"""
تسک‌های Celery برای واکشی داده‌های خاک از API SoilGrids.
"""

from decimal import Decimal

import requests
from config.celery import app
from django.db import transaction

from .models import SoilDepthData, SoilLocation

SOILGRIDS_BASE = "https://rest.isric.org/soilgrids/v2.0/properties/query"
PROPERTIES = [
    "bdod", "cec", "cfvo", "clay", "nitrogen", "ocd", "ocs",
    "phh2o", "sand", "silt", "soc", "wv0010", "wv0033", "wv1500",
]
VALUES = ["Q0.5", "Q0.05", "Q0.95", "mean", "uncertainty"]
DEPTHS = ["0-5cm", "5-15cm", "15-30cm"]


def _fetch_soilgrids(lon: float, lat: float, depth: str) -> dict | None:
    """درخواست به API SoilGrids برای یک عمق."""
    params = {
        "lon": lon,
        "lat": lat,
        "depth": depth,
    }
    for p in PROPERTIES:
        params.setdefault("property", []).append(p)
    for v in VALUES:
        params.setdefault("value", []).append(v)

    resp = requests.get(
        SOILGRIDS_BASE,
        params=params,
        headers={"accept": "application/json"},
        timeout=60,
    )
    resp.raise_for_status()
    return resp.json()


def _parse_response_to_fields(data: dict) -> dict:
    """
    استخراج مقادیر mean از response و ساخت dict مناسب برای SoilDepthData.
    """
    fields = {p: None for p in PROPERTIES}
    layers = data.get("properties", {}).get("layers", [])
    for layer in layers:
        name = layer.get("name")
        if name not in fields:
            continue
        depths_list = layer.get("depths", [])
        if depths_list:
            values = depths_list[0].get("values", {})
            mean_val = values.get("mean")
            if mean_val is not None:
                fields[name] = float(mean_val)
    return fields


def fetch_soil_data_for_coordinates(
    latitude: float,
    longitude: float,
    task_id: str = "",
    progress_callback=None,
):
    """
    واکشی سنکرون داده خاک برای مختصات داده‌شده و ذخیره در DB.
    این helper هم توسط Celery task و هم توسط endpointهای sync استفاده می‌شود.
    """
    lat = Decimal(str(round(float(latitude), 6)))
    lon = Decimal(str(round(float(longitude), 6)))

    with transaction.atomic():
        location, created = SoilLocation.objects.select_for_update().get_or_create(
            latitude=lat,
            longitude=lon,
            defaults={"task_id": task_id},
        )
        if not created and task_id:
            location.task_id = task_id
            location.save(update_fields=["task_id"])

    for i, depth in enumerate(DEPTHS):
        if progress_callback is not None:
            progress_callback(
                state="PROGRESS",
                meta={
                    "current": i + 1,
                    "total": len(DEPTHS),
                    "message": f"در حال واکشی عمق {depth}...",
                },
            )
        data = _fetch_soilgrids(float(lon), float(lat), depth)
        fields = _parse_response_to_fields(data)
        with transaction.atomic():
            SoilDepthData.objects.update_or_create(
                soil_location=location,
                depth_label=depth,
                defaults=fields,
            )

    if task_id:
        with transaction.atomic():
            location.task_id = ""
            location.save(update_fields=["task_id"])

    return {
        "status": "completed",
        "location_id": location.id,
        "depths": DEPTHS,
    }


@app.task(bind=True)
def fetch_soil_data_task(self, latitude: float, longitude: float):
    """
    واکشی داده‌های خاک برای مختصات داده‌شده از SoilGrids و ذخیره در DB.
    برای هر عمق (0-5cm, 5-15cm, 15-30cm) یک ریکوئست جدا زده می‌شود.
    """
    try:
        return fetch_soil_data_for_coordinates(
            latitude=latitude,
            longitude=longitude,
            task_id=self.request.id,
            progress_callback=self.update_state,
        )
    except requests.RequestException as e:
        lat = Decimal(str(round(float(latitude), 6)))
        lon = Decimal(str(round(float(longitude), 6)))
        location = SoilLocation.objects.filter(latitude=lat, longitude=lon).first()
        return {
            "status": "error",
            "location_id": getattr(location, "id", None),
            "error": str(e),
        }