TaskModel.py

import datetime
import operator
import csv

class TaskHandler(object):
  def __init__( self, *tasks ):
    self.tasks = list(tasks)
    
  def __repr__(self):
    return "\n".join(map(str, (self.sorted())))
  
  # Returns an array of tasks sorted by due date, then priority, then title
  def sorted(self):
    return sorted(self.tasks, key=operator.attrgetter('priority', 'due', 'title'))
    
  # Does pretty much the same thing as __repr__ except it numbers each of the 
  # items (for use in menus and whatnot)
  def numbered(self):
    output = []
    for i, task in enumerate(self.sorted()):
      output.append("%2i. %s\n" % (i, task))
    return "".join(output)
  
  def extend(self, *tasks):
    self.tasks.extend(tasks)
  
  def saveToCSV(self):
    writer = csv.writer(open('tasks.csv', 'wb'))
    for task in self.tasks:
      writer.writerow([task.title, task.description, task.date, task.due, task.priority])
  
  def loadFromCSV(self):
    self.tasks = []
    reader = csv.reader(open('tasks.csv', 'r'))
    for row in reader:
      task              = Task(row[0])
      task.description  = row[1]
      task.date         = datetime.datetime.strptime(row[2], "%Y-%m-%d")
      task.due          = datetime.datetime.strptime(row[3], "%Y-%m-%d")
      task.priority     = -int(row[4])
      self.extend(task)
    
  
# This class provides the basic scaffolding for every task in the program
class Task:
  # This provides a simple method of expressing priorites as a string
  # We use negative values for priorites for sorting reasons
  priorities = { 0 : 'undefined', -1 : 'low', -2 : 'medium', -3 : 'high' }
  
  # After much internal debate, I decided to keep initialisation simple, hence
  # it only requiring one parameter. This goes along with the ideal of minimum
  # time wastage.
  def __init__( self, title ):
    self.title        = title
    self.description  = ''
    self.date         = datetime.date.today()
    self.due          = datetime.date.today()
    self.priority     = 0
  
  # This controls what the class returns to a print statement
  def __repr__( self ):
    return "%s - Due %s, %s priority" % ( self.title, self.due.strftime( "%A, %B %d %Y" ), 
                                            self.priorities[self.priority].capitalize() )
  
tasks = TaskHandler(Task("Error, unable to load tasks"))
tasks.loadFromCSV()
print tasks.numbered()

tasks.csv