wttr

#!/usr/bin/sh
# @author nate zhou
# @since 2023,2024,2025,2026
# @depends: libnotify, dunst(or equivalent daemon)
# wttr - weather report script

# This script has completions: `.config/{z,ba}sh/completions/_scripts.{z,ba}sh`

CITY="${HOME}/.cache/city"
WTTR="${HOME}/.cache/wttr"
DAMBLOCKS="${XDG_RUNTIME_DIR}/damblocks.pid"

update_frequency=3600 # in seconds

usage() {
    cat << _EOF_
USAGE
            $(basename $0) [CITY] [OPTION]
            without CITY, read the local cache in $WTTR
OPTIONS
            -u,--update     update the local cache in $WTTR
            -c,--cron       to be run as a cron job that checks the last update
                            time with the defined update_frequency($update_frequency seconds)
            -e,--edit       edit the CITY in $CITY
            -g,--geo)       print the city in $CITY
            -h,--help       print this usage manual
_EOF_
    exit 0
}

send_signal() {
    kill -44 "$(cat $DAMBLOCKS)"
}

update_cmd() {
    curl wttr.in/${city}?format=1
}

notify() {
    msg="$1"

    [ "$XDG_SESSION_TYPE" != "tty" ] && notify-send -r 23 "$(basename $0)" "$msg"
}

abort() {
    msg="$1"

    RED='\033[0;31m'
    RESET='\033[0m'

    echo "${RED}${1}${RESET}"

    notify "$msg" >&2
    exit 1
}

check_cache() {
    wttr=$(cat $WTTR 2>/dev/null)

    if [ ! -f "$CITY" ]; then
        msg="$CITY doesn't exist, try \"$(basename $0) -e\" first."
        abort "$msg"
    elif [ -z "$wttr" ]; then
        update
    fi
}

update() {
    city="$(cat $CITY)"
    local silent="${1:-false}"
    msg=$(update_cmd)
    if echo "$msg" | grep -q '°C'; then
        echo "$msg" | sed 's/[[:space:]]\+/ /g; s/°C/℃/' | tee "$WTTR"
        [ "$silent" != "true" ] && notify "$msg"
        exit 0
    else
        msg="downloading failed, please check the connection to wttr.in"
        abort "$msg"
    fi
}


get_local_wttr() {
    check_cache

    wttr=$(cat $WTTR)
    msg="$wttr"
    echo "$msg"
    notify "$msg"

}

get_city_wttr() {
    city="$1"
    msg=$(update_cmd)
    echo "$msg"
    notify "$msg"
}

edit_city() {
    $EDITOR $CITY
}

print_city() {
    cat $CITY
}

cron() {
    check_cache

    local current_time="$(date +%s)"
    local update_time="$(stat -c '%Y' "$WTTR")"


    if [ $(( $current_time - $update_time )) -gt "$update_frequency" ]; then
        update "true"  # silent=true
    else
        msg="Already update within past $(( $update_frequency / 3600)) hours"
        echo $msg
    fi

}

trap send_signal EXIT

[ -z "$1" ] && get_local_wttr

if [ -n "$1" ]; then
    case "$1" in
        -u|--update) update ;;
        -c|--cron) cron "$1" ;;
        -e|--edit) edit_city ;;
        -g|--geo) print_city ;;
        -*) usage ;;
        *) get_city_wttr "$1" ;;
    esac
fi