# sfputil.py
#
# Platform-specific SFP transceiver interface for SONiC
#

try:
    import time
    from sonic_sfp.sfputilbase import SfpUtilBase
except ImportError as e:
    raise ImportError("%s - required module not found" % str(e))


class SfpUtil(SfpUtilBase):
    """Platform-specific SfpUtil class"""

    PORT_START = 0
    PORT_END = 31
    PORTS_IN_BLOCK = 32

    EEPROM_OFFSET = 10

    _port_to_eeprom_mapping = {}

    @property
    def port_start(self):
        return self.PORT_START

    @property
    def port_end(self):
        return self.PORT_END

    @property
    def qsfp_ports(self):
        return range(0, self.PORTS_IN_BLOCK + 1)

    @property
    def port_to_eeprom_mapping(self):
        return self._port_to_eeprom_mapping

    def __init__(self):
        eeprom_path = "/sys/class/i2c-adapter/i2c-{0}/{0}-0050/eeprom"

        for x in range(0, self.port_end + 1):
            self._port_to_eeprom_mapping[x] = eeprom_path.format(x + self.EEPROM_OFFSET)

        SfpUtilBase.__init__(self)

    def get_presence(self, port_num):
        # Check for invalid port_num
        if port_num < self.port_start or port_num > self.port_end:
            return False

        if port_num > 16:
            cpld_addr=33
        else:
            cpld_addr=32

        file_path="/sys/bus/i2c/devices/1-00" + str(cpld_addr) + "/port" + str(port_num) + "/port" + str(port_num) + "_present"

        try:
            reg_file = open("file_path")
        except IOError as e:
            print "Error: unable to open file: %s" % str(e)
            return False

        content = reg_file.readline().rstrip()

        # content is a string containing the hex representation of the register
        reg_value = int(content, 16)


        # ModPrsL is active low
        if reg_value == 0:
            return True

        return False

    def get_low_power_mode(self, port_num):
        # Check for invalid port_num
        if port_num < self.port_start or port_num > self.port_end:
            return False

        if port_num > 16:
            cpld_addr=33
        else:
            cpld_addr=32


        file_path="/sys/bus/i2c/devices/1-00" + str(cpld_addr) + "/port" + str(port_num) + "/port" + str(port_num) + "_lpmode"

        try:
            reg_file = open(file_path)
        except IOError as e:
            print "Error: unable to open file: %s" % str(e)

        content = reg_file.readline().rstrip()

        # content is a string containing the hex representation of the register
        reg_value = int(content, 16)

        # LPMode is active high
        if reg_value == 0:
            return False

        return True

    def set_low_power_mode(self, port_num, lpmode):
        # Check for invalid port_num
        if port_num < self.port_start or port_num > self.port_end:
            return False

        if port_num > 16:
            cpld_addr=33
        else:
            cpld_addr=32

        file_path="/sys/bus/i2c/devices/1-00" + str(cpld_num) + "/port" + str(port_num) + "/port" + str(port_num) + "_lpmode"

        try:
            reg_file = open(file_path, "r+")
        except IOError as e:
            print "Error: unable to open file: %s" % str(e)
            return False

        # LPMode is active high; set or clear the bit accordingly
        if lpmode is True:
            reg_value = 1 
        else:
            reg_value = 0

        # Convert our register value back to a hex string and write back
        content = hex(reg_value)

        reg_file.seek(0)
        reg_file.write(content)
        reg_file.close()

        return True

    def reset(self, port_num):

        # Check for invalid port_num
        if port_num < self.port_start or port_num > self.port_end:
            return False

        if port_num > 16:
            cpld_addr=33
        else:
            cpld_addr=32

        file_path="/sys/bus/i2c/devices/1-00" + str(cpld_num) + "/port" + str(port_num) + "/port" + str(port_num) + "_rst"

        try:
            reg_file = open(file_path, "r+")
        except IOError as e:
            print "Error: unable to open file: %s" % str(e)
            return False

        # ResetL is active low
        reg_value = 0

        # Convert our register value back to a hex string and write back
        reg_file.seek(0)
        reg_file.write(hex(reg_value))
        reg_file.close()

        # Sleep 1 second to allow it to settle
        time.sleep(1)

        # Flip the bit back high and write back to the register to take port out of reset
        try:
            reg_file = open(QSFP_RESET_REGISTER_DEVICE_FILE, "w")
        except IOError as e:
            print "Error: unable to open file: %s" % str(e)
            return False

        reg_value = 1
        reg_file.seek(0)
        reg_file.write(hex(reg_value))
        reg_file.close()

        return True

    def get_transceiver_change_event(self):
        """
        TODO: This function need to be implemented
        when decide to support monitoring SFP(Xcvrd)
        on this platform.
        """
        raise NotImplementedError