From adb85e2569deaaf25c7ebcf80cd0e62ed01b673c Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 29 Aug 2025 11:38:21 +0530
Subject: [PATCH] Start work on supporting multiple AI providers via plugins

---
 src/calibre/ai/open_router/__init__.py | 13 ++++++++++++
 src/calibre/ai/open_router/backend.py  |  5 +++++
 src/calibre/customize/__init__.py      | 29 ++++++++++++++++++++++++++
 src/calibre/customize/builtins.py      | 11 ++++++----
 src/calibre/customize/ui.py            | 14 +++++++++++++
 5 files changed, 68 insertions(+), 4 deletions(-)
 create mode 100644 src/calibre/ai/open_router/__init__.py
 create mode 100644 src/calibre/ai/open_router/backend.py

diff --git a/src/calibre/ai/open_router/__init__.py b/src/calibre/ai/open_router/__init__.py
new file mode 100644
index 0000000000..d92f8fb465
--- /dev/null
+++ b/src/calibre/ai/open_router/__init__.py
@@ -0,0 +1,13 @@
+#!/usr/bin/env python
+# License: GPLv3 Copyright: 2025, Kovid Goyal <kovid at kovidgoyal.net>
+
+
+from calibre.customize import AIProviderPlugin
+
+
+class OpenRouterAI(AIProviderPlugin):
+    name = 'OpenRouter'
+    version        = (1, 0, 0)
+    description    = _('AI services from OpenRouter.ai. Allows choosing from hundreds of different AI models to query.')
+    author = 'Kovid Goyal'
+    builtin_live_module_name = 'calibre.ai.open_router.backend'
diff --git a/src/calibre/ai/open_router/backend.py b/src/calibre/ai/open_router/backend.py
new file mode 100644
index 0000000000..0d85d204e5
--- /dev/null
+++ b/src/calibre/ai/open_router/backend.py
@@ -0,0 +1,5 @@
+#!/usr/bin/env python
+# License: GPLv3 Copyright: 2025, Kovid Goyal <kovid at kovidgoyal.net>
+
+
+module_version = 1  # needed for live updates
diff --git a/src/calibre/customize/__init__.py b/src/calibre/customize/__init__.py
index 7f8f4c53d9..2737c0dc02 100644
--- a/src/calibre/customize/__init__.py
+++ b/src/calibre/customize/__init__.py
@@ -817,3 +817,32 @@ class LibraryClosedPlugin(Plugin):  # {{{
         raise NotImplementedError('LibraryClosedPlugin '
                 'run method must be overridden in subclass')
 # }}}
+
+
+class AIProviderPlugin(Plugin):  # {{{
+    '''
+    AIProvider plugins abstract AI services that can be used by the rest of calibre.
+    '''
+    type = _('AI provider')
+
+    # minimum version when support for this plugin type was added
+    minimum_calibre_version = (8, 10, 0)
+
+    # Used by builtin AI Provider plugins to live load the backend code
+    builtin_live_module_name = ''
+
+    @property
+    def builtin_live_module(self):
+        if not self.builtin_live_module_name:
+            return None
+        if (ans := self._builtin_live_module) is None:
+            from calibre.live import Strategy, load_module
+            ans = self._builtin_live_module = load_module(self.builtin_live_module_name, strategy=Strategy.fast)
+        return ans
+
+    def initialize(self):
+        self._builtin_live_module = None
+
+    def customization_help(self):
+        return ''
+# }}}
diff --git a/src/calibre/customize/builtins.py b/src/calibre/customize/builtins.py
index 4349da9086..2625fa2f58 100644
--- a/src/calibre/customize/builtins.py
+++ b/src/calibre/customize/builtins.py
@@ -4,6 +4,7 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 import glob
 import os
 
+from calibre.ai.open_router import OpenRouterAI
 from calibre.constants import numeric_version
 from calibre.customize import FileTypePlugin, InterfaceActionBase, MetadataReaderPlugin, MetadataWriterPlugin, PreferencesPlugin, StoreBase
 from calibre.ebooks.html.to_zip import HTML2ZIP
@@ -434,9 +435,9 @@ plugins += [x for x in list(locals().values()) if isinstance(x, type) and
 
 # }}}
 
-
 # Metadata writer plugins {{{
 
+
 class EPUBMetadataWriter(MetadataWriterPlugin):
 
     name = 'Set EPUB metadata'
@@ -851,9 +852,9 @@ plugins += [GoogleBooks, GoogleImages, Amazon, Edelweiss, OpenLibrary, BigBookSe
 
 # }}}
 
-
 # Interface Actions {{{
 
+
 class ActionAdd(InterfaceActionBase):
     name = 'Add Books'
     actual_plugin = 'calibre.gui2.actions.add:AddAction'
@@ -1191,9 +1192,9 @@ plugins += [ActionAdd, ActionAllActions, ActionColumnTooltip, ActionFetchAnnotat
 
 # }}}
 
-
 # Preferences Plugins {{{
 
+
 class LookAndFeel(PreferencesPlugin):
     name = 'Look & Feel'
     icon = 'lookfeel.png'
@@ -1468,9 +1469,9 @@ plugins += [LookAndFeel, Behavior, Columns, Toolbar, Search, InputOptions,
 
 # }}}
 
-
 # Store plugins {{{
 
+
 class StoreAmazonKindleStore(StoreBase):
     name = 'Amazon Kindle'
     description = 'Kindle books from Amazon.'
@@ -1976,6 +1977,8 @@ plugins += [
 
 # }}}
 
+plugins.extend((OpenRouterAI,))
+
 if __name__ == '__main__':
     # Test load speed
     import subprocess
diff --git a/src/calibre/customize/ui.py b/src/calibre/customize/ui.py
index 4e76e8e0e9..09a9a0de41 100644
--- a/src/calibre/customize/ui.py
+++ b/src/calibre/customize/ui.py
@@ -7,10 +7,12 @@ import shutil
 import sys
 import traceback
 from collections import defaultdict
+from collections.abc import Iterator
 from itertools import chain, repeat
 
 from calibre.constants import DEBUG, ismacos, numeric_version, system_plugins_loc
 from calibre.customize import (
+    AIProviderPlugin,
     CatalogPlugin,
     EditBookToolPlugin,
     FileTypePlugin,
@@ -357,6 +359,18 @@ def has_library_closed_plugins():
 # }}}
 
 
+# AI Provider Plugins {{{
+def available_ai_provider_plugins() -> Iterator[AIProviderPlugin]:
+    customization = config['plugin_customization']
+    for plugin in _initialized_plugins:
+        if isinstance(plugin, AIProviderPlugin):
+            if not is_disabled(plugin):
+                plugin.site_customization = customization.get(plugin.name, '')
+                yield plugin
+
+# }}}
+
+
 # Store Plugins # {{{
 
 def store_plugins():