require "libs.shcmd"

-- The caching idea is borrowed from MattJ's riddim code,
-- and the function parse_xeps() as well.

local xeplisturl = "curl http://xmpp.org/extensions/xeps.xml"

local xeps = {}

-- parse_xep() from Matthew Wild (aka MattJ)
local function parse_xeps(t)
if not t or t == "" then return nil end
local currxep = {}
    for b in string.gmatch(t,"<xep>(.-)</xep>") do
        for k,v in string.gmatch(b,"<(%w+)>(.-)</%1>") do
            currxep[k] = v
        end
        xeps[currxep.number] = { }
        for k, v in pairs(currxep) do xeps[currxep.number][k] = v end
    end
    return true
end

local function fetch_xeps ()
    local now = os.time()
    if os.difftime(now, xeps_updated_at) < 43200 then return end
    -- Let's get some fresh data
    local xepdata = shcmd(xeplisturl)
    xeps_updated_at = now
    parse_xeps(xepdata)
end

-- Logics comes from MattJ's riddim bot
local function lookup_xep (xepnum)
    if (xepnum) then xepnum = xepnum:gsub("[%s%?%.%!]+$", "") end
    -- Check that xepnum is a valid number
    xepnum = tonumber(xepnum)
    if not xepnum or xepnum <= 0 or xepnum > 9999 then return nil, "What XEP?" end
    xepnum = tostring(xepnum)
    -- Download XEP list
    fetch_xeps()
    -- Expand to full 4 char number
    xepnum = string.rep("0", 4-xepnum:len())..xepnum
    xep = xeps[tostring(xepnum)]
    if not xep then return nil,"Sorry, XEP-"..xepnum.." not found" end
    return "XEP-"..xep.number.." is \""..xep.name.."\"\n"..
           -- xep.type..", "..xep.status..", last updated "..xep.updated.."\n"..
           "URL: <http://xmpp.org/extensions/xep-"..xep.number..".html>"
end

mcbot_register_command("xep", lookup_xep)