added open ai provider

Author: Nope1405

backend/app/services/openai_provider.py

@@ -0,0 +1,46 @@
+
+import os
+from openai import OpenAI
+from typing import Sequence, Any
+
+from .ai_service import AIProvider, Character, Message
+
+
+class OpenAIProvider:
+    def __init__(self, api_key: str, model_name: str = 'gpt-4.5-turbo'):
+        self.client = OpenAI(api_key=api_key)
+        self.model_name = model_name
+
+    def _format_history_for_openai(self, character: Character, history: Sequence[Message]) -> list[dict[str, str]]:
+        openai_history = []
+        if character.system_prompt:
+            openai_history.append({"role": "system", "content": character.system_prompt})
+
+        for message in history:
+            role = 'user' if message.sender == 'user' else 'assistant'
+            openai_history.append({"role": role, "content": message.content})
+
+        return openai_history
+
+    def get_completion(self, character: Character, history: Sequence[Message]) -> str:
+        if not history:
+            return "Error: No conversation history provided."
+        messages = self._format_history_for_openai(character, history)
+
+        try:
+            response = self.client.chat.completions.create(
+                model=self.model_name,
+                messages=messages
+            )
+            ai_response_text = response.choices[0].message.content
+
+            if not ai_response_text:
+                print("Warning: OpenAI API returned no text.")
+                return "I cannot generate a response for that request."
+
+
+            return ai_response_text
+
+        except Exception as e:
+            print(f"Error calling OpenAI API: {e}")
+            return "Sorry, I encountered an erro."