environ.lua

local environ = {}
local math = require "math"
-- States are a tuple of dealer's first card (1-10) and the player's sum
-- Set of actions

environ.A = {'no input', 'P1 A', 'P1 B', 'P1 R', 'P1 Z', 'up full', 'up half', 'up right full', 'up right half', 'right full', 'right half', 'down right full', 'down right half', 'down full', 'down half', 'down left full', 'down left half', 'left full', 'left half', 'up left full', 'up left half', 'A + up full', 'A + up half', 'A + right full', 'A + right half', 'A + down full', 'A + down half', 'A + left full', 'A + left half', 'B + up full', 'B + down full', 'Z + left full', 'Z + right full'} --rolling
-- 33 possible actions
-- State transitions are not explicitly stored

-- Draws a card (with replacement)
local drawCard = function()
  -- Draw number uniformly from 1-10
  local num = torch.random(1, 10)
  -- Draw colour red with p = 1/3 and black with p = 2/3
  if torch.uniform() <= 1/3 then
    return {num, 'red'}
  else
    return {num, 'black'}
  end
end

-- Adds a card to an existing sum
local addCard = function(sum, card)
  if card[2] == 'black' then
    return sum + card[1]
  else
    return sum - card[1]
  end
end

-- Checks if bust
local checkBust = function(sum)
  return sum > 21 or sum < 1
end

-- Perform a step in the environment
environ.step = function(s,a, newScore, oldScore)
  -- Current state

  local sPrime = {}

  -- Enemy Death * (11000) + Self Death * (-10000) + Enemy Percent * (300) + Self Percent * (-143) + Self Destruct * (-30000) + 
  local r = newScore - oldScore

  return sPrime, r
end


--[[
-- Performs a step in the environment
environ.step = function(s, a)
  -- Current state
  local dealersFirstCard = s[1]
  local playersSum = s[2]
  -- Next state (initialised with deep copy of current state)
  local sPrime = {}
  sPrime[1] = dealersFirstCard
  sPrime[2] = playersSum
  -- Reward (0 by default)
  local r = 0

  -- Process actions
  if a == 'hit' then
    -- Draw and add next card
    sPrime[2] = addCard(playersSum, drawCard())

    -- Check player fail conditions
    if checkBust(sPrime[2]) then
      r = -1
    end
  elseif a == 'stick' then
    local dealersSum = dealersFirstCard

    -- Dealer sticks when on 17 or higher
    while dealersSum < 17 and dealersSum >= 1 do
      -- Draw and add next card
      dealersSum = addCard(dealersSum, drawCard())
    end

    -- Check dealer fail conditions and winning conditions otherwise (player with largest sum)
    if checkBust(dealersSum) or dealersSum < playersSum then
      r = 1
    elseif dealersSum > playersSum then
      r = -1
    end
  end

  return sPrime, r
end
]]--

-- Calculates if the current state is terminal given previous action and reward
environ.isTerminal = function(a, r)
  return a == 'stick' or r == -1
end

environ.cartesianDistanceFromEnemy = function()
    Xdiff = self_x - enemy_x
    Ydiff = self_y - enemy_y
    XdiffSquared = Xdiff * Xdiff
    YdiffSquared = Ydiff * Ydiff
    return math.sqrt(XdiffSquared + YdiffSquared)
end

return environ