From a3236c8a066294da39ddc812077229c0f6fb2a2e Mon Sep 17 00:00:00 2001
From: Mick Killianey <mk@cs.stanford.edu>
Date: Wed, 1 Jun 2022 16:22:14 -0700
Subject: [PATCH] Add Ruby port of 08_Batnum

---
 08_Batnum/ruby/batnum.rb | 130 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 130 insertions(+)
 create mode 100755 08_Batnum/ruby/batnum.rb

diff --git a/08_Batnum/ruby/batnum.rb b/08_Batnum/ruby/batnum.rb
new file mode 100755
index 00000000..a390e339
--- /dev/null
+++ b/08_Batnum/ruby/batnum.rb
@@ -0,0 +1,130 @@
+#!/usr/bin/env ruby
+
+def instructions
+    puts <<~EOF
+    THIS PROGRAM IS A 'BATTLE OF NUMBERS' GAME, WHERE THE
+    COMPUTER IS YOUR OPPONENT.
+
+    THE GAME STARTS WITH AN ASSUMED PILE OF OBJECTS. YOU
+    AND YOUR OPPONENT ALTERNATELY REMOVE OBJECTS FROM THE PILE.
+    WINNING IS DEFINED IN ADVANCE AS TAKING THE LAST OBJECT OR
+    NOT. YOU CAN ALSO SPECIFY SOME OTHER BEGINNING CONDITIONS.
+    DON'T USE ZERO, HOWEVER, IN PLAYING THE GAME.
+    ENTER A NEGATIVE NUMBER FOR NEW PILE SIZE TO STOP PLAYING.
+    EOF
+end
+
+def ask_for_pile_size
+    loop do
+        puts "ENTER PILE SIZE:"
+        pile_size = gets.to_i
+        break pile_size if pile_size != 0
+    end
+end
+
+GOAL_TAKE_LAST = 1
+GOAL_AVOID_LAST = 2
+def ask_for_goal
+    loop do
+        puts "ENTER WIN OPTION - #{GOAL_TAKE_LAST} TO TAKE LAST, #{GOAL_AVOID_LAST} TO AVOID LAST:"
+        response = gets.to_i
+        break response if [GOAL_TAKE_LAST, GOAL_AVOID_LAST].member? response
+    end
+end
+
+def ask_for_min_max_take
+    loop do
+        puts "ENTER MIN AND MAX, SEPARATED BY A COMMA:"
+        response = gets.split(',').map {|piece| piece.to_i}
+        next if response.length != 2
+        min_take, max_take = response
+        break min_take, max_take if 0 < min_take && min_take <= max_take
+    end
+end
+
+COMPUTER_MOVE = 1
+PLAYER_MOVE = 2
+def ask_who_makes_first_move
+    loop do
+        puts "ENTER START OPTION - #{COMPUTER_MOVE} COMPUTER FIRST, #{PLAYER_MOVE} YOU FIRST:"
+        response = gets.to_i
+        break response if [COMPUTER_MOVE, PLAYER_MOVE].member? response
+    end
+end
+
+def ask_for_player_take(min_take:, max_take:)
+    loop do
+        puts "YOUR MOVE:"
+        response = gets.to_i
+        break response if response == 0 || response == response.clamp(min_take, max_take)
+        puts "ILLEGAL MOVE, REENTER IT."
+    end
+end
+
+def battle(pile:, goal:, min_take:, max_take:, first_move:)
+    next_move = first_move
+    loop do
+        if next_move == COMPUTER_MOVE
+            next_move = PLAYER_MOVE
+            take = (
+                if goal == GOAL_TAKE_LAST
+                    pile % (min_take + max_take)
+                else
+                    (pile - 1) % (min_take + max_take)
+                end
+            ).clamp(min_take, max_take)
+            pile = pile - take
+            if pile > 0
+                puts "COMPUTER TAKES #{take} AND LEAVES #{pile}"
+            else
+                if goal == GOAL_TAKE_LAST
+                    puts "COMPUTER TAKES #{take} AND WINS."
+                    break
+                else
+                    puts "COMPUTER TAKES #{take} AND LOSES."
+                    break
+                end
+            end
+        else
+            next_move = COMPUTER_MOVE
+            take = ask_for_player_take(min_take: min_take, max_take: max_take)
+            if take == 0
+                puts "I TOLD YOU NOT TO USE ZERO! COMPUTER WINS BY FORFEIT."
+                break
+            end
+            pile = pile - take
+            if pile > 0
+                puts "PLAYER TAKES #{take} AND LEAVES #{pile}"
+            else
+                if goal == GOAL_TAKE_LAST
+                    puts "CONGRATULATIONS, YOU WIN."
+                    break
+                else
+                    puts "TOUGH LUCK, YOU LOSE."
+                    break
+                end
+            end
+        end
+    end
+end
+
+
+def main
+    instructions
+    loop do
+        pile = ask_for_pile_size
+        break if pile < 0
+        goal = ask_for_goal
+        min_take, max_take = ask_for_min_max_take
+        first_move = ask_who_makes_first_move
+        battle(
+            pile: pile,
+            goal: goal,
+            min_take: min_take,
+            max_take: max_take,
+            first_move: first_move,
+        )
+    end
+end
+
+main