first commit

app/services/coverage.py

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+from __future__ import annotations
+
+import asyncio
+from typing import Any
+
+from app.config import settings
+from app.models.schemas import CoverageRequest, GeoAntenna
+from app.services.geodesy import grid_in_circle, line_distance_m
+from app.services.link_calculator import LinkCalculator
+
+
+class CoverageService:
+  def __init__(self, link_calculator: LinkCalculator) -> None:
+    self.link_calculator = link_calculator
+
+  async def calculate_coverage(self, request: CoverageRequest) -> dict[str, Any]:
+    grid_points = grid_in_circle(
+      request.origin.lat,
+      request.origin.lng,
+      request.radius_m,
+      request.resolution_m,
+    )
+
+    if len(grid_points) > settings.max_grid_points:
+      raise ValueError(
+        f"Grid has {len(grid_points)} points, exceeds max_grid_points={settings.max_grid_points}"
+      )
+
+    semaphore = asyncio.Semaphore(settings.coverage_concurrency)
+    features: list[dict[str, Any]] = []
+
+    async def evaluate_point(lat: float, lng: float) -> dict[str, Any]:
+      async with semaphore:
+        to_point = GeoAntenna(lat=lat, lng=lng, antenna_height_m=request.origin.antenna_height_m)
+        result = await self.link_calculator.calculate_link(
+          from_pt=request.origin,
+          to_pt=to_point,
+          frequency_mhz=request.frequency_mhz,
+          fresnel_clearance=request.fresnel_clearance,
+          tx_power_dbm=request.tx_power_dbm,
+          rx_sensitivity_dbm=request.rx_sensitivity_dbm,
+          sample_step_m=request.sample_step_m,
+        )
+
+        covered = result.los and result.fresnel_clear and result.link_budget.status != "poor"
+        distance = line_distance_m(request.origin.lat, request.origin.lng, lat, lng)
+
+        return {
+          "type": "Feature",
+          "geometry": {
+            "type": "Point",
+            "coordinates": [round(lng, 6), round(lat, 6)],
+          },
+          "properties": {
+            "covered": covered,
+            "los": result.los,
+            "fresnel_clear": result.fresnel_clear,
+            "margin_db": result.link_budget.margin_db,
+            "status": result.link_budget.status,
+            "distance_m": round(distance, 1),
+          },
+        }
+
+    tasks = [evaluate_point(lat, lng) for lat, lng in grid_points]
+    features = await asyncio.gather(*tasks)
+
+    return {
+      "type": "FeatureCollection",
+      "features": features,
+    }