#!/bin/python

# Fenrir TTY screen reader
# By Chrys, Storm Dragon, and contributers.

import hashlib
import difflib
import textwrap
from subprocess import Popen, PIPE

import utils.debug
import speech.es as es
import speech.sd as sd

runtime = {
'running':True,
'columns': 0,
'lines': 0,
'screenDriver': '/dev/vcsa',
'delta': '',
'oldCursor':{'x':0,'y':0},
'oldContentBytes': b'',
'oldContentText': '',
'oldContentAttrib': b'',
'newCursor':{'x':0,'y':0},
'newContentBytes': b'',
'newContentText': '',
'newContentAttrib': b'',
'oldTTY':'0',
'newTTY':'0',
'speechDriverString':'es',
'speechDriver': es.speech()
}

while(runtime['running']):
  # read screen
  currTTY = open('/sys/devices/virtual/tty/tty0/active','r')
  runtime['newTTY'] = currTTY.read()[3:-1]
  currTTY.close()
  p = Popen("fgconsole", stdout=PIPE, stderr=PIPE, shell=True)
  runtime['newTTY'], stderr = p.communicate()
  runtime['newTTY'] = str(int(runtime['newTTY']))
  #runtime['newTTY'] = str(currTTY)
  try:
    vcsa = open(runtime['screenDriver'] + runtime['newTTY'] ,'rb')
    runtime['newContentBytes'] = vcsa.read()
    vcsa.close()
  except:
    continue

  # get metadata like cursor or screensize
  runtime['lines'] = int( runtime['newContentBytes'][0])
  runtime['columns'] = int( runtime['newContentBytes'][1])
  runtime['newCursor']['x'] = int( runtime['newContentBytes'][2])
  runtime['newCursor']['y'] = int( runtime['newContentBytes'][3])

  # analyze content
  runtime['newContentText'] = str(runtime['newContentBytes'][4:][::2].decode('cp1252').encode('utf-8'))
  runtime['newContentAttrib'] = runtime['newContentBytes'][5:][::2]
  runtime['newContentText'] = '\n'.join(textwrap.wrap(runtime['newContentText'], runtime['columns']))[:-1] 
  if runtime['newTTY'] != runtime['oldTTY']:
    runtime['oldContentBytes'] = b''
    runtime['oldContentAttrib'] = b''
    runtime['oldContentText'] = ''
    runtime['oldCursor']['x'] = 0
    runtime['oldCursor']['y'] = 0

  # changes on the screen
  if runtime['oldContentBytes'] != runtime['newContentBytes']:
    if len(runtime['delta']) < 3:
      runtime['speechDriver'].cancel()
    diff = difflib.ndiff(runtime['oldContentText'], runtime['newContentText'])
    runtime['delta'] = ''.join(x[2:] for x in diff if x.startswith('+ '))
    runtime['speechDriver'].speak(runtime['delta'])

    # set new "old" values
    runtime['oldContentBytes'] = runtime['newContentBytes']
    runtime['oldContentText'] = runtime['newContentText']
    runtime['oldContentTextAttrib'] = runtime['newContentAttrib']
    runtime['oldCursor']['x'] = runtime['newCursor']['x']
    runtime['oldCursor']['y'] = runtime['newCursor']['y']
    runtime['oldTTY'] = runtime['newTTY']