#!/usr/bin/env ruby

HORIZONTAL_ACCURACY = 32.0
VERTICAL_ACCURACY = 32.0

# board spec from WDF rules
WIRE_WIDTH = 1.56
INNER_DIAMETER_BULL = 12.7
INNER_DIAMETER_25 = 31.8
DOUBLE_OUTER_EDGE = 170.0
TREBLE_OUTER_EDGE = 107.4
DOUBLE_INSIDE_WIDTH = 8.0
TREBLE_INSIDE_WIDTH = 8.0
SECTORS = %w[20 1 18 4 13 6 10 15 2 17 3 19 7 16 8 11 14 9 12 5].map(&:to_i)

SECTOR_ANGLES = SECTORS.each_with_index.inject({}) do |m, (v, i)|
  m[v] = (90 - (i * 360 / SECTORS.length)) % 360
  m
end

# distance from centre to apex of outer wire
# must be ordered outwards from centre
OUTER_DISTS = {
  bull: INNER_DIAMETER_BULL/2 + WIRE_WIDTH/2,
  '25': INNER_DIAMETER_25/2 + WIRE_WIDTH/2,
  small: TREBLE_OUTER_EDGE - WIRE_WIDTH - TREBLE_INSIDE_WIDTH - WIRE_WIDTH/2,
  treble: TREBLE_OUTER_EDGE - WIRE_WIDTH/2,
  big: DOUBLE_OUTER_EDGE - WIRE_WIDTH - DOUBLE_INSIDE_WIDTH - WIRE_WIDTH/2,
  double: DOUBLE_OUTER_EDGE - WIRE_WIDTH/2
}

CENTRE_DISTS = OUTER_DISTS.inject([{}, nil]) { |(h, prev), (k, v)|
  h[k] = prev ? (v - ((v - prev) / 2)) : 0.0
  [h, v]
}[0]

def get_coordinates(angle, radius)
  t = angle * Math::PI / 180
  x = radius * Math.cos(t)
  y = radius * Math.sin(t)

  [x, y]
end

def throw_dart(angle, radius)
  x, y = get_coordinates(angle, radius)
  x += rand(-HORIZONTAL_ACCURACY..HORIZONTAL_ACCURACY)
  y += rand(-VERTICAL_ACCURACY..VERTICAL_ACCURACY)

  d_angle = Math.atan2(y, x) * 180 / Math::PI
  d_radius = Math.sqrt(x**2 + y**2)

  [d_angle, d_radius]
end

def get_sector(angle)
  sector = SECTOR_ANGLES.detect do |v, c|
    dist = (c - angle).abs % 360
    dist = 360 - dist if dist > 180
    dist < 360 / SECTORS.length / 2 #TODO hit wire
  end

  sector && sector.first
end

def get_ring(radius)
  ring = OUTER_DISTS.detect do |sym, dist|
    radius**2 < dist**2
  end

  ring ? ring[0] : :out
end

def get_segment(angle, radius)
  sec = get_sector(angle)
  ring = get_ring(radius)

  case ring
  when :bull
    'BULL'
  when :'25'
    '25'
  when :small, :big
    "#{sec}"
  when :double
    "D#{sec}"
  when :treble
    "T#{sec}"
  when :out
    'OUT'
  end
end

def get_points(segment)
  case segment
  when 'BULL'
    50
  when /^T(\d+)$/
    3 * $1.to_i
  when /^D(\d+)$/
    2 * $1.to_i
  when /^(\d+)$/
    $1.to_i
  else
    0
  end
end

def get_segment_coordinates(segment)
  sector, ring =
    case segment
    when 'BULL'
      [20, :bull]
    when '25'
      [20, :'25']
    when /^T(\d+)$/
      [$1.to_i, :treble]
    when /^D(\d+)$/
      [$1.to_i, :double]
    when /^(\d+)$/
      [$1.to_i, :big]
    end

  [SECTOR_ANGLES[sector], CENTRE_DISTS[ring]]
end

def next_dart(rem)
  segment =
    if rem > 40
      'T20'
    elsif rem % 2 == 1
      '1'
    else
      "D#{rem/2}"
    end

  get_segment_coordinates(segment)
end

def play_visit(rem)
  v_rem = rem

  darts = []
  bust = false

  3.times do
    t_angle, t_radius = next_dart(v_rem)
    d_angle, d_radius = throw_dart(t_angle, t_radius)

    segment = get_segment(d_angle, d_radius)
    darts << segment
    d_points = get_points(segment)
    v_rem -= d_points

    if v_rem < 0 || v_rem == 1 || (v_rem == 0 && segment !~ /^D/)
      v_rem = rem
      bust = true
      break
    end

    break if v_rem.zero?
  end

  [v_rem, rem - v_rem, darts, bust]
end

def colour_score(score)
  scor = "%3s" % score

  if score == 180
    "\e[1;38;5;82m#{scor}\e[0m"
  elsif score > 139
    "\e[38;5;82m#{scor}\e[0m"
  elsif score > 99
    "\e[38;5;154m#{scor}\e[0m"
  elsif score > 59
    "\e[38;5;226m#{scor}\e[0m"
  elsif score > 39
    "\e[38;5;214m#{scor}\e[0m"
  elsif score > 19
    "\e[38;5;202m#{scor}\e[0m"
  else
    "\e[38;5;196m#{scor}\e[0m"
  end
end

def visit_darts(darts)
  str = darts.map { |x| '%3s' % x }.join(' ')
  str += '    ' * (3 - darts.length)
  str
end

def output_visit(n, rem, points = nil, darts = nil, bust = false)
  str = '(%2s)  %3s' % [n, rem]
  str << '  %s' % colour_score(points) if points
  str << "    \e[38;5;235m%s\e[0m" % visit_darts(darts) if darts
  str << " \e[38;5;88mBUST\e[0m" if bust
  str << " \e[38;5;76mWIN\e[0m" if rem.zero?

  puts str
end

def play_match(start_points = 501, output = true)
  rem = start_points
  m_darts = []

  output_visit(m_darts.length, rem) if output

  while rem != 0
    rem, score, darts, bust = play_visit(rem)
    m_darts << darts

    output_visit(m_darts.length, rem, score, darts, bust) if output

    if rem.zero? && output
      puts
      req = (((m_darts.length - 1) * 3) + m_darts[-1].length)
      puts "darts: %s" % req
      puts "average: %.2f" % (start_points.to_f / req * 3)
    end
  end

  m_darts
end

def test_average
  averages = (0..10000).map do |x|
    m_darts = play_match(501, false)
    req = (((m_darts.length - 1) * 3) + m_darts[-1].length)
    (501.to_f / req * 3)
  end

  puts
  puts averages.inject { |sum, x| sum += x } / averages.length
end

play_match
#test_average