import base64
import logging
import os
import threading

import httpx

MODAL_ENDPOINT = os.environ.get("MODAL_ENDPOINT_WHISPER", "")
MODAL_AUTH_TOKEN = os.environ.get("MODAL_AUTH_TOKEN", "")

log = logging.getLogger(__name__)

# Minimal 44-byte WAV header + 1 sample of silence — enough to trigger container spin-up
_MINIMAL_WAV = (
    b"RIFF$\x00\x00\x00WAVEfmt \x10\x00\x00\x00\x01\x00\x01\x00"
    b"\x44\xac\x00\x00\x88\x01\x00\x00\x02\x00\x10\x00data\x00\x00\x00\x00"
)
_MINIMAL_B64 = base64.b64encode(_MINIMAL_WAV).decode()


def warmup():
    """Fire-and-forget request to wake the Whisper Modal container.

    Called once on page load from reset_session(). The container
    auto-scales down after scaledown_window (90s).
    """
    if not MODAL_ENDPOINT:
        return

    def _ping():
        try:
            resp = httpx.post(
                MODAL_ENDPOINT,
                json={"audio_base64": _MINIMAL_B64, "token": MODAL_AUTH_TOKEN},
                timeout=60,
            )
            log.info("Modal warmup: status=%d", resp.status_code)
        except Exception as e:
            log.warning("Modal warmup failed (non-critical): %s", e)

    threading.Thread(target=_ping, daemon=True).start()


def transcribe(audio_path: str) -> str | None:
    if not MODAL_ENDPOINT:
        raise RuntimeError("MODAL_ENDPOINT_WHISPER not set")

    with open(audio_path, "rb") as f:
        b64 = base64.b64encode(f.read()).decode()

    resp = httpx.post(
        MODAL_ENDPOINT,
        json={"audio_base64": b64, "token": MODAL_AUTH_TOKEN},
        timeout=30,
    )
    resp.raise_for_status()
    return resp.json().get("text")