add preferences UI including cache settings

1 files changed, 58 insertions, 0 deletions

diff --git a/lib/utils/settings.py b/lib/utils/settings.py
new file mode 100644
index 00000000..f2ce276d
--- /dev/null
+++ b/lib/utils/settings.py
@@ -0,0 +1,58 @@
+from collections.abc import MutableMapping
+import json
+import os
+
+from .paths import get_user_dir
+
+# These settings are the defaults for SVG metadata settings of the same name in
+# lib.extensions.base.InkstitchMetadata
+DEFAULT_METADATA = {
+    "min_stitch_len_mm": 0,
+    "collapse_len_mm": 3,
+}
+
+DEFAULT_SETTINGS = {
+    "cache_size": 100
+}
+
+
+class GlobalSettings(MutableMapping):
+    def __init__(self):
+        super().__init__()
+        self.__settings_file = os.path.join(get_user_dir(), "settings.json")
+        self.__settings = {}
+
+        for name, value in DEFAULT_METADATA.items():
+            self.__settings[f"default_{name}"] = value
+
+        self.__settings.update(DEFAULT_SETTINGS)
+
+        try:
+            with open(self.__settings_file, 'r') as settings_file:
+                self.__settings.update(json.load(settings_file))
+        except (OSError, json.JSONDecodeError, ValueError):
+            pass
+
+    def __setitem__(self, item, value):
+        self.__settings[item] = value
+
+        with open(self.__settings_file, 'w') as settings_file:
+            json.dump(self.__settings, settings_file)
+
+    def __getitem__(self, item):
+        return self.__settings[item]
+
+    def __delitem__(self, item):
+        del self.__settings[item]
+
+    def __iter__(self):
+        return iter(self.__settings)
+
+    def __len__(self):
+        return len(self.__settings)
+
+    def __json__(self):
+        return self.__settings
+
+
+global_settings = GlobalSettings()