from http import HTTP
import time
import os
import subprocess
import shutil

SIGN = '--'
CRLR = '\r\n'

MAX_CHUNK = 1024 * 512
progress = 0.0
PATH = '/mnt/data/fw'
TARGET = 'rootfs.ubi'

def skipHeader(inp, size):
  while True:
    line = inp.readline()
    size -= len(line)
    if line == CRLR:
      break
  return size


def readFile(inp, out, size, separator):
  global progress
  datasize = size - len(separator)
  toread = datasize
  progress = 0.0
  while toread > 0:
    time.sleep(0.3)
    if toread >= MAX_CHUNK:
      bytes = inp.read(MAX_CHUNK)
      toread -= MAX_CHUNK
    else:
      bytes = inp.read(toread)
      toread = 0

    out.write(bytes)
    progress = float(datasize - toread) / datasize
  progress = 1.0
  out.flush()
  return len(separator)

def suckAll(inp):
  try:
    while True:
      inp.read(MAX_CHUNK)
  except:
    pass

def process(request, environ):
  global progress

  # progress request
  if environ['REQUEST_URI'].startswith('/BS350/default/upload/upload/progress'):
    raise HTTP(202, str(progress))

  # prepare path
  if not os.access(PATH, os.F_OK):
    try:
      os.mkdir(PATH)
    except:
      progress = 0.0
      environ['wsgi.input'].read(int(environ['CONTENT_LENGTH']))
      raise HTTP(202, '{"success":false, "msg":"Firmware update error: error creating path"}')

  if not os.access(PATH, os.W_OK):
    suckAll(environ['wsgi.input'])
    raise HTTP(202, '{"success":false, "msg":"Firmware update error: cannot write to target path"}')
 
  try:
    socket = environ['wsgi.input']
    size = int(environ['CONTENT_LENGTH'])
    ct = environ['HTTP_CONTENT_TYPE']
    boundary = ct[ct.index('boundary=') + 9:]
    separator = CRLR + SIGN + boundary + SIGN + CRLR

    size = skipHeader(socket, size)

    with open(os.path.join(PATH, TARGET), 'wb') as out:
      size = readFile(socket, out, size, separator)
    socket.read(size)

  except Exception as e:
    suckAll(environ['wsgi.input'])
    errStr = "Firmware update error: %s " % str(e)
    shutil.rmtree(PATH)
    raise HTTP(202, '{"success":false, "msg":"%s"}' % errStr)
  progress = 0.0
  raise HTTP(202, '{"success":true, "msg":"File uploaded"}')