--[[
    This is a library to read 15693 tags. It can be used something like this

    local reader = require('read15')
    local info, err = reader.read()
    if not info then
        print(err)
        return
    end
    print(info.UID)

--]]
-- Loads the commands-library
local cmds = require('commands')
local utils = require('utils')

 -- Shouldn't take longer than 2 seconds
local TIMEOUT = 2000

local ISO15_COMMAND = {
    ISO15_REQ_SUBCARRIER_SINGLE = 0,
    ISO15_REQ_DATARATE_HIGH = 2,
    ISO15_REQ_NONINVENTORY = 0,
}

local function errorString15693(number)
    local errors = {}
    errors[0x01] =  "The command is not supported"
    errors[0x02] =  "The command is not recognised"
    errors[0x03] =  "The option is not supported."
    errors[0x0f] =  "Unknown error."
    errors[0x10] =  "The specified block is not available (doesn’t exist)."
    errors[0x11] =  "The specified block is already -locked and thus cannot be locked again"
    errors[0x12] =  "The specified block is locked and its content cannot be changed."
    errors[0x13] =  "The specified block was not successfully programmed."
    errors[0x14] =  "The specified block was not successfully locked."

    return errors[number] or "Reserved for Future Use or Custom command error."
end

local function parse15693(data)
    local bytes = utils.ConvertAsciiToBytes(data)
    local tmp = utils.ConvertAsciiToHex(data)

    -- define ISO15_CRC_CHECK 0F47
    local crcStr = utils.Crc15(tmp, #tmp)

    if string.sub(crcStr, #crcStr - 3) ~= '470F' then
        print('CRC', crc )
        return nil, 'CRC failed'
    end

    if bytes[1] % 2 == 1 then
        -- Above is a poor-mans bit check:
        -- recv[0] & ISO15_RES_ERROR //(0x01)
        local err = 'Tag returned error %i: %s'
        err = string.format(err, bytes[1], errorString15693(bytes[1]))
        return nil, err
    end
    local uid = utils.ConvertBytesToHex( bytes, true )
    uid = uid:sub(5, #uid-4)
    return { uid = uid, }
end

-- This function does a connect and retrieves som info
-- @param dont_disconnect - if true, does not disable the field
-- @return if successful: an table containing card info
-- @return if unsuccessful : nil, error
local function read15693(slow, dont_readresponse)

--[[
    We start by trying this command:
    MANDATORY (present in ALL iso15693 tags) command (the example below is sent to a tag different from the above one):

        pm3> hf 15 info --ua
        UID=E007C1A257394244
        Tag Info: Texas Instrument; Tag-it HF-I Standard; 8x32bit
        pm3>

    From which we obtain less information than the above one.

    "260100" means
    0x26
    -- #define ISO15_REQ_SUBCARRIER_SINGLE  0x00    // Tag should respond using one subcarrier (ASK)
    -- #define ISO15_REQ_DATARATE_HIGH      0x02    // Tag should respond using high data rate
    -- #define ISO15_REQ_NONINVENTORY       0x00
    0x01
        inventory
    0x00

    --]]

    local command, result, info, err, data

    data = utils.Crc15("260100")

    command = Command:newMIX{
            cmd = cmds.CMD_HF_ISO15693_COMMAND,
            arg1 = #data / 2,
            arg2 = 1,
            arg3 = 1,
            data = data
            }

    if slow then
        command.arg2 = 0
    end
    if dont_readresponse then
        command.arg3 = 0
    end

    local result, err = command:sendMIX()
    if result then
        local count, cmd, len, arg2, arg3 = bin.unpack('LLLL', result)
        if len == 0 then
            return nil, 'iso15693 card select failed'
        end
        data = string.sub(result, count, count+len-1)
        info, err = parse15693(data)
    else
        err = 'No response from card'
    end

    if err then
        print(err)
        return nil, err
    end
    return info
end

---
-- Waits for a ISO15693 card to be placed within the vicinity of the reader.
-- @return if successful: an table containing card info
-- @return if unsuccessful : nil, error
local function waitFor15693()
    print('Waiting for card... press <Enter> to quit')
    while not core.kbd_enter_pressed() do
        res, err = read15693()
        if res then return res end
        -- err means that there was no response from card
    end
    return nil, 'Aborted by user'
end

-- Sends an instruction to do nothing, only disconnect
local function disconnect15693()
    local c = Command:newMIX{cmd = cmds.CMD_HF_ISO15693_COMMAND}
    -- We can ignore the response here, no ACK is returned for this command
    -- Check /armsrc/iso14443a.c, ReaderIso14443a() for details
    return c:sendMIX(true)
end

local library = {
    read = read15693,
    waitFor15693 = waitFor15693,
    parse15693 = parse15693,
    disconnect = disconnect15693,
}

return library