# coding=utf-8

import importlib
import json
import os.path
import sys

SCAN_MODULES = ('_winapi', 'ctypes', 'errno', 'os', 'select',
           'signal', 'socket', 'mmap', 'msilib', 'msvcrt',
           'multiprocessing', 'winsound', 'winreg')

DUMP_FILE_NAME = 'winsdk_dump.json'
VERSION_KEY = '0'

def get_dict():
    def get_constant_list(module_name):
        module = importlib.import_module(module_name)
        return [s for s in dir(module) if s.isupper()]
    
    dic = dict()

    # use '0' to represent python version string
    dic[VERSION_KEY] = sys.version

    for module in SCAN_MODULES:
        dic[module] = get_constant_list(module)

    return dic
    
def dump():
    dic = get_dict()

    with open(DUMP_FILE_NAME, 'w', encoding='utf-8') as f:
        json.dump(dic, f, indent=2)

        msg = 'Constants of "%s" has been dump to %s' % \
              (dic[VERSION_KEY], DUMP_FILE_NAME)
        print(msg)

def load():
    with open(DUMP_FILE_NAME, encoding='utf-8') as f:
        dic = json.load(f)

    return dic

def compare():
    if not os.path.isfile(DUMP_FILE_NAME):
        print('File %s does not exist.' % DUMP_FILE_NAME)
        return

    current_dict = get_dict()
    
    file_dict = load()
    assert current_dict.keys() == file_dict.keys(),\
           "Modules list are different, maybe SCAN_MODULES has been changed."

    msg = "Comparing from A to B:\nA: %s\nB: %s\n" % \
          (file_dict[VERSION_KEY], current_dict[VERSION_KEY])
    print(msg)

    count = 0
    for k, v in file_dict.items():
        if k == VERSION_KEY:
            continue
        
        old_set = set(v)
        new_set = set(current_dict[k])

        if old_set == new_set:
            continue

        added = new_set.difference(old_set)
        removed = old_set.difference(new_set)

        if added:
            print('%s added %d constants: %s' % (k, len(added), added))
        if removed:
            print('%s removed %d constants: %s' % (k, len(removed), removed))
        count += 1
        print()

    print('Finished, %d modules changed constants.' % count)

def main():
    if len(sys.argv) == 2 and sys.argv[1].lower() == 'dump':
        dump()
        return
    if len(sys.argv) == 2 and sys.argv[1].lower() == 'compare':
        compare()
        return
    else:
        msg = (f'''\
Usage:
  1. dump current constants to {DUMP_FILE_NAME}:
    winsdk_watchdog.py dump
  2. compare current constants with {DUMP_FILE_NAME}:
    winsdk_watchdog.py compare
''')
        print(msg)

if __name__ == '__main__':
    main()