feat: implement UI config flow with single-instance enforcement (#4)

custom_components/nestquest/config_flow.py

@@ -0,0 +1,28 @@
+"""Config flow for NestQuest."""
+from __future__ import annotations
+
+from typing import Any
+
+from homeassistant import config_entries
+from homeassistant.data_entry_flow import FlowResult
+
+from .const import DOMAIN
+
+
+class NestQuestConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
+    """Handle a config flow for NestQuest."""
+
+    VERSION = 1
+
+    async def async_step_user(
+        self, user_input: dict[str, Any] | None = None
+    ) -> FlowResult:
+        """Handle the user step of the config flow."""
+        await self.async_set_unique_id(DOMAIN, raise_on_progress=False)
+        if self._async_in_progress() or self._async_current_entries():
+            return self.async_abort(reason="single_instance_allowed")
+
+        if user_input is None:
+            return self.async_show_form(step_id="user")
+
+        return self.async_create_entry(title="NestQuest", data=user_input)

custom_components/nestquest/strings.json

@@ -0,0 +1,17 @@
+{
+  "title": "NestQuest",
+  "config": {
+    "step": {
+      "user": {
+        "title": "Add NestQuest",
+        "description": "Set up NestQuest to start coordinating the household. No additional configuration is required."
+      }
+    },
+    "abort": {
+      "single_instance_allowed": "NestQuest is already configured. Only a single instance is allowed."
+    },
+    "create_entry": {
+      "default": "NestQuest was successfully configured."
+    }
+  }
+}

custom_components/nestquest/translations/en.json

@@ -0,0 +1,17 @@
+{
+  "title": "NestQuest",
+  "config": {
+    "step": {
+      "user": {
+        "title": "Add NestQuest",
+        "description": "Set up NestQuest to start coordinating the household. No additional configuration is required."
+      }
+    },
+    "abort": {
+      "single_instance_allowed": "NestQuest is already configured. Only a single instance is allowed."
+    },
+    "create_entry": {
+      "default": "NestQuest was successfully configured."
+    }
+  }
+}