#!/usr/bin/env python

#############################################################################
# Mellanox
#
# Module contains an implementation of SONiC Platform Base API and
# provides the PSUs status which are available in the platform
#
#############################################################################

try:
    import os.path
    from sonic_platform_base.psu_base import PsuBase
    from sonic_py_common.logger import Logger
    from sonic_platform.fan import Fan
    from .led import PsuLed, SharedLed, ComponentFaultyIndicator
    from .device_data import DEVICE_DATA
except ImportError as e:
    raise ImportError (str(e) + "- required module not found")


# Global logger class instance
logger = Logger()

psu_list = []

PSU_CURRENT = "current"
PSU_VOLTAGE = "voltage"
PSU_POWER = "power"

# in most platforms the file psuX_curr, psuX_volt and psuX_power contain current, voltage and power data respectively. 
# but there are exceptions which will be handled by the following dictionary

platform_dict_psu = {'x86_64-mlnx_msn3420-r0':1, 'x86_64-mlnx_msn3700-r0': 1, 'x86_64-mlnx_msn3700c-r0': 1, 'x86_64-mlnx_msn3800-r0': 1, 'x86_64-mlnx_msn4600c-r0':1, 'x86_64-mlnx_msn4700-r0': 1}

psu_profile_list = [
    # default filename convention
    {
        PSU_CURRENT : "power/psu{}_curr",
        PSU_VOLTAGE : "power/psu{}_volt",
        PSU_POWER : "power/psu{}_power"
    },
    # for 3420, 3700, 3700c, 3800, 4600c, 4700
    {
        PSU_CURRENT : "power/psu{}_curr",
        PSU_VOLTAGE : "power/psu{}_volt_out2",
        PSU_POWER : "power/psu{}_power"
    }
]

class Psu(PsuBase):
    """Platform-specific Psu class"""

    shared_led = None

    def __init__(self, psu_index, platform):
        global psu_list
        PsuBase.__init__(self)
        # PSU is 1-based on Mellanox platform
        self.index = psu_index + 1
        psu_list.append(self.index)
        self.psu_path = "/var/run/hw-management/"
        psu_oper_status = "thermal/psu{}_pwr_status".format(self.index)
        #psu_oper_status should always be present for all platforms
        self.psu_oper_status = os.path.join(self.psu_path, psu_oper_status)
        self._name = "PSU{}".format(psu_index + 1)

        if platform in platform_dict_psu:
            filemap = psu_profile_list[platform_dict_psu[platform]]
        else:
            filemap = psu_profile_list[0]

        self.psu_data = DEVICE_DATA[platform]['psus']

        if not self.psu_data['hot_swappable']:
            self.always_present = True
            self.psu_voltage = None
            self.psu_current = None
            self.psu_power = None
            self.psu_presence = None
            self.psu_temp = None
            self.psu_temp_threshold = None
        else:
            self.always_present = False
            psu_voltage = filemap[PSU_VOLTAGE].format(self.index)
            psu_voltage = os.path.join(self.psu_path, psu_voltage)
            self.psu_voltage = psu_voltage

            psu_current = filemap[PSU_CURRENT].format(self.index)
            psu_current = os.path.join(self.psu_path, psu_current)
            self.psu_current = psu_current

            psu_power = filemap[PSU_POWER].format(self.index)
            psu_power = os.path.join(self.psu_path, psu_power)
            self.psu_power = psu_power

            psu_presence = "thermal/psu{}_status".format(self.index)
            psu_presence = os.path.join(self.psu_path, psu_presence)
            self.psu_presence = psu_presence

            self.psu_temp = os.path.join(self.psu_path, 'thermal/psu{}_temp'.format(self.index))
            self.psu_temp_threshold = os.path.join(self.psu_path, 'thermal/psu{}_temp_max'.format(self.index))

        # unplugable PSU has no FAN
        if self.psu_data['hot_swappable']:
            fan = Fan(psu_index, None, True)
            self._fan_list.append(fan)

        if self.psu_data['led_num'] == 1:
            self.led = ComponentFaultyIndicator(Psu.get_shared_led())
        else: # 2010/2100
            self.led = PsuLed(self.index)


    def get_name(self):
        return self._name


    def _read_generic_file(self, filename, len):
        """
        Read a generic file, returns the contents of the file
        """
        result = 0
        try:
            if not os.path.exists(filename):
                return result
            with open(filename, 'r') as fileobj:
                result = int(fileobj.read().strip())
        except Exception as e:
            logger.log_info("Fail to read file {} due to {}".format(filename, repr(e)))
        return result


    def get_powergood_status(self):
        """
        Retrieves the operational status of power supply unit (PSU) defined

        Returns:
            bool: True if PSU is operating properly, False if not
        """
        status = self._read_generic_file(os.path.join(self.psu_path, self.psu_oper_status), 0)

        return status == 1


    def get_presence(self):
        """
        Retrieves the presence status of power supply unit (PSU) defined

        Returns:
            bool: True if PSU is present, False if not
        """
        if self.always_present:
            return self.always_present
        else:
            status = self._read_generic_file(self.psu_presence, 0)
            return status == 1


    def get_voltage(self):
        """
        Retrieves current PSU voltage output

        Returns:
            A float number, the output voltage in volts, 
            e.g. 12.1 
        """
        if self.psu_voltage is not None and self.get_powergood_status():
            voltage = self._read_generic_file(self.psu_voltage, 0)
            return float(voltage) / 1000
        else:
            return None


    def get_current(self):
        """
        Retrieves present electric current supplied by PSU

        Returns:
            A float number, the electric current in amperes, e.g 15.4
        """
        if self.psu_current is not None and self.get_powergood_status():
            amperes = self._read_generic_file(self.psu_current, 0)
            return float(amperes) / 1000
        else:
            return None

    def get_power(self):
        """
        Retrieves current energy supplied by PSU

        Returns:
            A float number, the power in watts, e.g. 302.6
        """
        if self.psu_power is not None and self.get_powergood_status():
            power = self._read_generic_file(self.psu_power, 0)
            return float(power) / 1000000
        else:
            return None

    def set_status_led(self, color):
        """
        Sets the state of the PSU status LED

        Args:
            color: A string representing the color with which to set the
                   PSU status LED

        Returns:
            bool: True if status LED state is set successfully, False if not

        Notes:
            Only one led for all PSUs.
        """
        return self.led.set_status(color)


    def get_status_led(self):
        """
        Gets the state of the PSU status LED

        Returns:
            A string, one of the predefined STATUS_LED_COLOR_* strings above
        """
        if self.psu_data['led_num'] == 1:
            return Psu.get_shared_led().get_status()
        else:
            return self.led.get_status()


    def get_power_available_status(self):
        """
        Gets the power available status

        Returns:
            True if power is present and power on. 
            False and "absence of PSU" if power is not present.
            False and "absence of power" if power is present but not power on.
        """
        if not self.get_presence():
            return False, "absence of PSU"
        elif not self.get_powergood_status():
            return False, "absence of power"
        else:
            return True, ""

    @classmethod
    def get_shared_led(cls):
        if not cls.shared_led:
            cls.shared_led = SharedLed(PsuLed(None))
        return cls.shared_led

    def get_temperature(self):
        """
        Retrieves current temperature reading from PSU

        Returns:
            A float number of current temperature in Celsius up to nearest thousandth
            of one degree Celsius, e.g. 30.125 
        """
        if self.psu_temp is not None and self.get_powergood_status():
            try:
                temp = self._read_generic_file(self.psu_temp, 0)
                return float(temp) / 1000
            except Exception as e:
                logger.log_info("Fail to get temperature for PSU {} due to - {}".format(self._name, repr(e)))
        
        return None

    def get_temperature_high_threshold(self):
        """
        Retrieves the high threshold temperature of PSU

        Returns:
            A float number, the high threshold temperature of PSU in Celsius
            up to nearest thousandth of one degree Celsius, e.g. 30.125
        """
        if self.psu_temp_threshold is not None and self.get_powergood_status():
            try:
                temp_threshold = self._read_generic_file(self.psu_temp_threshold, 0)
                return float(temp_threshold) / 1000
            except Exception as e:
                logger.log_info("Fail to get temperature threshold for PSU {} due to - {}".format(self._name, repr(e)))
        
        return None

    def get_voltage_high_threshold(self):
        """
        Retrieves the high threshold PSU voltage output

        Returns:
            A float number, the high threshold output voltage in volts, 
            e.g. 12.1 
        """
        # hw-management doesn't expose those sysfs for now
        raise NotImplementedError

    def get_voltage_low_threshold(self):
        """
        Retrieves the low threshold PSU voltage output

        Returns:
            A float number, the low threshold output voltage in volts, 
            e.g. 12.1 
        """
        # hw-management doesn't expose those sysfs for now
        raise NotImplementedError