added covarage

api/app/core/antenna_pattern_file.py

@@ -0,0 +1,50 @@
+from __future__ import annotations
+
+import csv
+from pathlib import Path
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from app.core.antenna import AntennaPattern
+
+
+def _parse_float(value: str) -> float:
+    return float(value.strip())
+
+
+def load_pattern_file(path: str | Path) -> list[tuple[float, float, float]]:
+    file_path = Path(path)
+    if not file_path.exists():
+        raise FileNotFoundError(f"Antenna pattern file not found: {file_path}")
+
+    samples: list[tuple[float, float, float]] = []
+    with file_path.open(encoding="utf-8", newline="") as handle:
+        reader = csv.reader(handle)
+        for row in reader:
+            if not row or row[0].startswith("#"):
+                continue
+            if len(row) < 3:
+                continue
+            if row[0].lower() in {"azimuth_deg", "az", "azimuth"}:
+                continue
+            samples.append((_parse_float(row[0]), _parse_float(row[1]), _parse_float(row[2])))
+
+    if not samples:
+        raise ValueError(f"No antenna pattern samples found in {file_path}")
+    return samples
+
+
+def gain_from_file(
+    pattern: AntennaPattern,
+    az_deg: float,
+    el_deg: float,
+) -> float:
+    if not pattern.pattern_file:
+        raise ValueError("pattern_file is required for file patterns")
+
+    samples = load_pattern_file(pattern.pattern_file)
+    nearest = min(
+        samples,
+        key=lambda item: abs(item[0] - az_deg) + abs(item[1] - el_deg),
+    )
+    return pattern.gain_dbi + nearest[2]