feat(lox-orbits): implement frame and origin change for coordinates

crates/lox-orbits/src/python.rs

@@ -41,6 +41,7 @@ use crate::propagators::semi_analytical::{Vallado, ValladoError};
 use crate::propagators::sgp4::{Sgp4, Sgp4Error};
 use crate::propagators::Propagator;
 use crate::states::ToCartesian;
+use crate::trajectories::TrajectoryTransformationError;
 use crate::{
     frames::FrameTransformationProvider,
     states::State,
@@ -49,6 +50,13 @@ use crate::{
 
 mod generated;
 
+impl From<TrajectoryTransformationError> for PyErr {
+    fn from(err: TrajectoryTransformationError) -> Self {
+        // FIXME: wrong error type
+        PyValueError::new_err(err.to_string())
+    }
+}
+
 impl From<FindEventError> for PyErr {
     fn from(err: FindEventError) -> Self {
         // FIXME: wrong error type
@@ -382,9 +390,19 @@ impl PyState {
     }
 
     fn to_origin(&self, target: &Bound<'_, PyAny>, ephemeris: &Bound<'_, PySpk>) -> PyResult<Self> {
+        if self.0.reference_frame() != PyFrame::Icrf {
+            return Err(PyValueError::new_err(
+                "only inertial frames are supported for conversion to Keplerian elements",
+            ));
+        }
         let target = PyBody::try_from(target)?;
-        let spk = ephemeris.borrow();
-        todo!()
+        let spk = &ephemeris.borrow().0;
+        let s1 = self
+            .0
+            .with_frame(Icrf)
+            .to_origin(target, spk)?
+            .with_frame(PyFrame::Icrf);
+        Ok(Self(s1))
     }
 
     fn to_keplerian(&self) -> PyResult<PyKeplerian> {
@@ -620,6 +638,32 @@ impl PyTrajectory {
         }
         Err(PyValueError::new_err("invalid time argument"))
     }
+
+    #[pyo3(signature = (frame, provider=None))]
+    fn to_frame(
+        &self,
+        frame: PyFrame,
+        provider: Option<&Bound<'_, PyUt1Provider>>,
+    ) -> PyResult<Self> {
+        let mut states: Vec<State<PyTime, PyBody, PyFrame>> =
+            Vec::with_capacity(self.0.states().len());
+        for s in self.0.states() {
+            states.push(PyState(s).to_frame(frame.clone(), provider)?.0);
+        }
+        Ok(PyTrajectory(Trajectory::new(&states)?))
+    }
+
+    fn to_origin(&self, target: &Bound<'_, PyAny>, ephemeris: &Bound<'_, PySpk>) -> PyResult<Self> {
+        let target = PyBody::try_from(target)?;
+        let spk = &ephemeris.borrow().0;
+        let s1 = self
+            .0
+            .clone()
+            .with_frame(Icrf)
+            .to_origin(target, spk)?
+            .with_frame(PyFrame::Icrf);
+        Ok(Self(s1))
+    }
 }
 
 #[pyclass(name = "Event", module = "lox_space", frozen)]