"""
Given a package name (E.g. numpy), write a file which contains a list of
all possible function and ufunc imports.
"""
import inspect
import os
import sys
import importlib

MY_NAME = "pkgfuncs"
REPORT_FILE = "pkgfunc_report.py"
OUTPUT_HANDLE = -1
count = 0

def command_line_error(arg_text):
    """
    The specified command line is in error.
    Exit to the O/S after printing arg_text.
    """
    print("\n*** Command line error: {}\n".format(arg_text))
    print("Command line should be:   {}   PACKAGE-NAME\n".format(MY_NAME))
    sys.exit(86)

def oops(arg_text):
    """
    Exit to the O/S after printing arg_text.
    """
    print("\n*** Oops, {}\n".format(arg_text))
    sys.exit(86)

def spew_one(arg_name, arg_strung):
    """
    Write one line: from PKG_NAME import UFUNC-or-FUNCTION
    """
    try:
        OUTPUT_HANDLE.write("from {} import {} # {}\n".format(PKG_NAME, arg_name, arg_strung))
    except IOError as exc:
        oops("Cannot write {}, reason: {}".format(REPORT_FILE, exc.strerror))

#========================================================================#

NARGS = len(sys.argv)
MY_NAME = sys.argv[0]
if NARGS != 2:
    command_line_error("Exactly 1 argument should be specified")
PKG_NAME = sys.argv[1]
REPORT_FILE = PKG_NAME + "_list.py"

try:
    PKG = importlib.import_module(PKG_NAME)
except ModuleNotFoundError:
    oops("Package {} not found".format(PKG_NAME))

if os.path.exists(REPORT_FILE):
    os.remove(REPORT_FILE)
try:
    OUTPUT_HANDLE = open(REPORT_FILE, "wt")
except IOError as exc:
    oops("Cannot open {}, reason: {}".format(REPORT_FILE, exc.strerror))

EXPORTABLES = inspect.getmembers(PKG)
for currow in EXPORTABLES:
    name = str(currow[0]).strip()
    strung = str(currow[1]).strip()
    if len(strung) < 6:
        continue
    if strung[:6] == "<ufunc":
        spew_one(name, strung)
        count += 1
        continue
    if len(strung) < 9:
        continue
    if strung[:9] == "<function":
        spew_one(name, strung)
        count += 1

try:
    OUTPUT_HANDLE.close()
except IOError as exc:
    oops("Cannot close {}, reason: {}".format(REPORT_FILE, exc.strerror))

print("Row count =", count)