-- Copyright 2008 Steven Barth <steven@midlink.org>
-- Licensed to the public under the Apache License 2.0.

local io = require "io"
local math = require "math"
local table = require "table"
local debug = require "debug"
local ldebug = require "luci.debug"
local string = require "string"
local coroutine = require "coroutine"
local tparser = require "luci.template.parser"
local json = require "luci.jsonc"
local lhttp = require "lucihttp"

local _ubus = require "ubus"
local _ubus_connection = nil

local getmetatable, setmetatable = getmetatable, setmetatable
local rawget, rawset, unpack, select = rawget, rawset, unpack, select
local tostring, type, assert, error = tostring, type, assert, error
local ipairs, pairs, next, loadstring = ipairs, pairs, next, loadstring
local require, pcall, xpcall = require, pcall, xpcall
local collectgarbage, get_memory_limit = collectgarbage, get_memory_limit

module "luci.util"

--
-- Pythonic string formatting extension
--
getmetatable("").__mod = function(a, b)
	local ok, res

	if not b then
		return a
	elseif type(b) == "table" then
		local k, _
		for k, _ in pairs(b) do if type(b[k]) == "userdata" then b[k] = tostring(b[k]) end end

		ok, res = pcall(a.format, a, unpack(b))
		if not ok then
			error(res, 2)
		end
		return res
	else
		if type(b) == "userdata" then b = tostring(b) end

		ok, res = pcall(a.format, a, b)
		if not ok then
			error(res, 2)
		end
		return res
	end
end


--
-- Class helper routines
--

-- Instantiates a class
local function _instantiate(class, ...)
	local inst = setmetatable({}, {__index = class})

	if inst.__init__ then
		inst:__init__(...)
	end

	return inst
end

-- The class object can be instantiated by calling itself.
-- Any class functions or shared parameters can be attached to this object.
-- Attaching a table to the class object makes this table shared between
-- all instances of this class. For object parameters use the __init__ function.
-- Classes can inherit member functions and values from a base class.
-- Class can be instantiated by calling them. All parameters will be passed
-- to the __init__ function of this class - if such a function exists.
-- The __init__ function must be used to set any object parameters that are not shared
-- with other objects of this class. Any return values will be ignored.
function class(base)
	return setmetatable({}, {
		__call  = _instantiate,
		__index = base
	})
end

function instanceof(object, class)
	local meta = getmetatable(object)
	while meta and meta.__index do
		if meta.__index == class then
			return true
		end
		meta = getmetatable(meta.__index)
	end
	return false
end


--
-- Scope manipulation routines
--

coxpt = setmetatable({}, { __mode = "kv" })

local tl_meta = {
	__mode = "k",

	__index = function(self, key)
		local t = rawget(self, coxpt[coroutine.running()]
		 or coroutine.running() or 0)
		return t and t[key]
	end,

	__newindex = function(self, key, value)
		local c = coxpt[coroutine.running()] or coroutine.running() or 0
		local r = rawget(self, c)
		if not r then
			rawset(self, c, { [key] = value })
		else
			r[key] = value
		end
	end
}

-- the current active coroutine. A thread local store is private a table object
-- whose values can't be accessed from outside of the running coroutine.
function threadlocal(tbl)
	return setmetatable(tbl or {}, tl_meta)
end


--
-- Debugging routines
--

function perror(obj)
	return io.stderr:write(tostring(obj) .. "\n")
end

function dumptable(t, maxdepth, i, seen)
	i = i or 0
	seen = seen or setmetatable({}, {__mode="k"})

	for k,v in pairs(t) do
		perror(string.rep("\t", i) .. tostring(k) .. "\t" .. tostring(v))
		if type(v) == "table" and (not maxdepth or i < maxdepth) then
			if not seen[v] then
				seen[v] = true
				dumptable(v, maxdepth, i+1, seen)
			else
				perror(string.rep("\t", i) .. "*** RECURSION ***")
			end
		end
	end
end


--
-- String and data manipulation routines
--

function pcdata(value)
	return value and tparser.pcdata(tostring(value))
end

function urlencode(value)
	if value ~= nil then
		local str = tostring(value)
		return lhttp.urlencode(str, lhttp.ENCODE_IF_NEEDED + lhttp.ENCODE_FULL)
			or str
	end
	return nil
end

function urldecode(value, decode_plus)
	if value ~= nil then
		local flag = decode_plus and lhttp.DECODE_PLUS or 0
		local str = tostring(value)
		return lhttp.urldecode(str, lhttp.DECODE_IF_NEEDED + flag)
			or str
	end
	return nil
end

function striptags(value)
	return value and tparser.striptags(tostring(value))
end

function shellquote(value)
	return string.format("'%s'", string.gsub(value or "", "'", "'\\''"))
end

-- for bash, ash and similar shells single-quoted strings are taken
-- literally except for single quotes (which terminate the string)
-- (and the exception noted below for dash (-) at the start of a
-- command line parameter).
function shellsqescape(value)
   local res
   res, _ = string.gsub(value, "'", "'\\''")
   return res
end

-- bash, ash and other similar shells interpret a dash (-) at the start
-- of a command-line parameters as an option indicator regardless of
-- whether it is inside a single-quoted string.  It must be backlash
-- escaped to resolve this.  This requires in some funky special-case
-- handling.  It may actually be a property of the getopt function
-- rather than the shell proper.
function shellstartsqescape(value)
   res, _ = string.gsub(value, "^%-", "\\-")
   return shellsqescape(res)
end

-- containing the resulting substrings. The optional max parameter specifies
-- the number of bytes to process, regardless of the actual length of the given
-- string. The optional last parameter, regex, specifies whether the separator
-- sequence is interpreted as regular expression.
--					pattern as regular expression (optional, default is false)
function split(str, pat, max, regex)
	pat = pat or "\n"
	max = max or #str

	local t = {}
	local c = 1

	if #str == 0 then
		return {""}
	end

	if #pat == 0 then
		return nil
	end

	if max == 0 then
		return str
	end

	repeat
		local s, e = str:find(pat, c, not regex)
		max = max - 1
		if s and max < 0 then
			t[#t+1] = str:sub(c)
		else
			t[#t+1] = str:sub(c, s and s - 1)
		end
		c = e and e + 1 or #str + 1
	until not s or max < 0

	return t
end

function trim(str)
	return (str:gsub("^%s*(.-)%s*$", "%1"))
end

function cmatch(str, pat)
	local count = 0
	for _ in str:gmatch(pat) do count = count + 1 end
	return count
end

-- one token per invocation, the tokens are separated by whitespace. If the
-- input value is a table, it is transformed into a string first. A nil value
-- will result in a valid iterator which aborts with the first invocation.
function imatch(v)
	if type(v) == "table" then
		local k = nil
		return function()
			k = next(v, k)
			return v[k]
		end

	elseif type(v) == "number" or type(v) == "boolean" then
		local x = true
		return function()
			if x then
				x = false
				return tostring(v)
			end
		end

	elseif type(v) == "userdata" or type(v) == "string" then
		return tostring(v):gmatch("%S+")
	end

	return function() end
end

-- value or 0 if the unit is unknown. Upper- or lower case is irrelevant.
-- Recognized units are:
--	o "y"	- one year   (60*60*24*366)
--  o "m"	- one month  (60*60*24*31)
--  o "w"	- one week   (60*60*24*7)
--  o "d"	- one day    (60*60*24)
--  o "h"	- one hour	 (60*60)
--  o "min"	- one minute (60)
--  o "kb"  - one kilobyte (1024)
--  o "mb"	- one megabyte (1024*1024)
--  o "gb"	- one gigabyte (1024*1024*1024)
--  o "kib" - one si kilobyte (1000)
--  o "mib"	- one si megabyte (1000*1000)
--  o "gib"	- one si gigabyte (1000*1000*1000)
function parse_units(ustr)

	local val = 0

	-- unit map
	local map = {
		-- date stuff
		y   = 60 * 60 * 24 * 366,
		m   = 60 * 60 * 24 * 31,
		w   = 60 * 60 * 24 * 7,
		d   = 60 * 60 * 24,
		h   = 60 * 60,
		min = 60,

		-- storage sizes
		kb  = 1024,
		mb  = 1024 * 1024,
		gb  = 1024 * 1024 * 1024,

		-- storage sizes (si)
		kib = 1000,
		mib = 1000 * 1000,
		gib = 1000 * 1000 * 1000
	}

	-- parse input string
	for spec in ustr:lower():gmatch("[0-9%.]+[a-zA-Z]*") do

		local num = spec:gsub("[^0-9%.]+$","")
		local spn = spec:gsub("^[0-9%.]+", "")

		if map[spn] or map[spn:sub(1,1)] then
			val = val + num * ( map[spn] or map[spn:sub(1,1)] )
		else
			val = val + num
		end
	end


	return val
end

-- also register functions above in the central string class for convenience
string.pcdata      = pcdata
string.striptags   = striptags
string.split       = split
string.trim        = trim
string.cmatch      = cmatch
string.parse_units = parse_units


function append(src, ...)
	for i, a in ipairs({...}) do
		if type(a) == "table" then
			for j, v in ipairs(a) do
				src[#src+1] = v
			end
		else
			src[#src+1] = a
		end
	end
	return src
end

function combine(...)
	return append({}, ...)
end

function contains(table, value)
	for k, v in pairs(table) do
		if value == v then
			return k
		end
	end
	return false
end

-- Both table are - in fact - merged together.
function update(t, updates)
	for k, v in pairs(updates) do
		t[k] = v
	end
end

function keys(t)
	local keys = { }
	if t then
		for k, _ in kspairs(t) do
			keys[#keys+1] = k
		end
	end
	return keys
end

function clone(object, deep)
	local copy = {}

	for k, v in pairs(object) do
		if deep and type(v) == "table" then
			v = clone(v, deep)
		end
		copy[k] = v
	end

	return setmetatable(copy, getmetatable(object))
end


-- Serialize the contents of a table value.
function _serialize_table(t, seen)
	assert(not seen[t], "Recursion detected.")
	seen[t] = true

	local data  = ""
	local idata = ""
	local ilen  = 0

	for k, v in pairs(t) do
		if type(k) ~= "number" or k < 1 or math.floor(k) ~= k or ( k - #t ) > 3 then
			k = serialize_data(k, seen)
			v = serialize_data(v, seen)
			data = data .. ( #data > 0 and ", " or "" ) ..
				'[' .. k .. '] = ' .. v
		elseif k > ilen then
			ilen = k
		end
	end

	for i = 1, ilen do
		local v = serialize_data(t[i], seen)
		idata = idata .. ( #idata > 0 and ", " or "" ) .. v
	end

	return idata .. ( #data > 0 and #idata > 0 and ", " or "" ) .. data
end

-- with loadstring().
function serialize_data(val, seen)
	seen = seen or setmetatable({}, {__mode="k"})

	if val == nil then
		return "nil"
	elseif type(val) == "number" then
		return val
	elseif type(val) == "string" then
		return "%q" % val
	elseif type(val) == "boolean" then
		return val and "true" or "false"
	elseif type(val) == "function" then
		return "loadstring(%q)" % get_bytecode(val)
	elseif type(val) == "table" then
		return "{ " .. _serialize_table(val, seen) .. " }"
	else
		return '"[unhandled data type:' .. type(val) .. ']"'
	end
end

function restore_data(str)
	return loadstring("return " .. str)()
end


--
-- Byte code manipulation routines
--

-- will be stripped before it is returned.
function get_bytecode(val)
	local code

	if type(val) == "function" then
		code = string.dump(val)
	else
		code = string.dump( loadstring( "return " .. serialize_data(val) ) )
	end

	return code -- and strip_bytecode(code)
end

-- numbers and debugging numbers will be discarded. Original version by
-- Peter Cawley (http://lua-users.org/lists/lua-l/2008-02/msg01158.html)
function strip_bytecode(code)
	local version, format, endian, int, size, ins, num, lnum = code:byte(5, 12)
	local subint
	if endian == 1 then
		subint = function(code, i, l)
			local val = 0
			for n = l, 1, -1 do
				val = val * 256 + code:byte(i + n - 1)
			end
			return val, i + l
		end
	else
		subint = function(code, i, l)
			local val = 0
			for n = 1, l, 1 do
				val = val * 256 + code:byte(i + n - 1)
			end
			return val, i + l
		end
	end

	local function strip_function(code)
		local count, offset = subint(code, 1, size)
		local stripped = { string.rep("\0", size) }
		local dirty = offset + count
		offset = offset + count + int * 2 + 4
		offset = offset + int + subint(code, offset, int) * ins
		count, offset = subint(code, offset, int)
		for n = 1, count do
			local t
			t, offset = subint(code, offset, 1)
			if t == 1 then
				offset = offset + 1
			elseif t == 4 then
				offset = offset + size + subint(code, offset, size)
			elseif t == 3 then
				offset = offset + num
			elseif t == 254 or t == 9 then
				offset = offset + lnum
			end
		end
		count, offset = subint(code, offset, int)
		stripped[#stripped+1] = code:sub(dirty, offset - 1)
		for n = 1, count do
			local proto, off = strip_function(code:sub(offset, -1))
			stripped[#stripped+1] = proto
			offset = offset + off - 1
		end
		offset = offset + subint(code, offset, int) * int + int
		count, offset = subint(code, offset, int)
		for n = 1, count do
			offset = offset + subint(code, offset, size) + size + int * 2
		end
		count, offset = subint(code, offset, int)
		for n = 1, count do
			offset = offset + subint(code, offset, size) + size
		end
		stripped[#stripped+1] = string.rep("\0", int * 3)
		return table.concat(stripped), offset
	end

	return code:sub(1,12) .. strip_function(code:sub(13,-1))
end


--
-- Sorting iterator functions
--

function _sortiter( t, f )
	local keys = { }

	local k, v
	for k, v in pairs(t) do
		keys[#keys+1] = k
	end

	local _pos = 0

	table.sort( keys, f )

	return function()
		_pos = _pos + 1
		if _pos <= #keys then
			return keys[_pos], t[keys[_pos]], _pos
		end
	end
end

-- the provided callback function.
function spairs(t,f)
	return _sortiter( t, f )
end

-- The table pairs are sorted by key.
function kspairs(t)
	return _sortiter( t )
end

-- The table pairs are sorted by value.
function vspairs(t)
	return _sortiter( t, function (a,b) return t[a] < t[b] end )
end


--
-- System utility functions
--

function bigendian()
	return string.byte(string.dump(function() end), 7) == 0
end

function exec(command)
	local pp   = io.popen(command)
	local data = pp:read("*a")
	pp:close()

	return data
end

function execi(command)
	local pp = io.popen(command)

	return pp and function()
		local line = pp:read()

		if not line then
			pp:close()
		end

		return line
	end
end

-- Deprecated
function execl(command)
	local pp   = io.popen(command)
	local line = ""
	local data = {}

	while true do
		line = pp:read()
		if (line == nil) then break end
		data[#data+1] = line
	end
	pp:close()

	return data
end


local ubus_codes = {
	"INVALID_COMMAND",
	"INVALID_ARGUMENT",
	"METHOD_NOT_FOUND",
	"NOT_FOUND",
	"NO_DATA",
	"PERMISSION_DENIED",
	"TIMEOUT",
	"NOT_SUPPORTED",
	"UNKNOWN_ERROR",
	"CONNECTION_FAILED"
}

local function ubus_return(...)
	if select('#', ...) == 2 then
		local rv, err = select(1, ...), select(2, ...)
		if rv == nil and type(err) == "number" then
			return nil, err, ubus_codes[err]
		end
	end

	return ...
end

function ubus(object, method, data)
	if not _ubus_connection then
		_ubus_connection = _ubus.connect()
		assert(_ubus_connection, "Unable to establish ubus connection")
	end

	if object and method then
		if type(data) ~= "table" then
			data = { }
		end
		return ubus_return(_ubus_connection:call(object, method, data))
	elseif object then
		return _ubus_connection:signatures(object)
	else
		return _ubus_connection:objects()
	end
end

function serialize_json(x, cb)
	local js = json.stringify(x)
	if type(cb) == "function" then
		cb(js)
	else
		return js
	end
end


function libpath()
	return require "nixio.fs".dirname(ldebug.__file__)
end

function checklib(fullpathexe, wantedlib)
	local fs = require "nixio.fs"
	local haveldd = fs.access('/usr/bin/ldd')
	local haveexe = fs.access(fullpathexe)
	if not haveldd or not haveexe then
		return false
	end
	local libs = exec(string.format("/usr/bin/ldd %s", shellquote(fullpathexe)))
	if not libs then
		return false
	end
	for k, v in ipairs(split(libs)) do
		if v:find(wantedlib) then
			return true
		end
	end
	return false
end

-------------------------------------------------------------------------------
-- Coroutine safe xpcall and pcall versions
--
-- Encapsulates the protected calls with a coroutine based loop, so errors can
-- be dealed without the usual Lua 5.x pcall/xpcall issues with coroutines
-- yielding inside the call to pcall or xpcall.
--
-- Authors: Roberto Ierusalimschy and Andre Carregal
-- Contributors: Thomas Harning Jr., Ignacio Burgueño, Fabio Mascarenhas
--
-- Copyright 2005 - Kepler Project
--
-- $Id: coxpcall.lua,v 1.13 2008/05/19 19:20:02 mascarenhas Exp $
-------------------------------------------------------------------------------

-------------------------------------------------------------------------------
-- Implements xpcall with coroutines
-------------------------------------------------------------------------------
local coromap = setmetatable({}, { __mode = "k" })

local function handleReturnValue(err, co, status, ...)
	if not status then
		return false, err(debug.traceback(co, (...)), ...)
	end
	if coroutine.status(co) == 'suspended' then
		return performResume(err, co, coroutine.yield(...))
	else
		return true, ...
	end
end

function performResume(err, co, ...)
	return handleReturnValue(err, co, coroutine.resume(co, ...))
end

local function id(trace, ...)
	return trace
end

function coxpcall(f, err, ...)
	local current = coroutine.running()
	if not current then
		if err == id then
			return pcall(f, ...)
		else
			if select("#", ...) > 0 then
				local oldf, params = f, { ... }
				f = function() return oldf(unpack(params)) end
			end
			return xpcall(f, err)
		end
	else
		local res, co = pcall(coroutine.create, f)
		if not res then
			local newf = function(...) return f(...) end
			co = coroutine.create(newf)
		end
		coromap[co] = current
		coxpt[co] = coxpt[current] or current or 0
		return performResume(err, co, ...)
	end
end

function copcall(f, ...)
	return coxpcall(f, id, ...)
end
