language-learning-app/api/app/services/llm.py

import asyncio
import anthropic

from ..config import settings


def _create_anthropic_client() -> anthropic.Anthropic:
    return anthropic.Anthropic(api_key=settings.anthropic_api_key)


def _create_system_prompt_summarise_text(
        complexity_level: str,
        from_language: str,
        to_language: str,
        length_preference="200-400 words",
) -> str:
    return (
        f"You are a language learning content creator.\n"
        f"The user will provide input, you will generate an engaging realistic summary text in {to_language} "
        f"at {complexity_level} proficiency level (CEFR scale).\n\n"
        f"The text you generate will:\n"
        f"- Contain ONLY the generated text in {to_language}.\n"
        f"- Be appropriate for a {complexity_level} {to_language} speaker.\n"
        f"- Never generate inappropriate (hateful, sexual, violent) content.  It is preferable to return no text than to generate such content.\n"
        f"- Speak directly to the reader/listener, adopting the tone and style of a semi-formal news reporter or podcaster.\n"
        f"- Where appropriate (fluency level, content), use a small number of idiomatic expressions.\n"
        f"- Be formatted in markdown with paragraphs and line breaks.\n"
        f"- Be {length_preference} long.\n"
        f"- Be inspired by the following source material "
        f"(but written originally in {from_language}):\n\n"
    )


def _create_prompt_summarise_text(
        source_material: str,
) -> str:
    return (
        f"Source material follows: \n\n"
        f"{source_material}"
    )


async def generate_summary_text(
        content_to_summarise: str,
        complexity_level: str,
        from_language: str,
        to_language: str,
        length_preference="200-400 words",) -> str:
    """Generate text using Anthropic."""
    def _call() -> str:
        client = _create_anthropic_client()
        message = client.messages.create(
            model="claude-sonnet-4-6",
            max_tokens=1024,
            messages=[
                {
                    "role": "system",
                    "content": _create_system_prompt_summarise_text(
                        complexity_level=complexity_level,
                        from_language=from_language,
                        to_language=to_language,
                        length_preference=length_preference,
                    )
                },
                {
                    "role": "user",
                    "content": _create_prompt_summarise_text(
                        content_to_summarise
                    )
                }
            ],
        )
        return message.content[0].text

    return await asyncio.to_thread(_call)