cli-clock

#!/bin/bash


DIGIT_COLOR=RED
LETTER_COLOR=YELLOW
PUNCT_COLOR=YELLOW

#TIMEZONES="America/New_York Europe/London Asia/Baghdad Asia/Singapore Asia/Tokyo"

BLACK=0 RED=1 GREEN=2 YELLOW=3 BLUE=4 MAGENTA=5 CYAN=6 WHITE=7
DC="\e[3${!DIGIT_COLOR};4${!DIGIT_COLOR}m"
LC="\e[3${!LETTER_COLOR};4${!LETTER_COLOR}m"
PC="\e[3${!PUNCT_COLOR};4${!PUNCT_COLOR}m"
NC="\e[m"

NUM[0]="######|##__##|##__##|##__##|######"
NUM[1]="____##|____##|____##|____##|____##"
NUM[2]="######|____##|######|##____|######"
NUM[3]="######|____##|######|____##|######"
NUM[4]="##__##|##__##|######|____##|____##"
NUM[5]="######|##____|######|____##|######"
NUM[6]="######|##____|######|##__##|######"
NUM[7]="######|____##|____##|____##|____##"
NUM[8]="######|##__##|######|##__##|######"
NUM[9]="######|##__##|######|____##|____##"
A="_AAAA_|AA__AA|AAAAAA|AA__AA|AA__AA"
B="AAAAA_|AA__AA|AAAAA_|AA__AA|AAAAAA"
C="_AAAA_|AA__AA|AA____|AA__AA|_AAAA_"
D="AAAAA_|AA__AA|AA__AA|AA__AA|AAAAA_"
E="AAAAAA|AA____|AAAAAA|AA____|AAAAAA"
F="AAAAAA|AA____|AAAA__|AA____|AA____"
G="_AAAA_|AA____|AA_AAA|AA__AA|_AAAA_"
H="AA__AA|AA__AA|AAAAAA|AA__AA|AA__AA"
I="AAAA|_AA_|_AA_|_AA_|AAAA"
J="___AAA|____AA|____AA|AA__AA|_AAAA_"
K="AA__AA|AA_AA_|AAAA__|AA_AA_|AA__AA"
L="AA____|AA____|AA____|AA____|AAAAAA"
M="AA___AA|AAA_AAA|AAAAAAA|AA_A_AA|AA___AA"
N="AA__AA|AAA_AA|AAAAAA|AA_AAA|AA__AA"
O="_AAAA_|AA__AA|AA__AA|AA__AA|_AAAA_"
P="AAAAAA|AA__AA|AAAAAA|AA____|AA____"
Q="_AAAA_|AA__AA|AA__AA|AA_AAA|_AAAA_"
R="AAAAA_|AA__AA|AAAAAA|AA_AA_|AA__AA"
S="_AAAAA|AA____|_AAAA_|____AA|AAAAA_"
T="AAAAAA|__AA__|__AA__|__AA__|__AA__"
U="AA__AA|AA__AA|AA__AA|AA__AA|_AAAA_"
V="AA__AA|AA__AA|AA__AA|_AAAA_|__AA__"
W="AA___AA|AA_A_AA|AAAAAAA|AAA_AAA|AA___AA"
X="AA__AA|_AAAA_|__AA__|_AAAA_|AA__AA"
Y="AA__AA|AA__AA|_AAAA_|__AA__|__AA__"
Z="AAAAAA|___AA_|__AA__|_AA___|AAAAAA"
INDENT="________|________|________|________|________"
COLON="__|::|__|::|__"
COMMA="__|__|__|::|_:"
EXCLEMATION="::|::|::|__|::"
PERIOD="__|__|__|__|::"
SEMICOLON="__|::|__|::|_:"
SPACE="__|__|__|__|__"
NEWLINE="NEWLINE"
SPACE_WIDTH=2
LINE_HEIGHT=$(awk -F\| '{ print NF }' <<<${COLON})
LOCAL_TIMEZONE=$(awk -F'"' '/ZONE=/ { print $2 }' /etc/sysconfig/clock)


initStrings() {
	local string_name
	for string_name in {0..9} {A..Z} ':' ',' '!' '.' ';' ' ' '>' $'\n'; do
		case ${string_name} in
			[a-z])  string_name=${string_name^^};;
			:)      string_name=COLON;;
			,)      string_name=COMMA;;
			!)      string_name=EXCLEMATION;;
			.)      string_name=PERIOD;;
			\;)     string_name=SEMICOLON;;
			' ')    string_name=SPACE;;
			'>')	string_name=INDENT;;
			$'\n')  string_name=NEWLINE;;
		esac
		string_names+=("${string_name}")


		
		local string
		if [[ ${string_name} =~ [0-9] ]]; then
			string=${NUM[${string_name}]}
		else
			string=${!string_name}
		fi

		local char_width=$(cut -f 1 -d '|' <<<${string})
		char_width=${#char_width}
		char_widths+=("${char_width}")

		local movement='\\e['${char_width}'D\\e[1B'

		# bash has memory leaks when using parameter substitution, so sed is employed instead
		string=$(sed "s/\(#\+\)/\\${DC}\1\\${NC}/g;\
			      s/\(A\+\)/\\${LC}\1\\${NC}/g;\
			      s/\(:\+\)/\\${PC}\1\\${NC}/g;\
			      s/_/ /g;\
			      s/|/\\${movement}/g" <<<${string}
			)
		
		strings+=("${string}")
	done
}


screenSetup() {
	# determine terminal size
	dimensions=$(
		tput -S <<-!
			lines
			cols
		!
	)
	lines=${dimensions%%$'\n'*}
	cols=${dimensions##*$'\n'}

	# redraw screen if terminal dimensions change
	if [[ ${dimensions} != ${dimensions_log} ]]; then
		dimensions_log=${dimensions}
		printf "\Ec" # clear terminal
		tput civis
	fi

	# put the cursor in the correct position to center the clock in the terminal
	start_row=$(( ( lines - HEIGHT ) / 2 ))
	start_col=$(( ( cols - WIDTH ) / 2 ))
	start_row=2
	start_col=$(( SPACE_WIDTH + 1 ))
	vert_offset=0
	printf "\E[$(( start_row + vert_offset ));${start_col}f"
	space_on_line=$(( cols - start_col ))
}


drawChar() {
	local char="$1"

	# translate string
        case ${char} in
                [a-z])  char=${char^^};;
                :)      char=COLON;;
                ,)      char=COMMA;;
                !)      char=EXCLEMATION;;
                .)      char=PERIOD;;
                \;)     char=SEMICOLON;;
                ' ')    char=SPACE;;
		'>')	char=INDENT;;
                $'\n')  char=NEWLINE;;
        esac

	local i
	for (( i=0; ${i} < ${#string_names[@]}; i++ )); do
		if [[ "${string_names[${i}]}" == "${char}" ]]; then
			local string="${strings[${i}]}"
			local char_width=${char_widths[${i}]}
			break
		fi
	done

	# newline check
	if [[ ${char_width} -gt ${space_on_line} || ${string} == "NEWLINE" ]]; then
		(( vert_offset+=$(( LINE_HEIGHT + 1 )) ))
		printf "\E[$(( start_row + vert_offset ));${start_col}f"
		space_on_line=$(( cols - start_col ))
		[[ ${string} == "NEWLINE" ]] && return
	fi

	# after the formatted character, and move cursor right and up to prepare for next character
	printf "${string}\e[${SPACE_WIDTH}C\e[4A"

	# keep track of remaining space on the current line
	(( space_on_line-=$(( ${char_width} + ${SPACE_WIDTH} )) ))
}


printString() {
	local string="${@}"
	while [[ ${string} ]]; do
		# print the first character in ${string}
		local char="${string:0:1}"
		drawChar "${char}"
		# remove the character we printed from ${string}
		string="${string:1}"
	done
}


getDate() {
	local TZ
	if [[ ! ${@} ]]; then
		local date_string="%I:%M:%S"
		TZ=${LOCAL_TIMEZONE} date +"${date_string}"
	else
		local date_string="%H:%M:%S %Z"
		TZ=${LOCAL_TIMEZONE} date +"${date_string}"

		date_string="%I:%M %Z"
		local i
		for i in ${@}; do
			printf ">"
			TZ=${i} date +"${date_string}"
		done
	fi
}


end() {
	# put cursor below any output, make it visibile, and exit
	printf "\n%.s" $(eval echo {0..${LINE_HEIGHT}})
	tput cvvis
	exit
}



trap end SIGHUP SIGINT SIGTERM

initStrings

# Main Loop
while sleep ${delay:-0}; do
	screenSetup

	date="$(getDate ${TIMEZONES})"

	printString "${@:-${date}}"
	[[ ${@} ]] && end

	# determine how long to sleep before the next update
	nanoseconds=10#$(date +%N)
	delay=0.$(( 1000000000 - ${nanoseconds} ))
done