require 'pp'
require 'minitest/autorun'

F=
# 198
->g,w,h{m=->y,x,d,v=[]{q=y,x
r=->s{([""]*h+g)[y+h,h].map{|l|(?x*w+l)[x+w,w]}.join.count s}
z=k=r[?v]-r[?^],j=r[?>]-r[?<]
q[d=[d,1,0][j*j<=>k*k]]+=z[d]<=>0
v&[q<<d]!=[]?q!=v[-1]:m[*q,v<<q]}
m[0,0,1]}

# Debug version
# ->g,w,h{m=->y,x,d,v=[]{r=->s{g[[0,y].max...y+h].map{|l|l[[0,x].max...x+w]}.join.count s}
# j=r[?>]-r[?<]
# k=r[?v]-r[?^]
# q=y,x
#   z=g.map{|l|l.dup}
#   z[[0,y].max...y+h].map!{|l|
#     r=[0,x].max...x+w
#     n = l
#     n[r]=?#*r.size
#     n
#   }
#   puts z
#   p [*q,d]
# q[d=[d,1,0][j*j<=>k*k]]+=[k,j][d]<=>0
# q<<d
#   p q
# puts
# v&[q]!=[]?q!=v[-1]:m[q[0],q[1],d,v<<q]}
# m[0,0,1]}

describe :X do
  describe 'Grid 1 (2x2)' do
    before do
      @g = [
        '>v',
        '^<' ]
    end

    it 'detects loop for 1x1' do assert F[@g, 1, 1] end
    it 'detects loop for 1x2' do assert F[@g, 1, 2] end
    it 'detects loop for 2x1' do assert F[@g, 2, 1] end
    it 'detects rest for 2x2' do refute F[@g, 2, 2] end
  end

  describe 'Grid 2 (3x3)' do
    before do
      @g = [
        '> v',
        '   ',
        '^ <' ]
    end

    it 'detects rest for 1x1' do refute F[@g, 1, 1] end
    it 'detects rest for 1x2' do refute F[@g, 1, 2] end
    it 'detects rest for 1x3' do refute F[@g, 1, 3] end
    it 'detects rest for 2x1' do refute F[@g, 2, 1] end
    it 'detects loop for 2x2' do assert F[@g, 2, 2] end
    it 'detects loop for 2x3' do assert F[@g, 2, 3] end
    it 'detects rest for 3x1' do refute F[@g, 3, 1] end
    it 'detects loop for 3x2' do assert F[@g, 3, 2] end
    it 'detects rest for 3x3' do refute F[@g, 3, 3] end
  end

  describe 'Grid 3 (4x3)' do
    before do
      @g = [
        '>^>v',
        'v^v ',
        '^ <<',
      ]
    end

    it 'detects rest for 2x2' do refute F[@g, 2, 2] end
  end

  describe 'Grid 4 (6x5)' do
    before do
      @g = [
        '>v>v>v',
        '^v^v^v',
        '^v^v^v',
        '^>^>^v',
        '^<<<<<']
    end

    it 'detects loop for 1x1' do assert F[@g, 1, 1] end
    it 'detects rest for 1x2' do refute F[@g, 1, 2] end
    it 'detects loop for 2x1' do assert F[@g, 2, 1] end
    it 'detects loop for 2x2' do assert F[@g, 2, 2] end
    it 'detects loop for 2x4' do assert F[@g, 2, 4] end
    it 'detects rest for 2x5' do refute F[@g, 2, 5] end
    it 'detects rest for 3x1' do refute F[@g, 3, 1] end
    it 'detects loop for 3x2' do assert F[@g, 3, 2] end
    it 'detects loop for 3x3' do assert F[@g, 3, 3] end
    it 'detects loop for 3x5' do assert F[@g, 3, 5] end
    it 'detects rest for 6x2' do refute F[@g, 6, 2] end
    it 'detects loop for 6x3' do assert F[@g, 6, 3] end
    it 'detects rest for 6x5' do refute F[@g, 6, 5] end
  end

  describe 'Grid 5 (10x6)' do
    before do
      @g = [
        '> <vv    <',
        ' v ^ >v v ',
        '  >v^^>vv^',
        '    ^>^ v ',
        '>  v<v  >>',
        '  >v v<^  ']
    end

    it 'detects rest for 1x1' do refute F[@g, 1, 1] end
    it 'detects rest for 2x3' do refute F[@g, 2, 3] end
    it 'detects rest for 2x6' do refute F[@g, 2, 6] end
    it 'detects loop for 3x2' do assert F[@g, 3, 2] end
    it 'detects rest for 5x4' do refute F[@g, 5, 4] end
    it 'detects loop for 6x1' do assert F[@g, 6, 1] end
    it 'detects rest for 10x6' do refute F[@g, 10, 6] end
  end

  describe 'Incorrect cycle detection' do
    before do
      @g = [
        '>>v ',
        ' >v ',
        '>> >',
        '^  v',
        '^ v ',
        '  <<'
      ]
    end

    it 'detects rest for 2x2' do refute F[@g, 2, 2] end
  end
end