local spread_probability = 0.6

local display_inputinfo_counter = 0
local display_probability_counter = 1

local tiles = {}
local tiletypes = {unknown = 0, empty = 1, wall = 2}

local queue = {}

function initializeTiles()
	tiles = {}
	queue = {}

	tiles.width = math.floor(love.graphics.getWidth() / 10)
	tiles.height = math.floor(love.graphics.getHeight() / 10)

	for x = 1, tiles.width do
		local list = {}
		for y = 1, tiles.height do
			table.insert(list, tiletypes.unknown)
		end
		table.insert(tiles, list)
	end

	local first_tile_x = math.random(2, tiles.width - 1)
	local first_tile_y = math.random(2, tiles.height - 1)

	tiles[first_tile_x][first_tile_y] = tiletypes.empty

	table.insert(queue, {x = first_tile_x, y = first_tile_y - 1})
	table.insert(queue, {x = first_tile_x, y = first_tile_y + 1})
	table.insert(queue, {x = first_tile_x - 1, y = first_tile_y})
	table.insert(queue, {x = first_tile_x + 1, y = first_tile_y})
end

function love.load()
	math.randomseed(os.time())

	initializeTiles()
end

function love.update(dt)
	-- Update counters
	display_probability_counter = display_probability_counter - dt
	if display_probability_counter < 0 then
		display_probability_counter = 0
	end
	display_inputinfo_counter = display_inputinfo_counter - dt
	if display_inputinfo_counter < 0 then
		display_inputinfo_counter = 0
	end

	local new_queue = {}

	for i, location in ipairs(queue) do
		if tiles[location.x][location.y] == tiletypes.unknown then
			-- We haven't covered this tile yet

			if math.random() < spread_probability then
				-- Empty
				tiles[location.x][location.y] = tiletypes.empty

				-- Up
				if location.y - 1 >= 1 then
					table.insert(new_queue, {x = location.x, y = location.y - 1})
				end

				-- Down
				if location.y + 1 <= tiles.height then
					table.insert(new_queue, {x = location.x, y = location.y + 1})
				end

				-- Left
				if location.x - 1 >= 1 then
					table.insert(new_queue, {x = location.x - 1,  y = location.y})
				end

				-- Right
				if location.x + 1 <= tiles.width then
					table.insert(new_queue, {x = location.x + 1, y = location.y})
				end
			else
				-- Wall
				tiles[location.x][location.y] = tiletypes.wall
			end
		end
	end

	queue = new_queue
end

function love.keypressed(key)
	if key == 'r' then
		initializeTiles()
	elseif key == 'u' then
		spread_probability = spread_probability + 0.01
		if spread_probability > 1 then
			spread_probability = 1
		end
		display_probability_counter = 1
	elseif key == 'd' then
		spread_probability = spread_probability - 0.01
		if spread_probability < 0 then
			spread_probability = 0
		end
		display_probability_counter = 1
	elseif key == 'q' then
		love.event.quit()
	else
		display_inputinfo_counter = 1
	end
end

function love.draw()
	local x_scale = love.graphics.getWidth() / tiles.width
	local y_scale = love.graphics.getHeight() / tiles.height
	for tile_x, list in ipairs(tiles) do
		local x = (tile_x - 1) * x_scale
		for tile_y, tile in ipairs(list) do
			local y = (tile_y - 1) * y_scale
			
			if tile == tiletypes.empty then
				love.graphics.setColor(0, 0, 0)
			elseif tile == tiletypes.wall then
				love.graphics.setColor(1, 1, 1)
			else
				love.graphics.setColor(1, 0.5, 0.5)
			end

			love.graphics.rectangle('fill', x, y, x_scale, y_scale)
		end
	end

	if display_probability_counter > 0 then
		love.graphics.setColor(0.1, 0.1, 0.1)
		love.graphics.rectangle('fill', 10, 10, 32, 16)
		love.graphics.setColor(1, 1, 1)
		love.graphics.print(spread_probability, 10, 10)
	end
	if display_inputinfo_counter > 0 then
		love.graphics.setColor(0.1, 0.1, 0.1)
		love.graphics.rectangle('fill', 10, 30, 500, 16)
		love.graphics.setColor(1, 1, 1)
		love.graphics.print("r - restart, u - increase spread probability, d - decrease spread probability, q - quit", 10, 30)
	end
end