Check package requirements before importing them

DungeonRandomizer.py

@@ -1,11 +1,11 @@
 #!/usr/bin/env python3
-import argparse
+if __name__ == '__main__':
-import copy
+    from source.meta.check_requirements import check_requirements
+    check_requirements(console=True)
+
 import os
 import logging
 import RaceRandom as random
-import textwrap
-import shlex
 import sys
 
 from source.classes.BabelFish import BabelFish

Gui.py

@@ -1,3 +1,7 @@
+if __name__ == '__main__':
+    from source.meta.check_requirements import check_requirements
+    check_requirements()
+
 import json
 import os
 import sys

source/meta/check_requirements.py

@@ -0,0 +1,41 @@
+import importlib.util
+import webbrowser
+from tkinter import Tk, Label, Button, Frame
+
+
+def check_requirements(console=False):
+    check_packages = {'aenum': 'aenum',
+                      'fast-enum': 'fast_enum',
+                      'python-bps-continued': 'bps',
+                      'colorama': 'colorama',
+                      'aioconsole' : 'aioconsole',
+                      'websockets' : 'websockets',
+                      'pyyaml': 'yaml'}
+    missing = []
+    for package, import_name in check_packages.items():
+        spec = importlib.util.find_spec(import_name)
+        if spec is None:
+            missing.append(package)
+    if len(missing) > 0:
+        packages = ','.join(missing)
+        if console:
+            import logging
+            logger = logging.getLogger('')
+            logger.error('You need to install the following python packages:')
+            logger.error(f'{packages}')
+            logger.error('See the step about "Installing Platform-specific dependencies":')
+            logger.error('https://github.com/aerinon/ALttPDoorRandomizer/blob/DoorDev/docs/BUILDING.md')
+        else:
+            master = Tk()
+            master.title('Error')
+            frame = Frame(master)
+            frame.pack(expand=True, padx =50, pady=50)
+            Label(frame, text='You need to install the following python packages:').pack()
+            Label(frame, text=f'{packages}').pack()
+            Label(frame, text='See the step about "Installing Platform-specific dependencies":').pack()
+            url = 'https://github.com/aerinon/ALttPDoorRandomizer/blob/DoorDev/docs/BUILDING.md'
+            link = Label(frame, fg='blue', cursor='hand2', text=url)
+            link.pack()
+            link.bind('<Button-1>', lambda e: webbrowser.open_new_tab(url))
+            Button(master, text='Ok', command=master.destroy).pack()
+            master.mainloop()