--[[

LuCI LXC module

Copyright (C) 2014, Cisco Systems, Inc.

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

Author: Petar Koretic <petar.koretic@sartura.hr>

]]--

module("luci.controller.lxc", package.seeall)

local uci  = require "luci.model.uci".cursor()
local util = require "luci.util"
local fs   = require "nixio"

function index()
	if not nixio.fs.access("/etc/config/lxc") then
		return
	end

	page = node("admin", "services", "lxc")
	page.target = cbi("lxc")
	page.title = _("LXC Containers")
	page.order = 70

	entry({"admin", "services", "lxc_create"}, call("lxc_create"), nil).leaf = true
	entry({"admin", "services", "lxc_action"}, call("lxc_action"), nil).leaf = true
	entry({"admin", "services", "lxc_get_downloadable"}, call("lxc_get_downloadable"), nil).leaf = true
	entry({"admin", "services", "lxc_configuration_get"}, call("lxc_configuration_get"), nil).leaf = true
	entry({"admin", "services", "lxc_configuration_set"}, call("lxc_configuration_set"), nil).leaf = true
end

function lxc_get_downloadable()
	local target = lxc_get_arch_target()
	local templates = {}
	local ssl_status = lxc_get_ssl_status()

	local f = io.popen('sh /usr/share/lxc/templates/lxc-download --list %s --server %s 2>/dev/null'
		%{ ssl_status, util.shellquote(uci:get("lxc", "lxc", "url")) }, 'r')
	local line
	for line in f:lines() do
		local dist, version, dist_target = line:match("^(%S+)%s+(%S+)%s+(%S+)%s+default%s+%S+$")
		if dist and version and dist_target and dist_target == target then
			templates[#templates+1] = "%s:%s" %{ dist, version }
		end
	end
	f:close()

	luci.http.prepare_content("application/json")
	luci.http.write_json(templates)
end

function lxc_create(lxc_name, lxc_template)
	luci.http.prepare_content("text/plain")

	local check = lxc_get_config_path()
	if not check then
		return
	end

	local ssl_status = lxc_get_ssl_status()

	local src_err
	local lxc_dist, lxc_release = lxc_template:match("^(.+):(.+)$")
	luci.http.write(util.ubus("lxc", "create", {
		name = lxc_name,
		template = "download",
		args = {
			"--server", uci:get("lxc", "lxc", "url"),
			"--dist", lxc_dist,
			"--release", lxc_release,
			"--arch", lxc_get_arch_target(),
			ssl_status
		}
	}), src_err)
end

function lxc_action(lxc_action, lxc_name)
	local data, ec = util.ubus("lxc", lxc_action, lxc_name and { name = lxc_name } or {})

	luci.http.prepare_content("application/json")
	luci.http.write_json(ec and {} or data)
end

function lxc_get_config_path()
	local f = io.open("/etc/lxc/lxc.conf", "r")
	local content = f:read("*all")
	f:close()

	local ret = content:match('^%s*lxc.lxcpath%s*=%s*([^%s]*)')
	if ret then
		if nixio.fs.access(ret) then
			local min_space = tonumber(uci:get("lxc", "lxc", "min_space")) or 100000
			local free_space = tonumber(util.exec("df " ..ret.. " | awk '{if(NR==2)print $4}'"))
			if free_space and free_space >= min_space then
				local min_temp = tonumber(uci:get("lxc", "lxc", "min_temp")) or 100000
				local free_temp = tonumber(util.exec("df /tmp | awk '{if(NR==2)print $4}'"))
				if free_temp and free_temp >= min_temp then
					return ret .. "/"
				else
					util.perror("lxc error: not enough temporary space (< " ..min_temp.. " KB)")
				end
			else
				util.perror("lxc error: not enough space (< " ..min_space.. " KB)")
			end
		else
			util.perror("lxc error: directory not found")
		end
	else
		util.perror("lxc error: config path is empty")
	end
end

function lxc_configuration_get(lxc_name)
	luci.http.prepare_content("text/plain")

	local f = io.open(lxc_get_config_path() .. lxc_name .. "/config", "r")
	local content = f:read("*all")
	f:close()

	luci.http.write(content)
end

function lxc_configuration_set(lxc_name)
	luci.http.prepare_content("text/plain")

	local lxc_configuration = luci.http.formvalue("lxc_conf")
	if lxc_configuration == nil then
		util.perror("lxc error: config formvalue is empty")
		return
	end

	local f, err = io.open(lxc_get_config_path() .. lxc_name .. "/config","w+")
	if not f then
		util.perror("lxc error: config file not found")
		return
	end

	f:write(lxc_configuration)
	f:close()

	luci.http.write("0")
end

function lxc_get_arch_target()
	local target = fs.uname().machine
	local target_map = {
		armv5  = "armel",
		armv6  = "armel",
		armv7  = "armhf",
		armv8  = "arm64",
		x86_64 = "amd64"
	}
	local k, v
	for k, v in pairs(target_map) do
		if target:find("^" ..k.. "$") then
			return v
		end
	end
	return target
end

function lxc_get_ssl_status()
	local ssl_enabled = uci:get("lxc", "lxc", "ssl_enabled")
	local ssl_status = "--no-validate"

	if ssl_enabled and ssl_enabled == "1" then
		ssl_status = ""
	end
	return ssl_status
end