#! /usr/bin/env lua

--  This module is part of the McBot / mcabbot project

--  RFC index parser

--

-- Copyright (C) 2010-2012 Mikael Berthe <mikael@lilotux.net>

--

-- This program is free software; you can redistribute it and/or modify

-- it under the terms of the GNU General Public License as published by

-- the Free Software Foundation; either version 2 of the License, or (at

-- your option) any later version.

--

-- Please check the license in the COPYING file at the root of the tree.

--

-- TXT index database, retrieved from

-- <ftp://ftp.rfc-editor.org/in-notes/rfc-index.txt>

local urlbase = "http://tools.ietf.org/html/rfc"

local rfc = { ["desc"] = "Search RFC database" }

local rfcdb = {}

local function parse_file (fname)

    local fh = io.open(fname)

    if not fh then return nil, "Cannot open RFC database" end

    -- Skip header

    local count = 0

    for line in fh:lines() do

        count = count + 1

        if line:match("^%s+RFC INDEX%s*$") and count > 30 then

            break

        end

    end

    -- Skip 2 more lines

    fh:read("*l")

    fh:read("*l")

    local contents = fh:read("*a")

    fh:close()

    for entry in contents:gfind("(%d%d%d%d .-)\n\n") do

        entry = entry:gsub("\n     ", " ")

        local n = entry:match("^(%d%d%d%d) ")

        entry = entry:gsub("^(%d%d%d%d) ", "")

        local data = {}

        data.title = entry:match("^(.-)%. ")

        entry = entry:gsub("^(.-)%. ", "")

        data.date = entry:match("%. (.-)%. %(Format:")

        data.obsoletes = entry:match("%(Obsoletes (.-)%)")

        data.obsoleted_by = entry:match("%(Obsoleted by (.-)%)")

        data.updates = entry:match("%(Updates (.-)%)")

        data.updated_by = entry:match("%(Updated by (.-)%)")

        data.also = entry:match("%(Also (.-)%)")

        data.status = entry:match("%(Status: (.-)%)")

        if data.title then

            rfcdb[n] = data

        end

    end

    return true

end

local function rfc_lookup_string (rfcstring)

    rfcstring = rfcstring:lower()

    local r = ""

    for id, data in pairs(rfcdb) do

        if data.title:lower():find(rfcstring) then

            r = r.."RFC"..id..": "..data.title.."\n"

        end

    end

    r = r:gsub("\n$", "")

    if r ~= "" then return r; end

    return nil, "Sorry, I couldn't find any relevant RFC"

end

local function rfc_lookup_number (rfcnum)

    rfcnum = tostring(rfcnum)

    rfcnum = string.rep("0", 4 - rfcnum:len()) .. rfcnum

    local data = rfcdb[rfcnum]

    if not data then return nil, "Sorry, RFC not found" end

    local r = "RFC"..rfcnum .. " is " .. data.title .. "\n"

    if data.status then

        r = r .. "Status:\t" .. data.status:lower() .. "\n"

    end

    if data.obsoletes then

        r = r .. "Obsoletes:\t" .. data.obsoletes .. "\n"

    end

    if data.obsoleted_by then

        r = r .. "Obsoleted by:\t" .. data.obsoleted_by .. "\n"

    end

    if data.updates then

        r = r .. "Updates:\t" .. data.updates .. "\n"

    end

    if data.updated_by then

        r = r .. "Updated by:\t" .. data.updated_by .. "\n"

    end

    if data.also then

        r = r .. "Also:\t" .. data.also .. "\n"

    end

    r = r .. "URL:\t" .. urlbase..rfcnum

    return r

end

function rfc.cmd (rfcnum)

    local empty = true

    for i,v in pairs(rfcdb) do empty = false; break end

    if empty then

        local r, err = parse_file(indexfname)

        if not r then return nil, err end

    end

    if (rfcnum) then

        rfcnum = rfcnum:gsub("^RFC[%s%-]*", "")

        rfcnum = rfcnum:gsub("^rfc[%s%-]*", "")

        rfcnum = rfcnum:gsub("[!%?%s:]+$", "")

    end

    if not rfcnum or rfcnum == "" then

        return nil, "What RFC do you want?"

    end

    local n = tonumber(rfcnum)

    if not n then return rfc_lookup_string(rfcnum) end

    return rfc_lookup_number(n)

end

mcbot_register_command("rfc", rfc)