-- Ability to read what card is there
local getopt = require('getopt')
local cmds = require('commands')
local taglib = require('taglib')

local desc = 
[[This script will automatically recognize and dump full content of a NFC NDEF Initialized tag; non-initialized tags will be ignored.

It also write the dump to an eml-file <uid>.eml.

(The difference between an .eml-file and a .bin-file is that the eml file contains
ASCII representation of the hex-data, with linebreaks between 'rows'. A .bin-file contains the 
raw data, but when saving into that for, we lose the infromation about how the memory is structured. 
For example: 24 bytes could be 6 blocks of 4 bytes, or vice versa. 
Therefore, the .eml is better to use file when saving dumps.)

Arguments:
	-d 				debug logging on
	-h 				this help

]]
local example = "script run xxx"
local author = "Martin Holst Swende & Asper"
---
-- PrintAndLog
function prlog(...)
	-- TODO; replace this with a call to the proper PrintAndLog
	print(...)
end
--- 
-- This is only meant to be used when errors occur
function oops(err)
	prlog("ERROR: ",err)
	return nil,err
end


-- Perhaps this will be moved to a separate library at one point
local utils = {
	--- 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 unsuccessfull
	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,
}



--- 
-- Usage help
function help()
	prlog(desc)
	prlog("Example usage")
	prlog(example)
end

function debug(...)
	if DEBUG then 
		prlog("debug:", ...)
	end
end


local function show(data)
	if DEBUG then
	    local formatString = ("H%d"):format(string.len(data))
	    local _,hexdata = bin.unpack(formatString, data)
	    debug("Hexdata" , hexdata)
	end
end
--- Fire up a connection with a tag, return uid
-- @return UID if successfull
-- @return nil, errormessage if unsuccessfull

local function open()
	debug("Opening connection")
	core.clearCommandBuffer()
	local x = string.format("hf 14a raw -r -p -s")
	debug(x)
	core.console(x)	
	debug("done")
	data, err = waitCmd(true)
	if err then return oops(err) end		
	show(data)
	local formatString = ("H%d"):format(string.len(data))
	local _,uid = bin.unpack(formatString, data)
	return uid
end
--- Shut down tag communication
-- return no return values
local function close()
	debug("Closing connection")
	core.clearCommandBuffer()
	local x = string.format("hf 14a raw -r")
	debug(x)
	core.console(x)	
	debug("done")
	--data, err = waitCmd(true)
	--data, err = waitCmd(false)

end


---_ Gets data from a block
-- @return {block, block+1, block+2, block+3} if successfull
-- @return nil, errormessage if unsuccessfull
local function getBlock(block)
	local data, err

	core.clearCommandBuffer()
	
	local x = string.format("hf 14a raw -r -c -p 30 %02x", block)
	debug(x)
	core.console(x)	
	debug("done")
	-- By now, there should be an ACK waiting from the device, since 
	-- we used the -r flag (don't read response).

	data, err = waitCmd(false)
	if err then return oops(err) end
	show(data)
	
	if string.len(data) < 18 then
		return nil, ("Expected at least 18 bytes, got %d - this tag is not NDEF-compliant"):format(string.len(data))
	end
	-- Now, parse out the block data
	-- 0534 00B9 049C AD7F 4A00 0000 E110 1000 2155
	-- b0b0 b0b0 b1b1 b1b1 b2b2 b2b2 b3b3 b3b3 CRCC
	b0 = string.sub(data,1,4)
	b1 = string.sub(data,5,8)
	b2 = string.sub(data,9,12)
	b3 = string.sub(data,13,16)
	return {b0,b1,b2,b3}
end


--- This function is a lua-implementation of
-- cmdhf14a.c:waitCmd(uint8_t iSelect)
function waitCmd(iSelect)
	local response = core.WaitForResponseTimeout(cmds.CMD_ACK,1000)
	if response then
		local count,cmd,arg0,arg1,arg2 = bin.unpack('LLLL',response)
		
		local iLen = arg0
		if iSelect then	iLen = arg1 end
	    debug(("Received %i octets (arg0:%d, arg1:%d)"):format(iLen, arg0, arg1))
	    if iLen == 0 then return nil, "No response from tag" end
		local recv = string.sub(response,count, iLen+count-1)
	    return recv
	end
	return nil, "No response from device"
end



local function main( args)
	debug("script started")
	local err, data, data2,k,v,i
	-- Read the parameters
	for o, a in getopt.getopt(args, 'hd') do
		if o == "h" then help() return end
		if o == "d" then DEBUG = true end
	end

	-- Info contained within the tag (block 0 example)
	-- 0534 00B9 049C AD7F 4A00 0000 E110 1000 2155
	-- b0b0 b0b0 b1b1 b1b1 b2b2 b2b2 b3b3 b3b3 CRCC	
	-- MM?? ???? ???? ???? ???? ???? NNVV SS?? ----
	-- M = Manufacturer info
	-- N = NDEF-Structure-Compliant (if value is E1)
	-- V = NFC Forum Specification version (if 10 = v1.0)

	-- First, 'connect' (fire up the field) and get the uid
	local uidHexstr = open()

	-- First, get blockt 3 byte 2
	local blocks, err = getBlock(0)
	if err then return oops(err) end
	-- Block 3 contains number of blocks
	local b3chars = {string.byte(blocks[4], 1,4)}
	local numBlocks = b3chars[3] * 2 + 6
	prlog("Number of blocks:", numBlocks)

	-- NDEF compliant?
	if b3chars[1] ~= 0xE1 then 
		return oops("This tag is not NDEF-Compliant")
	end 

	local ndefVersion = b3chars[2] 	

	-- Block 1, byte 1 contains manufacturer info
	local bl1_b1 = string.byte(blocks[1], 1)
	local manufacturer = taglib.lookupManufacturer(bl1_b1)

	-- Reuse existing info
	local blockData = {blocks[1],blocks[2],blocks[3],blocks[4]}


	--[[ Due to the infineon my-d move bug 
	(if I send 30 0F i receive block0f+block00+block01+block02 insted of block0f+block10+block11+block12) 
	the only way to avoid this is to send the read command as many times as block numbers 
	removing bytes from 5 to 18 from each answer.
	--]]
	prlog("Dumping data...please wait")
	for i=4,numBlocks-1,1 do
		blocks, err = getBlock(i)
		if err then return oops(err) end
		table.insert(blockData,blocks[1])
	end
	-- Deactivate field
	close()
	-- Print results
	prlog(string.format("Tag manufacturer: %s", manufacturer))
	prlog(string.format("Tag UID: %s", uidHexstr))
	prlog(string.format("Tag NDEF version: 0x%02x", ndefVersion))
	
	for k,v in ipairs(blockData) do
		prlog(string.format("Block %02x: %02x %02x %02x %02x",k-1, string.byte(v, 1,4)))
	end
	local filename, err = utils.writeDumpFile(uidHexstr, blockData)
	if err then return oops(err) end

	prlog(string.format("Dumped data into %s", filename))

end
main(args)