#!/usr/bin/ruby

#First introduce the idea of the game
puts "It's time to play pick a number!"
puts "First pick a number in your head, don't tell me that number!"
puts "Now pick a number HIGHER than that number, we will use it as an upper bound."
puts "So what was the number?"
upper_bound = gets.to_i

#This equation is the maxiumum number of turns it will take to guess the users number.
turns = (Math.log10(upper_bound) / Math.log10(2)).to_i + 1
puts "Now I will guess your number in #{turns} (lg upper bound) turns!"
high = upper_bound
low = 1

#Always guess an average of the bounds for maximum efficiency.
number = (high + low) / 2
guesses = 0
#Initially, the number is not found.
found = false

#While the number hasn't been found and the NumberPicker hasnt been given
#more than 7 guesses keep trying to guess the number.
while(!found and guesses <= 7)
    guesses = guesses + 1
    puts "#{guesses}: Is #{number} too high (1), too low (2), or correct (0)?"
    response = gets.to_i
    if response == 1
        #When the number is too high, the bounds are the low bound and the number.
        high = number
        number = (low + number) / 2
    elsif response == 2
       #When the number is too low, the bounds are the high bound and the number.
        low = number
        number = (high + number) / 2
    else
        found = true
    end      
end

#At this point the game is over, output the number of guesses needed.
#The else statement will only execute when the user gives the computer
#false feedback as to whether the number was too high or low.
if found
    puts "Looks like I was correct within #{guesses} guesses!"
else 
    puts "Oh My!  I've failed!  Or is it that you've cheated?"
end

#So the console screen doesnt automatically exit.
puts "Press ENTER to exit"
gets