Centralise checking ready for use

src/calibre/ai/config.py

@@ -4,8 +4,7 @@
 from qt.core import QComboBox, QDialog, QGroupBox, QHBoxLayout, QLabel, QStackedLayout, QVBoxLayout, QWidget
 
 from calibre.ai import AICapabilities
-from calibre.ai.prefs import prefs
-from calibre.customize.ui import available_ai_provider_plugins
+from calibre.ai.prefs import plugins_for_purpose, prefs
 from calibre.gui2 import Application, error_dialog
 
 
@@ -13,7 +12,7 @@ class ConfigureAI(QWidget):
 
     def __init__(self, purpose: AICapabilities = AICapabilities.text_to_text, parent: QWidget | None = None):
         super().__init__(parent)
-        plugins = tuple(p for p in available_ai_provider_plugins() if p.capabilities & purpose == purpose)
+        plugins = tuple(plugins_for_purpose(purpose))
         self.available_plugins = plugins
         self.purpose = purpose
         self.plugin_config_widgets: tuple[QWidget, ...] = tuple(p.config_widget() for p in plugins)

src/calibre/ai/open_router/backend.py

@@ -8,16 +8,22 @@ import tempfile
 from contextlib import closing, suppress
 from functools import lru_cache
 from threading import Thread
-from typing import NamedTuple
+from typing import Any, NamedTuple
 
 from calibre import browser
 from calibre.ai import AICapabilities
+from calibre.ai.open_router import OpenRouterAI
+from calibre.ai.prefs import pref_for_provider
 from calibre.constants import __version__, cache_dir
 from calibre.utils.lock import SingleInstance
 
 module_version = 1  # needed for live updates
 
 
+def pref(key: str, defval: Any = None) -> Any:
+    return pref_for_provider(OpenRouterAI.name, key, defval)
+
+
 def get_browser():
     ans = browser(user_agent=f'calibre {__version__}')
     return ans
@@ -151,6 +157,14 @@ def save_settings(config_widget):
     config_widget.save_settings()
 
 
+def api_key() -> str:
+    return pref('api_key')
+
+
+def is_ready_for_use() -> bool:
+    return bool(api_key())
+
+
 if __name__ == '__main__':
     from pprint import pprint
     for m in get_available_models().values():

src/calibre/ai/prefs.py

@@ -1,10 +1,14 @@
 #!/usr/bin/env python
 # License: GPLv3 Copyright: 2025, Kovid Goyal <kovid at kovidgoyal.net>
 
+from collections.abc import Iterator
 from copy import deepcopy
 from functools import lru_cache
 from typing import Any
 
+from calibre.ai import AICapabilities
+from calibre.customize import AIProviderPlugin
+from calibre.customize.ui import available_ai_provider_plugins
 from calibre.utils.config import JSONConfig
 
 
@@ -24,3 +28,19 @@ def set_prefs_for_provider(name: str, pref_map: dict[str, Any]) -> None:
     p = prefs()
     p['providers'][name] = deepcopy(pref_map)
     p.set('providers', p['providers'])
+
+
+def plugins_for_purpose(purpose: AICapabilities) -> Iterator[AIProviderPlugin]:
+    for p in sorted(available_ai_provider_plugins(), key=lambda p: (p.priority, p.name.lower())):
+        if p.capabilities & purpose == purpose:
+            yield p
+
+
+def plugin_for_purpose(purpose: AICapabilities) -> AIProviderPlugin | None:
+    compatible_plugins = {p.name: p for p in plugins_for_purpose(purpose)}
+    q = prefs()['purpose_map'].get(str(purpose), '')
+    if ans := compatible_plugins.get(q):
+        return ans
+    if compatible_plugins:
+        return next(iter(compatible_plugins.values()))
+    return None

src/calibre/customize/__init__.py

@@ -846,6 +846,12 @@ class AIProviderPlugin(Plugin):  # {{{
             ans = self._builtin_live_module = load_module(self.builtin_live_module_name, strategy=Strategy.fast)
         return ans
 
+    @property
+    def is_ready_for_use(self) -> bool:
+        if not self.builtin_live_module_name:
+            return False
+        return self.builtin_live_module.is_ready_for_use()
+
     def initialize(self):
         self._builtin_live_module = None
 

src/calibre/gui2/viewer/llm.py

@@ -34,7 +34,9 @@ from qt.core import (
     pyqtSignal,
 )
 
+from calibre.ai import AICapabilities
 from calibre.ai.config import ConfigureAI
+from calibre.ai.prefs import plugin_for_purpose
 from calibre.ebooks.metadata import authors_to_string
 from calibre.gui2 import Application, error_dialog
 from calibre.gui2.dialogs.confirm_delete import confirm
@@ -42,7 +44,6 @@ from calibre.gui2.viewer.config import vprefs
 from calibre.gui2.viewer.highlights import HighlightColorCombo
 from calibre.gui2.widgets2 import Dialog
 from calibre.utils.icu import primary_sort_key
-from polyglot.binary import from_hex_unicode
 
 # --- Backend Abstraction & Cost Data ---
 MODEL_COSTS = {
@@ -115,14 +116,10 @@ API_PROVIDERS = {
 
 
 class LLMAPICall(Thread):
-    def __init__(self, conversation_history, api_key, model_id, signal_emitter, provider_config):
-        super().__init__()
+    def __init__(self, conversation_history, signal_emitter):
+        super().__init__(daemon=True)
         self.conversation_history = conversation_history
-        self.api_key = api_key
-        self.model_id = model_id
         self.signal_emitter = signal_emitter
-        self.provider_config = provider_config
-        self.daemon = True
 
     def run(self):
         try:
@@ -299,13 +296,16 @@ class LLMPanel(QWidget):
         dialog.actions_updated.connect(self.rebuild_actions_ui)
         dialog.exec()
 
+    @property
+    def is_ready_for_use(self) -> bool:
+        p = plugin_for_purpose(AICapabilities.text_to_text)
+        return p is not None and p.is_ready_for_use
+
     def show_initial_message(self):
         self.save_note_button.setEnabled(False)
-        api_key_hex = vprefs.get('llm_api_key', '') or ''
-        api_key = from_hex_unicode(api_key_hex)
-        if not api_key:
+        if not self.is_ready_for_use:
             self.show_response('<p>' + _(
-                'Please add your API key for an AI service by clicking the <b>Settings</b> button below.'), {})
+                'Please configure an AI provider by clicking the <b>Settings</b> button below.'), {})
         else:
             self.show_response(_('Select text in the book to begin.'), {})
 
@@ -399,10 +399,9 @@ class LLMPanel(QWidget):
         return html_output
 
     def start_api_call(self, action_prompt):
-        api_key_hex = vprefs.get('llm_api_key', '') or ''
-        api_key = from_hex_unicode(api_key_hex)
-        if not api_key:
-            self.show_response(f"<p style='color:orange;'><b>{_('API Key Missing.')}</b> Click the <b>{_('Settings')}</b> button to add your key.</p>", {})
+        if not self.is_ready_for_use:
+            self.show_response(f"<p style='color:orange;'><b>{_('AI provider not configured')}</b> Click the <b>{_(
+                'Settings')}</b> button to configure an AI service provider.</p>", {})
             return
         if not self.latched_conversation_text:
             self.show_response(f"<p style='color:red;'><b>{_('Error')}:</b> {_('No text is selected for this conversation.')}</p>", {})
@@ -438,11 +437,7 @@ class LLMPanel(QWidget):
         self.result_display.verticalScrollBar().setValue(self.result_display.verticalScrollBar().maximum())
         self.set_all_inputs_enabled(False)
 
-        model_id = vprefs.get('llm_model_id', 'google/gemini-1.5-flash')
-        provider_config = API_PROVIDERS['openrouter']
-        api_call_thread = LLMAPICall(
-            api_call_history, api_key, model_id, self.response_received, provider_config
-        )
+        api_call_thread = LLMAPICall(api_call_history, self.response_received)
         api_call_thread.start()
 
     def show_response(self, response_text, usage_data):