import os
import json

from typing import List
from numpy import float64


# calculates throughput in gib/s from the meassured
# transfer duration (in nanoseconds) for a given element
# with the size of this given in bytes
def calc_throughput(size_bytes,time_ns):
    time_seconds = time_ns * 1e-9
    size_gib = size_bytes / (1024 ** 3)
    throughput_gibs = size_gib / time_seconds
    return throughput_gibs


# reverse array search: return index of value in array
def index_from_element(value,array):
    for (idx,val) in enumerate(array):
        if val == value: return idx
    return 0


# loads the measurements from a given file
def load_time_mesurements(file_path) -> List[float64]:
    with open(file_path, 'r') as file:
        data = json.load(file)
        count = data["count"]
        runcount_divisor = data["list"][0]["task"]["reps"]

        # if theres more than one thread, the internal repetition
        # count should be the same. if you decide it shouldnt
        # remove the check below

        if count > 1:
            for i in range(count):
                if runcount_divisor != data["list"][i]["task"]["reps"]:
                    print("Runcount missmatch between tasks. Check the commend above, aborting for now.")
                    os.abort()

        return [ x / runcount_divisor for x in data["timings"]]