game.rb

require_relative 'cell.rb'
require_relative 'grid.rb'

class Game

	attr_reader :grid, :rows, :columns

	def initialize(rows, columns)

		@rows = rows
		@columns = columns
		@grid = Grid.new(@rows, @columns)
		populateGrid()
	end

	# Puts a cell in each grid space
	def populateGrid

		@grid.matrix.each_with_index do | row, i |

			row.each_with_index do | col, j |

				@grid.matrix[i][j] = Cell.new(i, j, false)
			end
		end
	end

	# Define which cells in Grid begin the game alive
	# Param pattern is an array of arrays
	def loadPattern(pattern)

		pattern.each do | coordinate |

			# Wrap out-of-bounds coordinates
			x = @grid.toroidalRow(coordinate[0])
			y = @grid.toroidalColumn(coordinate[1])

			cell = getCell(x, y)
			cell.state = true
		end
	end

	# Return the cell at the specified row and column coordinates
	def getCell(row, column)

		return @grid.getElement(row, column)
	end

	# Iterate over each cell in grid and set to alive or dead conforming
	# to game rules
	def turn()

		newGrid = Grid.new(grid.rows, grid.columns)
		
		@grid.iterate do | cell |
			nextState = deadOrAlive(cell)
			newGrid.matrix[cell.row][cell.column] = Cell.new(cell.row, cell.column, nextState)
		end

		@grid = newGrid
	end

	# Set cell state based on number of alive neighbours
	def deadOrAlive(cell)

		livingNeighbours = 0
		
		# Count number of living neighbours
		neighbours(cell).each do | neighbour |

			if neighbour.state

				livingNeighbours += 1
			end
		end

		# Dead cells come alive when exactly three adjacent neighbours are alive
		# Alive cells die without two or three living adjacent neighbours
		if cell.state == false && livingNeighbours == 3
			return true
		elsif cell.state == true && livingNeighbours.between?(2, 3)
			return true
		else
			return false
		end

	end

	# Return array of all neighbouring cells
	def neighbours(cell)

		row = cell.row
		column = cell.column
		neighbours = []

		# Subsample eight cells adjacent to given cell
		for i in ((row - 1)..(row + 1))
			for j in ((column - 1)..(column + 1))
				# Do not include given cell in sample
				if !(i == row && j == column)
					neighbours << getCell(i, j)
				end
			end
		end

		return neighbours
	end
end