ecg-app: write setting to and load from file to persistent across launches

preload/apps/ecg/settings.py

@@ -7,30 +7,72 @@ class Settings(simple_menu.Menu):
     color_1 = color.CAMPGREEN
     color_2 = color.CAMPGREEN_DARK
 
-    options = {}
+    selected_options = {}
 
     def __init__(self):
         super().__init__([("return", False)])
-        self.config_path = "/".join(__file__.split("/")[0:-1])
 
     def on_select(self, value, index):
         if index == 0:
             self.exit()
         else:
-            self.options[value[0]] = next(value[1])
+            self.selected_options[value[0]] = next(value[1])
+            self.write_to_file()
 
     def entry2name(self, value):
         if value[0] == "return":
             return value[0]
         else:
-            return "{}: {}".format(value[0], self.options[value[0]][0])
+            return "{}: {}".format(value[0], self.selected_options[value[0]][0])
 
     def add_option(self, option):
         self.entries.append(option)
-        self.options[option[0]] = next(option[1])
+        self.selected_options[option[0]] = next(option[1])
 
     def get_option(self, name):
-        return self.options[name][1]
+        return self.selected_options[name][1]
+
+    def load_from_file(self):
+        config_path = "/".join(__file__.split("/")[0:-1])
+        try:
+            f = open("{}/config.cfg".format(config_path), "r")
+            for line in f:
+                parts = [x.strip() for x in line.split(":")]
+                if parts[0] in self.selected_options:
+                    # find corresponding entry from menu to get access to the corresponding itertools.cycle
+                    option_cycle = next(x for x in self.entries if x[0] == parts[0])[1]
+                    if self.selected_options[parts[0]][0] != parts[1]:
+                        previous = self.selected_options[parts[0]][0]
+                        self.selected_options[parts[0]] = next(option_cycle)
+                        while self.selected_options[parts[0]][0] not in {
+                            parts[1],
+                            previous,
+                        }:
+                            self.selected_options[parts[0]] = next(option_cycle)
+
+                        if self.selected_options[parts[0]][0] == previous:
+                            print(
+                                "Settings: unknown option '{}' for key '{}'".format(
+                                    parts[1], parts[0]
+                                )
+                            )
+                else:
+                    print("Settings: unknown key '{}'".format(parts[0]))
+            f.close()
+        except OSError:
+            print("Settings could not be loaded from file. Maybe it did not exist yet?")
+
+    def write_to_file(self):
+        config_path = "/".join(__file__.split("/")[0:-1])
+        try:
+            f = open("{}/config.cfg".format(config_path), "w")
+            for option_name in self.selected_options:
+                f.write(
+                    "{}:{}\n".format(option_name, self.selected_options[option_name][0])
+                )
+            f.close()
+        except OSError as e:
+            print("Settings could not be written to file! Error: {}".format(e))
 
 
 def ecg_settings():
@@ -66,4 +108,6 @@ def ecg_settings():
         )
     )
 
+    config.load_from_file()
+
     return config