"""HTTP client for the shared ai-service container."""
import json

import httpx

from app.core.config import settings
from app.services.prompts import SYSTEM_PROMPT, USER_PROMPT_TEMPLATE

_client = httpx.AsyncClient(timeout=120.0)


class AIServiceError(Exception):
    pass


async def classify_document(text: str) -> dict:
    """
    Send document text to ai-service for classification.
    Returns the parsed JSON result dict.
    Raises AIServiceError on HTTP errors or unexpected response shapes.
    """
    messages = [
        {"role": "system", "content": SYSTEM_PROMPT},
        {"role": "user", "content": USER_PROMPT_TEMPLATE.format(text=text[:50_000])},
    ]

    try:
        response = await _client.post(
            f"{settings.AI_SERVICE_URL}/chat",
            json={
                "messages": messages,
                "max_tokens": 2048,
                "temperature": 0,
                "response_format": "json",
            },
        )
    except httpx.RequestError as exc:
        raise AIServiceError(f"Could not reach ai-service: {exc}") from exc

    if response.status_code != 200:
        raise AIServiceError(
            f"ai-service returned {response.status_code}: {response.text[:200]}"
        )

    try:
        content = response.json()["content"]
        return json.loads(content)
    except (KeyError, json.JSONDecodeError) as exc:
        raise AIServiceError(f"Unexpected ai-service response: {exc}") from exc