#!/usr/bin/env ruby

$PROGRAM_NAME = "moltenbar"

# Base worker class
class Worker
	@@collector = []

	class << self
		def instances
			return @@collector
		end
	end

	def initialize(config, name, pipe)
		@config = config
		@name = name
		@pipe_in = pipe

		@my_config = config["mod"][name]
	end

	def run()
		@wpid = fork do
			$PROGRAM_NAME = "moltenbar: worker (#{@name})"
			Signal.trap("INT") do; end

			mainloop()
		end

		@@collector << self

		return nil
	end

	def mainloop()
		loop do
			self.write("I am a dummy")
			sleep(1)
		end
	end

	def kill()
		begin
			if Process.getpgid(@wpid) == Process.getpgid($$)
				printf("Killing pid: %s\n", @wpid)
				Process.kill("HUP", @wpid)
			end
		rescue Errno::ESRCH => err
			printf("%s: %s\n", err, @wpid)
		end
	end

	def write(data)
		@pipe_in.printf("%s\0%s\n", @name, data)
	end
end

class DoSystem < Worker
	def initialize(name, pipe)
		@name = name
		@pipe = pipe
	end

	def mainloop()
		@pipe.each do |cmd|
			system(cmd)
		end
	end
end

module Modules
	@modules = {}

	def self.add(name, class_name)
		@modules[name] = class_name
	end

	def self.get()
		return @modules
	end
end

class Template
	def initialize(template)
		@template = template
	end

	def render(config, data)
		@config = config
		@panel_data = data

		return ERB.new(@template).result(binding())
	end
end

# Kill the workers.
def cleanup
	Worker.instances.each do |w|
		w.kill
	end

	exit(0)
end

def get_x_dims()
	return `xrandr`.scan(/current (\d+) x (\d+)/).flatten
end

require 'erb'
require 'yaml'
require 'optparse'

panel_data = {}
options = {}

OptionParser.new do |opts|
	opts.banner = "Usage: moltenvar [-c]"

	opts.on("-cCONFIG_PATH", "--config=CONFIG_PATH", "Specify and alternative config location") do |v|
		options[:config_file] = v
	end

	opts.on("-h", "--help", "Show this message") do
		printf("%s", opts)
		exit(0)
	end
end.parse!

if ENV["XDG_CONFIG_HOME"] == nil
	conf_dir = ENV["HOME"] + "/.config/moltenbar"
else
	conf_dir = ENV["XDG_CONFIG_HOME"] + "/moltenbar"
end

options[:config_file] ||= conf_dir + "/rc.yaml"

config = YAML.load_file(options[:config_file])

config['mod_dir'] ||= conf_dir + "/mod"

for m in config['modules'] do
	load("#{config['mod_dir']}/#{m}")
end

pipe_r, pipe_w = IO.pipe

Modules.get.each do |k, v|
	Object.const_get(v).new(config, k, pipe_w).run
end

Signal.trap("INT") do cleanup; end
Signal.trap("TERM") do cleanup; end

if config['geometry'] == nil
	config['gap'] ||= 0
	config['height'] ||= 14

	gap = config['gap'].to_i

	if config['width'] == nil
		y, x = get_x_dims()
		config['width'] = y.to_i - (gap * 2)
	end

	config['geometry'] = "%{w}x%{h}+%{gap}+%{gap}" % [
		w: config['width'],
		h: config['height'],
		gap: gap
	]
end

lemonbar_cmd = [
	"lemonbar",
	"-g", config['geometry'],
	"-f", config['fontspec'],
	"-n", config['window_name'],
	"-a", config['active_areas'],
	"-F", config['colours']['fg'],
	"-B", config['colours']['bg']
]

printf("Launching lemonbar as:\n  %s\n", lemonbar_cmd.join(" "))

IO.popen(lemonbar_cmd, "w+") do |pipe_lb|
	pipe_lb.sync = true

	DoSystem.new("system", pipe_lb).run

	pipe_r.each do |line|
		mod_name, data = line.chomp.split("\0")
		panel_data[mod_name] = data

		t = Template.new(config['format'])
		pipe_lb.printf("%s\n", t.render(config, panel_data))
	end
end