#!/usr/bin/env python3

import argparse
import json
import os
from pathlib import Path
import statistics
import subprocess
import sys
import time


def check(condition, message):
	if not condition:
		raise RuntimeError(message)


def run_sample(args, disabled):
	environment = os.environ.copy()
	if sys.platform == "darwin":
		executable_directory = str(Path(args.executable).resolve().parent)
		current_library_path = environment.get("DYLD_LIBRARY_PATH")
		environment["DYLD_LIBRARY_PATH"] = (
			executable_directory
			if not current_library_path
			else executable_directory + os.pathsep + current_library_path
		)
	if disabled:
		environment["EEPP_DISABLE_ACCESSIBILITY"] = "1"
	else:
		environment.pop("EEPP_DISABLE_ACCESSIBILITY", None)
	start = time.perf_counter()
	completed = subprocess.run(
		[
			args.executable,
			"--benchmark-inactive",
			"--benchmark-iterations",
			str(args.iterations),
		],
		check=True,
		capture_output=True,
		text=True,
		timeout=args.timeout,
		env=environment,
	)
	wall_ms = (time.perf_counter() - start) * 1000
	result = json.loads(completed.stdout)
	result["wall_ms"] = wall_ms
	result["initialization_ms"] = result.pop("initialization_us") / 1000
	result["readiness_ms"] = result.pop("readiness_us") / 1000
	result["notifications_ms"] = result.pop("notifications_us") / 1000
	return result


def median_sample(samples):
	return {
		key: statistics.median(sample[key] for sample in samples)
		for key in samples[0]
	}


def collect_samples(args, first_index, count, enabled_samples, disabled_samples):
	for index in range(first_index, first_index + count):
		# Reverse each adjacent pair so neither mode consistently benefits from running second.
		modes = (True, False) if index % 2 == 0 else (False, True)
		for disabled in modes:
			result = run_sample(args, disabled)
			(disabled_samples if disabled else enabled_samples).append(result)


def summarize(enabled_samples, disabled_samples):
	enabled = median_sample(enabled_samples)
	disabled = median_sample(disabled_samples)
	check(disabled["notifications_ms"] > 0, "disabled notification measurement was zero")
	check(disabled["wall_ms"] > 0, "disabled wall-time measurement was zero")
	return {
		"disabled": disabled,
		"enabled": enabled,
		"raw_disabled": disabled_samples,
		"raw_enabled": enabled_samples,
		"notification_ratio": enabled["notifications_ms"] / disabled["notifications_ms"],
		"wall_ratio": enabled["wall_ms"] / disabled["wall_ms"],
	}


def main():
	parser = argparse.ArgumentParser(description="Benchmark inactive accessibility overhead")
	parser.add_argument("--executable", default="bin/eepp-ui-accessibility")
	parser.add_argument("--iterations", type=int, default=100000)
	parser.add_argument("--samples", type=int, default=5)
	parser.add_argument("--confirmation-samples", type=int, default=10)
	parser.add_argument("--timeout", type=float, default=10)
	parser.add_argument("--max-initialization-ms", type=float, default=250)
	parser.add_argument("--max-notification-ratio", type=float, default=1.01)
	parser.add_argument("--max-wall-ratio", type=float, default=1.25)
	parser.add_argument("--json", action="store_true")
	args = parser.parse_args()
	check(args.iterations > 0 and args.samples > 0, "iterations and samples must be positive")
	check(args.confirmation_samples >= 0, "confirmation samples must not be negative")

	enabled_samples = []
	disabled_samples = []
	collect_samples(args, 0, args.samples, enabled_samples, disabled_samples)
	output = summarize(enabled_samples, disabled_samples)
	if (
		output["notification_ratio"] > args.max_notification_ratio
		or output["wall_ratio"] > args.max_wall_ratio
	) and args.confirmation_samples:
		collect_samples(
			args,
			args.samples,
			args.confirmation_samples,
			enabled_samples,
			disabled_samples,
		)
		output = summarize(enabled_samples, disabled_samples)

	enabled = output["enabled"]
	failed = (
		enabled["initialization_ms"] > args.max_initialization_ms
		or output["notification_ratio"] > args.max_notification_ratio
		or output["wall_ratio"] > args.max_wall_ratio
	)
	if failed:
		print(json.dumps(output, sort_keys=True), file=sys.stderr)
	check(
		enabled["initialization_ms"] <= args.max_initialization_ms,
		"inactive native backend initialization exceeded threshold",
	)
	check(
		output["notification_ratio"] <= args.max_notification_ratio,
		"inactive accessibility notification overhead exceeded threshold",
	)
	check(
		output["wall_ratio"] <= args.max_wall_ratio,
		"inactive accessibility wall-time overhead exceeded threshold",
	)
	if args.json:
		print(json.dumps(output, sort_keys=True))
	else:
		print(
			"Inactive accessibility benchmark passed: "
			f"initialization {enabled['initialization_ms']:.3f}ms, "
			f"notifications {enabled['notifications_ms']:.3f}ms "
			f"({output['notification_ratio']:.3f}x disabled), "
			f"wall {output['wall_ratio']:.3f}x disabled"
		)


if __name__ == "__main__":
	main()