--[[
LuCI - Lua Configuration Interface

shared module for luci-app-ddns-v2
Copyright 2014 Christian Schoenebeck <christian dot schoenebeck at gmail dot com>

function parse_url copied from https://svn.nmap.org/nmap/nselib/url.lua
Parses a URL and returns a table with all its parts according to RFC 2396.
@author Diego Nehab	@author Eddie Bell <ejlbell@gmail.com>

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

	http://www.apache.org/licenses/LICENSE-2.0

]]--

module("luci.tools.ddns", package.seeall)

require "luci.sys"
require "nixio.fs"

function check_ipv6()
	return nixio.fs.access("/proc/net/ipv6_route") 
	   and nixio.fs.access("/usr/sbin/ip6tables")
end

function check_ssl()
	if (luci.sys.call([[ grep -iq "\+ssl" /usr/bin/wget 2>/dev/null ]]) == 0) then
		return true
	else
		return nixio.fs.access("/usr/bin/curl")
	end
end

function check_proxy()
	-- we prefere GNU Wget for communication
	if (luci.sys.call([[ grep -iq "\+ssl" /usr/bin/wget 2>/dev/null ]]) == 0) then
		return true

	-- if not installed cURL must support proxy
	elseif nixio.fs.access("/usr/bin/curl") then
		return (luci.sys.call([[ grep -iq all_proxy /usr/lib/libcurl.so* 2>/dev/null ]]) == 0)

	-- only BusyBox Wget is installed
	else
		return nixio.fs.access("/usr/bin/wget")
	end
end

function check_bind_host()
	return nixio.fs.access("/usr/bin/host")
end

-- function to calculate seconds from given interval and unit
function calc_seconds(interval, unit)
	if not tonumber(interval) then
		return nil
	elseif unit == "days" then
		return (tonumber(interval) * 86400)	-- 60 sec * 60 min * 24 h
	elseif unit == "hours" then
		return (tonumber(interval) * 3600)	-- 60 sec * 60 min
	elseif unit == "minutes" then
		return (tonumber(interval) * 60)	-- 60 sec
	elseif unit == "seconds" then
		return tonumber(interval)
	else
		return nil
	end
end

-- read PID from run file and verify if still running
function get_pid(section, run_dir)
	local pid = tonumber(nixio.fs.readfile("%s/%s.pid" % { run_dir, section } ) or 0 )
	if pid > 0 and not luci.sys.process.signal(pid, 0) then
		pid = 0
	end
	return pid
end

-- replacement of build-in read of UCI option
-- modified AbstractValue.cfgvalue(self, section) from cbi.lua
-- needed to read from other option then current value definition
function read_value(self, section, option)
	local value
	if self.tag_error[section] then
		value = self:formvalue(section)
	else
		value = self.map:get(section, option)
	end

	if not value then
		return nil
	elseif not self.cast or self.cast == type(value) then
		return value
	elseif self.cast == "string" then
		if type(value) == "table" then
			return value[1]
		end
	elseif self.cast == "table" then
		return { value }
	end
end

-----------------------------------------------------------------------------
-- copied from https://svn.nmap.org/nmap/nselib/url.lua
-- @author Diego Nehab
-- @author Eddie Bell <ejlbell@gmail.com>
--[[
    URI parsing, composition and relative URL resolution
    LuaSocket toolkit.
    Author: Diego Nehab
    RCS ID: $Id: url.lua,v 1.37 2005/11/22 08:33:29 diego Exp $
    parse_query and build_query added For nmap (Eddie Bell <ejlbell@gmail.com>)
]]--
---
-- Parses a URL and returns a table with all its parts according to RFC 2396.
--
-- The following grammar describes the names given to the URL parts.
-- <code>
-- <url> ::= <scheme>://<authority>/<path>;<params>?<query>#<fragment>
-- <authority> ::= <userinfo>@<host>:<port>
-- <userinfo> ::= <user>[:<password>]
-- <path> :: = {<segment>/}<segment>
-- </code>
--
-- The leading <code>/</code> in <code>/<path></code> is considered part of
-- <code><path></code>.
-- @param url URL of request.
-- @param default Table with default values for each field.
-- @return A table with the following fields, where RFC naming conventions have
--   been preserved:
--     <code>scheme</code>, <code>authority</code>, <code>userinfo</code>,
--     <code>user</code>, <code>password</code>, <code>host</code>,
--     <code>port</code>, <code>path</code>, <code>params</code>,
--     <code>query</code>, and <code>fragment</code>.
-----------------------------------------------------------------------------
function parse_url(url)	--, default)
	-- initialize default parameters
	local parsed = {}
--	for i,v in base.pairs(default or parsed) do 
--		parsed[i] = v
--	end

	-- remove whitespace
--	url = string.gsub(url, "%s", "")
	-- get fragment
	url = string.gsub(url, "#(.*)$", 
		function(f)
			parsed.fragment = f
			return ""
		end)
	-- get scheme. Lower-case according to RFC 3986 section 3.1.
	url = string.gsub(url, "^([%w][%w%+%-%.]*)%:",
		function(s)
			parsed.scheme = string.lower(s);
			return ""
		end)
	-- get authority
	url = string.gsub(url, "^//([^/]*)",
		function(n)
			parsed.authority = n
			return ""
		end)
	-- get query stringing
	url = string.gsub(url, "%?(.*)",
		function(q)
			parsed.query = q
			return ""
		end)
	-- get params
	url = string.gsub(url, "%;(.*)",
		function(p)
			parsed.params = p
			return ""
		end)
	-- path is whatever was left
	parsed.path = url

	local authority = parsed.authority
	if not authority then 
		return parsed
	end
	authority = string.gsub(authority,"^([^@]*)@",
		function(u)
			parsed.userinfo = u;
			return ""
		end)
	authority = string.gsub(authority, ":([0-9]*)$",
		function(p)
			if p ~= "" then
				parsed.port = p
			end;
			return ""
		end)
	if authority ~= "" then
		parsed.host = authority
	end

	local userinfo = parsed.userinfo
	if not userinfo then
		return parsed
	end
	userinfo = string.gsub(userinfo, ":([^:]*)$",
		function(p)
			parsed.password = p;
			return ""
		end)
	parsed.user = userinfo
	return parsed
end