#!/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

		if config["mod"][name] != nil
			@my_config = config["mod"][name]
		end
	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 Panel
	attr_accessor :modData

	def initialize(config)
		@modData = {}
		@config = config
	end

	def render
		panel = @config["format"]
		@modData.each do |modName, modData|
			panel = panel.gsub(/@{#{modName}}/, modData)
		end

		@config["colours"].each do |colName, colValue|
			panel = panel.gsub(/C{#{colName}}/, colValue)
		end

		return panel
	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 'yaml'
require 'optparse'

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"

Dir.new("#{config['mod_dir']}").each_child do |m|
	printf("Loading module: #{m}\n")
	load("#{config['mod_dir']}/#{m}")
end

config["panels"].each do |panelName, panelConf|
	pipe_r, pipe_w = IO.pipe

	panelConf["modules"].each do |modName, modType|
		modClass = Modules.get[modType]
		Object.const_get(modClass).new(panelConf, modName, pipe_w).run
	end

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

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

		gap = panelConf['gap'].to_i

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

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

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

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

	p = Panel.new(panelConf)
	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")
			data ||= ""
			p.modData[mod_name] = data
			pipe_lb.printf("%s\n", p.render())
		end
	end
end