"""Microbenchmark for datetime call_tzinfo_method (gh-150942)."""
import datetime as dt
import time
from datetime import timezone
from zoneinfo import ZoneInfo

ny = ZoneInfo("America/New_York")
utc_dt = dt.datetime(2024, 6, 7, 16, 30, tzinfo=timezone.utc)
ny_dt = dt.datetime(2024, 6, 7, 12, 30, tzinfo=ny)


def bench(fn, N=1_000_000, repeat=7):
    best = float("inf")
    for _ in range(repeat):
        start = time.perf_counter()
        for _ in range(N):
            fn()
        best = min(best, (time.perf_counter() - start) / N * 1e9)
    return best


CASES = {
    "astimezone() UTC->local": lambda: utc_dt.astimezone(ny),
    "timestamp()":             lambda: ny_dt.timestamp(),
    "isoformat()":             lambda: ny_dt.isoformat(),
    "utcoffset()":             lambda: ny_dt.utcoffset(),
    "now().isoformat()":       lambda: dt.datetime.now().isoformat(),  # naive: control
    "tzname()  [control]":     lambda: ny_dt.tzname(),
}

print(f"{'operation':<26}{'ns/op':>10}")
print("-" * 36)
for name, fn in CASES.items():
    print(f"{name:<26}{bench(fn):>9.1f}")