pickdate

#!/bin/bash
# rofi date picker
#
# requires rofi, cal, awk

# defaults
default_command='echo "$REPLY"'
default_format='%F'
default_cal='cal'
default_buttons=' <:<<: .:>>: >'
default_attrs='weight="bold"'
default_themestr=''

# environment variables
export PICKDATE_CMD="${PICKDATE_CMD-$default_command}"
export PICKDATE_FMT="${PICKDATE_FMT-$default_format}"
export PICKDATE_CAL="${PICKDATE_CAL-$default_cal}"
export PICKDATE_BUTTONS="${PICKDATE_BUTTONS-$default_buttons}"
export PICKDATE_SPANATTRS="${PICKDATE_SPANATTRS-$default_attrs}"
export PICKDATE_THEMESTR="${PICKDATE_THEMESTR-$default_themestr}"

# prints message to stderr
warn() {
	local message="$1"
	shift
	printf "$message\n" "$@" >&2
}

# prints error and exits
die() {
	[[ "$1" =~ ^[0-9]+$ ]] && { local retval="$1"; shift; }
	warn "$@"
	exit ${retval-1}
}

# parse $PICKDATE_BUTTONS
IFS=: read -a b <<< "$PICKDATE_BUTTONS"
buttons=()
(( ${#b[@]} )) && buttons=(
	"${b[0]:- }" "${b[1]:- }" " " "${b[2]:- }" " " "${b[3]:- }" "${b[4]:- }"
)

# prints rofi selections from $days part of `cal` output
selections() {
	local days="$*"
	local w="$2"
	for i in {0..6}; do
		cut -c $((i*w+1))-$((i*w+w-1)) <<< "$days"
		[[ -n "${buttons[i]}" ]] && echo "${buttons[i]}"
	done
}

# print usage
prog="${0##*/}"
usage="Usage: $prog [options]

    Picks a date with rofi. The following keybindings are available.

        p/n        Go to previous/next month
        P/N, </>   Go to previous/next year
        .          Jump to current month
        h/j/k/l    Vim-like movement (default movement bindings also work)

Options:

    -r COMMAND     Run COMMAND with \$REPLY set to the selected date.
    -f FORMAT      Control the output with a date(1) compatible FORMAT.
    -m POSITION    Position rofi with respect to the mouse.
    -w POSITION    Position rofi with respect to the focused window.
    -h, --help     Print this help message and exit.

    Valid POSITIONs: center, north, east, southwest, etc.
"
if [[ "$*" == *--help* ]]; then
	die 0 "$usage"
fi

# parse options
action=print
rofiargs=
declare -A anchors
anchors=(
	[northwest]=southeast [north]=south   [northeast]=southwest
	[west]=east           [center]=center [east]=west
	[southwest]=northeast [south]=north   [southeast]=northwest
	[top]=northeast [bottom]=southeast
)
while getopts "r:f:m:w:h" opt; do
	case $opt in
	r) PICKDATE_CMD="$OPTARG" ;;
	f) PICKDATE_FMT="$OPTARG" ;;
	m)
		if [[ "${!anchors[@]}" != *$OPTARG* ]]; then
			warn "Invalid position: $OPTARG"
			die "Try e.g. 'northwest' or 'center' instead"
		fi
		rofiargs='-m -3'
		PICKDATE_THEMESTR+="window {anchor: ${anchors[$OPTARG]}; location: northwest;}"
	;;
	w)
		if [[ "${!anchors[@]}" != *$OPTARG* ]]; then
			warn "Invalid position: $OPTARG"
			die "Try e.g. 'northwest' or 'center' instead"
		fi
		rofiargs='-m -2'
		PICKDATE_THEMESTR+="window {anchor: $OPTARG; location: $OPTARG;}"
	;;
	h) die 0 "$usage" ;;
	*) exit 1 ;;
	esac
done
shift $((OPTIND-1))

# parse args
(( $# > 1 )) && die "$usage"

# parse $ROFI_INFO
export ROFI_INFO="${ROFI_INFO-$(date +'%-Y-%-m')}"
IFS=- read year month day junk <<< "$ROFI_INFO"
day="$(date +%-d)"

# adjust date if necessary
case "$ROFI_RETV:$1" in
10:*|"1:${b[0]}") # rofi kb-custom-1: go to prev month
	year=$(( month-1 < 1 ? year-1 : year))
	month=$((month-1 < 1 ? 12     : month-1))
	ROFI_RETV=0
;;
11:*|"1:${b[4]}") # rofi kb-custom-2: go to next month
	year=$(( month+1 > 12 ? year+1 : year))
	month=$((month+1 > 12 ? 1      : month+1))
	ROFI_RETV=0
;;
12:*|"1:${b[1]}") # rofi kb-custom-3: go to prev year
	year=$(( year-1 ))
	ROFI_RETV=0
;;
13:*|"1:${b[3]}") # rofi kb-custom-4: go to next year
	year=$(( year+1 ))
	ROFI_RETV=0
;;
14:*|"1:${b[2]}") # rofi kb-custom-5: go to current month
	IFS=- read year month <<< $(date +'%-Y-%-m')
	ROFI_RETV=0
;;
esac

# get days of month
cal="$($PICKDATE_CAL $month $year)"
prompt="$(awk 'NR==1 {print}' <<< "$cal")"
weekdays="$(awk 'NR==2 {print}' <<< "$cal") "
days="$(awk 'NR>2 {print}' <<< "$cal")"
cellwidth=$(( ${#weekdays} / 7 ))

# figure out how the script was called
case "$ROFI_RETV" in
"") # script called directly

	# set styling
	themestr='* { font: "mono 16"; }
	configuration {
		kb-custom-1: "p";
		kb-custom-2: "n";
		kb-custom-3: "P,less";
		kb-custom-4: "N,greater";
		kb-custom-5: "period";
		kb-move-char-back: "h,Left,Control+b";
		kb-move-char-forward: "l,Right,Control+f";
		kb-row-up: "k,Up,Control+p";
		kb-row-down: "j,Down,Control+n";
	}'"
	$PICKDATE_THEMESTR
	window { width: $((${#weekdays}+1))ch; }
	listview {
		columns: 7;
		lines: $(( $(wc -l <<< "$days") + (${#b[@]}?1:0) ));
		scrollbar: false;
	}
	inputbar { children: [prompt]; }
	"

	# run rofi
	selected="$(selections "$days" $cellwidth | cat -n | awk "/\S\s+$day\s*$/ {print \$1 - 1; exit}")"
	trap 'rm -f "$_PICKDATE_TMP"' EXIT
	export _PICKDATE_TMP="$(mktemp --tmpdir "$prog.XXXXXXXXXX")" || exit 1
	rofi $rofiargs -show pickdate -modi "pickdate:$0" \
		-selected-row "$selected" \
		-theme-str "$themestr"

	# do something with the output
	read -r < "$_PICKDATE_TMP"
	[[ -n "$REPLY" ]] && eval "$PICKDATE_CMD"
;;
0) # rofi: initial call of script

	# check if called directly with rofi instead of through pickdate
	if [[ -z "$1$_PICKDATE_TMP" ]]; then
		warn "Invoked with 'rofi -modi'. To fix alignment issues, run 'pickdate' instead."
	fi

	# set rofi options
	echo -en "\0prompt\x1f$prompt\n"
	echo -en "\0message\x1f<span $PICKDATE_SPANATTRS>$weekdays</span>\n"
	echo -en "\0no-custom\x1ftrue\n"
	echo -en "\0use-hot-keys\x1ftrue\n"

	# check if we're displaying current month
	currentmonth=0
	[[ "$year-$month" == $(date +'%-Y-%-m') ]] && currentmonth=1

	# set rofi selections
	selections "$days" $cellwidth | awk "
		$currentmonth && /^\s*$day\s*$/ {print \"\0active\x1f\" NR-1}
		/[0-9]/    {printf \$0 \"\0info\x1f$year-$month\n\"}
		/[a-zA-Z]/ {printf \$0 \"\0info\x1f$year-$month\x1fnonselectable\x1ftrue\n\"}
		/^\s*$/    {printf \$0 \"\0info\x1f$year-$month\x1fnonselectable\x1ftrue\n\"}
		/[^0-9a-zA-Z ]/ {printf \$0 \"\0info\x1f$year-$month\n\"}
	"
;;
1) # rofi: selected an entry
	day="$1"
	if [[ -n "$_PICKDATE_TMP" ]]; then
		date -d "$year-$month-$day" +"${PICKDATE_FMT#+}" >> "$_PICKDATE_TMP"
	else
		date -d "$year-$month-$day" +"Selection: ${PICKDATE_FMT#+}" >&2
	fi
;;
2) # rofi: selected a custom entry
	die "Unknown entry selected (this is a bug): $1"
;;
esac