import random
import sys

import numpy as np


FILE_COLUMN_NAMES = [
    "n", "m", "v1", "v2", "v3", "p1", "p2", "p3",
]


def write_data_file(filename, n=20, missing_values=False):
    """Write a csv file with data
    """

    with open(filename, "w") as fp:
        fp.write(", ".join(FILE_COLUMN_NAMES) + ",\n")
        for i in range(n):
            vals = []
            vals.append(random.gauss(3., 0.5))
            vals.extend(
                (
                    random.gauss(0., 25),
                    random.gauss(0., 25),
                    random.gauss(0., 25),
                )
            )
            vals.extend(
                (
                    random.gauss(0., 1.5),
                    random.gauss(0., 1.5),
                    random.gauss(0., 1.5),
                )
            )
            if missing_values:
                if random.randint(0,10) < 1:
                    idx = random.randint(1, len(vals))
                    vals[idx] = np.nan
            line = f"{i}, " + ", ".join(f"{v:7.5f}" for v in vals) + ",\n"
            fp.write(line)


if __name__ == '__main__':
    missing_values = sys.argv[-1] == '-m'

    write_data_file("sample_data.csv", n=20, missing_values=True)