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

try:
    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 = 72
    PORTS_IN_BLOCK = 72

    _port_to_eeprom_mapping = {}
    _port_to_i2c_mapping = {
           49: 28, #QSFP49
           50: 28,
           51: 28,
           52: 28,
           53: 29, #QSFP50
           54: 29,
           55: 29,
           56: 29,
           57: 26, #QSFP51
           58: 26,
           59: 26,
           60: 26,
           61: 30, #QSFP52
           62: 30,
           63: 30,
           64: 30,
           65: 31, #QSFP53
           66: 31,
           67: 31,
           68: 31,
           69: 27, #QSFP54
           70: 27,
           71: 27,
           72: 27,
           }

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

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

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

    @property
    def qsfp_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 = '/sys/bus/i2c/devices/{0}-0050/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])

        SfpUtilBase.__init__(self)


    # For port 49~54 are QSFP, here presumed they're all split to 4 lanes.
    def get_cage_num(self, port_num):             
        cage_num = port_num
        if (port_num >= self.PORT_START):
            cage_num = (port_num - self.PORT_START)/4
            cage_num = cage_num + self.PORT_START

        return cage_num

    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
        
        cage_num = self.get_cage_num(port_num)
        path = "/sys/bus/i2c/devices/3-0062/module_present_{0}"
        port_ps = path.format(cage_num)

        try:
            val_file = open(port_ps)
        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_cpld(self, port_num):             
        if port_num < self.qsfp_port_start or port_num > self.qsfp_port_end:
            return False

        cage_num = self.get_cage_num(port_num)
        path = "/sys/bus/i2c/devices/3-0062/module_lpmode_{0}"
        lp_mode_path = path.format(cage_num)
        
        try:
            val_file = open(lp_mode_path)
        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):             
        if port_num < self.qsfp_port_start or port_num > self.qsfp_port_end:
            return False
        
        if not self.get_presence(port_num):
            return False

        try:
            eeprom = None

            eeprom = open(self.port_to_eeprom_mapping[port_num], mode="rb", buffering=0)
            eeprom.seek(93)
            lpmode = ord(eeprom.read(1))

            if not (lpmode & 0x1): # 'Power override' bit is 0
                return self.get_low_power_mode_cpld(port_num)
            else:
                if ((lpmode & 0x2) == 0x2):
                    return True # Low Power Mode if "Power set" bit is 1
                else:
                    return False # High Power Mode if "Power set" bit is 0
        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):
        if port_num < self.qsfp_port_start or port_num > self.qsfp_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
            regval = 0x3 if lpmode else 0x1 # 0x3:Low Power Mode, 0x1:High Power Mode
            buffer = create_string_buffer(1)
            buffer[0] = chr(regval)

            # Write to eeprom
            eeprom = open(self.port_to_eeprom_mapping[port_num], mode="r+b", buffering=0)
            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):
        if port_num < self.qsfp_port_start or port_num > self.qsfp_port_end:
            return False
         
        cage_num = self.get_cage_num(port_num)
        path = "/sys/bus/i2c/devices/3-0062/module_reset_{0}"
        port_ps = path.format(cage_num)
        try:
            reg_file = open(port_ps, mode="w", buffering=0)
        except IOError as e:
            print "Error: unable to open file: %s" % str(e)          
            return False

        #toggle reset
        reg_file.seek(0)
        reg_file.write('0')
        time.sleep(1)
        reg_file.seek(0)
        reg_file.write('1')
        reg_file.close()
        
        return True

    @property
    def _get_presence_bitmap(self):

        bitmap = ""
        try:
            reg_file = open("/sys/bus/i2c/devices/3-0062/module_present_all")
        except IOError as e:
            print "Error: unable to open file: %s" % str(e)
            return False
        bitmap += reg_file.readline().rstrip() + " "
        reg_file.close()

        rev = bitmap.split(" ")
        rev.pop() # Remove the last useless character

        # Save port 49-54 into buffer
        tmp = rev.pop()

        # Insert port 1-48
        for i in range (0, 6):
            rev.append(hex(0)[2:])
            rev[i] = rev[i].zfill(2)

        # Expand port 49-54
        for i in range (0, 6):
            val = (int(tmp,16) >> i) & 0x1
            rev.append(hex(val)[2:])

        rev = "".join(rev[::-1])
        return int(rev,16)

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

        start_time = time.time()
        port_dict = {}
        port = 0
        blocking = False

        if timeout == 0:
            blocking = True
        elif timeout > 0:
            timeout = timeout / float(1000) # Convert to secs
        else:
            print "get_transceiver_change_event:Invalid timeout value", timeout
            return False, {}

        end_time = start_time + timeout
        if start_time > end_time:
            print 'get_transceiver_change_event:' \
                       'time wrap / invalid timeout value', timeout

            return False, {} # Time wrap or possibly incorrect timeout

        while timeout >= 0:
            # Check for OIR events and return updated port_dict

            reg_value = self._get_presence_bitmap
            changed_ports = self.data['present'] ^ reg_value
            if changed_ports:
                for port in range (self.port_start, self.port_end+1):
                    # Mask off the bit corresponding to our port
                    mask = (1 << (port - 1))
                    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
                self.data['valid'] = 1
                return True, port_dict

            if blocking:
                time.sleep(1)
            else:
                timeout = end_time - time.time()
                if timeout >= 1:
                    time.sleep(1) # We poll at 1 second granularity
                else:
                    if timeout > 0:
                        time.sleep(timeout)
                    return True, {}
        print "get_transceiver_change_event: Should not reach here."
        return False, {}