"""
Vendored GRIBWavePuller from NWPS_SWAN project (trimmed only for runtime import here).
If Arctic-specific helpers are missing, the puller will log and continue with fallbacks.
"""

import os
import sys
import tempfile
import logging
import subprocess
from datetime import datetime, timedelta
import numpy as np
import xarray as xr
from ecmwf.opendata import Client
import requests

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# Optional Arctic handler
try:
    from arctic_grib_handler import ArcticGRIBHandler  # type: ignore
    ARCTIC_HANDLER_AVAILABLE = True
    logger.info("✅ Arctic GRIB Handler loaded (Docker production version)")
except Exception as e:
    logger.warning(f"Arctic GRIB handler not available: {e}")
    ARCTIC_HANDLER_AVAILABLE = False


class GRIBWavePuller:
    def __init__(self):
        self.client = Client("ecmwf")
        self.output_dir = os.getenv('OUTPUT_DIR', '/tmp/wave_data')
        os.makedirs(self.output_dir, exist_ok=True)
        self._setup_eccodes_environment()

    def _setup_eccodes_environment(self):
        try:
            os.environ['ECCODES_GRIB_STRICT_PARSING'] = '0'
            os.environ['ECCODES_GRIB_IGNORE_GRID_DEFINITION'] = '1'
        except Exception:
            pass

    def fetch_ecmwf_wave_grib(self, forecast_time=0):
        try:
            temp_file = tempfile.NamedTemporaryFile(delete=False, suffix='.grib2')
            try:
                self.client.retrieve(
                    type="fc",
                    param=["swh"],
                    time=0,
                    step=forecast_time,
                    target=temp_file.name,
                )
                return temp_file.name
            except Exception:
                if os.path.exists(temp_file.name):
                    os.unlink(temp_file.name)
                return None
        except Exception:
            return None

    def fetch_noaa_wave_grib(self, forecast_hour=0):
        """Fetch NOAA WW3 files (regional + global attempt). Returns list of (path, region, run, fh)."""
        try:
            base_url = "https://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod"
            now = datetime.utcnow()
            dates_to_try = [
                now.strftime("%Y%m%d"),
                (now - timedelta(days=1)).strftime("%Y%m%d"),
                (now - timedelta(days=2)).strftime("%Y%m%d"),
            ]
            if now.hour >= 18:
                preferred_runs = ["18", "12", "06", "00"]
            elif now.hour >= 12:
                preferred_runs = ["12", "06", "00", "18"]
            elif now.hour >= 6:
                preferred_runs = ["06", "00", "18", "12"]
            else:
                preferred_runs = ["00", "18", "12", "06"]

            for date_str in dates_to_try:
                for hour in preferred_runs:
                    successful = []
                    regional_files = [
                        (f"gfswave.t{hour}z.atlocn.0p16.f{forecast_hour:03d}.grib2", "Atlantic"),
                        (f"gfswave.t{hour}z.epacif.0p16.f{forecast_hour:03d}.grib2", "East_Pacific"),
                        (f"gfswave.t{hour}z.arctic.9km.f{forecast_hour:03d}.grib2", "Arctic"),
                        (f"gfswave.t{hour}z.global.0p16.f{forecast_hour:03d}.grib2", "Global"),
                    ]
                    for filename, region_name in regional_files:
                        url = f"{base_url}/gfs.{date_str}/{hour}/wave/gridded/{filename}"
                        try:
                            tf = tempfile.NamedTemporaryFile(delete=False, suffix='.grib2')
                            r = requests.get(url, timeout=300)
                            if r.status_code == 200:
                                tf.write(r.content)
                                tf.close()
                                successful.append((tf.name, region_name, hour, forecast_hour))
                            else:
                                tf.close(); os.unlink(tf.name)
                        except Exception:
                            try:
                                tf.close(); os.unlink(tf.name)
                            except Exception:
                                pass
                            continue
                    if successful:
                        return successful
            return None
        except Exception:
            return None

    def process_grib_file(self, grib_file_path, region_name=None):
        try:
            ds = xr.open_dataset(grib_file_path, engine='cfgrib', decode_timedelta=True)
        except Exception:
            return None, None

        # Identify variables
        vars_map = {name: ds[name] for name in ds.variables}
        wave_var = None
        for cand in ['swh', 'HTSGW', 'htsgw']:
            if cand in vars_map:
                wave_var = cand; break
        if wave_var is None:
            # fallback heuristic
            for n in vars_map:
                if 'wave' in n.lower() and 'height' in n.lower():
                    wave_var = n; break
        if wave_var is None:
            ds.close()
            return None, None

        wave_heights = vars_map[wave_var].values

        wave_dir = None
        for cand in ['dirpw', 'DIRPW', 'dp', 'wvdir', 'WVDIR', 'dir', 'mwd', 'MWD', 'MWDIR']:
            if cand in vars_map:
                wave_dir = vars_map[cand].values; break

        wave_per = None
        for cand in ['perpw', 'PERPW', 'tp', 'wvper', 'WVPER', 'per', 'pp1d', 'PP1D', 'mwp', 'MWP']:
            if cand in vars_map:
                wave_per = vars_map[cand].values; break

        lats = ds.latitude.values if 'latitude' in ds else ds.lat.values
        lons = ds.longitude.values if 'longitude' in ds else ds.lon.values

        # Sample points (downsample for visualization)
        lon_grid, lat_grid = np.meshgrid(lons, lats)
        flat_lats = lat_grid.flatten()
        flat_lons = lon_grid.flatten()
        flat_waves = wave_heights.flatten()
        mask = ~np.isnan(flat_waves)
        if wave_dir is not None:
            mask &= ~np.isnan(wave_dir.flatten())
        idx = np.random.choice(np.where(mask)[0], size=min(1000, mask.sum()), replace=False) if mask.any() else np.array([])

        points = []
        for i in idx:
            point = {
                'lat': float(flat_lats[i]),
                'lon': float(flat_lons[i]),
                'wave_height': float(flat_waves[i]),
            }
            if wave_dir is not None:
                d = float(wave_dir.flatten()[i])
                point['wave_direction'] = d
                mag = point['wave_height'] * 0.1
                rad = np.deg2rad(d)
                point['u_component'] = float(mag * np.sin(rad))
                point['v_component'] = float(-mag * np.cos(rad))
            if wave_per is not None:
                point['wave_period'] = float(wave_per.flatten()[i])
            points.append(point)

        data = {
            'timestamp': datetime.utcnow().isoformat(),
            'data_source': 'NOAA_GRIB' if 'gfswave' in os.path.basename(grib_file_path) else 'GRIB',
            'parameters_found': {
                'wave_height': wave_var,
                'wave_direction': 'present' if wave_dir is not None else None,
                'wave_period': 'present' if wave_per is not None else None,
                'has_velocity_components': wave_dir is not None,
            },
            'grid_info': {
                'lat_min': float(np.nanmin(lats)),
                'lat_max': float(np.nanmax(lats)),
                'lon_min': float(np.nanmin(lons)),
                'lon_max': float(np.nanmax(lons)),
                'grid_shape': list(wave_heights.shape),
            },
            'sample_points': points,
        }
        # Optional: include a downsampled U/V grid for velocity layers
        try:
            if wave_dir is not None:
                # Compute U/V on the native grid
                # Determine reasonable downsample strides to keep <= ~360x180
                ny, nx = wave_heights.shape
                sy = max(1, ny // 180)
                sx = max(1, nx // 360)
                lats_ds = lats[::sy]
                lons_ds = lons[::sx]
                # Align 2D arrays for downsample
                wh_ds = wave_heights[::sy, ::sx]
                wd_ds = wave_dir[::sy, ::sx]
                wp_ds = None
                if wave_per is not None:
                    try:
                        wp_ds = wave_per[::sy, ::sx]
                    except Exception:
                        wp_ds = None
                # Compute U/V
                dir_rad = np.deg2rad(wd_ds)
                # Base speed from period if present (deep water group velocity)
                if wp_ds is not None:
                    base = 0.78 * np.clip(wp_ds, 0, 20)
                else:
                    base = 1.0 + 0.2 * np.clip(wh_ds, 0, 10)

                # Add spatial variation via normalized wave height
                try:
                    p50 = float(np.nanpercentile(wh_ds, 50))
                    p90 = float(np.nanpercentile(wh_ds, 90))
                    denom = (p90 - p50) if (p90 - p50) > 1e-6 else 1.0
                    hnorm = np.clip((wh_ds - p50) / denom, -1.0, 2.0)
                except Exception:
                    hnorm = 0.0
                mag = base * (1.0 + 0.5 * hnorm)

                # Clamp to a reasonable range for visualization
                mag = np.clip(mag, 0.0, 15.0)
                u_ds = mag * np.sin(dir_rad)
                v_ds = -mag * np.cos(dir_rad)
                data['grid_uv'] = {
                    'lats': lats_ds.tolist() if hasattr(lats_ds, 'tolist') else list(map(float, lats_ds)),
                    'lons': lons_ds.tolist() if hasattr(lons_ds, 'tolist') else list(map(float, lons_ds)),
                    'u': np.nan_to_num(u_ds, nan=0.0, posinf=0.0, neginf=0.0).tolist(),
                    'v': np.nan_to_num(v_ds, nan=0.0, posinf=0.0, neginf=0.0).tolist(),
                }
                try:
                    sp = np.sqrt(u_ds*u_ds + v_ds*v_ds)
                    data['grid_uv_info'] = {
                        'speed_min': float(np.nanmin(sp)),
                        'speed_max': float(np.nanmax(sp)),
                        'speed_mean': float(np.nanmean(sp)),
                    }
                except Exception:
                    pass
        except Exception:
            # If any step fails, just skip embedding grid_uv
            pass
        ds.close()
        return data, grib_file_path

    def process_multiple_regional_files(self, regional_files):
        combined = []
        for path, region_name, *_ in regional_files:
            try:
                res, _ = self.process_grib_file(path, region_name=region_name)
                if res and 'sample_points' in res:
                    combined.extend(res['sample_points'])
            finally:
                try:
                    if os.path.exists(path):
                        os.unlink(path)
                except Exception:
                    pass
        if not combined:
            return None
        return {
            'timestamp': datetime.utcnow().isoformat(),
            'data_source': 'NOAA_MULTI_REGIONAL_GRIB',
            'parameters_found': {'has_velocity_components': True},
            'grid_info': {},
            'sample_points': combined,
        }

    def fetch_global_wave_data(self, forecast_hour=0):
        result = self.fetch_noaa_wave_grib(forecast_hour)
        if isinstance(result, list) and result:
            if any(region == 'Global' for _, region, *_ in result):
                # Prefer the global grid if present
                global_entry = next((t for t in result if t[1] == 'Global'), None)
                if global_entry:
                    data, _ = self.process_grib_file(global_entry[0], region_name='Global')
                    return data
            # Otherwise combine sample points from regions
            return self.process_multiple_regional_files(result)

        # Fallback ECMWF (may not include waves)
        grib_file = self.fetch_ecmwf_wave_grib(forecast_hour)
        if grib_file:
            data, _ = self.process_grib_file(grib_file)
            try:
                os.unlink(grib_file)
            except Exception:
                pass
            return data
        return None