require "ext"
local parse_map = true
local map = {}
local row,col = 0,0
local start
local commands = {}
local face_size = 
for line in io.lines() do
	row = row + 1
	if line ~= "" and parse_map then
		col = 0
		for char in line:gmatch("(.)") do
			col = col + 1
			local locf = string.format("%d,%d",row,col)
			if char == "." then
				if start == nil then
					start = locf
				end
				map[locf] = true
			elseif char == "#" then
				map[locf] = false
			end --else, it's nil
		end
	elseif line == "" and parse_map then
		parse_map = false
	elseif not parse_map then
		local ccursor = line
		while ccursor ~= "" do
			if ccursor:find("^%d") then
				table.insert(commands,{type="walk",n=ccursor:match("^(%d+)")})
				ccursor = ccursor:gsub("^(%d+)","")
			elseif ccursor:find("^[LR]") then
				table.insert(commands,{type="turn",n=ccursor:match("^([LR])")})
				ccursor = ccursor:gsub("^[LR]","")
			end
		end
	end
end

local directions = {
	up = {-1, 0},
	down = {1,0},
	left = {0,-1},
	right = {0,1}
}
local dirmap = {
	[0] = {
		name = "right",
		R = 1,
		L = 3
	},
	[1] = {
		name = "down",
		R = 2,
		L = 0
	},
	[2] = {
		name = "left",
		R = 3,
		L = 1
	},
	[3] = {
		name = "up",
		R = 0,
		L = 2
	}
}

local mem_loop = {}
local function find_loop_loc(sloc, direction)
	print("Finding loop location from",sloc,"dir",direction)
	if mem_loop[sloc] and mem_loop[sloc][direction] then
		return mem_loop[sloc][direction]
	end
	local srow, scol = sloc:match("(%d+),(%d+)")
	local radd, cadd = -direction[1], -direction[2]
	while map[string.format("%d,%d",srow,scol)] ~= nil do
		print("Examining",string.format("%d,%d",srow,scol),"was not nil")
		srow, scol = srow + radd, scol + cadd
	end
	print("Examining",string.format("%d,%d",srow,scol),"was nil")
	local ret = string.format("%d,%d",srow + direction[1],scol + direction[2])
	mem_loop[ret] = mem_loop[ret] or {}
	mem_loop[ret][direction] = ret
	print("Returning",ret)
	return ret
end
print("map",map)
print("commands",commands)
local state = {
	location = start,
	direction = 0
}
print("Starting state:",state)

local function open(location,direction)
	local crow, ccol = state.location:match("(%d+),(%d+)")
	local rrow, rcol = crow + direction[1], ccol + direction[2]
	local rloc = string.format("%d,%d",rrow,rcol)
	if map[rloc] then
		return true, rloc
	elseif map[rloc] == false then
		return false
	else
		local loop_loc = find_loop_loc(location,direction)
		assert(map[loop_loc] ~= nil)
		if map[loop_loc] then
			return true, loop_loc
		else
			return false
		end
	end
end

local function run(state, instructions)
	local function walk(state,n)
		for i = 1, n do
			local dir = directions[dirmap[state.direction].name]
			local isopen, newloc = open(state.location,dir)
			if isopen then
				print("Walked to",newloc)
				state.location = newloc
			else
				break
			end
		end
	end
	local function turn(state,dir)
		state.direction = dirmap[state.direction][dir]
	end
	while #instructions > 0 do
		local ins = table.remove(instructions,1)
		if ins.type == "walk" then
			walk(state,ins.n)
		elseif ins.type == "turn" then
			turn(state,ins.n)
		end
	end
end

run(state,commands)
print(state)
local row, col = state.location:match("(%d+),(%d+)")
print((row*1000) + (col * 4) + state.direction)