#!/bin/bash
# Days since the last simple_backup for xmobar, e.g. " 9d | ": hidden under 7 days, orange from 7, red from 14
# Reads simple_backup's state file and the journal (versions before the state file only log there), whichever is newer.
# With "list": show the date in a notification (for a click on the bar)
# With "remind": notify only when a backup is overdue (run daily by backup-reminder.timer)

warn=7 overdue=14
state="${XDG_STATE_HOME:-$HOME/.local/state}/simple_backup/last_backup"

last=0 dir=""
if [[ -r $state ]]; then
    { read -r time; read -r dir; } < "$state"
    last=$(date -d "$time" +%s 2>/dev/null) || last=0
fi

# The journal drops old entries, so after a long gap there may be nothing left to find
line=$(journalctl -q -t /usr/bin/simple_backup -r -o short-unix 2>/dev/null | grep -m1 'Backup completed')
jlast=${line%%.*}
if [[ $jlast =~ ^[0-9]+$ ]] && (( jlast > last )); then
    last=$jlast dir=""
fi

days=$(( ($(date +%s) - last) / 86400 ))

age() {
    case $days in
        0) echo "today" ;;
        1) echo "1 day ago" ;;
        *) echo "$days days ago" ;;
    esac
}

case ${1:-} in
    list)
        if (( last )); then
            body="$(date -d "@$last" '+%Y-%m-%d %H:%M') ($(age))"
            [[ -n $dir ]] && body+=$'\n'"$dir"
        else
            body="No backup found"
        fi
        notify-send "Last backup" "$body"
        exit ;;
    remind)
        (( last && days < overdue )) && exit 0
        if (( last )); then
            body="Last backup $(age) ($(date -d "@$last" '+%Y-%m-%d'))"
        else
            body="No backup found"
        fi
        # A failure (e.g. no notification daemon yet) makes the service retry
        exec notify-send "Backup overdue" "$body. Plug in the backup disk." ;;
esac

(( last && days < warn )) && exit 0
icon=$'\xef\x82\xa0'    # nf-fa-hdd_o, as UTF-8 bytes so the locale doesn't matter
if (( ! last )); then
    text="<fc=#f7768e>$icon ?</fc>"
elif (( days >= overdue )); then
    text="<fc=#f7768e>$icon ${days}d</fc>"
else
    text="<fc=#ffb86c>$icon ${days}d</fc>"
fi
echo "$text | "