#!/usr/bin/python
#
# Urwid example fibonacci sequence viewer / unbounded data demo
#    Copyright (C) 2004-2007  Ian Ward
#
#    This library is free software; you can redistribute it and/or
#    modify it under the terms of the GNU Lesser General Public
#    License as published by the Free Software Foundation; either
#    version 2.1 of the License, or (at your option) any later version.
#
#    This library is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#    Lesser General Public License for more details.
#
#    You should have received a copy of the GNU Lesser General Public
#    License along with this library; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# Urwid web site: http://excess.org/urwid/

"""
Urwid example fibonacci sequence viewer / unbounded data demo

Features:
- custom list walker class for browsing infinite set
- custom wrap mode "numeric" for wrapping numbers to right and bottom
"""

import urwid
import urwid.curses_display
		
class FibonacciWalker(urwid.ListWalker):
	"""ListWalker-compatible class for browsing fibonacci set.
	
	positions returned are (value at position-1, value at poistion) tuples.
	"""
	def __init__(self):
		self.focus = (0L,1L)
		self.numeric_layout = NumericLayout()
	
	def _get_at_pos(self, pos):
		"""Return a widget and the position passed."""
		return urwid.Text("%d"%pos[1], layout=self.numeric_layout), pos
	
	def get_focus(self): 
		return self._get_at_pos( self.focus )
	
	def set_focus(self, focus):
		self.focus = focus
		self._modified()
	
	def get_next(self, start_from):
		a, b = start_from
		focus = b, a+b
		return self._get_at_pos( focus )
	
	def get_prev(self, start_from):
		a, b = start_from
		focus = b-a, a
		return self._get_at_pos( focus )

class FibonacciDisplay(object):
	palette = [
		('body','black','dark cyan', 'standout'),
		('foot','light gray', 'black'),
		('key','light cyan', 'black', 'underline'),
		('title', 'white', 'black',),
		]
		
	footer_text = [
		('title', "Fibonacci Set Viewer"), "    ",
		('key', "UP"), ", ", ('key', "DOWN"), ", ",
		('key', "PAGE UP"), " and ", ('key', "PAGE DOWN"),
		" move view  ",
		('key', "Q"), " exits",
		]
	
	def __init__(self):
		self.listbox = urwid.ListBox( FibonacciWalker() )
		self.footer = urwid.AttrWrap( urwid.Text( self.footer_text ),
			'foot')
		self.view = urwid.Frame( urwid.AttrWrap( self.listbox, 'body'),
			footer=self.footer )

	def main(self):
		self.ui = urwid.curses_display.Screen()
		self.ui.register_palette( self.palette )
		self.ui.run_wrapper( self.run )

	def run(self):
		size = self.ui.get_cols_rows()
		while 1:
			canvas = self.view.render( size, focus=1 )
			self.ui.draw_screen( size, canvas )
			keys = None
			while not keys: 
				keys = self.ui.get_input()
			for k in keys:
				if k == 'window resize':
					size = self.ui.get_cols_rows()
				elif k in ('q','Q'):
					return
				self.view.keypress( size, k )


class NumericLayout(urwid.TextLayout):
	"""
	TextLayout class for bottom-right aligned numbers
	"""
	def layout( self, text, width, align, wrap ):
		"""
		Return layout structure for right justified numbers.
		"""
		lt = len(text)
		r = lt % width # remaining segment not full width wide
		if r:
			linestarts = range( r, lt, width )
			return [
				# right-align the remaining segment on 1st line
				[(width-r,None),(r, 0, r)]
				# fill the rest of the lines
				] + [[(width, x, x+width)] for x in linestarts]
		else:
			linestarts = range( 0, lt, width )
			return [[(width, x, x+width)] for x in linestarts]


def main():
	FibonacciDisplay().main()
	


if __name__=="__main__": 
	main()
