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

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

SFP_STATUS_INSERTED = '1'
SFP_STATUS_REMOVED = '0'

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

    PORT_START = 49
    PORT_END = 54
    PORTS_IN_BLOCK = 54
    QSFP_START = 53

    BASE_OOM_PATH = "/sys/bus/i2c/devices/{0}-0050/"
    BASE_CPLD_PATH = "/sys/bus/i2c/devices/3-0060/"

    _port_to_is_present = {}
    _port_to_lp_mode = {}

    _port_to_eeprom_mapping = {}
    _port_to_i2c_mapping = {
           49: [18],
           50: [19],
           51: [20],
           52: [21],
           53: [22],
           54: [23],
           }

    @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(self.PORT_START, self.PORTS_IN_BLOCK + 1)

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

    def __init__(self):
        eeprom_path = self.BASE_OOM_PATH + "eeprom"
        for x in range(self.port_start, self.port_end+1):
            self.port_to_eeprom_mapping[x] = eeprom_path.format(
                self._port_to_i2c_mapping[x][0])
        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

        present_path = self.BASE_CPLD_PATH + "module_present_" + str(port_num)
        self.__port_to_is_present = present_path

        try:
            val_file = open(self.__port_to_is_present)
        except IOError as e:
            print "Error: unable to open file: %s" % str(e)
            return False

        content = val_file.readline().rstrip()
        val_file.close()

        # content is a string, either "0" or "1"
        if content == "1":
            return True

        return False

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

        try:
            eeprom = None
            if not self.get_presence(port_num):
                return False
            eeprom = open(self.port_to_eeprom_mapping[port_num], "rb")
            eeprom.seek(93)
            lpmode = ord(eeprom.read(1))

            # if "Power override" bit is 1 and "Power set" bit is 1
            if ((lpmode & 0x3) == 0x3):
                return True

            # High Power Mode if one of the following conditions is matched:
            # 1. "Power override" bit is 0
            # 2. "Power override" bit is 1 and "Power set" bit is 0
            else:
                return False

        except IOError as e:
            print "Error: unable to open file: %s" % str(e)
            return False
        finally:
            if eeprom is not None:
                eeprom.close()
                time.sleep(0.01)

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

        try:
            eeprom = None
            if not self.get_presence(port_num):
                return False # Port is not present, unable to set the eeprom

            # Fill in write buffer
            # 0x3:Low Power Mode, 0x1:High Power Mode
            regval = 0x3 if lpmode else 0x1

            buffer = create_string_buffer(1)
            buffer[0] = chr(regval)

            # Write to eeprom
            eeprom = open(self.port_to_eeprom_mapping[port_num], "r+b")
            eeprom.seek(93)
            eeprom.write(buffer[0])
            return True
        except IOError as e:
            print "Error: unable to open file: %s" % str(e)
            return False
        finally:
            if eeprom is not None:
                eeprom.close()
                time.sleep(0.01)

    def reset(self, port_num):
        raise NotImplementedError

    @property
    def _get_presence_bitmap(self):

        bits = []
        for x in range(self.port_start, self.port_end+1):
          bits.append(str(int(self.get_presence(x))))

        rev = "".join(bits[::-1])
        return int(rev,2)

    data = {'present':0}
    def get_transceiver_change_event(self, timeout=0):
        port_dict = {}

        if timeout == 0:
            cd_ms = sys.maxint
        else:
            cd_ms = timeout

        #poll per second
        while cd_ms > 0:
            reg_value = self._get_presence_bitmap
            changed_ports = self.data['present'] ^ reg_value
            if changed_ports != 0:
                break
            time.sleep(1)
            cd_ms = cd_ms - 1000

        if changed_ports != 0:
            for port in range (self.port_start, self.port_end+1):
                # Mask off the bit corresponding to our port
                mask = (1 << (port - self.port_start))
                if changed_ports & mask:
                    if (reg_value & mask) == 0:
                        port_dict[port] = SFP_STATUS_REMOVED
                    else:
                        port_dict[port] = SFP_STATUS_INSERTED

            # Update cache
            self.data['present'] = reg_value
            return True, port_dict
        else:
            return True, {}
        return False, {}