updates on the api endpoints on the customer page and more

internal/legs/legs.go

@@ -0,0 +1,71 @@
+// Package legs answers one question, in one place: does a parcel go straight to
+// its receiver, or does it go via a base first?
+//
+// It exists because two packages need that answer and neither can import the
+// other. controllers decides it at pickup-complete (which state the consignment
+// lands in, and which base the rider is sent to); internal/routing needs it when
+// it sequences a rider's stops, because a hub-routed parcel's next stop is the
+// BASE, not the address on the booking. controllers already imports
+// internal/routing, so routing cannot import back — and a second copy of the
+// rule in routing is exactly the kind of duplication this codebase has been
+// bitten by before (the rival status table in dispatchShared, the batch windows
+// that drifted between two pages).
+//
+// So the rule lives here and both call it. Neither owns it.
+package legs
+
+import "math"
+
+// HaversineKM is the straight-line distance between two points, in kilometres.
+// One definition for the whole codebase — controllers.haversineKM delegates to
+// it rather than keeping a second copy.
+func HaversineKM(lat1, lon1, lat2, lon2 float64) float64 {
+	const earthRadiusKM = 6371.0
+	toRad := func(deg float64) float64 { return deg * math.Pi / 180 }
+	dLat := toRad(lat2 - lat1)
+	dLon := toRad(lon2 - lon1)
+	a := math.Sin(dLat/2)*math.Sin(dLat/2) +
+		math.Cos(toRad(lat1))*math.Cos(toRad(lat2))*math.Sin(dLon/2)*math.Sin(dLon/2)
+	return earthRadiusKM * 2 * math.Atan2(math.Sqrt(a), math.Sqrt(1-a))
+}
+
+// MaxHyperlocalKM bounds the straight-line pickup→delivery distance under which
+// a booking with a missing or unusable pincode is still treated as hyperlocal.
+// It is ONLY consulted when the pincode rule cannot decide: console-created
+// kitchen→customer bookings frequently carry accurate coordinates and no
+// delivery pincode, and must not be routed through a base because of it.
+const MaxHyperlocalKM = 30.0
+
+// SamePostalArea reports whether two pincodes fall in the same 3-digit postal
+// area. Pincodes shorter than 3 characters are treated as unknown rather than
+// matching, so bad data falls back to the safe hub route instead of quietly
+// claiming two parcels belong together.
+func SamePostalArea(pickupPincode, deliveryPincode string) bool {
+	if len(pickupPincode) < 3 || len(deliveryPincode) < 3 {
+		return false
+	}
+	return pickupPincode[:3] == deliveryPincode[:3]
+}
+
+// IsHyperlocal decides whether a parcel can skip the base and be carried
+// straight to the receiver by the collecting rider.
+//
+// The pincode-prefix rule decides outright when both pincodes are present — a
+// matching prefix is hyperlocal, a differing one is genuinely inter-area, and
+// distance does not get a vote. Pollachi is 40km from Coimbatore, closer than
+// plenty of runs treated as local, and it is still a different postal area.
+//
+// Only when a pincode is missing or too short does the straight-line distance
+// decide instead. With neither pincodes nor coordinates the answer is false,
+// which routes via a base — the safe direction to be wrong in, because a parcel
+// that reaches a base can still be forwarded, while one handed to a rider who
+// cannot reach the receiver is stuck.
+func IsHyperlocal(pickupPincode, deliveryPincode string, pLat, pLng, dLat, dLng float64) bool {
+	if len(pickupPincode) >= 3 && len(deliveryPincode) >= 3 {
+		return SamePostalArea(pickupPincode, deliveryPincode)
+	}
+	if pLat != 0 && pLng != 0 && dLat != 0 && dLng != 0 {
+		return HaversineKM(pLat, pLng, dLat, dLng) <= MaxHyperlocalKM
+	}
+	return false
+}