#!/usr/bin/env lua

-- by Egor Skriptunoff here:https://stackoverflow.com/questions/23590304/finding-a-url-in-a-string-lua-pattern
local extractor = {}
function extractor.getURLS(text_with_URLs)
    local domains =
        [[.ac.ad.ae.aero.af.ag.ai.al.am.an.ao.aq.ar.arpa.as.asia.at.au
	 .aw.ax.az.ba.bb.bd.be.bf.bg.bh.bi.biz.bj.bm.bn.bo.br.bs.bt.bv.bw.by.bz.ca
	 .cat.cc.cd.cf.cg.ch.ci.ck.cl.cm.cn.co.com.coop.cr.cs.cu.cv.cx.cy.cz.dd.de
	 .dj.dk.dm.do.dz.ec.edu.ee.eg.eh.er.es.et.eu.fi.firm.fj.fk.fm.fo.fr.fx.ga
	 .gb.gd.ge.gf.gh.gi.gl.gm.gn.gov.gp.gq.gr.gs.gt.gu.gw.gy.hk.hm.hn.hr.ht.hu
	 .id.ie.il.im.in.info.int.io.iq.ir.is.it.je.jm.jo.jobs.jp.ke.kg.kh.ki.km.kn
	 .kp.kr.kw.ky.kz.la.lb.lc.li.lk.lr.ls.lt.lu.lv.ly.ma.mc.md.me.mg.mh.mil.mk
	 .ml.mm.mn.mo.mobi.mp.mq.mr.ms.mt.mu.museum.mv.mw.mx.my.mz.na.name.nato.nc
	 .ne.net.nf.ng.ni.nl.no.nom.np.nr.nt.nu.nz.om.org.pa.pe.pf.pg.ph.pk.pl.pm
	 .pn.post.pr.pro.ps.pt.pw.py.qa.re.ro.ru.rw.sa.sb.sc.sd.se.sg.sh.si.sj.sk
	 .sl.sm.sn.so.sr.ss.st.store.su.sv.sy.sz.tc.td.tel.tf.tg.th.tj.tk.tl.tm.tn
	 .to.tp.tr.travel.tt.tv.tw.tz.ua.ug.uk.um.us.uy.va.vc.ve.vg.vi.vn.vu.web.wf
	 .ws.xxx.ye.yt.yu.za.zm.zr.zw]]

    local tlds = {}

    for tld in domains:gmatch '%w+' do tlds[tld] = true end
    local function max4(a, b, c, d)
        return math.max(a + 0, b + 0, c + 0, d + 0)
    end
    local protocols = {
        [''] = 0,
        ['http://'] = 0,
        ['https://'] = 0,
        ['ftp://'] = 0
    }
    local finished = {}

    for pos_start, url, prot, subd, tld, colon, port, slash, path in
        text_with_URLs:gmatch '()(([%w_.~!*:@&+$/?%%#-]-)(%w[-.%w]*%.)(%w+)(:?)(%d*)(/?)([%w_.~!*:@&+$/?%%#=-]*))' do
        if protocols[prot:lower()] == (1 - #slash) * #path and
            not subd:find '%W%W' and
            (colon == '' or port ~= '' and port + 0 < 65536) and
            (tlds[tld:lower()] or tld:find '^%d+$' and
                subd:find '^%d+%.%d+%.%d+%.$' and
                max4(tld, subd:match '^(%d+)%.(%d+)%.(%d+)%.$') < 256) then
            finished[pos_start] = true
            print(pos_start, url)
        end
    end

    for pos_start, url, prot, dom, colon, port, slash, path in
        text_with_URLs:gmatch '()((%f[%w]%a+://)(%w[-.%w]*)(:?)(%d*)(/?)([%w_.~!*:@&+$/?%%#=-]*))' do
        if not finished[pos_start] and not (dom .. '.'):find '%W%W' and
            protocols[prot:lower()] == (1 - #slash) * #path and
            (colon == '' or port ~= '' and port + 0 < 65536) then
            print(pos_start, url)
        end
    end
end

local function main()
    local input = io.read("*a")
    for _, v in pairs(arg) do
        if v == "--url" then
            extractor.getURLS(input)
        else
            print("invalid args...")
            os.exit(1)
        end
    end
end

main()
return extractor