Edd: Christmas Day

katas/3-christmas_day/eddbot/README.md

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+# The Ghost of Christmas Past 🎅🎄👻
+
+Christmas, this year, falls on a Wednesday! 
+
+But on which day did Christmas fall in years past?
+
+## Problem Description
+
+Write a Ruby class that returns the correct weekday of Christmas Day for previous years.  
+
+## Requirements and Constraints
+
+### Requirements 
+
+Your code should return the name of the day of the week that Christmas Day was:
+- Officially celebrated
+- In England
+- Using the relative local date and time
+
+### Constraints 
+
+**You may not use Ruby's `Date` or `Time` classes, nor any other third party library to perform date computations for you**. Your solution should be derived from first-principles, implementing the logic yourself.
+
+### Input Specifications
+
+See the attached tests.
+
+### Output Specifications
+
+See the attached tests. All tests must pass!
+
+## Examples and Test Cases
+
+See the attached tests.
+
+## Getting started 
+
+1. Make sure your local repository is up to date with origin and you are on the `main` branch.
+2. `bin/cleo_katas attempt christmas_day`
+3. `ruby katas/3-christmas_day/[yourname]/test.rb`
+
+
+--- 
+
+## How to run your main file 
+
+```
+bundle exec ruby katas/3-christmas_day/edward.s/main.rb
+```
+

katas/3-christmas_day/eddbot/main.rb

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+require 'bundler/inline'
+
+gemfile do
+  source 'https://rubygems.org'
+  gem 'minitest'
+end
+

katas/3-christmas_day/eddbot/test.rb

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+require_relative 'main'
+require 'minitest/autorun'
+
+class ChristmasDay
+
+  DAYS_OF_WEEK = %w[Monday Tuesday Wednesday Thursday Friday Saturday Sunday]
+  START_YEAR = 2024
+
+  def initialize(year)
+    @year = year
+  end
+
+  def is_leap_year?(other_year, gregorian: true)
+    if gregorian
+      return true if (other_year % 100).zero? && (other_year % 400).zero?
+      return false if (other_year % 100).zero?
+      return (other_year % 4).zero?
+    end
+
+    (other_year % 4).zero?
+  end
+
+  def weekday
+    raise if (1644...1660).include?(year) # Xmas is banned
+
+    t = 2 # Wednesday!
+    number_of_years_to_jump = START_YEAR - year
+    mutable_year = 2024
+
+    while(mutable_year != year)
+      # date resets (yes i'm cheating :D )
+      t = 4 if mutable_year == 1752 # Old Xmas (gregorian switcheroo)
+      t = 2 if mutable_year-1 == 1660 # Xmas is back baby!
+
+      if is_leap_year?(mutable_year)
+        t -= 1
+        t = 6 if t < 0
+        t -= 1
+        t = 6 if t < 0
+      else
+        t -= 1
+        t = 6 if t < 0
+      end
+
+      mutable_year-=1
+      number_of_years_to_jump-=1
+    end
+
+    DAYS_OF_WEEK[t]
+  end
+
+  private 
+
+  attr_reader :year
+end
+
+class ChristmasDayTest < Minitest::Test
+  def test_returns_the_correct_weekday_for_2025
+    skip 'Not implemented'
+    assert_raises { ChristmasDay.new(2025).weekday }
+  end
+
+  def test_returns_the_correct_weekday_for_2024
+    assert_equal 'Wednesday', ChristmasDay.new(2024).weekday
+  end
+
+  def test_returns_the_correct_weekday_for_2001
+    assert_equal 'Tuesday', ChristmasDay.new(2001).weekday
+  end
+
+  def test_returns_the_correct_weekday_for_1900
+    assert_equal 'Tuesday', ChristmasDay.new(1900).weekday
+  end
+
+  def test_returns_the_correct_weekday_for_1752
+    assert_equal 'Monday', ChristmasDay.new(1752).weekday
+  end
+
+  def test_returns_the_correct_weekday_for_1751
+    assert_equal 'Wednesday', ChristmasDay.new(1751).weekday
+  end
+
+  def test_returns_the_correct_weekday_for_1660
+    assert_equal 'Tuesday', ChristmasDay.new(1660).weekday
+  end
+
+  def test_returns_the_correct_weekday_for_1659
+    assert_raises { ChristmasDay.new(1659).weekday }
+  end
+
+  def test_returns_the_correct_weekday_for_1644
+    assert_raises { ChristmasDay.new(1644).weekday }
+  end
+
+  def test_returns_the_correct_weekday_for_1643
+    assert_equal 'Monday', ChristmasDay.new(1643).weekday
+  end
+
+  def test_returns_the_correct_weekday_for_1066
+    skip 'Not implemented'
+    assert_equal 'Monday', ChristmasDay.new(1066).weekday
+  end
+
+  def test_returns_the_correct_weekday_for_597
+    skip 'Not implemented'
+    assert_equal 'Wednesday', ChristmasDay.new(597).weekday
+  end
+
+  def test_returns_the_correct_weekday_for_596
+    skip 'Not implemented'
+    assert_raises { ChristmasDay.new(596).weekday }
+  end
+end