#!/usr/bin/perl
# vim: set ai noet ts=4 sw=4 sts=4 ft=perl :

# set username
# set uptime
# set time
# set xtitle of focused window
# set list of windows for current tag
# set list of windows for all tags
# set la
# set current language
# set battery charge

# main loop impl. :
# save cur. str and compare it with prev. if it differs - update

# proposed: 3 types of loop:
# slow loop for batt charge, la
# 1 second loop for time, uptime - generally, it looks like we do not need poll every second
#                                  timers if clock granularity set to 1 minute or even coarse
# main (fast) loop for window name, language, it looks like we have some room here for greater
# improvement, when it'll be more clear how get info directly from x server

#use strict;
#use warnings "all";
use Fcntl qw(:seek);

binmode STDOUT;
binmode STDERR;

sub onesec_cron();
sub slow_cron();

sub gettimestr();
sub getuptimestr();
sub getlastr();
sub getbatterychargestr2();
sub meminfo();


my $slow_timer = 360; # 0.333 * 360 ~= 2 min
my $onesec_timer = 3; # 0.333 * 3   ~= 1 sec

my @months = ('Янв', 'Фев', 'Мар', 'Апр', 'Май', 'Июн', 'Июл', 'Авг', 'Сен', 'Окт', 'Ноя', 'Дек');
my @wdays = ('Вс', 'Пн', 'Вт', 'Ср', 'Чт', 'Пт', 'Сб');

my $pstr = '';

my $charge;
my $la;
my $uptime;
my $time;
my $mem;

my $UPTIMEHANDLE;
my $LAHANDLE;
my $MEMINFOHANDLE;

sleep 1;

while (1) {
	if ($onesec_timer >= 3) {
		onesec_cron();
		$onesec_timer = 0;
	}

	if ($slow_timer >= 360) {
		slow_cron();
		$slow_timer = 0;
	}

	my $str = '';
	$str .= $uptime;
	$str .= $la;
	$str .= $mem;
	$str .= $charge;
	$str .= $time;

	if ($pstr ne $str) {
		syswrite STDOUT, "$str\n";
		$pstr = $str;
	}

# tick timers
	$slow_timer++;
	$onesec_timer++;

# sleep for 0.333 second;
	select(undef, undef, undef, 0.333);
}

sub slow_cron() {
	$charge = getbatterychargestr2();
	$la = getlastr();
}

sub onesec_cron() {
	$uptime = getuptimestr();
	$time = gettimestr();
# as we report time with precision of 1 minute, update 1/60 seconds
	$mem = meminfo();
}


sub gettimestr() {
	my ($sec, $min, $hour, $mday, $mon, $year, $wday) = (localtime)[0,1,2,3,4,5,6];
	$year = $year + 1900;
	my $str .= sprintf(" |     %s, %s %s %s  %02s:%02s  ", $wdays[$wday], $mday, $months[$mon], $year, $hour, $min);

	return $str;
}

sub getuptimestr() {
	if (defined($UPTIMEHANDLE)) {
		open $UPTIMEHANDLE, "/proc/uptime" if (tell($UPTIMEHANDLE) == -1);
	} else {
		open $UPTIMEHANDLE, "/proc/uptime"; 
	}

	my $u = <$UPTIMEHANDLE>;
	seek $UPTIMEHANDLE, SEEK_SET, 0;
	$u = (split(/ /, $u, 2))[0];
	my $days = int($u / 86400); # 86400 = 1 day
	my $hours = int(($u - (86400 * $days)) / 3600); # 3600 = 1 hour
	my $minutes = int(($u - (86400 * $days) - (3600 * $hours)) / 60);
	my $seconds = int($u - (86400 * $days) - (3600 * $hours) - (60 * $minutes));
	my $str = sprintf(" | up: %sd,%02sh,%02sm ", $days, $hours, $minutes);

	return $str;
}

sub getlastr() {
	if (defined($LAHANDLE)) {
		open $LAHANDLE, "/proc/loadavg" if (tell($LAHANDLE) == -1);
	} else {
		open $LAHANDLE, "/proc/loadavg";
	}

	my $la = <$LAHANDLE>;
	seek $LAHANDLE, SEEK_SET, 0;
	$la = (split(/ /, $la, 2))[0];

	return (" | LA: $la ");
}

sub getbatterychargestr2() {
	my $str .= " | Power: ";
	my $acfile;

	if ( -f "/sys/class/power_supply/ADP1/online") {
		$acfile = "/sys/class/power_supply/ADP1/online";
	} elsif ("/sys/class/power_supply/AC/online") {
		$acfile = "/sys/class/power_supply/AC/online"
	}

	open AC, "<", $acfile;

	if (<AC> == 1) {
		$str .= "AC";
	} else {
		$str .= "DC";
	}

	close AC; # display % charge only if possible

	if (open DC,"/sys/class/power_supply/BAT0/capacity") {
		$str .= ' '. <DC>;
		close DC;
		chomp $str;
		$str .= '%';
	}

	return $str;
}

sub meminfo() {
	if (defined($MEMINFOHANDLE)) {
		open ($MEMINFOHANDLE, "/proc/meminfo") if (tell($MEMINFOHANDLE) == -1);
	} else {
		open ($MEMINFOHANDLE, "/proc/meminfo");
	}

	my @mem = <$MEMINFOHANDLE>;
	seek $MEMINFOHANDLE, SEEK_SET, 0;
	@mem = map { substr($_, 0, -4) } @mem;

	my $memavail = (split(/\s+/, $mem[2]))[1];
	my $swaptotal = (split(/\s+/, $mem[14]))[1];
	my $swapfree = (split(/\s+/, $mem[15]))[1];

	return sprintf (
		" | mem: %s M | sw: %s M",
		int($memavail / 1024),
		int(($swaptotal - $swapfree) / 1024)
	);
}