--[[

11  12  13  14

21  22  23  24

31  32  33  34

41  42  43  44

]]--

local win = false

a = {}
for i=1,4 do
	a[i] = {}
	for j=1,4 do
		a[i][j] = 0
	end
end

function determinant()
	a[2][1] = a[1][2]
	a[3][1] = a[1][3]
	a[4][1] = a[1][4]
	a[3][2] = a[2][3]
	a[4][2] = a[2][4]
	a[4][3] = a[3][4]
end

function update()
	--insert code
end

function reset()
	for i = 1,4 do
		for j = 1,4 do
			a[i][j] = 0
		end
	end
	update()
end

function newNum()
	local blank = 0
	for i = 1,4 do
		for j = 1,4 do
			if a[i][j] == 0 then
				blank = blank + 1
			end
		end
	end
	if blank == 0 then
		return false
	else
		while true do
			--insert random selection of x,y
			if a[x][y] == 0 then
				a[x][y] = 2
				break
			end
		end
	end
end

function score(val)
	--insert code for adding score
	for i = 1,4 do
		for j = 1,4 do
			if a[i][j] = 2048 then
				win = true
			end
		end
	end
end

function endScreen()
	--insert code here
end



--main body

while true do
	update()
	while true do
		event, key = os.pullEvent("key")
		if (key == "w" or key == "a" or key == "s" or key == "d" or key == "r") then
			break
		end
	end
	if key == "r" then
		reset()
	elseif key == "w" or key == "s" then
		determinant()
	end
	if key == "w" or key == "a" then
		for i = 1,4 do
			for j = 1,3 do
				if a[i][5-j] == a[i][4-j] then
					a[i][4-j] = a[i][5-j] + a[i][4-j]
					score(a[i][4-j])
				elseif a[i][4-j] == 0 then
					a[i][4-j] = a[i][5-j]
				end
				a[i][5-j] = 0
			end
			if a[i][2] == 0 and a[i][3] > 0 then
				a[i][2] = a[i][3]
				a[i][3] = 0
			end
		end
	elseif key == "s" or key == "d" then
		for i = 1,4 do
			for j = 1,3 do
				if a[i][j] == a[i][j+1] then
					a[i][j+1] = a[i][j] + a[i][j+1]
					score(a[i][j])
				elseif a[i][j+1] == 0 then
					a[i][j+1] = a[i][j]
				end	
				a[i][j] = 0
			end
			if a[i][3] == 0 and a[i][2] != 0 then
				a[i][3] = a[i][2]
				a[i][2] = 0
			end
		end
	end
	if key == "w" or key == "s" then
		determinant()
	end
	if not newNum() then
		local comb = false
		for b = 1,2 do
			for i = 1,4 do
				for j = 1,3 do
					if a[i][j] == a[i][j+1] then
						comb = true
						break
					end
					if comb then break end
				end
				if comb then break end
			end
			if comb then break end
			determinant()
		end
		endScreen()
		sleep(1000)
		reset()
	end
	if win == true then
		update()
		sleep(250)
		endScreen()
	end
end