"""Phase 1 step 1: ONE minimal ECDS s2s-reforecasts retrieval + GRIB verification.

Auth pattern matches the user's verified working script (My_swers.md):
  cdsapi.Client(url="https://ecds.ecmwf.int/api")  -> key read from ~/.cdsapirc
  (or CDSAPI_KEY env). The existing key authenticates against ECDS when the url
  is overridden in code, so ~/.cdsapirc need not be changed.

Request schema is the native ECDS syntax from that script (origin, year/month/day,
hyear/hmonth/hday, level_type, variable=paramId, forecast_type=control_forecast,
leadtime_hour="start_end", data_format, area=[N,W,S,E], grid). The concrete
request lives in config/ecds_minimal_request.json (reproduced from ECDS).

Verifies the returned GRIB with ecCodes CLI (grib_ls/grib_get) + cdo (D6);
cfgrib is NOT required. Keeps the original GRIB.
"""
import json
import os
import subprocess
import traceback

ROOT = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
OUT = os.path.join(ROOT, "data", "raw", "ecmwf_s2s_1p5deg")
os.makedirs(OUT, exist_ok=True)
target = os.path.join(OUT, "s2s_refc_cf_min.grib")
REQ_FILE = os.path.join(ROOT, "config", "ecds_minimal_request.json")
DATASET = "s2s-reforecasts"
ECDS_URL = "https://ecds.ecmwf.int/api"


def load_request():
    with open(REQ_FILE) as f:
        req = json.load(f)
    req.pop("_comment", None)
    return req


def have_key():
    if os.environ.get("CDSAPI_KEY"):
        return True
    rc = os.environ.get("CDSAPI_RC", os.path.expanduser("~/.cdsapirc"))
    if os.path.exists(rc):
        return any(l.strip().startswith("key") for l in open(rc))
    return False


def verify_grib(path):
    out = {}
    checks = {
        "grib_ls": ["grib_ls", path],
        "grib_get": ["grib_get", "-p",
                     "shortName,paramId,name,units,gridType,Ni,Nj,"
                     "iDirectionIncrementInDegrees,jDirectionIncrementInDegrees,"
                     "latitudeOfFirstGridPointInDegrees,longitudeOfFirstGridPointInDegrees,"
                     "dataDate,dataTime,stepRange,stepType,typeOfLevel,level,"
                     "marsType,marsStream,marsClass,numberOfDataPoints", path],
        "cdo_sinfon": ["cdo", "sinfon", path],
    }
    for name, cmd in checks.items():
        try:
            p = subprocess.run(cmd, capture_output=True, text=True, timeout=120)
            out[name] = (p.stdout or p.stderr)[:3000]
        except Exception as e:
            out[name] = f"{type(e).__name__}: {e}"
    return out


status = {"dataset": DATASET, "endpoint": ECDS_URL, "outcome": None}
try:
    req = load_request()
    status["request"] = req
    if not have_key():
        raise RuntimeError("no cdsapi key found (CDSAPI_KEY or ~/.cdsapirc)")
    import cdsapi
    client = cdsapi.Client(url=ECDS_URL)
    print(f"submitting minimal ECDS retrieval: {DATASET} (grid {req.get('grid')})", flush=True)
    client.retrieve(DATASET, req).download(target)
    ok = os.path.exists(target) and os.path.getsize(target) > 0
    status["outcome"] = "downloaded" if ok else "no_file"
    status["bytes"] = os.path.getsize(target) if ok else 0
    if ok:
        status["target"] = target
        status["grib_verification"] = verify_grib(target)
except Exception as e:
    status["outcome"] = "error"
    status["message"] = f"{type(e).__name__}: {e}"
    status["traceback"] = traceback.format_exc()[-2000:]

with open(os.path.join(ROOT, "metadata", "ecmwf_minimal_retrieval_status.json"), "w") as f:
    json.dump(status, f, indent=2)
print(json.dumps({k: status.get(k) for k in ("outcome", "endpoint", "bytes", "message")}, indent=2), flush=True)
if status.get("grib_verification"):
    print("\n--- grib_ls ---\n" + status["grib_verification"].get("grib_ls", ""), flush=True)
    print("\n--- grib_get ---\n" + status["grib_verification"].get("grib_get", ""), flush=True)