import platform
import ctypes
import os
import time
import queue
import threading

_lpath = (os.path.dirname(__file__))
if _lpath == '':
    _lpath = '.'
if platform.system() == "Windows":
    libftdicom =  ctypes.cdll.LoadLibrary(_lpath + "/libftdicom.dll")
else:
    libftdicom =  ctypes.cdll.LoadLibrary(_lpath + "/libftdicom.so")


class FTDI_Device(ctypes.Structure):
    _fields_ = [
        ('_1', ctypes.c_void_p),
        ('_2', ctypes.c_void_p),
    ]

pFTDI_Device = ctypes.POINTER(FTDI_Device)

# FTDIDevice_Open
FTDIDevice_Open = libftdicom.FTDIDevice_Open
FTDIDevice_Open.argtypes = [
        pFTDI_Device, # Dev
        ctypes.c_int  # Interface
    ]
FTDIDevice_Open.restype = ctypes.c_int

# FTDIDevice_Close
FTDIDevice_Close = libftdicom.FTDIDevice_Close
FTDIDevice_Close.argtypes = [pFTDI_Device]

FTDIDevice_SetMode = libftdicom.FTDIDevice_SetMode
FTDIDevice_SetMode.argtypes = [
        pFTDI_Device, # Dev
        ctypes.c_int, # Interface
        ctypes.c_int, # Mode
        ctypes.c_char, # PinDirection
        ctypes.c_char, # baudrate
    ]


FTDIDevice_Write = libftdicom.FTDIDevice_Write
FTDIDevice_Write.argtypes = [
        pFTDI_Device, # Dev
        ctypes.c_int, # Interface
        ctypes.c_char_p, # Buf
        ctypes.c_size_t, # N
        ctypes.c_bool, # async
    ]
FTDIDevice_Write.restype = ctypes.c_int

p_cb_StreamCallback = ctypes.CFUNCTYPE(
        ctypes.c_int,    # retval
        ctypes.POINTER(ctypes.c_uint8), # buf
        ctypes.c_int, # length
        ctypes.c_void_p, # progress
        ctypes.c_void_p) # userdata

FTDIDevice_ReadStream = libftdicom.FTDIDevice_ReadStream
FTDIDevice_ReadStream.argtypes = [
        pFTDI_Device,    # dev
        ctypes.c_int,    # interface
        p_cb_StreamCallback, # callback
        ctypes.c_void_p, # userdata
        ctypes.c_int, # packetsPerTransfer
        ctypes.c_int, # numTransfers
        ]
FTDIDevice_ReadStream.restype = ctypes.c_int

FTDI_INTERFACE_A = 1
FTDI_INTERFACE_B = 2

FTDI_BITMODE_SYNC_FIFO = (1 << 6)


class FTDIDevice:
    def __init__(self, interface, mode):
        self.__is_open = False
        self._dev = FTDI_Device()
        self.interface = interface
        self.mode = mode

    def __del__(self):
        if self.__is_open:
            self.__is_open = False
            FTDIDevice_Close(self._dev)

    def open(self):
        err = FTDIDevice_Open(self._dev, self.interface)
        if err:
            return err
        else:
            self.__is_open = True

        if self.mode == "synchronous":
            err = FTDIDevice_SetMode(self._dev, interface, FTDI_BITMODE_SYNC_FIFO,  0xFF, 0)

        return err

    def write(self, intf, buf, async=False):
        if not isinstance(buf, bytes):
            raise TypeError("buf must be bytes")

        return FTDIDevice_Write(self._dev, intf, buf, len(buf), async)

    def read(self, intf, n):
        buf = []

        def callback(b, prog):
            buf.extend(b)
            return int(len(buf) >= n)

        self.read_async(intf, callback, 4, 4)

        return buf

    def read_async(self, intf, callback, packetsPerTransfer, numTransfers):
        def callback_wrapper(buf, ll, prog, user):
            if ll:
                b = ctypes.string_at(buf, ll)
            else:
                b = b''
            return callback(b, prog)

        cb = p_cb_StreamCallback(callback_wrapper)

        return FTDIDevice_ReadStream(self._dev, intf, cb,
                None, packetsPerTransfer, numTransfers)


class ProtocolError(Exception):
    pass


class TimeoutError(Exception):
    pass


INCOMPLETE = -1
UNMATCHED = 0
class BaseService:
    def match_identifier(self, byt):
        r = True
        r = r and (byt[0] == 0x5A)
        r = r and (byt[1] == 0xA5)
        r = r and (byt[2] == 0x5A)
        r = r and (byt[3] == 0xA5)
        r = r and (byt[4] == self.tag)
        return r

    def get_needed_size_for_identifier(self):
        return self.NEEDED_FOR_SIZE

    def present_bytes(self, b):
        if len(b) < self.get_needed_size_for_identifier():
            return INCOMPLETE

        if not self.match_identifier(b):
            return UNMATCHED

        size = self.get_packet_size(b)

        if len(b) < size:
            return INCOMPLETE

        self.consume(b[:size])

        return size


class UART:
    class __UARTService(BaseService):
        NEEDED_FOR_SIZE = 9

        def __init__(self, tag):
            self.tag = tag
            self.q = queue.Queue()

        def get_packet_size(self, buf):
            return 10

        def consume(self, buf):
            self.q.put(buf[9])

    def __init__(self, tag):
        self.tag = tag
        self.service = UART.__UARTService(self.tag)

    def do_read(self, timeout=None):
        try:
            resp = self.service.q.get(True, timeout)
        except queue.Empty:
            return -1
        return resp

    def do_write(self, value):
        msg = [0x5A, 0xA5, 0x5A, 0xA5, self.tag, 0x00, 0x00, 0x00, 1, value&0xFF]
        self.service.write(bytes(msg))


class DMA:
    class __DMAService(BaseService):
        NEEDED_FOR_SIZE = 9

        def __init__(self, tag):
            self.tag = tag
            self.q = queue.Queue()

        def get_packet_size(self, buf):
            payload_size = buf[5] << 24
            payload_size |= buf[6] << 16
            payload_size |= buf[7] << 8
            payload_size |= buf[8] << 0
            return 9 + payload_size

        def consume(self, buf):
            self.q.put(buf[9:])

    def __init__(self, tag):
        self.tag = tag
        self.service = DMA.__DMAService(self.tag)

    def do_read(self, timeout=None):
        try:
            resp = list(self.service.q.get(True, timeout))
        except queue.Empty:
            raise TimeoutError("DMA read timed out")
        return resp

    def do_write(self, data):
        length = len(data)
        msg = [0x5A, 0xA5, 0x5A, 0xA5, self.tag,
            (length & 0xff000000) >> 24,
            (length & 0x00ff0000) >> 16,
            (length & 0x0000ff00) >> 8,
            (length & 0x000000ff) >> 0]
        msg += data
        self.service.write(bytes(msg))


class FTDIComDevice:
    def __init__(self, interface, mode, uart_tag=0, dma_tag=1, verbose=False):
        self.__is_open = False

        self.interface = interface
        self.mode = mode

        self.dev = FTDIDevice(interface, mode)
        self.verbose = verbose

        self.uart = UART(uart_tag)
        self.dma = DMA(dma_tag)

        self.__services = [self.uart.service, self.dma.service]

        # Inject a write function into the services
        for service in self.__services:
            def write(msg):
                if self.verbose:
                    print("< %s" % " ".join("%02x" % i for i in msg))

                self.dev.write(self.interface, msg, async=False)

            service.write = write

    def __comms(self):
        self.__buf = b""

        def callback(b, prog):
            try:
                if self.verbose and b:
                    print("> %s" % " ".join("%02x" % i for i in b))

                self.__buf += b

                incomplete = False

                while self.__buf and not incomplete:
                    for service in self.__services:
                        code = service.present_bytes(self.__buf)
                        if code == INCOMPLETE:
                            incomplete = True
                            break
                        elif code:
                            self.__buf = self.__buf[code:]
                            break
                    else:
                        self.__buf = self.__buf[1:]

                return int(self.__comm_term)
            except Exception as e:
                self.__comm_term = True
                self.__comm_exc = e
                return 1

        while not self.__comm_term:
            self.dev.read_async(self.interface, callback, 8, 16)

        if self.__comm_exc:
            raise self.__comm_exc

    def __del__(self):
        if self.__is_open:
            self.close()

    def open(self):
        if self.__is_open:
            raise ValueError("FTDICOMDevice doubly opened")

        stat = self.dev.open()
        if stat:
            print("USB: Error opening device\n")
            return stat

        self.commthread = threading.Thread(target=self.__comms, daemon=True)
        self.__comm_term = False
        self.__comm_exc = None

        self.commthread.start()

        self.__comm_term = False
        self.__is_open = True

    def close(self):
        if not self.__is_open:
            raise ValueError("FTDICOMDevice doubly closed")

        self.__comm_term = True
        self.commthread.join()

        self.__is_open = False

    def uartflush(self, timeout=0.25):
        while (self.uartread(timeout) != -1):
            pass

    def uartread(self, timeout=None):
        return self.uart.do_read(timeout)

    def uartwrite(self, value):
        return self.uart.do_write(value)

    def dmaread(self):
        return self.dma.do_read()

    def dmawrite(self, data):
        return self.dma.do_write(data)