#!/usr/bin/env python3
import argparse
import os
import subprocess
import tempfile
import time
from pathlib import Path

from google import genai


DEFAULT_PROMPT = (
    "Please describe the exact sequence of events in this video. "
    "Specifically, when does the loudest sound occur in relation to the visual impact?"
)


def run_cmd(cmd):
    subprocess.run(cmd, check=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True)


def make_video_only(input_video: Path, output_video: Path):
    # Remove audio track to simulate visual-only input.
    cmd = [
        "ffmpeg",
        "-y",
        "-i",
        str(input_video),
        "-map",
        "0:v:0",
        "-an",
        "-c:v",
        "copy",
        str(output_video),
    ]
    run_cmd(cmd)


def make_audio_only(input_video: Path, output_audio: Path):
    # Extract mono wav audio for audio-only case.
    cmd = [
        "ffmpeg",
        "-y",
        "-i",
        str(input_video),
        "-vn",
        "-ac",
        "1",
        "-ar",
        "16000",
        str(output_audio),
    ]
    run_cmd(cmd)


def wait_until_active(client: genai.Client, file_name: str, timeout_sec: int = 300):
    start = time.time()
    while True:
        meta = client.files.get(name=file_name)
        state = getattr(getattr(meta, "state", None), "name", None) or str(getattr(meta, "state", ""))
        if state == "ACTIVE":
            return
        if state == "FAILED":
            raise RuntimeError(f"Gemini file processing failed: {file_name}")
        if time.time() - start > timeout_sec:
            raise TimeoutError(f"Timed out waiting for Gemini file ACTIVE: {file_name}")
        time.sleep(2)


def is_503_unavailable(exc: Exception) -> bool:
    msg = str(exc)
    return "503" in msg and "UNAVAILABLE" in msg


def generate_with_retry(
    client: genai.Client,
    model: str,
    uploaded,
    prompt: str,
    max_retries: int,
    retry_wait_sec: float,
):
    attempt = 0
    while True:
        try:
            return client.models.generate_content(model=model, contents=[uploaded, prompt])
        except Exception as exc:  # SDK raises typed errors but this keeps compatibility
            if not is_503_unavailable(exc) or attempt >= max_retries:
                raise
            sleep_s = retry_wait_sec * (2 ** attempt)
            print(
                f"[retry] {model} busy (503). attempt {attempt + 1}/{max_retries}, "
                f"sleep {sleep_s:.1f}s ..."
            )
            time.sleep(sleep_s)
            attempt += 1


def run_case(
    client: genai.Client,
    model: str,
    fallback_model: str,
    case_name: str,
    media_path: Path,
    prompt: str,
    max_retries: int,
    retry_wait_sec: float,
):
    uploaded = client.files.upload(file=str(media_path))
    wait_until_active(client, uploaded.name)
    try:
        resp = generate_with_retry(
            client=client,
            model=model,
            uploaded=uploaded,
            prompt=prompt,
            max_retries=max_retries,
            retry_wait_sec=retry_wait_sec,
        )
    except Exception as exc:
        if fallback_model and is_503_unavailable(exc):
            print(f"[fallback] switch to model: {fallback_model}")
            resp = generate_with_retry(
                client=client,
                model=fallback_model,
                uploaded=uploaded,
                prompt=prompt,
                max_retries=max_retries,
                retry_wait_sec=retry_wait_sec,
            )
        else:
            raise
    text = (resp.text or "").strip()
    print(f"\n===== {case_name} =====")
    print(text if text else "<empty response>")


def main():
    parser = argparse.ArgumentParser(description="Gemini AV/Video-only/Audio-only test runner.")
    parser.add_argument("--video", required=True, help="Input video path.")
    parser.add_argument(
        "--model",
        default="gemini-3.1-pro-preview",
        help="Gemini model id.",
    )
    parser.add_argument(
        "--cases",
        default="av,video_only,audio_only",
        help="Comma-separated cases: av,video_only,audio_only",
    )
    parser.add_argument(
        "--fallback-model",
        default="",
        help="Optional fallback model if primary model returns 503.",
    )
    parser.add_argument(
        "--max-retries",
        type=int,
        default=5,
        help="Retries for transient 503 errors.",
    )
    parser.add_argument(
        "--retry-wait-sec",
        type=float,
        default=2.0,
        help="Base wait seconds for exponential backoff (2,4,8,...)",
    )
    parser.add_argument("--prompt", default=DEFAULT_PROMPT)
    args = parser.parse_args()

    api_key = os.getenv("GEMINI_API_KEY")
    if not api_key:
        raise RuntimeError("GEMINI_API_KEY is not set.")

    input_video = Path(args.video)
    if not input_video.exists():
        raise FileNotFoundError(f"Video not found: {input_video}")

    selected = {c.strip() for c in args.cases.split(",") if c.strip()}
    allowed = {"av", "video_only", "audio_only"}
    bad = selected - allowed
    if bad:
        raise ValueError(f"Unknown cases: {sorted(bad)}. Allowed: {sorted(allowed)}")

    client = genai.Client(api_key=api_key)
    print(f"Model: {args.model}")
    print(f"Video: {input_video}")
    print(f"Cases: {sorted(selected)}")

    with tempfile.TemporaryDirectory(prefix="gemini_mm_") as tmpdir:
        tmpdir = Path(tmpdir)
        muted_video = tmpdir / "video_only.mp4"
        audio_wav = tmpdir / "audio_only.wav"

        if "av" in selected:
            run_case(
                client,
                args.model,
                args.fallback_model,
                "AV (video + audio)",
                input_video,
                args.prompt,
                args.max_retries,
                args.retry_wait_sec,
            )

        if "video_only" in selected:
            make_video_only(input_video, muted_video)
            run_case(
                client,
                args.model,
                args.fallback_model,
                "Video only (muted video)",
                muted_video,
                args.prompt,
                args.max_retries,
                args.retry_wait_sec,
            )

        if "audio_only" in selected:
            make_audio_only(input_video, audio_wav)
            run_case(
                client,
                args.model,
                args.fallback_model,
                "Audio only (wav)",
                audio_wav,
                args.prompt,
                args.max_retries,
                args.retry_wait_sec,
            )

    print("\nDone.")


if __name__ == "__main__":
    main()