#!/usr/bin/lua
--[[

	Part of AREDN -- Used for creating Amateur Radio Emergency Data Networks
	Copyright (C) 2022 Tim Wilkinson
	See Contributors file for additional contributors

	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 version 3 of the License.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.

	Additional Terms:

	Additional use restrictions exist on the AREDN(TM) trademark and logo.
		See AREDNLicense.txt for more info.

	Attributions to the AREDN Project must be retained in the source code.
	If importing this code into a new or existing project attribution
	to the AREDN project must be added to the source code.

	You must not misrepresent the origin of the material contained within.

	Modified versions must be modified to attribute to the original source
	and be marked in reasonable ways as differentiate it from the original
	version

--]]

local olsrd_conf = "/tmp/etc/olsrd.conf"

-- Load olsrd.conf
local lines = {}
for line in io.lines(olsrd_conf)
do
    lines[#lines + 1] = line
end

-- Generate validated name services
local ns = {}
for line in io.popen("/usr/local/bin/olsrd-config olsrd validate"):lines()
do
    ns[#ns + 1] = line
end
table.remove(ns, 1) -- strip first line which is blank

-- Locate merge point, then merge new validated services
local change = false
local i = 1
while true
do
    if lines[i] == 'LoadPlugin "olsrd_nameservice.so.0.4"' then
        local n = 1
        while i <= #lines and n <= #ns
        do
            if lines[i] ~= ns[n] then
                lines[i] = ns[n]
                change = true
            end
            i = i + 1
            n = n + 1
        end
        if i <= #lines then
            -- truncated
            while i <= #lines
            do
                table.remove(lines, #lines)
            end
            change = true
        end
        if n <= #ns then
            -- append
            while n <= #ns
            do
                lines[#lines + 1] = ns[n]
                n = n + 1
            end
            change = true
        end
        break
    end
    i = i + 1
end

-- If services have changed we need to update and restart olsrd
if change then
    print("Change")
    local f = io.open(olsrd_conf, "w")
    if f then
        for _, line in ipairs(lines)
        do
            f:write(line .. "\n")
        end
        f:close()
        -- We use 'killall' to restart olsrd to stop if from regenerating the olsrd.conf file we
        -- just changed. We dont want to modify the standard process so these changes wont persist
        -- across restarts/reconfigurations but will only be applied daily when poor services are detected
        os.execute("/usr/bin/killall olsrd > /dev/null 2>&1")
    end
else
    print("Unchange")
end