require 'dbus'

module ProgressBar
	@klasses ||= []
	class <<self
		def register klass
			if klass.possible?
				@klasses.push klass
				true
			else
				false
			end
		end

		def new *a, **o
			klass = @klasses.find &:possible?
			klass.new *a, **o
		end
	end
end

class ProgressBar::Base
	attr_reader :max, :i, :text, :error
	attr_accessor :start
	def initialize max = nil, text = nil, **_options
		@start, @max, @i, @text, @error = Time.now, max || 100, 0, text || '', nil
		at_exit {finish}
	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-@start end

	def total_dur
		done_dur * max / i
	end

	def text= x
		@text = x
		change_text
	end

	def error= x
		@error = x
		change_error
	end

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

class ProgressBar::Console < ProgressBar::Base
	def self.possible?
		STDERR.tty?
	end

	def initialize *a
		super *a
		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
		STDOUT.printf "\r\e[J%s / %s [%-*s] %s", format_time(dd), format_time(td), 100, b, text
	end
	alias change_progress change_text

	def change_error
		STDERR.printf "\r\e[J%s\n", error
		change_text
	end

	def finish
		STDERR.puts
	end
end

class ProgressBar::KDE < ProgressBar::Base
	def self.possible?
		'KDE' == ENV['XDG_CURRENT_DESKTOP']
	end
	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, unit: 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?
		@errors = []
		@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 || $0, app_icon_name || '', flags
		@view = @service[view_path]['org.kde.JobViewV2']
		@view.setTotalAmount max, unit
	end

	def change_text
		@view.setInfoMessage text
	end

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

	def change_error
		@view.setError error
	end

	def finish
		@view.terminate
	end
end

class ProgressBar::KDialog < ProgressBar::Base
	def self.possible?
		path = Pathname.new `which kdialog`.chomp
		$?.exitstatus  and  path.executable?
	end

	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?
		@errors = []
		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.object @dialog_object_path
		@dialog_object.introspect
		@dialog_object.showCancelButton true
		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 '', 'value', i
		raise Interrupt  if @dialog_object.wasCancelled.first
	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.first
	rescue DBus::Error
		raise Interrupt  if $!.name == 'org.freedesktop.DBus.Error.ServiceUnknown'
		raise
	end

	def change_error()  @errors.push error  end
	def finish()
		@dialog_object.close rescue DBus::Error
		kdialog '--detailederror', "Some errors occured:", errors.join( "<br/>\n")  unless errors.empty?
	end

	def max= val
		@dialog_object.Set '', 'maximum', val
	end

	def max
		@dialog_object.Get '', 'maximum'
	end
end

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