[Core] Handle connection errors, fetch token from env var / db

Also reimplemented the old status codes

main.py

@@ -1,8 +1,10 @@
-from core.bot import Red
+from core.bot import Red, ExitCodes
 from core.global_checks import init_global_checks
 from core.events import init_events
 from core.json_flusher import init_flusher
 from core.settings import parse_cli_flags
+import asyncio
+import discord
 import logging.handlers
 import logging
 import os
@@ -46,9 +48,11 @@ def init_loggers(cli_flags):
     logger.addHandler(fhandler)
     logger.addHandler(stdout_handler)
 
+    return logger
+
 if __name__ == '__main__':
     cli_flags = parse_cli_flags()
-    init_loggers(cli_flags)
+    log = init_loggers(cli_flags)
     init_flusher()
     description = "Red v3 - Alpha"
     red = Red(cli_flags, description=description, pm_help=None)
@@ -57,4 +61,29 @@ if __name__ == '__main__':
     red.load_extension('core')
     if cli_flags.dev:
         pass # load dev cog here?
-    red.run(os.environ['RED_TOKEN'], bot=not cli_flags.not_bot)
+
+    token = os.environ.get("RED_TOKEN", red.db.get_global("token", None))
+
+    if token is None:
+        log.critical("No token to login with")
+        sys.exit(1)
+
+    loop = asyncio.get_event_loop()
+
+    try:
+        loop.run_until_complete(red.start(token, bot=not cli_flags.not_bot))
+    except discord.LoginFailure:
+        log.critical("This token doesn't seem to be valid. If it belongs to "
+                     "a user account, remember that the --not-bot flag "
+                     "must be used. For self-bot functionalities instead, "
+                     "--self-bot")
+    except KeyboardInterrupt:
+        log.info("Keyboard interrupt detected. Quitting...")
+        loop.run_until_complete(red.logout())
+        red._shutdown_mode = ExitCodes.SHUTDOWN
+    except Exception as e:
+        log.critical("Fatal exception", exc_info=e)
+        loop.run_until_complete(red.logout())
+    finally:
+        sys.exit(red._shutdown_mode.value)
+