#!/usr/bin/perl

##############################
# Calcul l'etat de la batterie
##############################

use strict;

use vars qw(@Batt_Data %Useful);

# renvoit une liste de hash des valeurs lues (un element par batterie)
sub  read_proc {
	my @batts = find_batts();
	my @Batt_Data;
	for (@batts) {
		my $batt_dir = $_;
		my %h1 = read_Batt_Data($batt_dir.'state');
		my %h2 = read_Batt_Data($batt_dir.'info');
		# TODO mieux?
		my %h = %h1;
		for my $key ( keys %h2 ) {
			$h{$key} = $h2{$key};
		}
		# le tableau contient une reference au hash
		push @Batt_Data, {%h};
	}
	return @Batt_Data;
}

# lit un fichier de donnees de la batterie dans proc
sub read_Batt_Data {
	my ($file) = @_;

	my %data;
	#print '>>',$file,"\n";
	open(DATA, "< $file") or next;
	while (<DATA>) {
		if (/^([^:]+):\s+(.+)/){
			#print "$1 -> $2\n";
			$data{$1} = $2;
		}
	}
	return %data;
}

# trouve les repertoires d'etat des batteries
sub find_batts {
	my @batts;
	my $proc_path = '/proc/acpi/battery/';

	# TODO verifier que c'est un repertoire
	opendir(BATTS, $proc_path) or die "can't open $proc_path: $!";
	while (defined(my $bat_dir = readdir(BATTS))) {
	# TODO verifier que c'est un repertoire
		if ($bat_dir =~ /BAT([0-9])/) {
			#print $1,$bat_dir,"\n";
			$batts[$1] = $proc_path.$bat_dir.'/';
		}
	}
	return @batts;
}

# synthetise les donnees utiles
sub summarize {
	# capacite totale des batteries
	#print $Batt_Data[0]{'present'},"\n";
	my $total_full_cap = 0;
	my $total_rem = 0;
	my $total_rate = 0;
	for my $href ( @Batt_Data ) {
		my $cap = $href->{'last full capacity'} || 0;
		# toujours en mAh ?
		$total_full_cap += $_ for ( $cap =~ /(\d+) mAh/ );

		#for ( keys %$href ) {
			#print $_,"\n";
		#}
		my $remaining = $href->{'remaining capacity'} || 0;
		#print $remaining,"\n";
		$total_rem += $_ for ( $remaining =~ /(\d+) mAh/ );

		my $rate = $href->{'present rate'} || 0;
		$total_rate += $_ for ( $rate =~ /(\d+) mA/ );
	}
	$Useful{'capacity'} = $total_full_cap;
	$Useful{'remaining'} = $total_rem;
	$Useful{'rate'} = $total_rate;
	# temps restant en heures (end of operation)
	$Useful{'eooTime'} = $total_rem / $total_rate;
	$Useful{'remainingPerc'} = 100*$total_rem/$total_full_cap;
	return %Useful;
}

# TODO adapter selon l'OS
@Batt_Data = read_proc();
summarize();
print <<EOL;
total full cap $Useful{'capacity'}
total remaining cap $Useful{'remaining'}
total rate $Useful{'rate'}
EOL
printf("remaining: %.3f%%\n", $Useful{'remainingPerc'});
# TODO formattage delai
printf("remaining time: %d min\n", 60 * $Useful{'eooTime'});
# TODO heure de fin de fonctionnement
# TODO operation en cours (charge, decharge)