vmsim

#!/usr/bin/env python3

import argparse
from pathlib import Path
from typing import Literal, get_args

from src import VMSimBase, VMSimClock, VMSimLRU, VMSimOpt, VMSimRand

AlgorithmStr = Literal["opt", "rand", "clock", "lru"]  # for type hinting

# map to get the algorithm from a string input
ALGORITHM_MAP: dict[AlgorithmStr, VMSimBase] = {
    "opt": VMSimOpt,
    "rand": VMSimRand,
    "clock": VMSimClock,
    "lru": VMSimLRU,
}


class VMSimArgs(argparse.Namespace):
    """This just adds type hints to the `args` variable in the main function"""

    n: int
    a: AlgorithmStr
    nv: bool  # Additional arg I added for 'not verbose' when testing
    tracefile: str


def main():
    """VMSim CLI entrypoint

    Args:
        n (int): Number of frames
        a (Algorithms): Algorithm to use (clock, lru, opt, rand)
        nv (bool): Enable non-verbose output
        tracefile (str): Path to trace trace_file

    Usage:
        usage: vmsim [-h] -n N -a {opt,rand,clock,lru} [-nv] tracefile

    Raises:
        FileNotFoundError: If the trace trace_file does not exist
        ValueError: If an non-positive integer is passed for the number of frames
    """
    parser = argparse.ArgumentParser()
    parser.add_argument("-n", type=int, required=True)
    parser.add_argument(
        "-a", type=str, choices=get_args(AlgorithmStr), required=True
    )  # `get_args` converts the literal type to a list of strings
    parser.add_argument("-nv", action="store_false")
    parser.add_argument("tracefile", type=str)

    args: VMSimArgs = parser.parse_args(namespace=VMSimArgs())

    if args.n < 1:
        raise ValueError("Number of frames must be a positive integer")

    trace_file_path = Path(args.tracefile)
    if trace_file_path.is_file() is False:
        raise FileNotFoundError(f"Trace trace_file does not exist: {trace_file_path}")

    vmsim: VMSimBase = ALGORITHM_MAP[args.a](args.n)
    vmsim.sim(trace_file_path.absolute(), verbose=args.nv)
    print(str(vmsim))


if __name__ == "__main__":
    main()