✨(backend) create ai endpoint

We created 2 new action endpoints on the document
to perform AI operations:
- POST /api/v1.0/documents/{uuid}/ai-transform
- POST /api/v1.0/documents/{uuid}/ai-translate

src/backend/core/services/ai_services.py

@@ -0,0 +1,89 @@
+"""AI services."""
+
+import json
+import re
+
+from django.conf import settings
+from django.core.exceptions import ImproperlyConfigured
+
+from openai import OpenAI
+
+from core import enums
+
+AI_ACTIONS = {
+    "prompt": (
+        "Answer the prompt in markdown format. Return JSON: "
+        '{"answer": "Your markdown answer"}. '
+        "Do not provide any other information."
+    ),
+    "correct": (
+        "Correct grammar and spelling of the markdown text, "
+        "preserving language and markdown formatting. "
+        'Return JSON: {"answer": "your corrected markdown text"}. '
+        "Do not provide any other information."
+    ),
+    "rephrase": (
+        "Rephrase the given markdown text, "
+        "preserving language and markdown formatting. "
+        'Return JSON: {"answer": "your rephrased markdown text"}. '
+        "Do not provide any other information."
+    ),
+    "summarize": (
+        "Summarize the markdown text, preserving language and markdown formatting. "
+        'Return JSON: {"answer": "your markdown summary"}. '
+        "Do not provide any other information."
+    ),
+}
+
+AI_TRANSLATE = (
+    "Translate the markdown text to {language:s}, preserving markdown formatting. "
+    'Return JSON: {{"answer": "your translated markdown text in {language:s}"}}. '
+    "Do not provide any other information."
+)
+
+
+class AIService:
+    """Service class for AI-related operations."""
+
+    def __init__(self):
+        """Ensure that the AI configuration is set properly."""
+        if (
+            settings.AI_BASE_URL is None
+            or settings.AI_API_KEY is None
+            or settings.AI_MODEL is None
+        ):
+            raise ImproperlyConfigured("AI configuration not set")
+        self.client = OpenAI(base_url=settings.AI_BASE_URL, api_key=settings.AI_API_KEY)
+
+    def call_ai_api(self, system_content, text):
+        """Helper method to call the OpenAI API and process the response."""
+        response = self.client.chat.completions.create(
+            model=settings.AI_MODEL,
+            response_format={"type": "json_object"},
+            messages=[
+                {"role": "system", "content": system_content},
+                {"role": "user", "content": json.dumps({"markdown_input": text})},
+            ],
+        )
+
+        content = response.choices[0].message.content
+        sanitized_content = re.sub(r"(?<!\\)\n", "\\\\n", content)
+        sanitized_content = re.sub(r"(?<!\\)\t", "\\\\t", sanitized_content)
+
+        json_response = json.loads(sanitized_content)
+
+        if "answer" not in json_response:
+            raise RuntimeError("AI response does not contain an answer")
+
+        return json_response
+
+    def transform(self, text, action):
+        """Transform text based on specified action."""
+        system_content = AI_ACTIONS[action]
+        return self.call_ai_api(system_content, text)
+
+    def translate(self, text, language):
+        """Translate text to a specified language."""
+        language_display = enums.ALL_LANGUAGES.get(language, language)
+        system_content = AI_TRANSLATE.format(language=language_display)
+        return self.call_ai_api(system_content, text)