#!/usr/bin/lua
--4chan automagical imagegrabber
require'lfs'
require'socket.http'
http = socket.http
set = {}
set.imgq={}
-----------
--DEFINES--
-----------
WAIT_TIME=60
MAX_NO_UPDATES=10 --if we get the page more than 10 times with no new images, stop (10 minutes with default settings)
DEFAULT_DIR="/home/jlulian38/store/lol_anime/tsukihime/Type name of new folder/lol_wut/idiot_folder/dump"
set.dir="" --current dir
set.run=true
set.nimgcnt=0

function explode(div,str)
	if (div=='') then return false end
	local pos,arr = 0,{}
	-- for each divider found
	for st,sp in function() return string.find(str,div,pos,true) end do
		table.insert(arr,string.sub(str,pos,st-1)) -- Attach chars left of current divider
		pos = sp + 1 -- Jump past current divider
	end
	table.insert(arr,string.sub(str,pos)) -- Attach chars right of last divider
	return arr
end

function getName(url)
	t = explode("/",url)
	return t[#t-2] , t[#t]	
end

function setupscrape(url)
	a,b = getName(url) --get purtier name	
	print(a,b) -- quick test
	set.name = a.."-"..b:gsub(".html","")
	set.url = url
	set.time=0
	set.imgqp = 1 --image queue position
end

function checkForDup(t,v)
	for _,v2 in pairs(t) do
		if v2==v then
			return true
		end
	end
	return false
end

function pLog(s)
	print(os.date(),s)
end

function addImage(p,v)
	imgu = v:sub(p,v:find("\"",p)-1)
	if not checkForDup(set.imgq,imgu) then
		pLog("Adding "..imgu.." to image queue")
		table.insert(set.imgq,imgu)
		set.nimgcnt = 0
	end
end

function scanpage()
	local url=set.url
	set.nimgcnt=set.nimgcnt+1
	pLog("Getting page: "..url.." count"..set.nimgcnt)
	b,c,h = http.request(url)
	pLog("Got page: "..url.." Status: "..c)
	if c ~= 200 then
		set.run=false
	end
	links = {}
	for w in string.gmatch(b,"%b<>") do
		if w:find("<a") then 
			table.insert(links,w) 
		end
	end
	for _,v in pairs(links) do
		img = v:find("http:\/\/.*\/src\/%d")
		if img then
			addImage(img,v)
		end
	end
end

function getimages()
	if set.imgq[set.imgqp] then
		local img = set.imgq[set.imgqp]
		set.imgqp=set.imgqp+1
		pLog("Getting "..img)
		local file=set.dir.."/"..set.name.."|"..img:sub(img:gsub("4chan",""):find("%d"),#img):gsub("/src/","")
		if not lfs.attributes(file) then
			b,c,h=http.request(img)
		else
			c=403
		end
		if c~=200 then
			pLog("Download of "..img.." failed!")
		else
			f=io.open(file,"w")
			f:write(b)
			f:close()
			pLog(img.." saved as "..file)
		end
	end
end

function doTask()
	if set.time + WAIT_TIME <= os.time() then
		scanpage()
		set.time=os.time()
	else
		getimages()
	end
	if set.nimgcnt >= MAX_NO_UPDATES then
		set.run=false
	end
end

function runscrape(url)
	setupscrape(url)
	while set.run do
		doTask()
	end
end

function checkDir()
	if not lfs.attributes(set.dir) then
		if not lfs.mkdir(set.dir) then
			self.run=false --FAILURE
		end
	end
end

if arg[1] then
	set.dir = DEFAULT_DIR .. "/" .. (arg[2] or "")
	checkDir()
	runscrape(arg[1])
else
	print("Lol need an URL")
end