#
# Copyright 2017 Ettus Research (National Instruments)
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
"""
N310 implementation module
"""

from __future__ import print_function
import os
from six import iteritems
from builtins import object
from .base import PeriphManagerBase
from ..net import get_iface_addrs
from ..net import byte_to_mac
from ..net import get_mac_addr
from ..mpmtypes import SID
from usrp_mpm.uio import UIO
from ..sysfs_gpio import SysFSGPIO
from ..ethtable import EthDispatcherTable
from .. import libpyusrp_periphs as lib


N3XX_DEFAULT_EXT_CLOCK_FREQ = 10e6
N3XX_DEFAULT_CLOCK_SOURCE = 'external'
N3XX_DEFAULT_TIME_SOURCE = 'internal'
N3XX_DEFAULT_ENABLE_GPS = True
N3XX_DEFAULT_ENABLE_FPGPIO = True

class TCA6424(object):
    """
    Abstraction layer for the port/gpio expander
    """
    pins = (
        'PWREN-CLK-MGT156MHz',
        'PWREN-CLK-WB-CDCM',
        'WB-CDCM-RESETn',
        'WB-CDCM-PR0',
        'WB-CDCM-PR1',
        'WB-CDCM-OD0',
        'WB-CDCM-OD1',
        'WB-CDCM-OD2',
        'PWREN-CLK-MAINREF',
        'CLK-MAINREF-SEL1',
        'CLK-MAINREF-SEL0',
        '12',
        '13',
        'FPGA-GPIO-EN',
        'PWREN-CLK-WB-20MHz',
        'PWREN-CLK-WB-25MHz',
        'GPS-PHASELOCK',
        'GPS-nINITSURV',
        'GPS-nRESET',
        'GPS-WARMUP',
        'GPS-SURVEY',
        'GPS-LOCKOK',
        'GPS-ALARM',
        'PWREN-GPS',
    )

    def __init__(self):
        # Default state: Turn on GPS power, take GPS out of reset or
        # init-survey, turn on 156.25 MHz clock
        self._gpios = SysFSGPIO('tca6424', 0xFFE7FF, 0x86E7FF, 0x860001)

    def set(self, name, value=None):
        """
        Assert a pin by name
        """
        assert name in self.pins
        self._gpios.set(self.pins.index(name), value=value)

    def reset(self, name):
        """
        Deassert a pin by name
        """
        self.set(name, value=0)

    def get(self, name):
        """
        Read back a pin by name
        """
        assert name in self.pins
        return self._gpios.get(self.pins.index(name))

class FP_GPIO(object):
    """
    Abstraction layer for the front panel GPIO
    """
    EMIO_BASE = 54
    FP_GPIO_OFFSET = 32 # Bit offset within the ps_gpio_* pins

    def __init__(self, ddr):
        self._gpiosize = 12
        self._offset = self.FP_GPIO_OFFSET + self.EMIO_BASE
        self.usemask = 0xFFF
        self.ddr = ddr
        self._gpios = SysFSGPIO(
            'zynq_gpio',
            self.usemask<<self._offset,
            self.ddr<<self._offset
        )

    def set_all(self, value):
        """
        Assert all pin to the value.
        This method will convert value into binary and take the first 6 bits
        assign to 6pins.
        """
        bin_value = '{0:06b}'.format(value)
        wr_value = bin_value[-(self._gpiosize):]
        for i in range(self._gpiosize):
            if  (1<<i)&self.ddr:
                self._gpios.set(self._offset+i, wr_value[i%6])

    def set(self, index, value=None):
        """
        Assert a pin by index
        """
        assert index in range(self._gpiosize)
        self._gpios.set(self._offset+index, value)

    def reset_all(self):
        """
         Deassert all pins
        """
        for i in range(self._gpiosize):
            self._gpios.reset(self._offset+i)

    def reset(self, index):
        """
         Deassert a pin by index
        """
        assert index in range(self._gpiosize)
        self._gpios.reset(self._offset+index)

    def get_all(self):
        """
        Read back all pins
        """
        result = 0
        for i in range(self._gpiosize):
            if not (1<<i)&self.ddr:
                value = self._gpios.get(self._offset+i)
                result = (result<<1) | value
        return result

    def get(self, index):
        """
        Read back a pin by index
        """
        assert index in range(self._gpiosize)
        return self._gpios.get(self._offset+index)

class n310(PeriphManagerBase):
    """
    Holds N310 specific attributes and methods
    """
    #########################################################################
    # Overridables
    #
    # See PeriphManagerBase for documentation on these fields
    #########################################################################
    pids = [0x4242,]
    mboard_eeprom_addr = "e0005000.i2c"
    mboard_eeprom_max_len = 256
    mboard_info = {"type": "n3xx"}
    dboard_eeprom_addr = "e0004000.i2c"
    dboard_eeprom_max_len = 64
    # We're on a Zynq target, so the following two come from the Zynq standard
    # device tree overlay (tree/arch/arm/boot/dts/zynq-7000.dtsi)
    dboard_spimaster_addrs = ["e0006000.spi", "e0007000.spi"]
    chdr_interfaces = ['eth1', 'eth2']
    # N310-specific settings
    eth_tables = {'eth1': 'misc-enet-regs0', 'eth2': 'misc-enet-regs1'}

    def __init__(self, args):
        super(n310, self).__init__(args)
        # Init peripherals
        self.log.trace("Initializing TCA6424 port expander controls...")
        self._gpios = TCA6424()
        self._gpios.set("PWREN-CLK-MGT156MHz")
        self.enable_gps(
            enable=bool(
                args.default_args.get('enable_gps', N3XX_DEFAULT_ENABLE_GPS)
            )
        )
        self.enable_fp_gpio(
            enable=bool(
                args.default_args.get(
                    'enable_fp_gpio',
                    N3XX_DEFAULT_ENABLE_FPGPIO
                )
            )
        )
        # Init clocking
        self.enable_ref_clock(enable=True)
        self._ext_clock_freq = None
        self._clock_source = None
        self._time_source = None
        self._init_ref_clock_and_time(args.default_args)
        # Init Ethernet
        self._eth_dispatchers = {
            x: EthDispatcherTable(self.eth_tables.get(x))
            for x in list(self._chdr_interfaces.keys())
        }
        for ifname, table in iteritems(self._eth_dispatchers):
            table.set_ipv4_addr(self._chdr_interfaces[ifname]['ip_addr'])
        # Init complete.
        self.log.info("mboard info: {}".format(self.mboard_info))

    def _init_ref_clock_and_time(self, default_args):
        """
        Initialize clock and time sources. After this function returns, the
        reference signals going to the FPGA are valid.
        """
        self._ext_clock_freq = float(
            default_args.get('ext_clock_freq', N3XX_DEFAULT_EXT_CLOCK_FREQ)
        )
        self.set_clock_source(
            default_args.get('clock_source', N3XX_DEFAULT_CLOCK_SOURCE)
        )
        self.set_time_source(
            default_args.get('time_source', N3XX_DEFAULT_TIME_SOURCE)
        )

    def init(self, args):
        """
        Calls init() on the parent class, and then programs the Ethernet
        dispatchers accordingly.
        """
        result = super(n310, self).init(args)
        for _, table in iteritems(self._eth_dispatchers):
            if 'forward_eth' in args or 'forward_bcast' in args:
                table.set_forward_policy(
                    args.get('forward_eth', False),
                    args.get('forward_bcast', False)
                )
        if 'preload_ethtables' in args:
            self._preload_ethtables(
                self._eth_dispatchers,
                args['preload_ethtables']
            )
        return result

    def _preload_ethtables(self, eth_dispatchers, table_file):
        """
        Populates the ethernet tables from a JSON file
        """
        import json
        try:
            eth_table_data = json.load(open(table_file))
        except ValueError as ex:
            self.log.warning(
                "Bad values in preloading table file: %s",
                str(ex)
            )
            return
        self.log.info(
            "Preloading Ethernet dispatch tables from JSON file `%s'.",
            table_file
        )
        for eth_iface, data in iteritems(eth_table_data):
            if eth_iface not in eth_dispatchers:
                self.log.warning(
                    "Request to preload eth dispatcher table for "
                    "iface `{}', but no such interface is "
                    "registered. Known interfaces: {}".format(
                        str(eth_iface),
                        ",".join(eth_dispatchers.keys())
                    )
                )
                continue
            eth_dispatcher = eth_dispatchers[eth_iface]
            self.log.debug("Preloading {} dispatch table".format(eth_iface))
            try:
                for dst_ep, udp_data in iteritems(data):
                    sid = SID()
                    sid.set_dst_ep(int(dst_ep))
                    eth_dispatcher.set_route(
                        sid,
                        udp_data['ip_addr'],
                        udp_data['port'],
                        udp_data.get('mac_addr', None)
                    )
            except ValueError as ex:
                self.log.warning(
                    "Bad values in preloading table file: %s",
                    str(ex)
                )

    def _allocate_sid(self, sender_addr, port, sid, xbar_src_addr, xbar_src_port, new_ep):
        """
        Get the MAC address of the sender and store it in the FPGA ARP table
        """
        mac_addr = get_mac_addr(sender_addr)
        if new_ep not in self._available_endpoints:
            raise RuntimeError("no more sids yo")
        self._available_endpoints.remove(new_ep)
        if mac_addr is not None:
            if sender_addr not in self.sid_endpoints:
                self.sid_endpoints.update({sender_addr: (new_ep,)})
            else:
                current_allocation = self.sid_endpoints.get(sender_addr)
                new_allocation = current_allocation + (new_ep,)
                self.sid_endpoints.update({sender_addr: new_allocation})
            sid = SID(sid)
            sid.set_src_addr(xbar_src_addr)
            sid.set_src_ep(new_ep)
            my_xbar = lib.xbar.xbar.make("/dev/crossbar0") # TODO
            my_xbar.set_route(xbar_src_addr, 0) # TODO
            eth_dispatcher = self._eth_dispatchers['eth1'] # TODO
            eth_dispatcher.set_route(sid.reversed(), sender_addr, port)
        return sid.get()

    def get_clock_sources(self):
        " Lists all available clock sources. "
        self.log.trace("Listing available clock sources...")
        return ('external', 'internal', 'gpsdo')

    def get_clock_source(self):
        " Returns the currently selected clock source "
        return self._clock_source

    def set_clock_source(self, *args):
        """
        Enable given external reference clock.

        Throws if clock_source is not a valid value.
        """
        clock_source = args[0]
        assert clock_source in self.get_clock_sources()
        self.log.trace("Setting clock source to `{}'".format(clock_source))
        if clock_source == 'internal':
            self._gpios.set("CLK-MAINREF-SEL0")
            self._gpios.set("CLK-MAINREF-SEL1")
        elif clock_source == 'gpsdo':
            self._gpios.set("CLK-MAINREF-SEL0")
            self._gpios.reset("CLK-MAINREF-SEL1")
        else: # external
            self._gpios.reset("CLK-MAINREF-SEL0")
            self._gpios.reset("CLK-MAINREF-SEL1")
        self._clock_source = clock_source
        ref_clk_freq = self.get_ref_clock_freq()
        self.log.info("Reference clock frequency is: {} MHz".format(
            ref_clk_freq/1e6
        ))
        for slot, dboard in enumerate(self.dboards):
            if hasattr(dboard, 'update_ref_clock_freq'):
                self.log.trace(
                    "Updating reference clock on dboard `{}' to {} MHz...".format(
                        slot, ref_clk_freq/1e6
                    )
                )
                dboard.update_ref_clock_freq(ref_clk_freq)

    def set_ref_clock_freq(self, freq):
        """
        Tell our USRP what the frequency of the external reference clock is.

        Will throw if it's not a valid value.
        """
        assert freq in (10e6, 20e6, 25e6)
        self.log.debug("We've been told the external reference clock " \
                       "frequency is {} MHz.".format(freq/1e6))
        self._ext_clock_freq = freq

    def get_ref_clock_freq(self):
        " Returns the currently active reference clock frequency"
        return {
            'internal': 25e6,
            'external': self._ext_clock_freq,
            'gpsdo': 20e6,
        }[self._clock_source]

    def get_time_sources(self):
        " Returns list of valid time sources "
        return ['internal', 'external']

    def get_time_source(self):
        " Return the currently selected time source "
        return self._time_source

    def set_time_source(self, time_source):
        " Set a time source "
        assert time_source in self.get_time_sources()
        self.log.trace("Setting time source to `{}'".format(time_source))
        # FIXME use uio
        if time_source == 'internal':
            os.system('devmem2 0x4001000C w 0x1')
        elif time_source == 'external':
            os.system('devmem2 0x4001000C w 0x0')
        else:
            assert False

    def enable_gps(self, enable):
        """
        Turn power to the GPS off or on.
        """
        self.log.trace("{} power to GPS".format(
            "Enabling" if enable else "Disabling"
        ))
        self._gpios.set("PWREN-GPS", int(bool(enable)))

    def enable_fp_gpio(self, enable):
        """
        Turn power to the front panel GPIO off or on.
        """
        self.log.trace("{} power to front-panel GPIO".format(
            "Enabling" if enable else "Disabling"
        ))
        self._gpios.set("FPGA-GPIO-EN", int(bool(enable)))

    def enable_ref_clock(self, enable):
        """
        Enables the ref clock voltage (+3.3-MAINREF). Without setting this to
        True, *no* ref clock works.
        """
        self.log.trace("{} power to reference clocks".format(
            "Enabling" if enable else "Disabling"
        ))
        self._gpios.set("PWREN-CLK-MAINREF", int(bool(enable)))