#!/bin/sh

# colors
red="$(printf '\033[31m')"
blue="$(printf '\033[34m')"
cyan_light="$(printf '\033[36m')"
yellow="$(printf '\033[33m')"
green="$(printf '\033[32m')"
italic="$(printf '\033[3m')"
reset="$(printf '\033[0m')"

deadlines="$HOME/docs/filios"/deadlines

die() { >&2 printf '%s\n' "$*"; exit 1; }
usage()
{
    cat <<EOF
usage: ddl [COMMAND] [ARGUMENT]
        ddl                 lists deadlines
COMMANDS
        new TEXT...         add a new deadline
        coming [NUM]        show the nearest coming deadline(s)
        delete NUM          delete deadline by number
        grep REGEX          show deadlines matching regex
        help                show usage
        edit                edit file in \$EDITOR
EOF
    exit 1
}
wrong_usage() { >&2 printf 'Wrong usage!\n'; usage; }

colorize()
{
    sed \
        -e "s/^#.*/${red}&${reset}/" \
        -e "s/^\s*[-?!*].*/${cyan_light}&${reset}/" \
        -e "s/([^()]\+)/${yellow}${italic}&${reset}/" \
        -e "s/^\s*#.*/${blue}${italic}&${reset}/"
}
list_deadlines() { cat "$deadlines"; }
# list dates in chronological order
list_dates()
{
    grep '^#' "$deadlines" |
        sort -t '/' -k 3 -k 2 -k 1 -n | 
        uniq |
        sed 's@/@.@g'
}


# shellcheck disable=SC2142

### MAIN

# Arguments without an option
case "$1" in
    h*) usage ;;

    e*) $EDITOR "$deadlines" ;;

    c*) 
        i=1
        list_dates | head -n "${2:-1}" |
            while read -r date
                do
                    sed -n "/$date/,/^#\|^$/p" "$deadlines" | 
                        colorize |
                        sed "1s/.*/& ($green$i$reset)/"
                    i=$((i+1))
                done ;;

    "") list_deadlines | colorize ;;

    *) false ;;

esac && exit

arg="$1"
shift
[ "$1" ] || wrong_usage

case "$arg" in

    d*) sed -i "/$(list_dates | sed -n "${1}p")/,/^$/d" "$deadlines" ;;

    *) wrong_usage ;;

esac