# Copyright (c) 2021 The Regents of the University of California
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from m5.ticks import fromSeconds
from m5.util.convert import toLatency, toMemoryBandwidth
from m5.objects import PyTrafficGen, Port, BaseTrafficGen

from .abstract_core import AbstractCore
from .abstract_generator_core import AbstractGeneratorCore

from ..utils.override import overrides

from typing import Iterator


class RandomGeneratorCore(AbstractGeneratorCore):
    def __init__(
        self,
        duration: str,
        rate: str,
        block_size: int,
        min_addr: int,
        max_addr: int,
        rd_perc: int,
        data_limit: int,
    ) -> None:
        super(RandomGeneratorCore, self).__init__()
        """ The random generator core interface.

        This class defines the interface for a generator core that will create
        a random traffic specific to the parameters below. This core uses
        PyTrafficGen to create and inject the synthetic traffic.

        :param duration: The number of ticks for the generator core to generate
        traffic.
        :param rate: The rate at which the synthetic data is read/written.
        :param block_size: The number of bytes to be read/written with each
        request.
        :param min_addr: The lower bound of the address range the generator
        will read/write from/to.
        :param max_addr: The upper bound of the address range the generator
        will read/write from/to.
        :param rd_perc: The percentage of read requests among all the generated
        requests. The write percentage would be equal to 100 - rd_perc.
        :param data_limit: The amount of data in bytes to read/write by the
        generator before stopping generation.
        """
        self.generator = PyTrafficGen()
        self._duration = duration
        self._rate = rate
        self._block_size = block_size
        self._min_addr = min_addr
        self._max_addr = max_addr
        self._rd_perc = rd_perc
        self._data_limit = data_limit

    @overrides(AbstractCore)
    def connect_dcache(self, port: Port) -> None:
        self.generator.port = port

    def _set_traffic(self) -> None:
        """
        This private function will set the traffic to be generated.
        """
        self._traffic = self._create_traffic()

    def _create_traffic(self) -> Iterator[BaseTrafficGen]:
        """
        A python generator that yields (creates) a random traffic with the
        specified params in the generator core and then yields (creates) an
        exit traffic.

        :rtype: Iterator[BaseTrafficGen]
        """
        duration = fromSeconds(toLatency(self._duration))
        rate = toMemoryBandwidth(self._rate)
        period = fromSeconds(self._block_size / rate)
        min_period = period
        max_period = period
        yield self.generator.createRandom(
            duration,
            self._min_addr,
            self._max_addr,
            self._block_size,
            min_period,
            max_period,
            self._rd_perc,
            self._data_limit,
        )
        yield self.generator.createExit(0)

    def start_traffic(self) -> None:
        """
        A call to this function will start generating the traffic, this call
        should happen before m5.simulate() and after m5.instantiate().
        """
        self._set_traffic()
        self.generator.start(self._traffic)
