module PiCalc

# File lib/pi_calc.rb, line 10
def self.buffons_needle(total = 100000)
  running = 0

  total.times do
    ln = line
    running += 1 if ln[:y][0].floor != ln[:y][1].floor
  end
  2.0 * total / running
end

# File lib/pi_calc.rb, line 20
def self.buffons_needle_optimized(total = 100000)
  running = 0

  total.times do
    ln = line_only_y
    running += 1 if ln[:y][0].floor != ln[:y][1].floor
  end
  2.0 * total / running
end

# File lib/pi_calc.rb, line 6
def self.constant(total=100000)
  PI
end

# File lib/pi_calc.rb, line 30
def self.gregory_leibniz(total = 100000)
  running = 0
  (1..total).each do |n|
    x = 4.0 / ((n * 2) - 1)
    running += n%2==0 ? x*-1 : x
  end
  running
end

# File lib/pi_calc.rb, line 74
def self.line
  angle0 = rand * PI * 2
  angle1 = rand * PI * 2

  length_on_line = rand * 100

  x0 = Math.cos(angle0) * length_on_line
  x1 = Math.cos(angle1) + x0

  y0 = Math.sin(angle0) * length_on_line
  y1 = Math.cos(angle1) + y0

  {:x => [x0, x1], :y => [y0, y1], :angle => angle1}
end

# File lib/pi_calc.rb, line 89
def self.line_only_y
  angle0 = rand * PI * 2
  angle1 = rand * PI * 2

  length_on_line = rand * 100

  y0 = Math.sin(angle0) * length_on_line
  y1 = Math.cos(angle1) + y0

  {:y => [y0, y1], :angle => angle1}
end

# File lib/pi_calc.rb, line 39
def self.nilakantha(total = 100000)
  running = 3
  total.times do |n|
    z = (n * 2) + 2
    x = 4.0 / (z * (z+1) * (z+2))
    running += n%2==0 ? x : x*-1
  end
  running
end

# File lib/pi_calc.rb, line 66
def self.test(total = 100000, verbose = true)
  output = PiCalc.time([:buffons_needle, :buffons_needle_optimized, :gregory_leibniz, :nilakantha, :constant], total, verbose).inspect
  puts output if verbose
  output
end

# File lib/pi_calc.rb, line 51
def self.time(methods = [], first = 100000, verbose = true)
  times = {}
  methods.each do |n|
    sym = n.to_sym
    t = Time.now
    output = PiCalc.send(sym, first)
    time = Time.now - t
    times[n] = {'time' => time, 'output' => output}
    puts "'#{n}' took #{time} seconds\n\tIt ouputted '#{output}'\n\n\n" if verbose
  end
  times
end