Implement support for generic OpenAI api (#213)

* Implement support for generic OpenAI api

- Implements support to route requests to any openAI capable provider ( Deepsek, Qwen, VLLM, LM Studio, Ollama ).
- Keeps support for pure OpenAI and uses the new better responses api
- Uses the /chat/completions api for the generic providers
- If uri_base is not set, uses default implementation.

* Fix json handling and indentation

* Fix linter error indent

* Fix tests to set env vars

* Fix updating settings

* Change to prefix checking for OAI models

* FIX check model if custom uri is set

* Change chat to sync calls

Some local models don't support streaming. Revert to sync calls for generic OAI api

* Fix tests

* Fix tests

* Fix for gpt5 message extraction

- Finds the message output by filtering for "type" == "message" instead of assuming it's at index 0
- Safely extracts the text using safe navigation operators (&.)
- Raises a clear error if no message content is found
- Parses the JSON as before

* Add more langfuse logging

- Add Langfuse to auto categorizer and merchant detector
- Fix monitoring on streaming chat responses
- Add Langfuse traces also for model errors now

* Update app/models/provider/openai.rb

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Signed-off-by: soky srm <sokysrm@gmail.com>

* handle nil function results explicitly

* Exposing some config vars.

* Linter and nitpick comments

* Drop back to `gpt-4.1` as default for now

* Linter

* Fix for strict tool schema in Gemini

- This fixes tool calling in Gemini OpenAI api
- Fix for getTransactions function, page size is not used.

---------

Signed-off-by: soky srm <sokysrm@gmail.com>
Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Co-authored-by: Juan José Mata <juanjo.mata@gmail.com>

app/controllers/settings/hostings_controller.rb

@@ -31,9 +31,6 @@ class Settings::HostingsController < ApplicationController
       Setting.twelve_data_api_key = hosting_params[:twelve_data_api_key]
     end
 
-    if hosting_params.key?(:openai_access_token)
-      Setting.openai_access_token = hosting_params[:openai_access_token]
-    end
     if hosting_params.key?(:openai_access_token)
       token_param = hosting_params[:openai_access_token].to_s.strip
       # Ignore blanks and redaction placeholders to prevent accidental overwrite
@@ -42,9 +39,25 @@ class Settings::HostingsController < ApplicationController
       end
     end
 
+    # Validate OpenAI configuration before updating
+    if hosting_params.key?(:openai_uri_base) || hosting_params.key?(:openai_model)
+      Setting.validate_openai_config!(
+        uri_base: hosting_params[:openai_uri_base],
+        model: hosting_params[:openai_model]
+      )
+    end
+
+    if hosting_params.key?(:openai_uri_base)
+      Setting.openai_uri_base = hosting_params[:openai_uri_base]
+    end
+
+    if hosting_params.key?(:openai_model)
+      Setting.openai_model = hosting_params[:openai_model]
+    end
+
     redirect_to settings_hosting_path, notice: t(".success")
-  rescue ActiveRecord::RecordInvalid => error
-    flash.now[:alert] = t(".failure")
+  rescue Setting::ValidationError => error
+    flash.now[:alert] = error.message
     render :show, status: :unprocessable_entity
   end
 
@@ -55,7 +68,7 @@ class Settings::HostingsController < ApplicationController
 
   private
     def hosting_params
-      params.require(:setting).permit(:require_invite_for_signup, :require_email_confirmation, :brand_fetch_client_id, :twelve_data_api_key, :openai_access_token)
+      params.require(:setting).permit(:require_invite_for_signup, :require_email_confirmation, :brand_fetch_client_id, :twelve_data_api_key, :openai_access_token, :openai_uri_base, :openai_model)
     end
 
     def ensure_admin