"""OpenRouter chat-completions client."""

from __future__ import annotations

import httpx
from app.config import get_settings


def complete_text(
    prompt: str,
    *,
    system_prompt: str | None = None,
    temperature: float = 0.2,
    max_tokens: int = 2048,
) -> str:
    """Send a prompt to OpenRouter and return the assistant text."""
    settings = get_settings()
    if not settings.openrouter_api_key:
        raise RuntimeError("OPENROUTER_API_KEY is not configured.")

    messages = []
    if system_prompt:
        messages.append({"role": "system", "content": system_prompt})
    messages.append({"role": "user", "content": prompt})

    response = httpx.post(
        "https://openrouter.ai/api/v1/chat/completions",
        headers={
            "Authorization": f"Bearer {settings.openrouter_api_key}",
            "Content-Type": "application/json",
            "HTTP-Referer": settings.openrouter_site_url,
            "X-Title": settings.openrouter_app_name,
        },
        json={
            "model": settings.openrouter_model,
            "messages": messages,
            "temperature": temperature,
            "max_tokens": max_tokens,
        },
        timeout=settings.openrouter_timeout_seconds,
    )
    try:
        response.raise_for_status()
    except httpx.HTTPStatusError as exc:
        detail = response.text[:500]
        raise RuntimeError(
            f"OpenRouter request failed with HTTP {response.status_code}: {detail}"
        ) from exc

    data = response.json()
    choices = data.get("choices") or []
    if not choices:
        raise RuntimeError("OpenRouter returned no choices.")

    content = choices[0].get("message", {}).get("content", "")
    if not content:
        raise RuntimeError("OpenRouter returned an empty response.")
    return content