@mytec: iteration3 done for testing

frontend/src/services/terrain.ts

@@ -0,0 +1,89 @@
+/**
+ * Terrain Service – Phase 4 stub.
+ *
+ * Provides elevation queries that future phases will use for:
+ *  - Line-of-sight (LOS) / non-LOS classification
+ *  - Diffraction loss (knife-edge / Bullington)
+ *  - Terrain-aware heatmaps
+ *
+ * For now we expose the interface and a flat-terrain mock.
+ * Switch to BackendTerrainService once the FastAPI `/api/terrain/*`
+ * endpoints are ready with real SRTM / DEM data.
+ */
+
+export interface TerrainService {
+  /** Return ground elevation (metres above sea level) at a point. */
+  getElevation(lat: number, lon: number): Promise<number>;
+
+  /**
+   * Return an elevation profile between two points.
+   * @param samples  Number of equidistant samples along the path.
+   * @returns        Array of elevations (metres) from start to end.
+   */
+  getElevationProfile(
+    lat1: number,
+    lon1: number,
+    lat2: number,
+    lon2: number,
+    samples: number,
+  ): Promise<number[]>;
+}
+
+// ---------------------------------------------------------------------------
+// Mock – flat terrain (elevation 0 everywhere)
+// ---------------------------------------------------------------------------
+export class MockTerrainService implements TerrainService {
+  async getElevation(_lat: number, _lon: number): Promise<number> {
+    return 0;
+  }
+
+  async getElevationProfile(
+    _lat1: number,
+    _lon1: number,
+    _lat2: number,
+    _lon2: number,
+    samples: number,
+  ): Promise<number[]> {
+    return Array(samples).fill(0);
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Backend – calls FastAPI terrain endpoints (Phase 4+)
+// ---------------------------------------------------------------------------
+export class BackendTerrainService implements TerrainService {
+  private apiUrl: string;
+
+  constructor(apiUrl: string) {
+    this.apiUrl = apiUrl;
+  }
+
+  async getElevation(lat: number, lon: number): Promise<number> {
+    const response = await fetch(
+      `${this.apiUrl}/api/terrain/elevation?lat=${lat}&lon=${lon}`,
+    );
+    if (!response.ok) throw new Error(`Terrain API error: ${response.status}`);
+    const data = await response.json();
+    return data.elevation;
+  }
+
+  async getElevationProfile(
+    lat1: number,
+    lon1: number,
+    lat2: number,
+    lon2: number,
+    samples: number,
+  ): Promise<number[]> {
+    const response = await fetch(
+      `${this.apiUrl}/api/terrain/profile?lat1=${lat1}&lon1=${lon1}&lat2=${lat2}&lon2=${lon2}&samples=${samples}`,
+    );
+    if (!response.ok) throw new Error(`Terrain API error: ${response.status}`);
+    const data = await response.json();
+    return data.profile;
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Default export – use Mock until backend is ready
+// ---------------------------------------------------------------------------
+export const terrainService: TerrainService = new MockTerrainService();