"""Time to first token for a fresh prompt: cold, and warmed up as if it had been typed.

usage (prain installed): python3 scripts/warm_effect.py http://127.0.0.1:8000
"""

import sys
import time
import uuid

from prain.chat import chat_body, first_model, post, stream_text, warm_body

PROMPT = ("You are reviewing a design for a home server that runs a mixture-of-experts language "
          "model on a single consumer graphics card with eight gigabytes of memory. The model has "
          "thirty layers with one hundred and twenty-eight experts each, and only a few experts per "
          "layer fit on the card at once. The rest wait in system memory or on an NVMe drive and "
          "are copied over PCI Express when a token needs them. List the three biggest risks of "
          "this design and, for each, one concrete way to measure it.")


def first_token_seconds(base_url, model, text):
    start = time.monotonic()
    body = chat_body(model, [{"role": "user", "content": text}], max_tokens=1)
    with post(base_url, "/v1/chat/completions", body) as response:
        next(stream_text(response), None)
    return time.monotonic() - start


def main(base_url):
    model = first_model(base_url)
    cold = first_token_seconds(base_url, model, f"[{uuid.uuid4().hex[:8]}] {PROMPT}")
    text = f"[{uuid.uuid4().hex[:8]}] {PROMPT}"  # a new tag: no prefix-cache hit from above
    post(base_url, "/v1/chat/completions", warm_body(model, [], text[:-40])).read()
    warm = first_token_seconds(base_url, model, text)
    print(f"first token: cold {cold:.2f} s, warmed {warm:.2f} s")


if __name__ == "__main__":
    main(sys.argv[1])