#!/usr/bin/env python3
  

  import sys
  import argparse

  import datetime

  import urllib.request

  from icalendar import Calendar

  from html.parser import HTMLParser

  from icalendar import vDatetime, Calendar, Event as CalEvent

  # Parse command line arguments

  parser = argparse.ArgumentParser(description='Convertit l\'emploi du temps IMA en ICS')
  parser.add_argument('annee', metavar='ANNEE', type=int, help='année (3 ou 4)')

  parser.add_argument('edt', metavar='EDT', type=str, help='la page pointant vers l\'emploi du temps concerné')
  parser.add_argument('-o', '--output', dest='file', type=str, default='-', help='fichier de sortie, - pour stdout')
  args = parser.parse_args()
  

  if args.annee == 3:
      url = 'http://dptima3.polytech-lille.net/' + args.edt + '.html'
      SLOTS = [(( 8,  0), (10,  0)),
               ((10, 20), (12, 20)),
               ((13, 50), (15, 50)),
               ((16, 10), (18, 10))]
      DATE_FORMAT = '%d/%m/%Y'
  elif args.annee == 4:
      url = 'http://www.lifl.fr/~forget/EDT/' + args.edt + '.html'
      SLOTS = [(( 8,  0), ( 9,  0)),
               (( 9, 10), (10, 10)),
               ((10, 20), (11, 20)),
               ((11, 30), (12, 30)),
               ((13, 50), (14, 50)),
               ((15, 00), (16, 00)),
               ((16, 10), (17, 10)),
               ((17, 20), (18, 20))]
      DATE_FORMAT = '%d/%m/%y'
  else:
      raise ValueError('Année inconnue : ' + annee)
  
  DAYS_PER_WEEK = 6
  
  TABLE_1_DATE_X = 1
  TABLE_1_FIRST_SLOT_X = 2
  
  TABLE_2_DATE_X = 0
  TABLE_2_FIRST_SLOT_X = 1
  
  class TableHTMLParser(HTMLParser):
      tables = [] # Tables
      table = False # Current table content
      line = False # Current line content
      cell = False # Current cell content
      cellx = 1
      celly = 1
  
      # Logic
      def iscell(self):
          """
          Return if we are currently in a cell
          """
          return isinstance(self.cell, str)
  
      def isline(self):
          """
          Return if we are currently in a line
          """
          return isinstance(self.line, list)
  
      def istable(self):
          """
          Return if we are currently in a table
          """
          return isinstance(self.table, list)
  
      # Actions
      def endcell(self):
          if self.iscell():
              self.line.append((self.cell.strip(), self.cellx, self.celly))
              self.cell = False
  
      def endline(self):
          self.endcell()
          if self.isline():
              self.table.append(self.line.copy())
              self.line = False
  
      def endtable(self):
          self.endline()
          if self.istable():
              self.tables.append(self.table.copy())
              self.table = False
  
      # Inheritance
      def handle_starttag(self, tag, attrs):

          if tag == 'table':
              self.table = []
          elif tag == 'tr':
              self.endline()
              self.line = []
          elif tag == 'td':
              self.endcell()
              self.cell = ''
              self.cellx = 1
              self.celly = 1
              for attr in attrs:
                  if attr[0] == 'colspan':
                      self.cellx = int(attr[1])
                  elif attr[0] == 'rowspan':
                      self.celly = int(attr[1])
  
      def handle_endtag(self, tag):

          if tag == 'table':
              self.endtable()
          elif tag == 'tr':
              self.endline()
          elif tag == 'td':
              self.endcell()
  
      def handle_data(self, data):

          if self.iscell():
              self.cell += data
  

  # TODO Use HTTP header date
  UPDATE_TIME = datetime.datetime.now()
  

  # TODO Do something that really is OOP or do not...
  
  class Event:
      # Mined data
      shortText = ''
      longText = ''
      date = False

      begSlot = 0
      endSlot = 0

  
      # Generated data
      shortName = ''
      longName = ''
      location = ''
      startTime = False
      endTime = False
      active = False
  
      def feedShortText(self, shortText):
          self.shortText = shortText
  
      def feedLongText(self, longText):
          self.longText = longText
  

      def feedBegSlot(self, slot):
          self.begSlot = slot
  
      def feedEndSlot(self, slot):
          self.endSlot = slot

  
      def feedDate(self, date):
          self.date = date
  
      def endFeed(self):
          self.shortName = self.shortText
          self.longName = self.longText
  
          if self.longName:
              self.active = True
  

          if self.date and isinstance(self.begSlot, int) and isinstance(self.endSlot, int):
              h, m = SLOTS[self.begSlot][0]

              self.startTime = self.date + datetime.timedelta(hours=h, minutes=m)

              h, m = SLOTS[self.endSlot][1]

              self.endTime = self.date + datetime.timedelta(hours=h, minutes=m)
  
          if self.longName:
              e = self.longName.split('(')
              if len(e) >= 2:
                  f = e[1].split(')')
                  self.longName = e[0].strip()
                  self.location = f[0].strip()
  
  
      def __str__(self):
          if self.active:

              return self.shortName + ' [' + self.longName + '] ' + (str(self.startTime) + ' - ' + (str(self.endTime) + ' ') if self.startTime else '') + (('@ ' + self.location) if self.location else '')

          else:
              return 'Inactive event'
  
      def getEvent(self):
          e = CalEvent()

          e.add('uid', '-'.join([
              'polytech',
              'ima' + str(args.annee),
              args.edt,
              vDatetime(self.startTime).to_ical().decode(),
              vDatetime(self.endTime).to_ical().decode(),
              self.shortName
          ]))

          e.add('summary', self.shortName)
          e.add('description', self.longName)
          e.add('dtstart', self.startTime)
          e.add('dtend', self.endTime)
          e.add('location', self.location)

          e.add('last-modified', UPDATE_TIME)
          e.add('dtstamp', UPDATE_TIME)

          return e
  
  with urllib.request.urlopen(url) as handle:

      htmlStr = handle.read().decode('iso-8859-15')

  
  # Read HTML tables
  parser = TableHTMLParser()
  parser.feed(htmlStr)
  
  # Dupplicates cells with colspan & rowspan
  tables = []
  
  for parserTable in parser.tables:
      # Figuring out dimensions
      X, Y = 0, 0
      for cell in parserTable[0]:
          X += cell[1]
      for line in parserTable:
          Y += line[0][2]
  
      # Constructing table with reals dimensions
      table = []
      for y in range(Y):
          line = []
          for x in range(X):
              line.append(False)
          table.append(line)
  
      # Filling table with parsed table
      x, y = 0, 0
      for line in parserTable:
          for cell in line:
              # Offsetting to the right if cell is not empty
              while isinstance(table[y][x], str):
                  x += 1
  
              # Copying values
              for y2 in range(y, y + cell[2]):
                  for x2 in range(x, x + cell[1]):
                      table[y2][x2] = cell[0]
          x = 0
          y += 1
  

      tables.append(table)
  
  # Creating events
  days = dict()
  
  # Parsing table 1
  for line in tables[0]:
      try:

          day1date = datetime.datetime.strptime(line[TABLE_1_DATE_X], DATE_FORMAT)

      except (ValueError, TypeError):
          # This is not a date, no data to grab here
          continue
  

      for day in range(DAYS_PER_WEEK):
          date = day1date + datetime.timedelta(days=day)
  
          if date not in days:
              days[date] = [Event() for s in range(len(SLOTS))]
  
          for slot in range(len(SLOTS)):

              try:
                  cell = line[day * len(SLOTS) + slot + TABLE_1_FIRST_SLOT_X]
              except IndexError:
                  # Out of the table: saturday afternoon
                  break
              days[date][slot].feedShortText(cell)

              continue
  
  # Parsing table 2
  for line in tables[1]:
      try:

          date = datetime.datetime.strptime(line[TABLE_2_DATE_X], DATE_FORMAT)

      except ValueError:
          # This is not a date, no data to grab here
          continue
  
      if date not in days:
          days[date] = [Event() for s in range(len(SLOTS))]
  
      for slot in range(len(SLOTS)):
          days[date][slot].feedLongText(line[slot + TABLE_2_FIRST_SLOT_X])
  
  # Feeding back time and slot to events
  events = []
  for day in days:

      prevEvent = False

      for slot in range(len(SLOTS)):
          event = days[day][slot]

          if prevEvent:

              if prevEvent.longText == event.longText:

                  prevEvent.feedEndSlot(slot)
              else:
                  prevEvent.endFeed()
                  events.append(prevEvent)

          if not prevEvent or (prevEvent and prevEvent.longText != event.longText):

              event.feedDate(day)
              event.feedBegSlot(slot)
              event.feedEndSlot(slot)
              prevEvent = event
      prevEvent.endFeed()
      events.append(prevEvent)

  
  # Creating calendar
  cal = Calendar()

  cal.add('proid', '-//geoffrey.frogeye.fr//NONSGML Icalendar Calendar//EN')

  cal.add('version', '2.0')

  cal.add('calscale', 'GREGORIAN')
  cal.add('x-wr-calname', 'Polytech IMA ' + str(args.annee) + ' ' + args.edt)

  
  for event in events:
      if event.active:

          print(event, file=sys.stderr)

          cal.add_component(event.getEvent())
  
  # Writing calendar to file

  data = cal.to_ical()
  if args.file == '-':
      sys.stdout.write(data.decode('utf-8'))
  else:
      with open(args.file, 'wb') as f:
          f.write(data)