--[[
	This may be moved to a separate library at some point (Holiman)
--]]
local Utils = 
{
	-- Asks the user for Yes or No
	confirm = function(message, ...)
		local answer
		message = message .. " [y/n] ?"
		repeat
			io.write(message)
			io.flush()
			answer=io.read()
			if answer == 'Y' or answer == "y" then
				return true
			elseif answer == 'N' or answer == 'n' then 
				return false
			end
		until false
	end,
	---
	-- Asks the user for input
	input = function (message , default)
		local answer
		if default ~= nil then
			message = message .. " (default: ".. default.. " )"
		end
		message = message .." \n > "
		io.write(message)
		io.flush()
		answer=io.read()
		if answer == '' then answer = default end

		return answer
	end,
	
	------------ FILE READING
	ReadDumpFile = function (filename)
	
		filename = filename or 'dumpdata.bin'
		if #filename == 0 then
			return nil, 'Filename length is zero'
		end

		infile = io.open(filename, "rb")
		if infile == nil then 
			return nil, string.format("Could not read file %s",filename)
		end
		local t = infile:read("*all")
		len = string.len(t)
		local  _,hex = bin.unpack(("H%d"):format(len),t)
		io.close(infile)
		return hex
	end,
	
	------------ FILE WRITING (EML)
	--- Writes an eml-file.
	-- @param uid - the uid of the tag. Used in filename
	-- @param blockData. Assumed to be on the format {'\0\1\2\3,'\b\e\e\f' ..., 
	-- that is, blockData[row] contains a string with the actual data, not ascii hex representation 
	-- return filename if all went well, 
	-- @reurn nil, error message if unsuccessfulls	
	WriteDumpFile = function(uid, blockData)
		local destination = string.format("%s.eml", uid)
		local file = io.open(destination, "w")
		if file == nil then 
			return nil, string.format("Could not write to file %s", destination)
		end
		local rowlen = string.len(blockData[1])

		for i,block in ipairs(blockData) do
			if rowlen ~= string.len(block) then
				prlog(string.format("WARNING: Dumpdata seems corrupted, line %d was not the same length as line 1",i))
			end

			local formatString = string.format("H%d", string.len(block))
			local _,hex = bin.unpack(formatString,block)
			file:write(hex.."\n")
		end
		file:close()	
		return destination
	end,
	
	------------ string split function
	Split = function( inSplitPattern, outResults )
		if not outResults then
			outResults = {}
		end
		local start = 1
		local splitStart, splitEnd = string.find( self, inSplitPattern, start )
		while splitStart do
			table.insert( outResults, string.sub( self, start, splitStart-1 ) )
			start = splitEnd + 1
			splitStart, splitEnd = string.find( self, inSplitPattern, start )
		end
		table.insert( outResults, string.sub( self, start ) )
		return outResults
	end,
	
	----ISO14443-B CRC
	Crc14b = function(s)
		if s == nil then return nil end
		if #s == 0 then return nil end
		if  type(s) == 'string' then
			local utils = require('utils')
			return utils.ConvertAsciiToHex(
							core.iso14443b_crc(s)
							)
		end
		return nil		
	end,
	
	------------ CRC-8 Legic checksums
	-- Takes a hex string and calculates a crc8
	Crc8Legic = function(s)
		if s == nil then return nil end
		if #s == 0 then return nil end
		if  type(s) == 'string' then
			local utils = require('utils')
			local asc = utils.ConvertHexToAscii(s)
			local hash = core.crc8legic(asc)
			return hash
		end
		return nil
	end,
	
	------------ CRC-16 ccitt checksums
	-- Takes a hex string and calculates a crc16
	Crc16 = function(s)
		if s == nil then return nil end
		if #s == 0 then return nil end
		if  type(s) == 'string' then
			local utils = require('utils')
			local asc = utils.ConvertHexToAscii(s)
			local hash = core.crc16(asc)
			return hash
		end
		return nil
	end,
	
	
	------------ CRC-64 ecma checksums
	-- Takes a hex string and calculates a crc64 ecma
	Crc64 = function(s)
		if s == nil then return nil end
		if #s == 0 then return nil end
		if  type(s) == 'string' then
			local utils = require('utils')
			local asc = utils.ConvertHexToAscii(s)
			local hash = core.crc64(asc)
			return hash
		end
		return nil
	end,

	------------ SHA1 hash
	-- Takes a string and calculates a SHA1 hash
	Sha1 = function(s)
		if s == nil then return nil end
		if #s == 0 then return nil end
		if  type(s) == 'string' then
			local utils = require('utils')
			--local asc = utils.ConvertHexToAscii(s)
			local hash = core.sha1(s)
			return hash
		end
		return nil
	end,	
	-- Takes a hex string and calculates a SHA1 hash
	Sha1Hex = function(s)
		if s == nil then return nil end
		if #s == 0 then return nil end
		if  type(s) == 'string' then
			local utils = require('utils')
			local asc = utils.ConvertHexToAscii(s)
			local hash = core.sha1(asc)
			return hash
		end
		return nil
	end,	

	
	-- input parameter is a string
	-- Swaps the endianess and returns a number,  
	-- IE:  'cd7a' -> '7acd'  -> 0x7acd
	SwapEndianness = function(s, len)
		if s == nil then return nil end
		if #s == 0 then return '' end
		if  type(s) ~= 'string' then return nil end
		
		local retval = 0
		if len == 16 then
			local t = s:sub(3,4)..s:sub(1,2)
			retval = tonumber(t,16)
		elseif len == 24 then
			local t = s:sub(5,6)..s:sub(3,4)..s:sub(1,2)
			retval = tonumber(t,16)
		elseif len == 32 then
			local t = s:sub(7,8)..s:sub(5,6)..s:sub(3,4)..s:sub(1,2)
			retval = tonumber(t,16)
		end
		return retval
	end,
	
	-- input parameter is a string
	-- Swaps the endianess and returns a string,  
	-- IE:  'cd7a' -> '7acd'  -> 0x7acd
	SwapEndiannessStr = function(s, len)
		if s == nil then return nil end
		if #s == 0 then return '' end
		if  type(s) ~= 'string' then return nil end
		
		local retval
		if len == 16 then
			retval = s:sub(3,4)..s:sub(1,2)
		elseif len == 24 then
			retval = s:sub(5,6)..s:sub(3,4)..s:sub(1,2)
		elseif len == 32 then
			retval = s:sub(7,8)..s:sub(5,6)..s:sub(3,4)..s:sub(1,2)
		end
		return retval
	end,	
	------------ CONVERSIONS
	
	--
	-- Converts DECIMAL to HEX
    ConvertDecToHex = function(IN)
		local B,K,OUT,I,D=16,"0123456789ABCDEF","",0
		while IN>0 do
			I=I+1
			IN , D = math.floor(IN/B), math.modf(IN,B)+1
			OUT = string.sub(K,D,D)..OUT
		end
		return OUT
	end,
	---
	-- Convert Byte array to string of hex
	ConvertBytesToHex = function(bytes)
		if bytes == nil then return '' end
		if #bytes == 0 then return '' end
		local s={}
		for i = 1, #bytes do
			s[i] = string.format("%02X",bytes[i]) 
		end
		return table.concat(s)
	end,	
	-- Convert byte array to string with ascii
    ConvertBytesToAscii = function(bytes)
		if bytes == nil then return '' end
		if #bytes == 0 then return '' end
		local s={}
		for i = 1, #(bytes) do
			s[i] = string.char(bytes[i]) 
		end
		return table.concat(s)		
	end,	 
	ConvertHexToBytes = function(s)
		local t={}
		if s == nil then return t end
		if #s == 0 then return t end
		for k in s:gmatch"(%x%x)" do
			table.insert(t,tonumber(k,16))
		end
		return t
	end,
	ConvertAsciiToBytes = function(s, reverse)
		local t = {}
		if s == nil then return t end
		if #s == 0 then return t end
		
		for k in s:gmatch"(.)" do
			table.insert(t, string.byte(k))
		end
		
		if not reverse then
			return t
		end
	
		local rev = {}
		if reverse then
			for i = #t, 1,-1 do
				table.insert(rev, t[i] )
			end
		end
		return rev
	end,
	
	ConvertHexToAscii = function(s, useSafechars)
		if s == nil then return '' end
		if #s == 0 then return '' end
		local t={}
		for k in s:gmatch"(%x%x)" do

			local n = tonumber(k,16)		
			local c 
			if useSafechars and ( (n < 32) or (n == 127) ) then
				c = '.';
			else
				c = string.char(n)
			end
			table.insert(t,c)
		end
		return table.concat(t)	
	end,
	
	ConvertAsciiToHex = function(s)		
		if s == nil then return '' end
		if #s == 0 then return '' end
		local t={}
		for k in s:gmatch"(.)" do
			table.insert(t, string.format("%02X", string.byte(k)))
		end
		return table.concat(t)
	end,
	
	Chars2num = function(s)
        return (s:byte(1)*16777216)+(s:byte(2)*65536)+(s:byte(3)*256)+(s:byte(4))
	end,
	
	-- use length of string to determine 8,16,32,64 bits
	bytes_to_int = function(str,endian,signed) 
		local t={str:byte(1,-1)}
		if endian=="big" then --reverse bytes
			local tt={}
			for k=1,#t do
				tt[#t-k+1]=t[k]
			end
			t=tt
		end
		local n=0
		for k=1,#t do
			n=n+t[k]*2^((k-1)*8)
		end
		if signed then
			n = (n > 2^(#t*8-1) -1) and (n - 2^(#t*8)) or n -- if last bit set, negative.
		end
		return n
	end,
	
	-- a simple implementation of a sleep command. Thanks to Mosci
	-- takes number of seconds to sleep
	Sleep = function(n)
		local clock = os.clock
		local t0 = clock()
		while clock() - t0 <= n do end
		return nil	
	end,
	
	-- function convertStringToBytes(str)
	-- local bytes = {}
	-- local strLength = string.len(str)
	-- for i=1,strLength do
		-- table.insert(bytes, string.byte(str, i))
	-- end

	-- return bytes
-- end

-- function convertBytesToString(bytes)
	-- local bytesLength = table.getn(bytes)
	-- local str = ""
	-- for i=1,bytesLength do
		-- str = str .. string.char(bytes[i])
	-- end

	-- return str
-- end

-- function convertHexStringToBytes(str)
	-- local bytes = {}
	-- local strLength = string.len(str)
	-- for k=2,strLength,2 do
		-- local hexString = "0x" .. string.sub(str, (k - 1), k)
		-- table.insert(bytes, hex.to_dec(hexString))
	-- end

	-- return bytes
-- end

-- function convertBytesToHexString(bytes)
	-- local str = ""
	-- local bytesLength = table.getn(bytes)
	-- for i=1,bytesLength do
		-- local hexString = string.sub(hex.to_hex(bytes[i]), 3)
		-- if string.len(hexString) == 1 then
			-- hexString = "0" .. hexString
		-- end
		-- str = str .. hexString
	-- end

	-- return str
-- end

}
return Utils