#!/usr/bin/env python3
"""Run an FZL VM benchmark and report wall-clock timing statistics."""

import argparse
import statistics
import subprocess
import sys
import time


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--runs", type=int, default=7, help="measured runs")
    parser.add_argument("--warmup", type=int, default=2, help="warm-up runs")
    parser.add_argument("--max-iter", type=int, default=2_000_000)
    parser.add_argument("--vm", required=True, help="path to the fz executable")
    parser.add_argument("--program", required=True, help="compiled .fzb program")
    args = parser.parse_args()

    if args.runs < 1 or args.warmup < 0 or args.max_iter < 1:
        parser.error("runs/max-iter must be positive and warmup must be non-negative")

    command = [args.vm, "--max-iter", str(args.max_iter), args.program]

    for _ in range(args.warmup):
        result = subprocess.run(command, capture_output=True, text=True)
        if result.returncode != 0:
            sys.stderr.write(result.stdout)
            sys.stderr.write(result.stderr)
            raise SystemExit(result.returncode)

    measurements = []
    for _ in range(args.runs):
        start = time.perf_counter()
        result = subprocess.run(
            command, capture_output=True, text=True
        )
        elapsed = time.perf_counter() - start
        if result.returncode != 0:
            sys.stderr.write(result.stdout)
            sys.stderr.write(result.stderr)
            raise SystemExit(result.returncode)
        measurements.append(elapsed)

    print(f"Runs:   {args.runs} (warm-up: {args.warmup})")
    print(f"Median: {statistics.median(measurements):.6f} s")
    print(f"Mean:   {statistics.mean(measurements):.6f} s")
    print(f"Min:    {min(measurements):.6f} s")
    print(f"Max:    {max(measurements):.6f} s")


if __name__ == "__main__":
    main()