local fireBlocks = {}
local tilesize = 8
local numberWidthBlocks = math.floor(ScrW() / tilesize)
local numberHeightBlocks = 48 -- means all the 36 colors with a little more space to remaining flames
local offsetY = ScrH() - (numberHeightBlocks * tilesize)

local colorLookup = {
    Color(7,7,7),
	Color(31,7,7),
	Color(47,15,7),
	Color(71,15,7),
	Color(87,23,7),
	Color(103,31,7),
	Color(119,31,7),
	Color(143,39,7),
	Color(159,47,7),
	Color(175,63,7),
	Color(191,71,7),
	Color(199,71,7),
	Color(223,79,7),
	Color(223,87,7),
	Color(223,87,7),
	Color(215,95,7),
	Color(215,95,7),
	Color(215,103,15),
	Color(207,111,15),
	Color(207,119,15),
	Color(207,127,15),
	Color(207,135,23),
	Color(199,135,23),
	Color(199,143,23),
	Color(199,151,31),
	Color(191,159,31),
	Color(191,159,31),
	Color(191,167,39),
	Color(191,167,39),
	Color(191,175,47),
	Color(183,175,47),
	Color(183,183,47),
	Color(183,183,55),
	Color(207,207,111),
	Color(223,223,159),
	Color(239,239,199),
    Color(255,255,25),
}

for i,v in ipairs(colorLookup) do
    v.a = (i/#colorLookup) * 255
end

for line = 1,numberHeightBlocks do
	table.insert(fireBlocks, {})

    local yValue = (line - 1) * tilesize + offsetY
    for col = 1,numberWidthBlocks do
		if line < numberHeightBlocks - 1 then
			table.insert(fireBlocks[line], {x = (col-1) * tilesize, y = yValue, color = 1})
		else
			table.insert(fireBlocks[line], {x = (col-1) * tilesize, y = yValue, color = 36})
		end
    end
end

local function draw()
	for line, cols in ipairs(fireBlocks) do
        for _, block in ipairs(cols) do
			surface.SetDrawColor(colorLookup[block.color])
			surface.DrawRect(block.x, block.y, tilesize, tilesize)
		end
	end
end

local nextUpdate = 0

local function update()

    if nextUpdate > RealTime() then
        return
    end

    nextUpdate = RealTime() + 1/16

	for line = 1,numberHeightBlocks - 1 do
		for col = 2,numberWidthBlocks - 1 do
			local windDirection = math.random()
			local decay = math.floor(math.random() * 3)
			local collumn_To_Apply = col
			if windDirection < 0.2 then
				collumn_To_Apply = (col - 1)
			elseif windDirection > 0.8 then
				collumn_To_Apply = (col + 1)
			end
			if fireBlocks[line+1][col].color - decay > 1 then
				fireBlocks[line][collumn_To_Apply].color = fireBlocks[line+1][col].color - decay
			else
				fireBlocks[line][collumn_To_Apply].color = 1
			end
		end
	end
end

hook.Add("HUDPaint", "doom", draw)
hook.Add("Think", "doom", update)