#!/usr/bin/python
# bpython 0.3.1::fancy curses interface to the Python repl::Bob Farrell 2008
#
# The MIT License
# 
# Copyright (c) 2008 Bob Farrell
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
#
# Requires at least Python 2.5 and pygments (apt-get install python-pyments)
#
import os
import sys
import curses
import code
import codeop
import traceback
import re
import time
import math
import urllib
import rlcompleter
import inspect
import signal
import struct
import termios
import fcntl
from bpython.formatter import BPythonFormatter

class Opts( object ):
	pass
OPTS = Opts()

try:
	from pygments import highlight
	from pygments.lexers import PythonLexer
except ImportError:
	OPTS.syntax = False
else:
	OPTS.syntax = True

try:
	from pyparsing import Forward, Suppress, QuotedString, dblQuotedString, \
		Group, OneOrMore, ZeroOrMore, Literal, Optional, Word, \
		alphas, alphanums, printables, ParseException
except ImportError:
	OPTS.argspec = False
else:
	import pydoc
	OPTS.argspec = True

# TODO:
#
# Triple-quoted strings over multiple lines are not colourised correctly.
#
# Numerous optimisations can be made but it seems to do all the lookup stuff
# fast enough on even my crappy server so I'm not too bothered about that
# at the moment.
#
# The popup window that displays the argspecs and completion suggestions
# needs to be an instance of a ListWin class or something so I can wrap
# the addstr stuff to a higher level.
#
def DEBUG(s):
	"""This shouldn't ever be called in any release of bpython, so
	beat me up if you find anything calling it."""
	open('/home/bob/tmp/plonker','a').write( "%s\n" % str( s )  )

def make_colours():
	"""Init all the colours in curses and bang them into a dictionary"""

	for i in range( 63 ):
		if i > 7: j = i / 8
		else: j = -1
		curses.init_pair( i+1, i % 8, j )

	c = {}
	# blacK, Red, Green, Yellow, Blue, Magenta, Cyan, White, Default:
	c["k"] = 0
	c["r"] = 1
	c["g"] = 2
	c["y"] = 3
	c["b"] = 4
	c["m"] = 5
	c["c"] = 6
	c["w"] = 7
	c["d"] = -1
	
	return c
	
class Interpreter( code.InteractiveInterpreter ):
	def showtraceback( self ):
		"""This needs to override the default traceback thing
		so it can put it into a pretty colour and maybe other
		stuff, I don't know"""

		try:
			t, v, tb = sys.exc_info()
			sys.last_type = t
			sys.last_value = v
			sys.last_traceback = tb
			tblist = traceback.extract_tb( tb )
			del tblist[:1]

			l = traceback.format_list( tblist )
			if l:
				l.insert( 0, "Traceback (most recent call last):\n" )
			l[len(l):] = traceback.format_exception_only( t, v )
		finally:
			tblist = tb = None
		
		self.writetb( l )

	def writetb( self, l ):
		"""This outputs the traceback and should be overridden for anything
		fancy."""
		map( self.write, [ "\x01y\x03%s" % i for i in l ] )


class Repl:
	"""Implements the necessary guff for a Python-repl-alike interface
	
	The execution of the code entered and all that stuff was taken from the
	Python code module, I had to copy it instead of inheriting it, I can't
	remember why. The rest of the stuff is basically what makes it fancy.

	It reads what you type, passes it to a lexer and highlighter which
	returns a formatted string. This then gets passed to echo() which
	parses that string and prints to the curses screen in appropriate
	colours and/or bold attribute.
	
	The Repl class also keeps two stacks of lines that the user has typed in:
	One to be used for the undo feature. I am not happy with the way this works.
	The only way I have been able to think of is to keep the code that's been
	typed in in memory and re-evaluate it in its entirety for each "undo"
	operation. Obviously this means some operations could be extremely slow.
	I'm not even by any means certain that this truly represents a genuine "undo"
	implementation, but it does seem to be generally pretty effective.

	If anyone has any suggestions for how this could be improved, I'd be happy
	to hear them and implement it/accept a patch. I researched a bit into
	the idea of keeping the entire Python state in memory, but this really
	seems very difficult (I believe it may actually be impossible to work)
	and has its own problems too. 

	The other stack is for keeping a history for pressing the up/down keys
	to go back and forth between lines.
	"""#TODO: Split the class up a bit so the curses stuff isn't so integrated.
	"""

	"""

	def __init__( self, scr, interp, statusbar=None, idle=None):
		"""Initialise the repl with, unfortunately, a curses screen passed to it.
		This needs to be split up so the curses crap isn't in here.

		interp is a Python code.InteractiveInterpreter instance

		The optional 'idle' parameter is a function that the repl call while
		it's blocking (waiting for keypresses). This, again, should be in a
		different class"""

		self.buffer = []
		self.scr = scr
		self.interp = interp
		self.match = False
		self.rl_hist = []
		self.stdout_hist = []
		self.s_hist = []
		self.history = []
		self.h_i = 0
		self.in_hist = False
		self.evaluating = False
		self.do_exit = False
		self.cpos = 0
# Use the interpreter's namespace only for the readline stuff:
		self.completer = rlcompleter.Completer( self.interp.locals )
		self.statusbar = statusbar
		self.list_win = curses.newwin( 1, 1, 1, 1 )
		self.idle = idle
		self.f_string = ''
		self.matches = []
		self.argspec = None
		self.s = ''
		
		if not OPTS.argspec:
			return

		pexp = Forward()
		chars = printables.replace('(', '')
		chars = chars.replace(')', '')
		pexpnest = Optional( Word( chars ) ) + Literal( "(" ) + Optional( Group( pexp ) ) + Optional( Literal( ")" ) )
		pexp << ( OneOrMore( Word( chars ) | pexpnest ) )
		self.pparser = pexp

	def cw( self ):
		"""Return the current word, i.e. the (incomplete) word
		directly to the left of the cursor"""

		if self.cpos: # I don't know if autocomplete should be disabled
# if the cursor isn't at the end of the line, but that's what this does for now.
			return

		l = len( self.s )

		if not self.s or ( not self.s[ l-1 ].isalnum() and self.s[ l-1 ] not in ( '.', '_' ) ):
			return
	
		i = 1
		while i < l+1:
			if not self.s[ -i ].isalnum() and self.s[ -i ] not in ( '.', '_' ):
				break
			i += 1
		return self.s[ -i +1: ]


	def get_args( self ):
		"""Check if an unclosed parenthesis exists, then attempt to get the argspec()
		for it. On success, update self.argspec and return True, otherwise set
		self.argspec to None and return False"""

		def getpydocspec( f, func ):
			try:
				argspec = pydoc.getdoc( f )
			except NameError:
				return None

			rx = re.compile( r'([a-zA-Z_][a-zA-Z0-9_]*?)\((.*?)\)' )
			s = rx.search( argspec )
			if s is None:
				return None

			if s.groups()[0] != func:
				return None
			
			args = [ i.strip() for i in s.groups()[1].split(',') ]
			return [func, (args, None, None, None)]#None, None, None]


		def getargspec( func ):
			try:
				if func in self.interp.locals:
					f = self.interp.locals[ func ]
			except TypeError:
				return None

			else:
				try:
					f = eval( func, self.interp.locals )
				except Exception: # Same deal with the exceptions :(
					return None

			try:
				if inspect.isclass(f):
					argspec = inspect.getargspec( f.__init__ )
				else:
					argspec = inspect.getargspec( f )
				self.argspec = [func, argspec]#[0]]#"Args for %s: " + ", ".join( argspec[0] )
				#self.argspec = self.argspec % func
				return True

			except (NameError, TypeError, KeyError), x:
				t = getpydocspec( f, func )
				if t is None:
					return None
				self.argspec = t
				return True
			except AttributeError: # no __init__
				return None

		def parse_parens( s ):
			"""Run a string through the pyparsing pattern for paren
			counting."""

			try:
				parsed = self.pparser.parseString( s ).asList()
			except ParseException:
				return False

			return parsed

		def walk( seq ):
			"""Walk a nested list and return the last list found that
			doesn't have a close paren in it (i.e. the active function)"""
			r = None
			if isinstance( seq, list ):
				if ")" not in seq and "(" in seq:
					r = seq[ seq.index('(') - 1 ]
				for i in seq:
					t = walk( i )
					if t:
						r = t
			return r

		if not OPTS.argspec:
			return False

		t = parse_parens( self.s )
		if not t:
			return False 

		func = walk( t )
		if not func:
			return False
		
		return getargspec( func )

	def complete( self ):
		"""Construct a full list of possible completions and construct and
		display them in a window. Also check if there's an available argspec
		(via the inspect module) and bang that on top of the completions too."""

		words = []
		i = 0
		
		if not self.get_args():
			self.argspec = None

		cw = self.cw()
		if not (cw or self.argspec):
			self.scr.redrawwin()
			self.scr.refresh()
			return None

		if not cw:
			self.matches = []

		try:
			self.completer.complete( cw, 0 )
		except Exception: # This sucks, but it's either that or list all the
# exceptions that could possibly be raised here, so if anyone wants to do that,
# feel free to send me a patch.
			e = True
		else:
			e = False

		if (e or not self.completer.matches) and not self.argspec:
			self.scr.redrawwin()
			return

		if not e and self.completer.matches:
			self.matches = sorted( set( self.completer.matches ) ) # remove duplicates and
# restore order
		self.show_list( self.matches, self.argspec )

	def show_list( self, items, topline=None ):
		"""Display a list of options on the screen."""

		y, x = self.scr.getyx()
		items = [ i.rpartition('.')[-1] for i in items ]
		
		def calc_lsize(r):
			"""Calculate the size required on screen to display the list.
			Unfortunately Python 2.x doesn't allow assigning to the scope
			one level up of a nested function, so the return list on this
			function is horrible. I could have used an object and mutated
			it from here but it doesn't seem like such a big deal. Hopefully
			I can make this prettier when py3k shows up. :)"""

			menu = self.make_list( items )
			if menu:
				wl = max( len( i ) for i in items ) + 1
			else:
				wl = 1
			l = len( items )
			h, w = self.scr.getmaxyx()
			optw = int( w * r )
			opth = ( l / ( optw / wl ) ) + 1 
			return menu, wl, l, h, w, optw, opth # uuuurgh

		menu, wl, l, h, w, optw, opth = calc_lsize( 0.6 ) # blllluuurgh
		down = ( y < h / 2 )
		
		trunc = False
		if down:
			max_h = h - y
		else:
			max_h = y + 1
	
		if topline:
			max_h -= 1

		while opth + 3 >= max_h:
			trunc = True
			items = items[ : -1 ]
			menu, wl, l, h, w, optw, opth = calc_lsize( 0.6 ) # bllllaaarrgghhh

		if topline and menu: opth += 1
		
		if trunc:
			menu.append('...')
			l += 1


		self.list_win.erase()
		self.scr.touchwin()
		self.scr.noutrefresh()
		self.list_win.resize( opth+3, optw+3 )


		if down:
			self.list_win.mvwin( y + 1, 1 )
		else:
			self.list_win.mvwin( y - opth - 3, 1 )

		rows = opth + 1
		cols = optw / wl

		if topline:
			l -= cols * self.mkargspec( topline, down )

		if menu:
			self.list_win.addstr( '\n  ' )
			for i in range( 0, l ):
				if i+1 >= cols and not i % cols:
					self.list_win.addstr( '\n  ' )
				self.list_win.addstr( menu[ i ] + ( " " * (wl - len(menu[ i ]))), curses.color_pair( self._C["c"]+1 ) )
		

		self.list_win.border()
		self.list_win.noutrefresh()
		
		self.scr.move( y, x )
		self.scr.refresh()
	
	def mkargspec( self, topline, down ):
		"""This figures out what to do with the argspec and puts it nicely into
		the list window. It returns the number of lines used to display the argspec.
		It's also kind of messy due to it having to call so many addstr() to get
		the colouring right, but it seems to be pretty sturdy."""

		r = 0
		fn = topline[0]
		args = topline[1][0]
		kwargs = topline[1][3]
		_args = topline[1][1]
		_kwargs = topline[1][2]

		self.list_win.addstr( '\n  ')
		self.list_win.addstr( fn, curses.color_pair( self._C["b"]+1 ) | curses.A_BOLD )
		self.list_win.addstr( ': ( ', curses.color_pair( self._C["y"]+1 ) )
		h, w = self.list_win.getmaxyx()
		maxh = self.scr.getmaxyx()[0]


		for k, i in enumerate( args ):
			y, x = self.list_win.getyx()
			ln = len( str(i) )
			kw = None
			if kwargs and k+1 > len(args) - len(kwargs):
				kw = '%s' % str(kwargs[ k - (len(args) - len(kwargs))])
				ln += len( kw ) + 1
		
			if ln + x >= w:
				ty = self.list_win.getbegyx()[0]
				if not down and ty > 0:
					h +=1
					self.list_win.mvwin( ty-1, 1 )
					self.list_win.resize(h,w)
				elif down and h + r < maxh-ty:
					h +=1
					self.list_win.resize(h,w)
				else:
					r += 1
				self.list_win.addstr('\n\t')

			self.list_win.addstr( str(i), curses.color_pair( self._C["g"]+1 ) | curses.A_BOLD )
			if kw:
				self.list_win.addstr( '=', curses.color_pair( self._C["c"]+1 ) )
				self.list_win.addstr( kw, curses.color_pair( self._C["g"]+1) )
			if k != len(args) -1:
				self.list_win.addstr( ', ', curses.color_pair( self._C["g"]+1 ) )

		if _args:
			self.list_win.addstr( ', ', curses.color_pair( self._C["g"]+1 ) )
			self.list_win.addstr( '*%s' % _args, curses.color_pair( self._C["m"]+1 ) )
		if _kwargs:
			self.list_win.addstr( ', ', curses.color_pair( self._C["g"]+1 ) )
			self.list_win.addstr( '**%s' % _kwargs, curses.color_pair( self._C["m"]+1 ) )
		self.list_win.addstr( ' )', curses.color_pair( self._C["y"]+1 ) )

		return r

	def getstdout( self ):
		"""This method returns the 'spoofed' stdout buffer, for writing to a file
		or sending to a pastebin or whatever."""

		return "\n".join( self.stdout_hist )

	def write2file( self ):
		"""Prompt for a filename and write the current contents of the stdout buffer
		to disk."""
	
		fn = self.statusbar.prompt( 'Save to file: ' )

		if '~' in fn:
			fn = os.path.expanduser( fn )

		s = self.getstdout()
		
		try:
			f = open( fn, 'w' )
			f.write( s )
			f.close()
		except IOError:
			self.statusbar.message("Disk write error for file '%s'." % fn )
		else:
			self.statusbar.message( 'Saved to %s' % fn )

	def pastebin( self ):
		"""Upload to a pastebin and display the URL in the status bar."""
		
		s = self.getstdout()
		url = 'http://rafb.net/paste/paste.php'
		pdata = { 'lang' : 'Python',
			'cvt_tabs' : 'No',
			'text' : s }
		pdata = urllib.urlencode( pdata )

		self.statusbar.message( 'Posting data to pastebin...' )
		u = urllib.urlopen( url, data=pdata )
		d = u.read()

		rx = re.search( '(http://rafb.net/p/[0-9a-zA-Z]+\.html)', d )
		if not rx:
			self.statusbar.message( 'Error parsing pastebin URL! Please report a bug.' )
			return
	
		
		r_url = rx.groups()[ 0 ]
		self.statusbar.message( 'Pastebin URL: %s' % r_url, 10 )


	def make_list( self, items ):
		"""Compile a list of items. At the moment this simply returns
		the list; it's here in case I decide to add any more functionality.
		I originally had this method return a list of items where each item
		was prepended with a number/letter so the user could choose an option
		but it doesn't seem appropriate for readline-like behaviour."""

		return items


	def push( self, s ):
		"""Push a line of code onto the buffer so it can process it all
		at once when a code block ends"""
		s = s.rstrip('\n')
		self.buffer.append( s )

		more = self.interp.runsource( "\n".join( self.buffer ) )
		
		if not more:
			self.buffer = []

		return more

	def undo( self, n=1 ):
		"""Go back in the undo history n steps and call reeavluate()
		Note that in the program this is called "Rewind" because I
		want it to be clear that this is by no means a true undo
		implementation, it is merely a convenience bonus.""" 
		if not self.history:
			return None

		if len( self.history ) < n:
			n = len( self.history )

		self.history = self.history[ : -n ]
		self.reevaluate()

	def enter_hist( self ):
		"""Set flags for entering into the history by pressing up/down"""
		if not self.in_hist:
			self.in_hist = True
			self.ts = self.s

	def back( self ):
		"""Replace the active line with previous line in history and
		increment the index to keep track"""

		if not self.rl_hist:
			return None
		
		self.cpos = 0
		self.enter_hist()

		if self.h_i < len( self.rl_hist ):
			self.h_i += 1
		
		self.s = self.rl_hist[ -self.h_i ].rstrip('\n')
		self.print_line( self.s, clr=True )
	
	def fwd( self ):
		"""Same as back() but, well, forward"""

		self.enter_hist()

		self.cpos = 0

		if self.h_i > 1:
			self.h_i -= 1
			self.s = self.rl_hist[ -self.h_i ]
		else:
			self.h_i = 0
			self.s = self.ts
			self.ts = ''
			self.in_hist = False
		
		self.print_line( self.s, clr=True )
		
	def redraw( self ):
		"""Redraw the screen."""
		self.scr.erase()
		for k, s in enumerate( self.s_hist ):
			if not s:
				continue
			self.iy, self.ix = self.scr.getyx()
			for i in s.split('\x04'):
				self.echo( i, redraw=False )
			if k < len( self.s_hist ) -1:
				self.scr.addstr( '\n' )
		self.iy, self.ix = self.scr.getyx()
		self.print_line( self.s )
		self.scr.refresh()
		self.statusbar.refresh()

	def reevaluate( self ):
		"""Clear the buffer, redraw the screen and re-evaluate the history"""

		self.evaluating = True
		self.stdout_hist = []
		self.f_string = ''
		self.stdout_hist = []
		self.buffer = []
		self.scr.erase()
		self.s_hist = []

		self.prompt( False )

		self.iy, self.ix = self.scr.getyx()
		for line in self.history:
			self.stdout_hist[-1] += line.rstrip('\n')
			self.print_line( line )
			self.s_hist[-1] += self.f_string
			self.scr.addstr( '\n' ) # I decided it was easier to just do this manually
# than to make the print_line and history stuff more flexible.
			more = self.push( line )
			self.prompt( more )
			self.iy, self.ix = self.scr.getyx()
			
		self.s = ''
		self.scr.refresh()

		self.evaluating = False
		#map( self.push, self.history ) # <-- That's how simple this function was at first :(

	def prompt( self, more ):
		"""Show the appropriate Python prompt"""
		if not more:
			self.echo( "\x01g\x03>>> " )
			self.stdout_hist.append('>>> ')
			self.s_hist.append( '\x01g\x03>>> \x04' )
		else:
			self.echo( "\x01r\x03... " )
			self.stdout_hist.append('... ')
			self.s_hist.append( '\x01r\x03... \x04' )

	def repl( self ):
		"""Initialise the repl and jump into the loop. This method also
		has to keep a stack of lines entered for the horrible "undo"
		feature. It also tracks everything that would normally go to stdout
		in the normal Python interpreter so it can quickly write it to
		stdout on exit after curses.endwin(), as well as a history of lines
		entered for using up/down to go back and forth (which has to be separate
		to the evaluation history, which will be truncated when undoing."""
		
		self.iy, self.ix = self.scr.getyx()
		more = False
		while not self.do_exit:
			self.f_string = ''
			self.prompt( more )
			try:
				inp = self.get_line()
			except KeyboardInterrupt:
				self.statusbar.message('KeyboardInterrupt')
				self.scr.addstr('\n')
				continue

			self.scr.redrawwin()
			if self.do_exit:
				return
			self.h_i = 0
			self.history.append( inp )
			self.s_hist[-1] += self.f_string
			self.stdout_hist[-1] += inp.rstrip('\n')
			self.rl_hist.append( inp ) # Keep two copies so you can go up and down in the hist
			more = self.push( inp )

	def size( self, scr ):
		"""Set instance attributes for x and y top left corner coordinates
		and width and heigth for the window."""
		h, w = stdscr.getmaxyx()
		self.y = 0 
		self.w = w
		self.h = h-1
		self.x = 0

	def resize( self ):
		"""This method exists simply to keep it straight forward when initialising
		a window and resizing it."""
		self.size( self.scr )
		self.scr.erase()
		self.scr.resize( self.h, self.w )
		self.scr.mvwin( self.y, self.x )
		self.redraw()

	def write( self, s ):
		"""For overriding stdout defaults"""
		if s.rstrip('\n'):
			if '\x03' in s:
				t = s.split('\x03')[1].rstrip('\n')
			else:
				t = s.rstrip('\n')
			self.stdout_hist.append( t )
		self.echo( s )
		self.s_hist.append( s.rstrip('\n') )

	def echo( self, s, redraw=True ):
		"""Parse and echo a formatted string with appropriate attributes. It uses the
		formatting method as defined in formatter.py to parse the srings. It won't update
		the screen if it's reevaluating the code (as it does with undo)."""

		a = curses.color_pair( 0 )
		if '\x01' in s:
			rx = re.search( '\x01([a-z])([a-z]?)', s )
			if rx:
				p = self._C[ rx.groups()[ 0 ] ]
				if rx.groups()[ 1 ]:
					p *= self._C[ rx.groups()[ 1 ] ]
				
				a = curses.color_pair( int( p ) + 1 )
				s = re.sub( '\x01[a-z][a-z]?', '', s )

		if '\x02' in s:
			a = a | curses.A_BOLD
			s = s.replace( '\x02', '' )
		s = s.replace( '\x03', '' )
		s = s.replace( '\x01', '' )


		self.scr.addstr( s, a )	

		if redraw and not self.evaluating:
			self.scr.refresh()

	def mvc( self, i, refresh=True ):
		"""This method moves the cursor relatively from the current
		position, where:
			0 == (right) end of current line
			length of current line len(self.s) == beginning of current line
		and:
			current cursor position + i
			for positive values of i the cursor will move towards the beginning
			of the line, negative values the opposite."""
		y, x = self.scr.getyx()

		if self.cpos == 0 and i < 0:
			return

		if x == self.ix and y == self.iy and i >= 1:
			return

		h, w = gethw()
		if x - i < 0:
			y -= 1
			x = w 

		if x - i >= w:
			y += 1
			x = 0 + i

		self.cpos += i
		self.scr.move( y, x - i )
		if refresh:
			self.scr.refresh()

	def bs( self ):
		"""Process a backspace"""
#TODO: All this curses code really ought to be somewhere else. :(

		y, x = self.scr.getyx()

		if x == self.ix and y == self.iy:
			return

		if x == 0:
			y -= 1
			x = gethw()[1]

		if not self.cpos:
			self.s = self.s[ : -1 ]
		else:
			self.s = self.s[ : -self.cpos-1 ] + self.s[ -self.cpos : ]
		self.scr.delch( y, x - 1 )
		self.scr.refresh()

	def clrtobol( self ):
		"""Clear from cursor to beginning of line; usual C-u behaviour"""
		if not self.cpos:
			self.s = ''
		else:
			self.s = self.s[ self.cpos : ]
		
		self.print_line( self.s, clr=True )
		self.scr.redrawwin()
		self.scr.refresh()

	def p_key( self ):
		"""Process a keypress"""


		if self.c is None:
			return ''

		if self.c in ( chr(127), 'KEY_BACKSPACE' ):
			self.bs()
			self.complete()
			return ''

		elif self.c == chr(18):# C-r
			self.undo()
			return ''

		elif self.c == 'KEY_UP': # Cursor Up
			self.back()
			return ''

		elif self.c == 'KEY_DOWN': # Cursor Down
			self.fwd()
			return ''

		elif self.c == 'KEY_LEFT': # Cursor Left
			self.mvc( 1 )
		
		elif self.c == 'KEY_RIGHT': # Cursor Right
			self.mvc( -1 )

		elif self.c in ('^U', chr(21) ): # C-u
			self.clrtobol()
			return ''

		elif self.c in ('^L', chr(12) ): # C-l
			self.redraw()
			return ''

		elif self.c in ( chr(4), '^D' ): # C-d
			self.do_exit = True
			return None

		elif self.c == 'KEY_F(2)':
			self.write2file()
			return ''

		elif self.c == 'KEY_F(8)':
			self.pastebin()
			return ''

		elif self.c == '\n':
			self.lf()
			return None
		
		elif self.c == '\t':
			return self.tab()

		elif len( self.c ) == 1 and ord( self.c ) <= 127:
			self.addc( self.c )
			self.print_line( self.s )

		else:
			return ''


		return True

	def tab( self ):
		"""Process the tab key being hit. If there's only whitespace
		in the line or the line is blank then process a normal tab,
		otherwise attempt to autocomplete to the best match of possible
		choices in the match list."""
		
		if self.atbol():
			self.addc( self.c )
			self.print_line( self.s )
			return True

		cw = self.cw()
		if cw:
			b = self.strbase( self.matches )
			if b:
				self.s += b[ len( cw ) : ]
				self.print_line( self.s )
		return True

	def strbase( self, l ):
		"""Probably not the best way of doing it but this function returns
		a common base string in a list of strings (for tab completion)."""

		if len( l ) == 1:
			return l[0]
		
		sl = sorted( l, key=str.__len__ )
		for i, c in enumerate( l[-1] ):
			if not all( k.startswith( l[-1][:i] ) for k in sl ):
				break

		return l[-1][:i-1]

	def atbol( self ):
		"""Return True or False accordingly if the cursor is at the beginning
		of the line (whitespace is ignored). This exists so that p_key() knows
		how to handle the tab key being pressed - if there is nothing but white
		space before the cursor then process it as a normal tab otherwise attempt
		tab completion."""
		
		if not self.s.lstrip():
			return True

	def lf( self ):
		"""Process a linefeed character; it only needs to check the
		cursor position and move appropriately so it doesn't clear
		the current line after the cursor."""
		if self.cpos:
			for i in range( self.cpos ):
				self.mvc( -1 )

		self.echo( "\n" )

	def addc( self, c ):
		"""Add a character to the current input line and figure out
		where it should go, depending on the cursor position."""
		if not self.cpos:
			self.s += self.c
		else:
			l = len( self.s ) 
			self.s = self.s[ : l - self.cpos ] + self.c + self.s[ l - self.cpos : ]

		self.complete()

	def print_line( self, s, clr=False ):
		"""Chuck a line of text through the highlighter, move the cursor
		to the beginning of the line and output it to the screen."""

		if not s:
			clr = True

		if OPTS.syntax:
			o = highlight( s, PythonLexer(), BPythonFormatter() )
		else:
			o = s

		self.f_string = o
		self.scr.move( self.iy, self.ix )

		if clr:
			self.scr.clrtoeol()

		if clr and not s:
			self.scr.refresh()
			
		if o:
			for t in o.split('\x04'):
				self.echo( t.rstrip('\n') )

		if self.cpos:
			t = self.cpos
			for i in range( self.cpos ):
				self.mvc( 1 )
			self.cpos = t

	def get_line( self ):
		"""Get a line of text and return it
		This function initialises an empty string and gets the 
		curses cursor position on the screen and stores it
		for the echo() function to use later (I think).
		Then it waits for key presses and passes them to p_key(),
		which returns None if Enter is pressed (that means "Return",
		idiot)."""

		self.ts = ''
		n_indent = re.split( '[^\t]', self.s, 1 )[0].count('\t')		
		indent = self.s.endswith(':')
		self.s = ''
		self.iy, self.ix = self.scr.getyx()

		for i in range(n_indent):
			self.c = '\t'
			self.p_key()

		if indent:
			self.c = '\t'
			self.p_key()

		self.c = None
		self.cpos = 0
		while True:
			if self.idle:
				self.idle( self )
			try:
				self.c = self.scr.getkey()
			except curses.error: # I'm quite annoyed with the ambiguity of
# this exception handler. I previously caught "curses.error, x" and accessed
# x.message and checked that it was "no input", which seemed a crappy way of
# doing it. But then I ran it on a different computer and the exception
# seems to have entirely different attributes. So let's hope getkey() doesn't
# raise any other crazy curses exceptions. :)
					continue

			if self.p_key() is None:
				return self.s
		
class Statusbar:
	"""This class provides the status bar at the bottom of the screen.
	It has message() and prompt() methods for user interactivity, as
	well as settext() and clear() methods for changing its appearance.

	The check() method needs to be called repeatedly if the statusbar is
	going to be aware of when it should update its display after a message()
	has been called (it'll display for a couple of seconds and then disappear).

	It should be called as:
		foo = Statusbar( stdscr, scr, 'Initial text to display' )
	or, for a blank statusbar:
		foo = Statusbar( stdscr, scr )

	It can also receive the argument 'c' which will be an integer referring
	to a curses colour pair, e.g.:
		foo = Statusbar( stdscr, 'Hello', c=4 )

	stdscr should be a curses window object in which to put the status bar.
	pwin should be the parent window. To be honest, this is only really here
	so the cursor can be returned to the window properly.
	
	"""

	def __init__( self, scr, pwin, s=None, c=None ):
		"""Initialise the statusbar and display the initial (text if there is any)"""
		self.size( scr )
		self.win = curses.newwin( self.h, self.w, self.y, self.x )

		self.s = s or ''	
		self._s = self.s
		self.c = c
		self.timer = 0
		self.pwin = pwin
		self.settext( s, c )
		
	def size( self, scr ):
		"""Set instance attributes for x and y top left corner coordinates
		and width and heigth for the window."""
		h, w = gethw()
		self.y = h-1
		self.w = w
		self.h = 1
		self.x = 0

	def resize( self ):
		"""This method exists simply to keep it straight forward when initialising
		a window and resizing it."""
		self.size( self.win )
		self.win.mvwin( self.y, self.x )
		self.win.resize( self.h, self.w )
		self.refresh()
	
	def refresh( self ):
		"""This is here to make sure the status bar text is redraw properly
		after a resize."""
		self.settext( self._s )

	def check( self ):
		"""This is the method that should be called every half second or so
		to see if the status bar needs updating."""
		if not self.timer:
			return
		
		if time.time() < self.timer:
			return
		
		self.settext( self._s )
		

	def message( self, s, n=3 ):
		"""Display a message for a short n seconds on the statusbar and return
		it to its original state."""
		self.timer = time.time() + n
		self.settext( s )
		

	def prompt( self, s='' ):
		"""Prompt the user for some input (with the optional prompt 's') and
		return the input text, then restore the statusbar to its original value."""
		
		self.settext( s or '? ', p=True )
		iy, ix = self.win.getyx()
		
		def bs( s ):
			y, x = self.win.getyx()
			if x == ix:
				return s
			s = s[:-1]
			self.win.delch(y,x-1)
			self.win.move(y,x-1)
			return s

		o = ''
		while True:
			c = self.win.getch()

			if c == 127:
				o = bs( o )
				continue

			if not c or c > 127:
				continue
			c = chr( c )

			if c == '\n':
				break

			self.win.addstr( c )
			o += c
		
		self.settext( self._s )
		return o

	def settext( self, s, c=None, p=False ):
		"""Set the text on the status bar to a new permanent value; this is the value
		that will be set after a prompt or message. c is the optional curses colour
		pair to use (if not specified the last specified colour pair will be used).
		p is True if the cursor is expected to stay in the status window (e.g. when
		prompting)."""
		
		self.win.erase()
		if len( s ) >= self.w:
			s = s[ : self.w-1 ]

		self.s = s
		if c:
			self.c = c

		if s:
			if self.c:
				self.win.addstr( s, curses.color_pair( self.c ) )
			else:
				self.win.addstr( s )

		if not p:
			self.win.noutrefresh()
			self.pwin.refresh()
		else:
			self.win.refresh()

	def clear( self ):
		"""Clear the status bar."""
		self.win.clear()

def init_wins( scr, cols ):
	"""Initialise the two windows (the main repl interface and the
	little status bar at the bottom with some stuff in it)"""
#TODO: Document better what stuff is on the status bar.

	h, w = gethw()

	main_win = curses.newwin( h-1, w, 0, 0 )
	main_win.scrollok( True )
	main_win.keypad(1) # Thanks to Angus Gibson for pointing out
# this missing line which was causing problems that needed dirty
# hackery to fix. :)

	statusbar = Statusbar( scr, main_win, ".:: <C-d> Exit  <C-r> Rewind  <F2> Save  <F8> Pastebin ::.", (cols["g"]) *cols["y"] +1 )

	return main_win, statusbar

def sigwinch( scr ):
	global DO_RESIZE
	DO_RESIZE = True

def gethw():
	"""I found this code on a usenet post, and snipped out the bit I needed,
	so thanks to whoever wrote that, sorry I forgot your name, I'm sure you're
	a great guy.
	
	It's unfortunately necessary (unless someone has any better ideas) in order 
	to allow curses and readline to work together. I looked at the code for
	libreadline and noticed this comment:

		/* This is the stuff that is hard for me.  I never seem to write good
		   display routines in C.  Let's see how I do this time. */

	So I'm not going to ask any questions.
	
	"""
	h, w = struct.unpack(
		"hhhh", fcntl.ioctl(sys.__stdout__, termios.TIOCGWINSZ, "\000"*8))[0:2]
	return h, w

def idle( caller ):
	"""This is called once every iteration through the getkey()
	loop (currently in the Repl class, see the get_line() method).
	The statusbar check needs to go here to take care of timed 
	messages and the resize handlers need to be here to make
	sure it happens conveniently."""

	global stdscr

	caller.statusbar.check()

	if DO_RESIZE:
		do_resize( caller )

def do_resize( caller ):
	"""This needs to hack around readline and curses not playing
	nicely together. See also gethw() above."""
	global DO_RESIZE
	h, w = gethw()
	if not h: 
		return # Hopefully this shouldn't happen. :) 

	curses.endwin()
	os.environ["LINES"] = str( h )
	os.environ["COLUMNS"] = str( w )
	curses.doupdate()
	DO_RESIZE = False

	caller.resize()
	caller.statusbar.resize()
	# The list win resizes itself every time it appears so no need to do it here.

def main( scr ):
	"""main function for the curses convenience wrapper

	Initialise the two main objects: the interpreter
	and the repl. The repl does what a repl does and lots
	of other cool stuff like syntax highlighting and stuff.
	I've tried to keep it well factored but it needs some
	tidying up, especially in separating the curses stuff
	from the rest of the repl.
	"""
	global stdscr
	global DO_RESIZE
	DO_RESIZE = False
	signal.signal( signal.SIGWINCH, lambda x,y: sigwinch(scr) )
	
	stdscr = scr
	curses.start_color()
	curses.use_default_colors()
	cols = make_colours() 

	scr.timeout( 300 )

	main_win, statusbar = init_wins( scr, cols )


	interpreter = Interpreter()

	repl = Repl( main_win, interpreter, statusbar, idle )
	repl._C = cols

	sys.stdout = repl
	sys.stderr = repl


	repl.repl()
	return repl.getstdout()

o = curses.wrapper( main )
sys.stdout = sys.__stdout__
sys.stdout.write( o ) # Fake stdout data so everything's still visible after exiting
sys.stdout.flush()
