#!/usr/bin/env python3

import os

from .print_msg import print_err_msg_exit
from .run_command import run_command
from .environment import set_env_var


def check_darwin(cmd):
    """Check if darwin command exists"""

    (err, _, _) = run_command(f"command -v {cmd}")
    if err != 0:
        print_err_msg_exit(
            f"""
            For Darwin-based operating systems (MacOS), the '{cmd}' utility is required 
            to run the UFS SRW Application. Reference the User's Guide for more information
            about platform requirements.

              Aborting."""
        )
    return True


def define_macos_utilities():
    """Set some environment variables for Darwin systems differently
    The variables are: READLINK, SED, DATE_UTIL and LN_UTIL
    """

    if os.uname()[0] == "Darwin":
        if check_darwin("greadlink"):
            set_env_var("READLINK", "greadlink")
        if check_darwin("gsed"):
            set_env_var("SED", "gsed")
        if check_darwin("gdate"):
            set_env_var("DATE_UTIL", "gdate")
        if check_darwin("gln"):
            set_env_var("LN_UTIL", "gln")
    else:
        set_env_var("READLINK", "readlink")
        set_env_var("SED", "sed")
        set_env_var("DATE_UTIL", "date")
        set_env_var("LN_UTIL", "ln")