gistfile1.rb

#!/usr/bin/env ruby

Colors = {
	:red => [99, 30],
	:blue => [10, 99],
	:green => [10, 99],
}

def ccalc(min, max, fraction)
	min + ((max - min) * fraction)
end

def pull_state
	bat_info = []
	%w(alarm info state).each { |file|
		bat_info += File.readlines('/proc/acpi/battery/BAT0/' + file)
	}

	bat_info.map! { |line| line.split(':').map { |i| i.strip } }

	pbi = Hash.new { |h,k| h[k] = bat_info.assoc(k).last }

	state = {
		:rate => pbi['present rate'].to_i,
		:capacity => pbi['last full capacity'].to_i,
		:present => pbi['remaining capacity'].to_i,
	}
	state[:plugged_in] = state[:rate].zero?

	state
end

def set_color
	state = pull_state
	fraction = state[:present].to_f / state[:capacity]
	#fraction = ARGV[1].to_f
	colors = []
	[:red, :green, :blue].each { |c|
		colors << ccalc(Colors[c].first, Colors[c].last, fraction).to_i
	}
	colors.map! { |c| '%02d' % c }
	system "xsetroot -solid rgb:#{colors.join('/')}"
end

case ARGV.first
when nil
	state = pull_state
	fullness = (state[:present] * 100) / state[:capacity]
	hours_left = state[:present].to_f / state[:rate]
	hlstring = if state[:plugged_in]
			"plugged in"
		   else
			sprintf "%0.2f hours remaining", hours_left
		   end
	printf "%d%% (#{hlstring})\n", fullness
when '-bg'
	set_color
when '-d'
	fork {
		Dir.chdir '/'
		loop { set_color; sleep 30 }
	}
end