require 'dbus'
require 'pathname'

#class DBus::Base
#	def initialize object
#		@object = object
#		@object.interfaces.each do |intname|
#			int = @object[intname]
#			int.methods do |name, |
#				meth
#			end
#		end
#	end
#end

module ProgressBar
	@klasses ||= []
	class <<self
		def register klass
			@klasses.push klass
		end

		def new *a, **o
			@klasses.map {|cl| cl.new *a, **o}.find &:possible?
		end
	end
end

class ProgressBar::Base
	attr_reader :max, :i, :text
	attr_accessor :startts
	def initialize max = nil, text = nil, **_options
		@startts, @max, @i, @text = nil, max || 100, 0, text || ''
	end

	def start
		at_exit {finish}
		@startts = Time.now
	end

	def i= x
		@i = x.to_i
		change_progress
	end

	def max= val
		@max = val
		change_progress
	end

	def increment!( x = nil) self.i += (x || 1) end
	alias to_i i
	alias inc! increment!
	def done_rel() 100.0*i/max end
	def done_dur() Time.now-@startts end

	def total_dur
		done_dur * max / i
	end

	def text= x
		@text = x
		change_text
	end

	def error( text)  end
	def change_progress()  end
	def change_text()  end
	def finish()  end
	def self.possible?()  false  end
end

class ProgressBar::Console < ProgressBar::Base
	attr_reader :outfd, :errfd

	def initialize *a, outfd: nil, errfd: nil, **_options
		@outfd = outfd || STDERR
		@errfd = errfd || @outfd
		super *a, **_options
	end

	def possible?
		@outfd.tty?
	end

	def start
		super
		change_text
	end

	def format_time t
		if t.finite?
			sprintf "%02d:%02d:%02d", t/3600, t/60 % 3600, t % 60
		else
			"--:--:--"
		end
	end

	def change_text
		l = [[100.0*i/max, 0].max, 100].min.to_i
		dd, td = done_dur, total_dur
		b = ?= * l
		b[-1] = ?>  unless 0 == l or 100 == l
		@outfd.printf "\r\e[J%s / %s [%-*s] %s", format_time(dd), format_time(td), 100, b, text
	end
	alias change_progress change_text

	def error text
		@errfd.printf "\r\e[J%s\n", text
		@errfd.flush
	end

	def finish
		@outfd.puts
		@outfd.flush
	end
end

class ProgressBar::KDE < ProgressBar::Base
	attr_reader :bus, :service, :view

	def initialize max, text = nil, title: nil,
				app_name: nil,
				app_icon_name: nil,
				unit: nil,
				is_cancable: nil,
				is_suspendable: nil,
				**_options

		super max, text
		text = @text
		text = nil   if text.nil?  or text.empty?
		title = nil  if title.nil? or title.empty?
		unit = ''    if unit.nil?  or unit.empty?
		@title, @text, @unit, @app_name, @app_icon_name, @is_cancable, @is_suspendable =
			title, text, unit, app_name || $0, app_icon_name || '', is_cancable, is_suspendable
		@errors = []
	end

	def possible?
		'KDE' == ENV['XDG_CURRENT_DESKTOP']
	end

	def start
		@finished = false
		@bus = DBus::SessionBus.instance
		@service = @bus['org.kde.JobViewServer']
		jvs = @service['/JobViewServer']['org.kde.JobViewServer']
		flags = (@is_cancable ? 0x1 : 0) | (@is_suspendable ? 0x2 : 0)
		view_path = jvs.requestView @app_name, @app_icon_name, flags
		@view = @service[view_path]['org.kde.JobViewV2']
		super
		@view.setTotalAmount @max, @unit
	end

	def change_text
		@view.setInfoMessage text
	end

	def change_progress
		@view.setProcessedAmount i, @unit
		@view.setPercent done_rel
	end

	def error text
		#STDERR.puts @view.object.introspect
		#@view.setError text
		@view.setDescriptionField 0, "Error", text
		#@view.setInfoMessage "#{text}\nError: #{error}"
	end

	def finish
		return  if @finished
		@view.terminate ''
		@finished = true
	end

	def max= value
		super value
		@view.setTotalAmount value, @unit
	end
end

class ProgressBar::KDialog < ProgressBar::Base
	attr_reader :dialog_service_path, :dialog_object_path, :errors, :dialog_object

	def initialize max, text = nil, title: nil, **_options
		super max, text
		text = @text
		text = nil   if text.nil? or text.empty?
		title = nil  if title.nil? or title.empty?
		@title = title
		@errors = []
	end

	def possible?
		path = Pathname.new `which kdialog`.chomp
		$?.exitstatus  and  path.executable?
	end

	def start
		@finished = false
		args = ['kdialog', @title ? ['--title', @title] : [], '--progressbar', @text || '.', @max].flatten.compact.map &:to_s
		@dialog_service_path, @dialog_object_path =
			IO.popen( args, 'r', &:readlines).join( "\n").split ' '
		@dialog_bus = DBus.session_bus
		@dialog_service = @dialog_bus[@dialog_service_path]
		@dialog_object = @dialog_service[ @dialog_object_path]
		#STDERR.puts "%p" %
			@dialog_object.introspect
		@dialog_object.showCancelButton 1
		super
		change_text  if text.nil?
		change_progress

	rescue DBus::Error
		raise Interrupt  if $!.name == 'org.freedesktop.DBus.Error.ServiceUnknown'
		raise
	end

	def self.kdialog *a
		windowid = ENV['WINDOWID']
		windowid = (windowid.is_a?(String) && !windowid.empty?) ? ['--attach', windowid] : []
		system 'kdialog', *windowid, *a
	end
	def kdialog(*a)  self.class.kdialog *a  end

	def change_progress()
		#@dialog_object.Set 'org.kde.kdialog.ProgressDialog', 'value', i
		@dialog_object['value'] = i
		raise Interrupt  if @dialog_object.wasCancelled
	rescue DBus::Error
		raise Interrupt  if $!.name == 'org.freedesktop.DBus.Error.ServiceUnknown'
		raise
	end

	def change_text()
		@dialog_object.setLabelText text
		raise Interrupt  if @dialog_object.wasCancelled
	rescue DBus::Error
		raise Interrupt  if $!.name == 'org.freedesktop.DBus.Error.ServiceUnknown'
		raise
	end

	def error text
		kdialog '--error', text
	end

	def finish()
		return  if @finished
		@dialog_object.close  rescue DBus::Error
		@finished = true
	end

	def max= val
		super val
		@dialog_object['maximum'] = val
	end
end

ProgressBar.register ProgressBar::Console
ProgressBar.register ProgressBar::KDE
ProgressBar.register ProgressBar::KDialog