fix(map): make area analysis scale-aware

frontend/src/components/map/mapWorkspaceUtils.test.ts

@@ -8,9 +8,12 @@ import {
   productCoversZones,
   resultMetricLabel,
   selectedAreaCoverageZones,
+  selectionAnalysisScale,
   selectionAreaSquareMetres,
+  selectionDimensions,
+  splitSelectionBbox,
 } from './mapWorkspaceUtils'
-import type { VectorSelectionResponse } from '../../types'
+import type { VectorSelectionBBox, VectorSelectionResponse } from '../../types'
 
 describe('map workspace selection guards', () => {
   it('normalizes drag corners into an EPSG:4326 bbox', () => {
@@ -90,4 +93,49 @@ describe('map workspace selection guards', () => {
       geometry_clipped_to_selection: true,
     })).toBe(false)
   })
+
+  it('classifies local, regional and overview selections before provider calls', () => {
+    const bbox = (widthDegrees: number, heightDegrees: number): VectorSelectionBBox => ({
+      min_x: 5,
+      min_y: 51,
+      max_x: 5 + widthDegrees,
+      max_y: 51 + heightDegrees,
+      crs: 'EPSG:4326',
+    })
+    expect(selectionAnalysisScale(bbox(0.1, 0.1))).toBe('detail')
+    expect(selectionAnalysisScale(bbox(0.35, 0.25))).toBe('regional')
+    expect(selectionAnalysisScale(bbox(1, 1))).toBe('overview')
+  })
+
+  it('splits regional selections into provider-safe tiles without changing the outer bounds', () => {
+    const selection: VectorSelectionBBox = {
+      min_x: 5,
+      min_y: 51,
+      max_x: 5.5,
+      max_y: 51.35,
+      crs: 'EPSG:4326',
+    }
+    const tiles = splitSelectionBbox(selection)
+    expect(tiles.length).toBeGreaterThan(1)
+    expect(Math.min(...tiles.map((tile) => tile.min_x))).toBe(selection.min_x)
+    expect(Math.min(...tiles.map((tile) => tile.min_y))).toBe(selection.min_y)
+    expect(Math.max(...tiles.map((tile) => tile.max_x))).toBe(selection.max_x)
+    expect(Math.max(...tiles.map((tile) => tile.max_y))).toBe(selection.max_y)
+    for (const tile of tiles) {
+      const dimensions = selectionDimensions(tile)
+      expect(dimensions.widthMetres).toBeLessThanOrEqual(18_100)
+      expect(dimensions.heightMetres).toBeLessThanOrEqual(18_100)
+    }
+  })
+
+  it('refuses an unbounded detail fan-out', () => {
+    const selection: VectorSelectionBBox = {
+      min_x: 4,
+      min_y: 50,
+      max_x: 6,
+      max_y: 52,
+      crs: 'EPSG:4326',
+    }
+    expect(() => splitSelectionBbox(selection)).toThrow('detailpartities')
+  })
 })