# 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 = 20

    _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

        try:
            reg_file = open("/sys/devices/platform/accton/qsfp_modprs")
        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)

        # Mask off the bit corresponding to our port
        mask = (1 << port_num)

        # ModPrsL is active low
        if reg_value & mask == 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

        try:
            reg_file = open("/sys/devices/platform/accton/qsfp_lpmode")
        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)

        # Mask off the bit corresponding to our port
        mask = (1 << port_num)

        # LPMode is active high
        if reg_value & mask == 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

        try:
            reg_file = open("/sys/devices/platform/accton/qsfp_lpmode", "r+")
        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)

        # Mask off the bit corresponding to our port
        mask = (1 << port_num)

        # LPMode is active high; set or clear the bit accordingly
        if lpmode is True:
            reg_value = reg_value | mask
        else:
            reg_value = reg_value & ~mask

        # 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):
        QSFP_RESET_REGISTER_DEVICE_FILE = "/sys/devices/platform/accton/qsfp_reset"

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

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

        content = reg_file.readline().rstrip()

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

        # Mask off the bit corresponding to our port
        mask = (1 << port_num)

        # ResetL is active low
        reg_value = reg_value & ~mask

        # 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 = reg_value | mask
        reg_file.seek(0)
        reg_file.write(hex(reg_value))
        reg_file.close()

        return True