    *) date +%Y%m%d ;;
  esac
}

if [[ -f $STAMP_FILE ]]; then
  last=$(tr -d '[:space:]' <"$STAMP_FILE")
  if [[ $last =~ ^[0-9]{8}([0-9]{6})?$ ]] && ! period_is_due "$last" "$DUE_SPEC"; then
    echo "skip ${INSTANCE}: not due (stamp ${last})" >&2
    exit 0
  fi
fi

mkdir --parents --verbose "$STAMP_DIR"
run-parts --regex='^[a-zA-Z0-9_\.-]+$' --exit-on-error -v -- "$FOLDER"
stamp_now >"$STAMP_FILE"

loginctl enable-linger "$USER"

systemctl --user daemon-reload
while read -r period spec _; do
  [[ -z ${period:-} || $period == \#* ]] && continue
  for state in on on_ac on_line on_line_ac; do
    systemctl --user enable --now "anacron@${period}-${state}.timer"
  done
done <"${XDG_CONFIG_HOME:-$HOME/.config}/anacron.periods"

crontab ~/.config/crontab

systemctl --user list-timers 'anacron@*'
journalctl --user -u anacron@daily-on_line.service
systemctl --user start anacron@weekly-on_ac.service

#!/bin/bash

set -o xtrace -o errtrace -o errexit -o nounset -o pipefail

[ -z "$HOSTNAME" ] && HOSTNAME="$(uname -n)"
if command -v sshstart >/dev/null 2>&1; then
  if [ "${CRONJOB:-0}" = 1 ]; then
    eval "$(sshstart -eGA)"
  else
    eval "$(sshstart -eA)"
  fi
fi

FROM_FOLDER=$HOME
TO_FOLDER="$USER@rsync.server.com:/users/$USER"

FILES_FILE=$XDG_CONFIG_HOME/backup/files
EXCLUDE_FILE=$XDG_CONFIG_HOME/backup/exclude
LOG_FILE=$XDG_CACHE_HOME/backup/cloud/log

RSYNC_BKP_ARGS="--recursive --archive --hard-links --ignore-errors --modify-window=1 --delete --compress --partial --human-readable --info=progress2 "
SSH_ARGS="-v -P"

mkdir --parents "$(dirname "${LOG_FILE}")"
rsync $RSYNC_BKP_ARGS --rsh="ssh $SSH_ARGS" --log-file="$LOG_FILE" --files-from="$FILES_FILE" --exclude-from="$EXCLUDE_FILE" "$FROM_FOLDER" "$TO_FOLDER"