Todo 1.0

todo1.rb

class Todo
  def initialize(file_name)
    @file_name = file_name
    @tasks = []
    load_file
  end

  def load_file
    @task_file = File.read(@file_name)
    @task_file.each_line { |line| @tasks << $1.strip if line =~ /^\d+. (.*)/ }
  end

  def write_to_file
    File.write(@file_name, self)
  end

  def to_s
    string = "MY TODOS\n----------\n"
    @tasks.each_with_index { |task, number| string += "#{number + 1}:  #{task}\n" }
    string
  end

  def add(task)
    @tasks << task
    write_to_file
  end

  def prepend(task)
    @tasks.unshift(task)
    write_to_file
  end

  def delete_task(task_number)
    @tasks.delete_at(task_number.to_i - 1)
    write_to_file
  end

  def complete_task(task_number)
    @tasks[task_number.to_i - 1].insert(-1, " - Completed")
    write_to_file
  end
end

todo = Todo.new('list.txt')

case ARGV[0]
when 'list'     then puts todo
when 'add'      then todo.add(ARGV[1..-1].join(' '))
when 'prepend'  then todo.prepend(ARGV[1..-1].join(' '))
when 'delete'   then todo.delete_task(ARGV[1])
when 'complete' then todo.complete_task(ARGV[1])
else                 puts 'Please enter valid command'
end