"""Immutable, resource-bounded phase-three scientific run and presentation."""
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 sha(path):
    return hashlib.sha256(path.read_bytes()).hexdigest()


def now():
    return dt.datetime.now(dt.timezone.utc).isoformat()


def main(run_id):
    base=Path(__file__).resolve().parent
    run=base/"results"/run_id
    if run.exists():
        raise FileExistsError("Refusing to overwrite a run")
    config=json.loads((base/"phase3_config.json").read_text())
    required=("schedule_benchmark.py","biased_policy.py","plot_phase3.py","summarize_phase3.py",
              "schedule_math.md","biased_math.md","PROTOCOL.md","phase3_config.json")
    for name in required:
        if not (base/name).is_file():
            raise FileNotFoundError(name)
    run.mkdir(parents=True)
    source=run/"source"
    source.mkdir()
    for path in sorted(base.glob("*.py")):
        shutil.copy2(path,source/path.name)
    shutil.copytree(base/"vendor",source/"vendor",ignore=shutil.ignore_patterns("__pycache__"))
    shutil.copytree(base/"inputs",run/"inputs")
    (run/"docs").mkdir()
    for name in ("schedule_math.md","biased_math.md"):
        shutil.copy2(base/name,run/"docs"/name)
    for name in ("PROTOCOL.md","phase3_config.json"):
        shutil.copy2(base/name,run/name)
    (run/"logs").mkdir()
    (run/"figures").mkdir()
    started=time.monotonic()
    status={"run_id":run_id,"status":"RUNNING","started_utc":now(),
        "python":sys.version,"platform":platform.platform(),
        "packages":{p:importlib.metadata.version(p) for p in ("numpy","scipy","matplotlib")},
        "config_sha256":sha(run/"phase3_config.json"),
        "source_sha256":{str(p.relative_to(source)):sha(p) for p in sorted(source.rglob("*.py"))},
        "input_sha256":{p.name:sha(p) for p in sorted((run/"inputs").glob("*.json"))},
        "stages":[]}

    def save():
        (run/"status.json").write_text(json.dumps(status,indent=2)+"\n")

    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")

    def limits():
        cap=int(config["address_space_gib"])*1024**3
        resource.setrlimit(resource.RLIMIT_AS,(cap,cap))

    def stage(name,arguments,seconds,allow_partial=False):
        row={"stage":name,"started_utc":now(),"timeout_seconds":seconds,"status":"RUNNING"}
        status["stages"].append(row)
        save()
        t=time.monotonic()
        print("START "+name,flush=True)
        try:
            with (run/"logs"/(name+".log")).open("w") as log:
                completed=subprocess.run([sys.executable,str(source/arguments[0]),*arguments[1:]],
                    env=env,stdout=log,stderr=subprocess.STDOUT,timeout=seconds,preexec_fn=limits)
            row.update(returncode=completed.returncode,
                       status="COMPLETE" if completed.returncode==0 else "PARTIAL" if allow_partial else "FAILED")
            if completed.returncode and not allow_partial:
                raise RuntimeError(f"{name} failed; inspect retained log")
        except Exception as error:
            row.update(status="FAILED",error=repr(error))
            raise
        finally:
            row["runtime_seconds"]=time.monotonic()-t
            save()
        print(f"END {name}: {row['status']}",flush=True)

    save()
    try:
        stage("schedules",["schedule_benchmark.py","--witnesses",str(run/"inputs"/"witnesses.json"),
            "--certificates",str(run/"inputs"/"certificates.json"),"--output",str(run/"schedules.json"),
            "--self-test"],config["schedule_stage_seconds"])
        stage("biased",["biased_policy.py","--config",str(run/"phase3_config.json"),
            "--output",str(run/"biased_results.json")],config["biased_stage_seconds"],allow_partial=True)
        stage("summary",["summarize_phase3.py","--run-dir",str(run)],90)
        stage("plots",["plot_phase3.py","--run-dir",str(run)],120)
        bias=json.loads((run/"biased_results.json").read_text())
        status["status"]="COMPLETE" if bias["status"]=="complete" else "COMPLETE_WITH_MISSING_BIASED_CASES"
    except Exception as error:
        status.update(status="FAILED",error=repr(error))
        raise
    finally:
        status.update(finished_utc=now(),runtime_seconds=time.monotonic()-started)
        save()


if __name__=="__main__":
    parser=argparse.ArgumentParser()
    parser.add_argument("--run-id",required=True)
    main(parser.parse_args().run_id)