Refactor Backend and config file operations

src/python/config_files.py

@@ -0,0 +1,78 @@
+# Copyright 2019 miruka
+# This file is part of harmonyqml, licensed under LGPLv3.
+
+import asyncio
+import json
+from pathlib import Path
+from typing import Any, Dict
+
+import aiofiles
+from dataclasses import dataclass, field
+
+from .backend import Backend
+
+WRITE_LOCK = asyncio.Lock()
+
+
+@dataclass
+class ConfigFile:
+    backend:  Backend = field()
+    filename: str     = field()
+
+    @property
+    def path(self) -> Path:
+        # pylint: disable=no-member
+        return Path(self.backend.app.appdirs.user_config_dir) / self.filename
+
+
+@dataclass
+class JSONConfigFile(ConfigFile):
+    async def read(self) -> Dict[str, Any]:
+        try:
+            return json.loads(self.path.read_text())
+        except (json.JSONDecodeError, FileNotFoundError):
+            return {}
+
+
+    async def write(self, data: Dict[str, Any]) -> None:
+        js = json.dumps(data, indent=4, ensure_ascii=False, sort_keys=True)
+
+        async with WRITE_LOCK:
+            self.path.parent.mkdir(parents=True, exist_ok=True)
+
+            async with aiofiles.open(self.path, "w") as new:
+                await new.write(js)
+
+
+@dataclass
+class Accounts(JSONConfigFile):
+    filename: str = "accounts.json"
+
+    async def any_saved(self) -> bool:
+        return bool(await self.read())
+
+
+    async def add(self, user_id: str) -> None:
+        # pylint: disable=no-member
+        client = self.backend.clients[user_id]
+
+        await self.write({
+            **await self.read(),
+            client.user_id: {
+                "homeserver": client.homeserver,
+                "token":      client.access_token,
+                "device_id":  client.device_id,
+            }
+        })
+
+
+    async def delete(self, user_id: str) -> None:
+        await self.write({
+            uid: info
+            for uid, info in (await self.read()).items() if uid != user_id
+        })
+
+
+@dataclass
+class UISettings(JSONConfigFile):
+    filename: str = "ui-settings.json"