# Patrick Coleman
# Comp Sys Res - 6th period - 2007-08
# Sugarscape - agent

require 'environment.rb'

class Agent
	
	#x-position, y-position, amount of sugar possessed, true if agent is dead, number time steps agent has been alive
	#color (red or blue) of the agent
	attr_accessor :posX, :posY, :wealth, :dead, :age, :color

	#Initializes variables based on location and random values
	def initialize (posX, posY, env=@@env, emptylocs=@@emptylocs)
		@posX = posX
		@posY = posY
		#Copy of environment shared by each agent object
		@@env = env

		@@emptylocs = emptylocs

		#Tells location an agent is there
		@@env[posY][posX].hasAgent= true

		#Initial random amount of sugar
		@wealth = rand(30)
		#Rate at which an agent consumes sugar
		@metabolism = 1 + rand(4)
		#Amount of spaces an agent can see in the environment
		@vision = 1 + rand(6)
		#Agent is alive
		@dead = false

		#Sets agent's starting age and at what age it will die
		@age = 0
		@ageLim = 1500 + rand(500)

		#Agent is randomly red or blue
		@color = rand(2)
	end


	#Moves, harvests sugar at that location, and consumes sugar
	def act
		#Age is incremented and agent dies if it has reached age limit
		@age += 1
		if @age == @ageLim
			@dead = true
			return
		end
	
		#Original location no longr has agent
		@@env[@posY][@posX].hasAgent= -1

		#Checks locations, picks direction of best one, and moves in that direction
		move

		#Tells the location it has an agent
		@@env[@posY][@posX].hasAgent= @color
		#Adds harvested sugar to wealth
		@wealth += @@env[@posY][@posX].harvest
		#Consumes sugar from the amount of sugar possessed
		@wealth -= @metabolism
		#Agent dies if it does not have enough sugar to consume
		@dead = true if @wealth < 0
	end

	def move
		@@emptylocs[[@posY,@posX]] = 0

		#Possible locations
		choices = [nil,nil,nil,nil]
		#Choices are invalid if there is an agent in the neighboring location
		choices[0] = [@@env[@posY+1][@posX],-1,0] if @posY+1 < @@env.length and @@env[@posY+1][@posX].hasAgent == -1 
		choices[1] = [@@env[@posY-1][@posX],-1,0] if @posY-1 >= 0 and @@env[@posY-1][@posX].hasAgent == -1 
		choices[2] = [@@env[@posY][@posX+1],-1,0] if @posX+1 < @@env.length and @@env[@posY][@posX+1].hasAgent == -1 
		choices[3] = [@@env[@posY][@posX-1],-1,0] if @posX-1 >= 0 and @@env[@posY][@posX-1].hasAgent == -1 

		#Choices are also invalid if they don't follow Schelling segregation rules
		for i in 0...4 do 
			choices[i] = nil if !validNeighbor(choices[i])
		end

		#Returns if no moves are valid
		return if choices == [nil,nil,nil,nil]

		#Looks out as far as vision permits in each of the four cardinal directions
		#Stores the adjacent location in that direction, the max sugar quantity, and the distance to the max sugar
		for k in 1..@vision do
			break if choices[0] == nil
			break if @posY+k >= @@env.length
			if @@env[@posY+k][@posX].sugarquant > choices[0][1]
				choices[0] = [@@env[@posY+1][@posX],@@env[@posY+k][@posX].sugarquant,@vision-k]
			end
		end
		for k in 1..@vision do
			break if choices[1] == nil
			break if @posY-k < 0
			if @@env[@posY-k][@posX].sugarquant > choices[1][1]
				choices[1] = [@@env[@posY-1][@posX],@@env[@posY-k][@posX].sugarquant,@vision-k]
			end
		end
		for k in 1..@vision do
			break if choices[2] == nil
			break if @posX+k >= @@env.length
			if @@env[@posX+k][@posX].sugarquant > choices[2][1]
				choices[2] = [@@env[@posY][@posX+1],@@env[@posY][@posX+k].sugarquant,@vision-k]
			end
		end
		for k in 1..@vision do
			break if choices[3] == nil
			break if @posX-k >= @@env.length
			if @@env[@posX-k][@posX].sugarquant > choices[3][1]
				choices[3] = [@@env[@posY][@posX-1],@@env[@posY][@posX-k].sugarquant,@vision-k]
			end
		end

		#Removes nil choices and sorts
		choices = choices.compact
		choices.sort! {|x,y| y[1] <=> x[1]}
		#Removes locations with less sugar than the best location
		while !(choices[-1][1] == choices[0][1] and choices[-1][-1] == choices[0][-1])
			choices.pop
		end

		#Randomly picks a location of the best one or more possible ones
		i = rand(choices.length)
		return if choices[i][0] == nil
		@posX = choices[i][0].posX
		@posY = choices[i][0].posY

		@@emptylocs.delete([@posY,@posX])
	end

	#Returns false if 1/2 or more neighbors are of opposite color
	def validNeighbor loc
		return false if loc == nil

		count = 0
		px = loc[0].posX
		py = loc[0].posY

		pxp = true if px+1 < @@env.length
		pxm = true if px-1 >= 0
		pyp = true if py+1 < @@env.length
		pym = true if py-1 >= 0

		nghbr = false

		count += 1 if pyp and @@env[py+1][px].hasAgent == (@color+1)%2
		count += 1 if pyp and pxp and @@env[py+1][px+1].hasAgent == (@color+1)%2
		count += 1 if pyp and pxm and @@env[py+1][px-1].hasAgent == (@color+1)%2
		count += 1 if pym and @@env[py-1][px].hasAgent == (@color+1)%2
		count += 1 if pym and pxp and @@env[py-1][px+1].hasAgent == (@color+1)%2
		count += 1 if pym and pxm and @@env[py-1][px-1].hasAgent == (@color+1)%2
		count += 1 if pxp and @@env[py][px+1].hasAgent == (@color+1)%2
		count += 1 if pxm and @@env[py][px-1].hasAgent == (@color+1)%2

		nghbr = true if count > 0

		count -= 1 if pyp and @@env[py+1][px].hasAgent == @color
		count -= 1 if pyp and pxp and @@env[py+1][px+1].hasAgent == @color
		count -= 1 if pyp and pxm and @@env[py+1][px-1].hasAgent == @color
		count -= 1 if pym and @@env[py-1][px].hasAgent == @color
		count -= 1 if pym and pxp and @@env[py-1][px+1].hasAgent == @color
		count -= 1 if pym and pxm and @@env[py-1][px-1].hasAgent == @color
		count -= 1 if pxp and @@env[py][px+1].hasAgent == @color
		count -= 1 if pxm and @@env[py][px-1].hasAgent == @color

		return true if !nghbr
		return false if count >= 0
		return true
	end
end