"""Helpers for the Gemini core-generation smoke tests: free-tier pacing (15 RPM/model) and one 429 retry."""
from __future__ import annotations

import base64
import re
import struct
import time
import zlib

_LAST_CALL = [0.0]
MIN_GAP_S = 4.2


def call(gemini, method: str, path: str, body=None, retries: int = 2, **kw):
    """gemini fixture wrapper: keeps >= MIN_GAP_S between calls; retries on 429 (RetryInfo delay) and transient 503."""
    for attempt in range(retries + 1):
        gap = MIN_GAP_S - (time.time() - _LAST_CALL[0])
        if gap > 0:
            time.sleep(gap)
        st, resp, hdrs = gemini(method, path, body, **kw)
        _LAST_CALL[0] = time.time()
        if st not in (429, 503) or attempt == retries:
            return st, resp, hdrs
        msg = resp.get("error", {}).get("message", "") if isinstance(resp, dict) else ""
        m = re.search(r"retry in ([0-9.]+)s", msg)
        time.sleep(float(m.group(1)) + 1 if m else 20)
    return st, resp, hdrs


def png_1x1_b64() -> str:
    def ch(t, d):
        c = struct.pack(">I", len(d)) + t + d
        return c + struct.pack(">I", zlib.crc32(t + d) & 0xFFFFFFFF)
    png = b"\x89PNG\r\n\x1a\n" + ch(b"IHDR", struct.pack(">IIBBBBB", 1, 1, 8, 2, 0, 0, 0)) + ch(b"IDAT", zlib.compress(b"\x00\xff\x00\x00")) + ch(b"IEND", b"")
    return base64.b64encode(png).decode()


def user(text: str) -> list[dict]:
    return [{"role": "user", "parts": [{"text": text}]}]


def text_of(body: dict) -> str:
    return "".join(p.get("text", "") for p in body["candidates"][0]["content"]["parts"] if not p.get("thought"))


def gc(model: str) -> str:
    return f"/v1beta/models/{model}:generateContent"