step one

internal/engine/constraints.go

@@ -0,0 +1,47 @@
+package engine
+
+// MaxAltitude triggers when altitude rises above Limit (in metres).
+// Used as the burst condition for ascent stages.
+type MaxAltitude struct {
+	Limit float64
+	On    Action
+}
+
+func (c MaxAltitude) Name() string                       { return "max_altitude" }
+func (c MaxAltitude) Violated(_ float64, s State) bool   { return s.Altitude >= c.Limit }
+func (c MaxAltitude) Action() Action                     { return c.On }
+
+// MinAltitude triggers when altitude falls at or below Limit (in metres).
+// With Limit=0 this is the "sea level" terminator.
+type MinAltitude struct {
+	Limit float64
+	On    Action
+}
+
+func (c MinAltitude) Name() string                     { return "min_altitude" }
+func (c MinAltitude) Violated(_ float64, s State) bool { return s.Altitude <= c.Limit }
+func (c MinAltitude) Action() Action                   { return c.On }
+
+// MaxTime triggers when t exceeds Limit (UNIX seconds). Used as a stop
+// condition for float profiles.
+type MaxTime struct {
+	Limit float64
+	On    Action
+}
+
+func (c MaxTime) Name() string                       { return "max_time" }
+func (c MaxTime) Violated(t float64, _ State) bool   { return t > c.Limit }
+func (c MaxTime) Action() Action                     { return c.On }
+
+// TerrainContact triggers when altitude has dropped at or below ground level.
+// Equivalent to Tawhiri's elevation termination.
+type TerrainContact struct {
+	Provider TerrainProvider
+	On       Action
+}
+
+func (c TerrainContact) Name() string { return "terrain_contact" }
+func (c TerrainContact) Violated(_ float64, s State) bool {
+	return c.Provider.Elevation(s.Lat, s.Lng) > s.Altitude
+}
+func (c TerrainContact) Action() Action { return c.On }