#!/usr/bin/env python3
"""Measure sampled per-term profiler overhead against the same clean candidate."""
from __future__ import annotations

import json
import os
import re
import subprocess
import time
from pathlib import Path


ROOT = Path(__file__).resolve().parents[4]
DATA = ROOT / "Standalone/data/owner_world.json"
OUT = ROOT / os.environ.get("VOXELFORGE_L76_PROFILE_OVERHEAD_OUT",
                            "Saved/Linux/l76/term-profiler-overhead")
BINARIES = {
    "clean": ROOT / "Standalone/bin/linux/VoxelForgeCoreHeadless-l76-clang",
    "profile": ROOT / "Standalone/bin/linux/VoxelForgeCoreHeadless-l76-termprofile-clang",
}
CAMERAS = {
    1: (25.8369140625, 3.19921875, -737.0),
    2: (19.166015625, -14.2001953125, -753.3740234375),
}
KV = re.compile(r"([a-zA-Z0-9_]+)=([^ ]+)")


def run(kind: str, strate: int, pair: int) -> dict:
    OUT.mkdir(parents=True, exist_ok=True)
    log = OUT / f"strate{strate}-pair{pair}-{kind}.log"
    camera = ",".join(f"{value:.12f}" for value in CAMERAS[strate]) + ",0,0"
    command = [
        "taskset", "-c", "0-11", "prlimit", "--as=6442450944", "--", "timeout",
        "1740s", str(BINARIES[kind]), str(DATA), "--world-assembler-prototype",
        "--stream-benchmark", "--stream-pipeline", "--force-generate", "--workers=8",
        "--clip-radius=3", "--max-clip-level=8", "--max-level=8", f"--camera={camera}",
        "--profile-lod-work", "--instrument-tile-drain", "--profile-passage-composer",
    ]
    started = time.monotonic()
    with log.open("w", encoding="utf-8") as output:
        result = subprocess.run(command, cwd=ROOT, stdout=output,
                                stderr=subprocess.STDOUT, check=False, timeout=1740)
    pipeline = {}
    with log.open(encoding="utf-8", errors="replace") as stream:
        for line in stream:
            if line.startswith("[StreamPipeline]"):
                pipeline = dict(KV.findall(line))
    if result.returncode != 0 or "whole_view_ready" not in pipeline:
        raise SystemExit(f"profiler-overhead run failed; see {log}")
    return {
        "kind": kind, "strate": strate, "pair": pair, "exit_code": result.returncode,
        "process_wall_s": round(time.monotonic() - started, 3),
        "whole_view_ready_s": float(pipeline["whole_view_ready"].removesuffix("s")),
        "log": str(log.relative_to(ROOT)),
    }


def main() -> int:
    missing = [str(path) for path in (*BINARIES.values(), DATA) if not path.is_file()]
    if missing:
        raise SystemExit("missing input: " + ", ".join(missing))
    rows = []
    for strate in (1, 2):
        for pair in range(3):
            order = ("clean", "profile") if pair % 2 == 0 else ("profile", "clean")
            pair_rows = {kind: run(kind, strate, pair) for kind in order}
            delta = pair_rows["profile"]["whole_view_ready_s"] \
                - pair_rows["clean"]["whole_view_ready_s"]
            result = {
                "strate": strate, "pair": pair,
                "clean_s": pair_rows["clean"]["whole_view_ready_s"],
                "profile_s": pair_rows["profile"]["whole_view_ready_s"],
                "delta_s": round(delta, 4),
                "delta_percent": round(100.0 * delta / pair_rows["clean"]["whole_view_ready_s"], 2),
                "runs": [pair_rows[kind] for kind in order],
            }
            rows.append(result)
            print("[L76TermProfilerOverhead] " + json.dumps(result, sort_keys=True), flush=True)
    (OUT / "summary.json").write_text(json.dumps(rows, indent=2) + "\n", encoding="utf-8")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())