From f84f97732d5a2debe54e9923594ec23e31baf041 Mon Sep 17 00:00:00 2001
From: Sumner Evans <sumner.evans98@gmail.com>
Date: Sat, 28 Dec 2019 12:10:46 -0700
Subject: [PATCH] Closes #75: added infrastructure for versioning of config

---
 sublime/cache_manager.py |  2 +-
 sublime/config.py        | 31 ++++++++++++++++++-------------
 sublime/state_manager.py | 10 +++++++++-
 sublime/ui/settings.py   |  7 ++++++-
 4 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/sublime/cache_manager.py b/sublime/cache_manager.py
index 63eb4e5..916e0de 100644
--- a/sublime/cache_manager.py
+++ b/sublime/cache_manager.py
@@ -816,7 +816,7 @@ class CacheManager(metaclass=Singleton):
 
     _instance: Optional[__CacheManagerInternal] = None
 
-    def __init__(self, server_config: ServerConfiguration):
+    def __init__(self):
         raise Exception('Do not instantiate the CacheManager.')
 
     @classmethod
diff --git a/sublime/config.py b/sublime/config.py
index 3bf7d2b..426f88c 100644
--- a/sublime/config.py
+++ b/sublime/config.py
@@ -5,6 +5,7 @@ from typing import List, Optional
 
 
 class ServerConfiguration:
+    version: int
     name: str
     server_address: str
     local_network_address: str
@@ -40,6 +41,9 @@ class ServerConfiguration:
         self.sync_enabled = sync_enabled
         self.disable_cert_verify = disable_cert_verify
 
+    def migrate(self):
+        pass
+
     @property
     def password(self):
         return keyring.get_password(
@@ -60,22 +64,23 @@ class AppConfiguration:
     prefetch_amount: int = 3
     concurrent_download_limit: int = 5
     port_number: int = 8080
+    version: int = 1
 
     def to_json(self):
-        # TODO can we simplify?
-        return {
-            'servers': [s.__dict__ for s in self.servers],
-            'current_server': self.current_server,
-            '_cache_location': getattr(self, '_cache_location', None),
-            'max_cache_size_mb': self.max_cache_size_mb,
-            'show_headers': self.show_headers,
-            'always_stream': self.always_stream,
-            'download_on_stream': self.download_on_stream,
-            'song_play_notification': self.song_play_notification,
-            'prefetch_amount': self.prefetch_amount,
-            'concurrent_download_limit': self.concurrent_download_limit,
-            'port_number': self.port_number,
+        exclude = ('servers')
+        json_object = {
+            k: getattr(self, k)
+            for k in self.__annotations__.keys()
+            if k not in exclude
         }
+        json_object.update({
+            'servers': [s.__dict__ for s in self.servers],
+        })
+        return json_object
+
+    def migrate(self):
+        for server in self.servers:
+            server.migrate()
 
     @property
     def cache_location(self):
diff --git a/sublime/state_manager.py b/sublime/state_manager.py
index c024d5b..d3b56bb 100644
--- a/sublime/state_manager.py
+++ b/sublime/state_manager.py
@@ -49,6 +49,7 @@ class ApplicationState:
     functions define what part of the state will be saved across application
     loads.
     """
+    version: int = 1
     config: AppConfiguration = AppConfiguration()
     config_file: str = None
     playing: bool = False
@@ -90,6 +91,7 @@ class ApplicationState:
         return json_object
 
     def load_from_json(self, json_object):
+        self.version = json_object.get('version', 0)
         self.current_song_index = json_object.get('current_song_index', -1)
         self.play_queue = json_object.get('play_queue', [])
         self.old_play_queue = json_object.get('old_play_queue', [])
@@ -130,10 +132,16 @@ class ApplicationState:
                     self.load_from_json(json.load(f))
                 except json.decoder.JSONDecodeError:
                     # Who cares, it's just state.
-                    pass
+                    self.load_from_json({})
         else:
             self.load_from_json({})
 
+        self.migrate()
+
+    def migrate(self):
+        """Use this function to migrate any state storage that has changed."""
+        self.config.migrate()
+
     def save(self):
         # Make the necessary directories before writing the state.
         os.makedirs(os.path.dirname(self.state_filename), exist_ok=True)
diff --git a/sublime/ui/settings.py b/sublime/ui/settings.py
index 4ee7568..aace4af 100644
--- a/sublime/ui/settings.py
+++ b/sublime/ui/settings.py
@@ -8,7 +8,12 @@ class SettingsDialog(EditFormDialog):
     title: str = 'Settings'
     initial_size = (450, 250)
     text_fields = [
-        ('Port Number (will take effect on restart)', 'port_number', False),
+        (
+            'Port Number (for streaming to Chromecasts on the local network, '
+            'will take effect on restart)',
+            'port_number',
+            False,
+        ),
     ]
     boolean_fields = [
         ('Show headers on song lists', 'show_headers'),