├── .gitignore
├── santa_logger.rb
├── config
    ├── smtp.yml.example
    └── people.yml.example
├── letter_template.erb
├── person.rb
├── email.rb
├── emailer.rb
├── README.md
└── secret_santa.rb


/.gitignore:
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1 | config/*.yml
2 | 


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/santa_logger.rb:
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 1 | class SantaLogger
 2 |   
 3 |   attr_accessor :sending
 4 | 
 5 |   def log(message)
 6 |     puts "#{message}" unless REALLY_SENDING # Sshh! It's a secret!
 7 |   end
 8 | 
 9 | end
10 | 


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/config/smtp.yml.example:
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1 | smtp_server: smtp.gmail.com
2 | domain: gmail.com
3 | account_address: hikingfan@gmail.com
4 | account_password: sUch_a_bEeFy_paSswOrd!_iT's_niGh_ImpeNetrable_29$(@*4729!_gOod_Luck_suckErS
5 | port: 587
6 | 


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/letter_template.erb:
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 1 | GREETINGS <%= recipient_name.upcase %>,
 2 | 
 3 | [INITIALIZING CHRISTMAS MERRIMENT ROUTINES...]
 4 | 
 5 | SANTABOT 5000 HAS BEEN ACTIVATED. YOU HAVE BEEN CHOSEN AS A SECRET SANTA.
 6 | YOUR TARGET IS AS FOLLOWS:
 7 | 
 8 | <%= target_name.upcase %>
 9 | 
10 | THIS INFORMATION HAS BEEN KEPT SECRET FROM ALL HUMANS BUT YOU.
11 | 
12 | YOU KNOW WHAT TO DO.
13 | 
14 | --SANTABOT 5000
15 | 


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/person.rb:
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 1 | class Person
 2 |   attr_accessor :name, :group, :email, :santa
 3 | 
 4 |   def initialize(attrs)
 5 |     self.name  = attrs["name"]
 6 |     self.group = attrs["group"]
 7 |     self.email = attrs["email"]
 8 |   end
 9 | 
10 |   def can_be_santa_of?(other)
11 |     group != other.group
12 |   end
13 | 
14 |   def can_swap_santas_with?(other)
15 |     santa.can_be_santa_of?(other) && other.santa.can_be_santa_of?(self)
16 |   end
17 | 
18 |   def to_s
19 |     "#{name} (#{group})"
20 |   end
21 | 
22 |   def with_santa
23 |     "#{self} - santa: #{santa}"
24 |   end
25 | 
26 | end
27 | 


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/email.rb:
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 1 | require 'time'
 2 | 
 3 | class Email
 4 |   attr_accessor :from_address, :to_address, :subject, :body
 5 | 
 6 |   def initialize(to_address, subject, body)
 7 |     self.to_address   = to_address
 8 |     self.subject      = subject
 9 |     self.body         = body
10 |   end
11 | 
12 |   def headers
13 |     raise "Must set `from_address` before getting headers!" unless from_address
14 |   <<EOF
15 | From: #{from_address}
16 | To: #{to_address}
17 | Subject: #{subject}
18 | Date: #{Time.now.rfc2822}
19 | EOF
20 |   end
21 | 
22 |   def message
23 |     headers + "\n" + body
24 |   end
25 | 
26 | end
27 | 


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/config/people.yml.example:
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 1 | people:
 2 |   -
 3 |     name: Edward
 4 |     group: New York Smiths
 5 |     email: edward@example.com
 6 |   -
 7 |     name: Kara
 8 |     group: New York Smiths
 9 |     email: kara@example.com
10 |   -
11 |     name: Alberto
12 |     group: Atlanta Smiths
13 |     email: alberto@example.com
14 |   -
15 |     name: Natasha
16 |     group: Atlanta Smiths
17 |     email: jeanette@exaple.com
18 |   -
19 |     name: Tyler
20 |     group: Seattle Joneses
21 |     email: tyler@example.com
22 |   -
23 |     name: Linda
24 |     group: Seattle Joneses
25 |     email: linda@example.com
26 |   -
27 |     name: Fiona
28 |     group: Seattle Joneses
29 |     email: fiona@example.com
30 | 


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/emailer.rb:
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 1 | require 'net/smtp'
 2 | 
 3 | class Emailer
 4 | 
 5 |   attr_accessor :smtp_server, :domain, :account_address, :account_password, :port
 6 | 
 7 |   def initialize(smtp_server, domain, account_address, account_password, port = 587)
 8 |     self.smtp_server      = smtp_server
 9 |     self.domain           = domain
10 |     self.account_address  = account_address
11 |     self.account_password = account_password
12 |     self.port             = port
13 |   end
14 | 
15 |   def send(email)
16 |     email.from_address = account_address
17 | 
18 |     if REALLY_SENDING
19 |       print "Mailing #{email.to_address}..."
20 | 
21 |       smtp = Net::SMTP.new(smtp_server, port)
22 |       smtp.enable_starttls
23 |       smtp.start(domain, account_address, account_password, :login) do |smtp|
24 |         smtp.send_message(email.message, email.from_address, email.to_address)
25 |       end
26 |       
27 |       print "sent!\n"
28 |     else
29 |       puts "**Testing; not really mailing anything**\nEmail would be as follows:\n\n"
30 |       puts email.message
31 |       puts "======"
32 |     end
33 |   end
34 | end
35 | 


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/README.md:
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 1 | # Secret Santa Script
 2 | 
 3 | This is a simple Ruby script for assigning secret Santas and emailing everyone their assignment. The basic rule is that nobody can be assigned to give a gift to someone in their own group (including, of course, themselves). In my family, group == household, but it could mean anything you like.
 4 | 
 5 | The script uses Dennis Ranke's solution from [The Ruby Quiz #2](http://www.rubyquiz.com/quiz2.html), which gives everyone a correct assignment in just a few passes through the list. Nice! :) The only tweaks I made were practical ones, like using config files, and a tiny bit of refactoring, logging, etc, to make it more apparent what's happening.
 6 | 
 7 | ## Usage
 8 | 
 9 | - Clone the repo
10 | - Copy each of the `.yml.example` files in `config/` to a corresponding `.yml` and customize.
11 |   - Security note: this script uses TLS to connect to your email account. If you're sending via a Gmail account, you can create a temporary password for this script at [https://security.google.com/settings/security/apppasswords](https://security.google.com/settings/security/apppasswords) and revoke it when you're done.
12 | - Run `ruby secret_santa.rb` and examine the output
13 | - Modify `letter_template.erb`, if you like, and repeat.
14 | - When you're satisfied, run `REALLY_SENDING=true ruby secret_santa.rb`
15 | 
16 | ## Dependencies
17 | 
18 | None, other than Ruby (I've used it with 1.9 and 2.2.3) and the standard library.
19 | 
20 | ## Thanks
21 | 
22 | Thanks to Dennis Ranke for a nice solution, and to James Edward Gray II for running The Ruby Quiz.
23 | 


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/secret_santa.rb:
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 1 | #!/usr/bin/env ruby
 2 | 
 3 | $LOAD_PATH << '.'
 4 | require 'erb'
 5 | require 'yaml'
 6 | require 'person'
 7 | require 'emailer'
 8 | require 'email'
 9 | require 'santa_logger'
10 | 
11 | # Do some testing, then set this to true when ready to send
12 | # Will cause logging output to be shushed and mails to be sent
13 | REALLY_SENDING = ENV.fetch("REALLY_SENDING", false)
14 | 
15 | Logger = SantaLogger.new
16 | 
17 | people_config = YAML.load_file('config/people.yml')
18 | 
19 | people = people_config['people'].map do |attrs|
20 |   Person.new(attrs)
21 | end
22 | 
23 | santas = people.dup
24 | people.each do |person|
25 |   person.santa = santas.delete_at(rand(santas.size))
26 | end
27 | 
28 | Logger.log "Initial Santa assignments:"
29 | people.each do |person|
30 |   Logger.log person.with_santa
31 | end
32 | 
33 | # This is the nice part of Dennis's solution: if there are any invalid
34 | # assignments, they are corrected in as few passes as possible. (I
35 | # originally said "a single pass", but that's not true because the
36 | # `select` that looks for someone to swap santas with is just a
37 | # way of saying "loop through the list of people looking for a match.")
38 | # This works because corrections are made in a way that ensures no new 
39 | # invalid assignments are created.
40 | Logger.log "Checking assignments for validity"
41 | people.each do |person|
42 |    unless person.santa.can_be_santa_of?(person)
43 |      Logger.log "\n#{person} can't get a gift from #{person.santa}! Let's try to fix that..."
44 |      swap_candidates = people.select {|p| person.can_swap_santas_with?(p) }
45 |      raise "Failure! No one can swap santas with #{person}" if swap_candidates.empty?
46 |      Logger.log "Any of these can swap santas with #{person}: #{swap_candidates.map(&:to_s)}"
47 |      swapper = swap_candidates.sample
48 |      Logger.log "Chose #{swapper} to swap santas with #{person}"
49 |      misplaced_santa = person.santa
50 |      person.santa    = swapper.santa
51 |      swapper.santa   = misplaced_santa
52 |    end
53 | end
54 | 
55 | Logger.log "\n\nFinal Santa assignments:"
56 | people.each do |person|
57 |   Logger.log person.with_santa
58 | end
59 | 
60 | smtp_config = YAML.load_file('config/smtp.yml')
61 | emailer     = Emailer.new(
62 |   smtp_config['smtp_server'], 
63 |   smtp_config['domain'], 
64 |   smtp_config['account_address'], 
65 |   smtp_config['account_password']
66 | )
67 | 
68 | template = File.read("letter_template.erb")
69 | people.each do |person|
70 |   recipient_name = person.santa.name
71 |   target_name    = person.name
72 |   message        = ERB.new(template).result(binding)
73 |   email = Email.new(
74 |     person.santa.email, "SANTABOT 5000: #{Time.now.year} TARGETS", message
75 |   )
76 |   emailer.send(email)
77 | end
78 | 


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