#!/bin/python

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

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

import utils.debug
import core.environment as environment
import speech.espeak as es
import speech.speechd as sd

runtime = environment.runtime
runtime['screenDriver'] = '/dev/vcsa'
runtime['speechDriverString'] = 'speechd'
runtime['speechDriver'] = sd.speech()

while(runtime['running']):
  # read screen
  currTTY = open('/sys/devices/virtual/tty/tty0/active','r')
  runtime['newTTY'] = currTTY.read()[3:-1]
  currTTY.close() 

  try:
    vcsa = open(runtime['screenDriver'] + runtime['newTTY'] ,'rb',0)
    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'))[2:-1]
  runtime['newContentAttrib'] = runtime['newContentBytes'][5:][::2]
  runtime['newContentText'] = '\n'.join(textwrap.wrap(runtime['newContentText'], runtime['columns']))[:-1]
  print("|"+runtime['newContentText'] +"|")
  print(runtime['newTTY'])
  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) or runtime['oldTTY'] != runtime['newTTY']):
      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']