"""Versioned CPU-only driver; freeze snapshots and retain failed stages."""
import argparse
import datetime as dt
import hashlib
import importlib.metadata
import json
import os
from pathlib import Path
import platform
import resource
import shutil
import subprocess
import sys
import time


def digest(path):
    return hashlib.sha256(path.read_bytes()).hexdigest()


def main():
    ap=argparse.ArgumentParser()
    ap.add_argument("--config",type=Path,required=True)
    ap.add_argument("--run-id",required=True)
    ap.add_argument("--smoke",action="store_true")
    args=ap.parse_args()
    root=Path(__file__).resolve().parents[1]
    if not args.run_id.startswith("run-") or "/" in args.run_id or ".." in args.run_id:
        raise ValueError("Unsafe run id")
    folder=root/"results"/args.run_id
    folder.mkdir(parents=True,exist_ok=False)
    for name in ("source","logs","figures"):
        (folder/name).mkdir()
    shutil.copy2(args.config,folder/"config.json")
    config=json.loads((folder/"config.json").read_text())
    files=sorted((root/"src").glob("*.py"))
    for file in files:
        shutil.copy2(file,folder/"source"/file.name)
    shutil.copy2(root/"PROTOCOL.md",folder/"PROTOCOL.md")
    if (root/"docs").exists():
        shutil.copytree(root/"docs",folder/"docs")
    status={"run_id":args.run_id,"status":"RUNNING","smoke":args.smoke,
        "started_utc":dt.datetime.now(dt.timezone.utc).isoformat(),"python":sys.version,
        "platform":platform.platform(),
        "packages":{p:importlib.metadata.version(p) for p in ("numpy","scipy","matplotlib")},
        "config_sha256":digest(folder/"config.json"),
        "source_sha256":{f.name:digest(f) for f in files},"stages":[]}
    def save():
        pending=folder/"status.pending.json"
        pending.write_text(json.dumps(status,indent=2)+"\n")
        pending.replace(folder/"status.json")
    def limits():
        limit=int(config["address_space_gib"])*1024**3
        resource.setrlimit(resource.RLIMIT_AS,(limit,limit))
    env=os.environ.copy()
    env.update(OMP_NUM_THREADS="1",OPENBLAS_NUM_THREADS="1",MKL_NUM_THREADS="1",
               NUMEXPR_NUM_THREADS="1",MPLBACKEND="Agg",PYTHONUNBUFFERED="1")
    search=[sys.executable,str(folder/"source/search_witnesses.py"),
            "--config",str(folder/"config.json"),"--output-dir",str(folder)]
    if args.smoke:
        search.append("--smoke")
    stages=[("search",search),
        ("certify",[sys.executable,str(folder/"source/certify_witness.py"),
                    "--input",str(folder/"witnesses.json"),
                    "--output",str(folder/"certificates.json"),"--self-test"]),
        ("validate_summary",[sys.executable,str(folder/"source/normalize_results.py"),
                             "--run-dir",str(folder)])]
    if not args.smoke:
        stages.append(("plots",[sys.executable,str(folder/"source/plot_phase2.py"),"--run-dir",str(folder)]))
    t0=time.monotonic()
    save()
    try:
        for name,command in stages:
            row={"stage":name,"status":"RUNNING"}
            status["stages"].append(row);save()
            started=time.monotonic()
            print(f"START {name}",flush=True)
            with (folder/"logs"/(name+".log")).open("w") as log:
                completed=subprocess.run(command,stdout=log,stderr=subprocess.STDOUT,
                    env=env,preexec_fn=limits,
                    timeout=max(1,config["total_timeout_seconds"]-(time.monotonic()-t0)))
            row.update(status="COMPLETE" if completed.returncode==0 else "FAILED",
                       returncode=completed.returncode,runtime_seconds=time.monotonic()-started)
            save()
            print(f"END {name}: {row['status']} ({row['runtime_seconds']:.1f}s)",flush=True)
            if completed.returncode:
                raise RuntimeError(f"{name} failed; inspect retained logs")
        status["status"]="COMPLETE"
    except Exception as exc:
        status["status"]="FAILED";status["error"]=repr(exc)
        if status["stages"] and status["stages"][-1]["status"]=="RUNNING":
            status["stages"][-1]["status"]="FAILED"
        raise
    finally:
        status["finished_utc"]=dt.datetime.now(dt.timezone.utc).isoformat()
        status["runtime_seconds"]=time.monotonic()-t0
        save()


if __name__=="__main__":
    main()