"""A second answer that arrives while a first one streams, through `prain web`: when does
its first token come, and how much of its draft survives the refine?

Run it against a proxy with drafts and one without ([draft] full_requests = max_requests)
and compare. usage: python3 scripts/draft_effect.py http://127.0.0.1:8080
"""

import json
import os
import sys
import threading
import time

from prain.chat import post

LONG = [{"role": "user", "content": "Write a detailed 400-word history of the printing press."}]
SHORT = [{"role": "user", "content": "Name three uses of copper, one line each."}]


def answer(url, session, messages, out):
    start, mode = time.monotonic(), "full"
    out.update(first=None, draft="", final="")
    with post(url, "/chat", {"session": session, "messages": messages}) as response:
        for raw in response:
            line = raw.decode().strip()
            if not line.startswith("data: ") or line == "data: [DONE]":
                continue
            data = json.loads(line[6:])
            if "prain" in data:
                mode = data["prain"]
                continue
            piece = data["choices"][0]["delta"].get("content")
            if piece:
                out["first"] = out["first"] or time.monotonic() - start
                out["draft" if mode == "draft" else "final"] += piece
    out["total"] = time.monotonic() - start


def main():
    url = sys.argv[1]
    first, second = {}, {}
    thread = threading.Thread(target=answer, args=(url, "first", LONG, first))
    thread.start()
    time.sleep(5)  # the first answer is decoding now
    answer(url, "second", SHORT, second)
    thread.join()
    kept = len(os.path.commonprefix([second["draft"], second["final"]]))
    print(f"second answer: first token {second['first']:.1f} s, done after {second['total']:.1f} s; "
          + (f"draft {len(second['draft'])} chars, {kept} kept by the refine"
             if second["draft"] else "no draft"))


if __name__ == "__main__":
    main()