feat(tours): add non-motorized day tour planning

client/src/components/shared/elevationProfileModel.ts

@@ -0,0 +1,55 @@
+import type { DistanceIndexedProfileSample } from '../../utils/routeGeometry'
+
+export interface ElevationProfileChartPoint {
+  x: number
+  y: number
+}
+
+export interface ElevationProfileChartModel {
+  minElevation: number
+  maxElevation: number
+  elevationSpan: number
+  maxDistance: number
+  hasGeographicCoordinates: boolean
+  points: ElevationProfileChartPoint[]
+  linePath: string
+  areaPath: string
+}
+
+export function prepareElevationProfileChart(
+  samples: readonly DistanceIndexedProfileSample[],
+  width: number,
+  height: number,
+): ElevationProfileChartModel {
+  if (samples.length === 0) return {
+    minElevation: 0,
+    maxElevation: 0,
+    elevationSpan: 1,
+    maxDistance: 1,
+    hasGeographicCoordinates: false,
+    points: [],
+    linePath: '',
+    areaPath: '',
+  }
+  const elevations = samples.map(sample => sample.elevationMeters)
+  const minElevation = Math.min(...elevations)
+  const maxElevation = Math.max(...elevations)
+  const elevationSpan = Math.max(maxElevation - minElevation, 1)
+  const maxDistance = samples[samples.length - 1].distanceMeters || 1
+  const points = samples.map(sample => ({
+    x: (sample.distanceMeters / maxDistance) * width,
+    y: height - ((sample.elevationMeters - minElevation) / elevationSpan) * (height - 8) - 4,
+  }))
+  const linePath = points.map((point, index) => `${index === 0 ? 'M' : 'L'}${point.x.toFixed(1)},${point.y.toFixed(1)}`).join(' ')
+
+  return {
+    minElevation,
+    maxElevation,
+    elevationSpan,
+    maxDistance,
+    hasGeographicCoordinates: samples.every(sample => Number.isFinite(sample.lat) && Number.isFinite(sample.lng)),
+    points,
+    linePath,
+    areaPath: `${linePath} L${width},${height} L0,${height} Z`,
+  }
+}