progress

gpx-rs/engine/src/engine/action.rs

@@ -0,0 +1,15 @@
+use crate::{Command, FileId};
+
+/// Everything the frontend can ask the engine to do.
+///
+/// Only [`Action::Edit`] changes the files (and records an undo step); the others act on the
+/// history or on the selection.
+#[derive(Debug)]
+pub enum Action<'a> {
+    Edit(Command<'a>),
+    Undo,
+    Redo,
+    Select { file_ids: Vec<FileId> },
+    AddSelect { file_ids: Vec<FileId> },
+    SelectAll,
+}

gpx-rs/engine/src/engine/command/applier.rs

@@ -1,114 +0,0 @@
-use crate::{File, State, parse, produce, update_each_selected_file};
-
-pub fn create_file(state: &mut State, name: &str) -> Result<(), String> {
-    produce(state, |_| {
-        let mut file = File::default();
-        file.info.name = name.to_owned();
-        vec![file]
-    });
-    Ok(())
-}
-
-pub fn load_file(state: &mut State, data: &[u8]) -> Result<(), String> {
-    let file = parse(data).map_err(|err| err.to_string())?;
-    produce(state, |_| vec![file]);
-    Ok(())
-}
-
-pub fn update_metadata(state: &mut State, name: &str, desc: &str) -> Result<(), String> {
-    update_each_selected_file(state, &mut |file| {
-        let mut next = (*file).clone();
-        next.info.name = name.to_owned();
-        next.info.desc = Some(desc.to_owned());
-        next
-    });
-    Ok(())
-}
-
-#[cfg(test)]
-mod tests {
-    use std::collections::HashSet;
-
-    use crate::{FileId, FileOrder, Selection, StackEntry};
-
-    use super::*;
-
-    #[derive(Default)]
-    struct Fixture {
-        files: StackEntry,
-        selection: Selection,
-        order: FileOrder,
-    }
-
-    impl Fixture {
-        fn state(&mut self) -> State<'_> {
-            State {
-                files: &mut self.files,
-                selection: &mut self.selection,
-                order: &mut self.order,
-            }
-        }
-
-        fn selected_ids(&self) -> HashSet<FileId> {
-            match &self.selection {
-                Selection::File { file_ids } => file_ids.clone(),
-                _ => HashSet::new(),
-            }
-        }
-    }
-
-    #[test]
-    fn test_create_file() {
-        let mut fx = Fixture::default();
-        assert!(create_file(&mut fx.state(), "new").is_ok());
-        assert_eq!(fx.files.len(), 1);
-        let file = fx.files.values().next().unwrap();
-        assert_eq!(file.info.name, "new");
-        assert!(file.trk.is_empty());
-        assert_eq!(fx.selected_ids(), HashSet::from([file.id]));
-        assert_eq!(fx.order.0, vec![file.id]);
-    }
-
-    #[test]
-    fn test_load_file() {
-        let mut fx = Fixture::default();
-        let data = std::fs::read("data/with_tracks.gpx").unwrap();
-        assert!(load_file(&mut fx.state(), &data).is_ok());
-        assert_eq!(fx.files.len(), 1);
-        let file = fx.files.values().next().unwrap();
-        assert!(!file.trk.is_empty());
-        assert_eq!(fx.selected_ids(), HashSet::from([file.id]));
-    }
-
-    #[test]
-    fn test_load_invalid_file_changes_nothing() {
-        let mut fx = Fixture::default();
-        assert!(create_file(&mut fx.state(), "keep").is_ok());
-        let selected = fx.selected_ids();
-
-        assert!(load_file(&mut fx.state(), b"<gpx><trk></gpx>").is_err());
-        assert_eq!(fx.files.len(), 1);
-        assert_eq!(fx.order.0.len(), 1);
-        assert_eq!(fx.selected_ids(), selected);
-    }
-
-    #[test]
-    fn test_update_metadata_applies_to_selected_file() {
-        let mut fx = Fixture::default();
-        create_file(&mut fx.state(), "first").unwrap();
-        create_file(&mut fx.state(), "second").unwrap(); // now selected
-        let selected = *fx.selected_ids().iter().next().unwrap();
-
-        update_metadata(&mut fx.state(), "renamed", "description").unwrap();
-
-        for (id, file) in fx.files.iter() {
-            if *id == selected {
-                assert_eq!(file.info.name, "renamed");
-                assert_eq!(file.info.desc.as_deref(), Some("description"));
-            } else {
-                assert_eq!(file.info.name, "first");
-                assert_eq!(file.info.desc, None);
-            }
-        }
-    }
-}

gpx-rs/engine/src/engine/command/apply.rs

@@ -0,0 +1,33 @@
+use std::fmt;
+
+use crate::State;
+
+/// The effect of a command on the engine state.
+///
+/// Each command is a small struct holding its arguments, with its effect implemented in its
+/// own file. Effects are built from the reusable patterns in `pattern/`.
+pub trait Apply {
+    fn apply(self, state: &mut State) -> Result<(), CommandError>;
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum CommandError {
+    /// The command is not implemented yet.
+    NotImplemented(&'static str),
+    /// The command would not change anything.
+    NothingToDo,
+    /// The input data could not be parsed.
+    InvalidData(String),
+}
+
+impl fmt::Display for CommandError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::NotImplemented(name) => write!(f, "{name} is not implemented yet"),
+            Self::NothingToDo => write!(f, "nothing to do"),
+            Self::InvalidData(err) => write!(f, "invalid data: {err}"),
+        }
+    }
+}
+
+impl std::error::Error for CommandError {}

gpx-rs/engine/src/engine/command/command.rs

@@ -1,102 +1,64 @@
-use crate::{FileId, LngLatBounds};
+use crate::{
+    Append, Clean, Crop, Delete, DeleteAll, Duplicate, Elevation, Extract, Load, Merge, Metadata,
+    MoveWaypoint, New, NewTrack, NewTrackSegment, NewWaypoint, Replace, Reverse, Split, Style,
+    Time,
+};
+use crate::{Apply, CommandError, State};
 
-/// A user action, decoded from the WASM boundary.
+/// A user action that edits the files. Each variant wraps the command's own struct, whose
+/// effect is implemented in its own file (see `Apply`).
 ///
 /// Bulk data (coordinates, file bytes) is borrowed straight from the wasm-bindgen argument
 /// buffers, so a command is built without copying; the engine only copies what it keeps.
+#[derive(Debug)]
 pub enum Command<'a> {
-    // File commands
-    New {
-        name: &'a str,
-    },
-    Load {
-        data: &'a [u8],
-    },
-    Duplicate,
-    Delete,
-    DeleteAll,
-    // Edit commands
-    Metadata {
-        name: &'a str,
-        desc: &'a str,
-    },
-    Style {
-        color: Option<&'a str>,
-        opacity: Option<f64>,
-        width: Option<f64>,
-    },
-    NewTrack,
-    NewTrackSegment,
-    // Tools
-    Reverse,
-    Append {
-        lng: &'a [f64],
-        lat: &'a [f64],
-        ele: &'a [f64],
-    },
-    Replace {
-        start: u32,
-        end: u32,
-        lng: &'a [f64],
-        lat: &'a [f64],
-        ele: &'a [f64],
-    },
-    NewWaypoint {
-        lng: f64,
-        lat: f64,
-        ele: f64,
-        name: &'a str,
-        desc: &'a str,
-        icon: &'a str,
-        link: &'a str,
-    },
-    MoveWaypoint {
-        lng: f64,
-        lat: f64,
-        ele: f64,
-    },
-    Crop {
-        start: u32,
-        end: u32,
-    },
-    Split {
-        at: u32,
-    },
-    Time,
-    Merge {
-        type_: MergeType,
-    },
-    Extract,
-    Elevation {
-        ele: &'a [f64],
-    },
-    Clean {
-        bounds: LngLatBounds,
-        type_: CleanType,
-        trkpt: bool,
-        wpt: bool,
-    },
-    // Undo-redo
-    Undo,
-    Redo,
-    // Selection
-    Select {
-        file_ids: Vec<FileId>,
-    },
-    AddSelect {
-        file_ids: Vec<FileId>,
-    },
-    SelectAll,
+    New(New<'a>),
+    Load(Load<'a>),
+    Duplicate(Duplicate),
+    Delete(Delete),
+    DeleteAll(DeleteAll),
+    Metadata(Metadata<'a>),
+    Style(Style<'a>),
+    NewTrack(NewTrack),
+    NewTrackSegment(NewTrackSegment),
+    Reverse(Reverse),
+    Append(Append<'a>),
+    Replace(Replace<'a>),
+    NewWaypoint(NewWaypoint<'a>),
+    MoveWaypoint(MoveWaypoint),
+    Crop(Crop),
+    Split(Split),
+    Time(Time),
+    Merge(Merge),
+    Extract(Extract),
+    Elevation(Elevation<'a>),
+    Clean(Clean),
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum MergeType {
-    Connect,
-    Group,
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum CleanType {
-    Inside,
-    Outside,
+impl Apply for Command<'_> {
+    fn apply(self, state: &mut State) -> Result<(), CommandError> {
+        match self {
+            Command::New(c) => c.apply(state),
+            Command::Load(c) => c.apply(state),
+            Command::Duplicate(c) => c.apply(state),
+            Command::Delete(c) => c.apply(state),
+            Command::DeleteAll(c) => c.apply(state),
+            Command::Metadata(c) => c.apply(state),
+            Command::Style(c) => c.apply(state),
+            Command::NewTrack(c) => c.apply(state),
+            Command::NewTrackSegment(c) => c.apply(state),
+            Command::Reverse(c) => c.apply(state),
+            Command::Append(c) => c.apply(state),
+            Command::Replace(c) => c.apply(state),
+            Command::NewWaypoint(c) => c.apply(state),
+            Command::MoveWaypoint(c) => c.apply(state),
+            Command::Crop(c) => c.apply(state),
+            Command::Split(c) => c.apply(state),
+            Command::Time(c) => c.apply(state),
+            Command::Merge(c) => c.apply(state),
+            Command::Extract(c) => c.apply(state),
+            Command::Elevation(c) => c.apply(state),
+            Command::Clean(c) => c.apply(state),
+        }
+    }
 }

gpx-rs/engine/src/engine/command/edit/metadata.rs

@@ -0,0 +1,86 @@
+use crate::{Apply, CommandError, Edit, Editor, File, State, Track, update_selected};
+
+#[derive(Debug)]
+pub struct Metadata<'a> {
+    pub name: &'a str,
+    pub desc: &'a str,
+}
+
+impl Apply for Metadata<'_> {
+    fn apply(mut self, state: &mut State) -> Result<(), CommandError> {
+        update_selected(state, &mut self);
+        Ok(())
+    }
+}
+
+impl Editor for Metadata<'_> {
+    fn file(&mut self, file: &mut File) -> Edit {
+        file.info.name = self.name.to_owned();
+        file.info.desc = Some(self.desc.to_owned());
+        Edit::Changed
+    }
+
+    fn track(&mut self, track: &mut Track) -> Edit {
+        track.info.name = Some(self.name.to_owned());
+        track.info.desc = Some(self.desc.to_owned());
+        Edit::Changed
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::collections::HashSet;
+
+    use crate::{New, Selection, engine::command::fixture::Fixture};
+
+    use super::*;
+
+    #[test]
+    fn test_metadata_applies_to_selected_file() {
+        let mut fx = Fixture::default();
+        New { name: "first" }.apply(&mut fx.state()).unwrap();
+        New { name: "second" }.apply(&mut fx.state()).unwrap(); // now selected
+        let selected = *fx.selected_files().iter().next().unwrap();
+
+        Metadata {
+            name: "renamed",
+            desc: "description",
+        }
+        .apply(&mut fx.state())
+        .unwrap();
+
+        for (id, file) in fx.files.iter() {
+            if *id == selected {
+                assert_eq!(file.info.name, "renamed");
+                assert_eq!(file.info.desc.as_deref(), Some("description"));
+            } else {
+                assert_eq!(file.info.name, "first");
+                assert_eq!(file.info.desc, None);
+            }
+        }
+    }
+
+    #[test]
+    fn test_metadata_applies_to_selected_track() {
+        let mut fx = Fixture::default();
+        let data = std::fs::read("data/with_tracks.gpx").unwrap();
+        crate::Load { data: &data }.apply(&mut fx.state()).unwrap();
+        let file = fx.files.values().next().unwrap().clone();
+        fx.selection = Selection::Track {
+            file_id: file.id,
+            trk_ids: HashSet::from([file.trk[0].id]),
+        };
+
+        Metadata {
+            name: "renamed",
+            desc: "",
+        }
+        .apply(&mut fx.state())
+        .unwrap();
+
+        let after = &fx.files[&file.id];
+        assert_eq!(after.info.name, file.info.name);
+        assert_eq!(after.trk[0].info.name.as_deref(), Some("renamed"));
+        assert_eq!(after.trk[1].info, file.trk[1].info);
+    }
+}

gpx-rs/engine/src/engine/command/edit/mod.rs

@@ -0,0 +1,9 @@
+mod metadata;
+mod new_track;
+mod new_track_segment;
+mod style;
+
+pub use metadata::*;
+pub use new_track::*;
+pub use new_track_segment::*;
+pub use style::*;

gpx-rs/engine/src/engine/command/edit/new_track.rs

@@ -0,0 +1,36 @@
+use crate::{Apply, CommandError, Edit, Editor, File, State, Track, update_selected};
+
+#[derive(Debug)]
+pub struct NewTrack;
+
+impl Apply for NewTrack {
+    fn apply(mut self, state: &mut State) -> Result<(), CommandError> {
+        update_selected(state, &mut self);
+        Ok(())
+    }
+}
+
+impl Editor for NewTrack {
+    fn file(&mut self, file: &mut File) -> Edit {
+        file.trk.push(Track::default());
+        Edit::Changed
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{New, engine::command::fixture::Fixture};
+
+    use super::*;
+
+    #[test]
+    fn test_new_track() {
+        let mut fx = Fixture::default();
+        New { name: "file" }.apply(&mut fx.state()).unwrap();
+        NewTrack.apply(&mut fx.state()).unwrap();
+        NewTrack.apply(&mut fx.state()).unwrap();
+        let file = fx.files.values().next().unwrap();
+        assert_eq!(file.trk.len(), 2);
+        assert_ne!(file.trk[0].id, file.trk[1].id);
+    }
+}

gpx-rs/engine/src/engine/command/edit/new_track_segment.rs

@@ -0,0 +1,36 @@
+use crate::{Apply, CommandError, Edit, Editor, State, Track, TrackSegment, update_selected};
+
+#[derive(Debug)]
+pub struct NewTrackSegment;
+
+impl Apply for NewTrackSegment {
+    fn apply(mut self, state: &mut State) -> Result<(), CommandError> {
+        update_selected(state, &mut self);
+        Ok(())
+    }
+}
+
+impl Editor for NewTrackSegment {
+    fn track(&mut self, track: &mut Track) -> Edit {
+        track.trkseg.push(TrackSegment::default());
+        Edit::Changed
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{New, NewTrack, engine::command::fixture::Fixture};
+
+    use super::*;
+
+    #[test]
+    fn test_new_track_segment_on_each_track_of_selected_file() {
+        let mut fx = Fixture::default();
+        New { name: "file" }.apply(&mut fx.state()).unwrap();
+        NewTrack.apply(&mut fx.state()).unwrap();
+        NewTrack.apply(&mut fx.state()).unwrap();
+        NewTrackSegment.apply(&mut fx.state()).unwrap();
+        let file = fx.files.values().next().unwrap();
+        assert!(file.trk.iter().all(|t| t.trkseg.len() == 1));
+    }
+}

gpx-rs/engine/src/engine/command/edit/style.rs

@@ -0,0 +1,66 @@
+use crate::{Apply, CommandError, Edit, Editor, State, Track, update_selected};
+
+#[derive(Debug)]
+pub struct Style<'a> {
+    pub color: Option<&'a str>,
+    pub opacity: Option<f64>,
+    pub width: Option<f64>,
+}
+
+impl Apply for Style<'_> {
+    fn apply(mut self, state: &mut State) -> Result<(), CommandError> {
+        update_selected(state, &mut self);
+        Ok(())
+    }
+}
+
+impl Editor for Style<'_> {
+    fn track(&mut self, track: &mut Track) -> Edit {
+        if let Some(color) = self.color {
+            track.info.color = Some(color.to_owned());
+        }
+        if self.opacity.is_some() {
+            track.info.opacity = self.opacity;
+        }
+        if self.width.is_some() {
+            track.info.width = self.width;
+        }
+        Edit::Changed
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::collections::HashSet;
+
+    use crate::{Selection, engine::command::fixture::Fixture};
+
+    use super::*;
+
+    #[test]
+    fn test_style_applies_to_all_tracks_of_selected_file_and_keeps_unset_fields() {
+        let mut fx = Fixture::default();
+        let data = std::fs::read("data/with_style.gpx").unwrap();
+        crate::Load { data: &data }.apply(&mut fx.state()).unwrap();
+        let id = *fx.files.keys().next().unwrap();
+        let before = fx.files[&id].clone();
+        assert!(!before.trk.is_empty());
+        fx.selection = Selection::File {
+            file_ids: HashSet::from([id]),
+        };
+
+        Style {
+            color: Some("ff0000"),
+            opacity: None,
+            width: Some(7.0),
+        }
+        .apply(&mut fx.state())
+        .unwrap();
+
+        for (b, a) in before.trk.iter().zip(fx.files[&id].trk.iter()) {
+            assert_eq!(a.info.color.as_deref(), Some("ff0000"));
+            assert_eq!(a.info.width, Some(7.0));
+            assert_eq!(a.info.opacity, b.info.opacity);
+        }
+    }
+}

gpx-rs/engine/src/engine/command/file/delete.rs

@@ -0,0 +1,11 @@
+use crate::{Apply, CommandError, State};
+
+#[derive(Debug)]
+pub struct Delete;
+
+impl Apply for Delete {
+    fn apply(self, _state: &mut State) -> Result<(), CommandError> {
+        // TODO
+        Err(CommandError::NotImplemented("delete"))
+    }
+}

gpx-rs/engine/src/engine/command/file/delete_all.rs

@@ -0,0 +1,38 @@
+use crate::{Apply, CommandError, Selection, State};
+
+#[derive(Debug)]
+pub struct DeleteAll;
+
+impl Apply for DeleteAll {
+    fn apply(self, state: &mut State) -> Result<(), CommandError> {
+        if state.files.is_empty() {
+            return Err(CommandError::NothingToDo);
+        }
+        state.files.clear();
+        state.order.0.clear();
+        *state.selection = Selection::Empty;
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::engine::command::fixture::Fixture;
+
+    use super::*;
+
+    #[test]
+    fn test_delete_all() {
+        let mut fx = Fixture::default();
+        assert_eq!(
+            DeleteAll.apply(&mut fx.state()),
+            Err(CommandError::NothingToDo)
+        );
+        crate::New { name: "a" }.apply(&mut fx.state()).unwrap();
+        crate::New { name: "b" }.apply(&mut fx.state()).unwrap();
+        assert!(DeleteAll.apply(&mut fx.state()).is_ok());
+        assert!(fx.files.is_empty());
+        assert!(fx.order.0.is_empty());
+        assert!(matches!(fx.selection, Selection::Empty));
+    }
+}

gpx-rs/engine/src/engine/command/file/duplicate.rs

@@ -0,0 +1,11 @@
+use crate::{Apply, CommandError, State};
+
+#[derive(Debug)]
+pub struct Duplicate;
+
+impl Apply for Duplicate {
+    fn apply(self, _state: &mut State) -> Result<(), CommandError> {
+        // TODO
+        Err(CommandError::NotImplemented("duplicate"))
+    }
+}

gpx-rs/engine/src/engine/command/file/load.rs

@@ -0,0 +1,48 @@
+use crate::{Apply, CommandError, State, parse, produce};
+
+#[derive(Debug)]
+pub struct Load<'a> {
+    pub data: &'a [u8],
+}
+
+impl Apply for Load<'_> {
+    fn apply(self, state: &mut State) -> Result<(), CommandError> {
+        let file = parse(self.data).map_err(|err| CommandError::InvalidData(err.to_string()))?;
+        produce(state, |_| vec![file]);
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::engine::command::fixture::Fixture;
+
+    use super::*;
+
+    #[test]
+    fn test_load() {
+        let mut fx = Fixture::default();
+        let data = std::fs::read("data/with_tracks.gpx").unwrap();
+        assert!(Load { data: &data }.apply(&mut fx.state()).is_ok());
+        assert_eq!(fx.files.len(), 1);
+        let file = fx.files.values().next().unwrap();
+        assert!(!file.trk.is_empty());
+        assert_eq!(fx.selected_files(), [file.id].into());
+    }
+
+    #[test]
+    fn test_load_invalid_file_changes_nothing() {
+        let mut fx = Fixture::default();
+        crate::New { name: "keep" }.apply(&mut fx.state()).unwrap();
+        let selected = fx.selected_files();
+
+        let result = Load {
+            data: b"<gpx><trk></gpx>",
+        }
+        .apply(&mut fx.state());
+        assert!(matches!(result, Err(CommandError::InvalidData(_))));
+        assert_eq!(fx.files.len(), 1);
+        assert_eq!(fx.order.0.len(), 1);
+        assert_eq!(fx.selected_files(), selected);
+    }
+}

gpx-rs/engine/src/engine/command/file/mod.rs

@@ -0,0 +1,11 @@
+mod delete;
+mod delete_all;
+mod duplicate;
+mod load;
+mod new;
+
+pub use delete::*;
+pub use delete_all::*;
+pub use duplicate::*;
+pub use load::*;
+pub use new::*;

gpx-rs/engine/src/engine/command/file/new.rs

@@ -0,0 +1,36 @@
+use crate::{Apply, CommandError, File, State, produce};
+
+#[derive(Debug)]
+pub struct New<'a> {
+    pub name: &'a str,
+}
+
+impl Apply for New<'_> {
+    fn apply(self, state: &mut State) -> Result<(), CommandError> {
+        produce(state, |_| {
+            let mut file = File::default();
+            file.info.name = self.name.to_owned();
+            vec![file]
+        });
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::engine::command::fixture::Fixture;
+
+    use super::*;
+
+    #[test]
+    fn test_new() {
+        let mut fx = Fixture::default();
+        assert!(New { name: "new" }.apply(&mut fx.state()).is_ok());
+        assert_eq!(fx.files.len(), 1);
+        let file = fx.files.values().next().unwrap();
+        assert_eq!(file.info.name, "new");
+        assert!(file.trk.is_empty());
+        assert_eq!(fx.selected_files(), [file.id].into());
+        assert_eq!(fx.order.0, vec![file.id]);
+    }
+}

gpx-rs/engine/src/engine/command/fixture.rs

@@ -0,0 +1,30 @@
+//! Shared helpers for the tests of the commands.
+
+use std::collections::HashSet;
+
+use crate::{FileId, FileOrder, Selection, StackEntry, State};
+
+#[derive(Default)]
+pub struct Fixture {
+    pub files: StackEntry,
+    pub selection: Selection,
+    pub order: FileOrder,
+}
+
+impl Fixture {
+    pub fn state(&mut self) -> State<'_> {
+        State {
+            files: &mut self.files,
+            selection: &mut self.selection,
+            order: &mut self.order,
+        }
+    }
+
+    /// Ids of the selected files, empty unless the selection is a file selection.
+    pub fn selected_files(&self) -> HashSet<FileId> {
+        match &self.selection {
+            Selection::File { file_ids } => file_ids.clone(),
+            _ => HashSet::new(),
+        }
+    }
+}

gpx-rs/engine/src/engine/command/mod.rs

@@ -1,7 +1,15 @@
-mod applier;
+mod apply;
 mod command;
+mod edit;
+mod file;
+#[cfg(test)]
+mod fixture;
 mod pattern;
+mod tools;
 
-pub use applier::*;
+pub use apply::*;
 pub use command::*;
+pub use edit::*;
+pub use file::*;
 pub use pattern::*;
+pub use tools::*;

gpx-rs/engine/src/engine/command/pattern.rs

@@ -1,179 +0,0 @@
-use std::{
-    collections::{HashSet, hash_map::Entry},
-    rc::Rc,
-};
-
-use crate::{File, FileId, Selection, State};
-
-pub fn produce<F>(state: &mut State, f: F)
-where
-    F: FnOnce(&State) -> Vec<File>,
-{
-    *state.selection = Selection::Empty;
-    for file in f(state).drain(..) {
-        let file_id = file.id;
-        state.files.insert(file_id, Rc::new(file));
-        state.order.0.push(file_id);
-        if matches!(*state.selection, Selection::Empty) {
-            let mut file_ids: HashSet<FileId> = Default::default();
-            file_ids.insert(file_id);
-            *state.selection = Selection::File { file_ids };
-        }
-    }
-}
-
-pub fn update_each_selected_file<F>(state: &mut State, f: &mut F)
-where
-    F: FnMut(&File) -> File,
-{
-    if let Selection::File { file_ids } = state.selection {
-        for file_id in file_ids.iter() {
-            if let Entry::Occupied(mut e) = state.files.entry(*file_id) {
-                let file = e.get();
-                let updated = Rc::new(f(file.as_ref()));
-                e.insert(updated);
-            }
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use crate::FileOrder;
-
-    use super::*;
-
-    fn named(name: &str) -> File {
-        let mut file = File::default();
-        file.info.name = name.to_string();
-        file
-    }
-
-    struct Fixture {
-        files: crate::StackEntry,
-        selection: Selection,
-        order: FileOrder,
-    }
-
-    impl Fixture {
-        fn new() -> Self {
-            Self {
-                files: Default::default(),
-                selection: Selection::Empty,
-                order: FileOrder::default(),
-            }
-        }
-
-        fn state(&mut self) -> State<'_> {
-            State {
-                files: &mut self.files,
-                selection: &mut self.selection,
-                order: &mut self.order,
-            }
-        }
-
-        fn selected(&self) -> HashSet<FileId> {
-            match &self.selection {
-                Selection::File { file_ids } => file_ids.clone(),
-                _ => HashSet::new(),
-            }
-        }
-    }
-
-    #[test]
-    fn test_produce_adds_orders_and_selects_first() {
-        let mut fx = Fixture::new();
-        let (a, b) = (named("a"), named("b"));
-        let (id_a, id_b) = (a.id, b.id);
-        produce(&mut fx.state(), |_| vec![a, b]);
-
-        assert_eq!(fx.files.len(), 2);
-        assert_eq!(fx.order.0, vec![id_a, id_b]);
-        assert_eq!(fx.selected(), HashSet::from([id_a]));
-    }
-
-    #[test]
-    fn test_produce_replaces_selection_and_keeps_order() {
-        let mut fx = Fixture::new();
-        let a = named("a");
-        let id_a = a.id;
-        produce(&mut fx.state(), |_| vec![a]);
-        let b = named("b");
-        let id_b = b.id;
-        produce(&mut fx.state(), |_| vec![b]);
-
-        assert_eq!(fx.order.0, vec![id_a, id_b]);
-        assert_eq!(fx.selected(), HashSet::from([id_b]));
-    }
-
-    #[test]
-    fn test_produce_nothing_clears_selection() {
-        let mut fx = Fixture::new();
-        let a = named("a");
-        produce(&mut fx.state(), |_| vec![a]);
-        produce(&mut fx.state(), |_| vec![]);
-        assert!(matches!(fx.selection, Selection::Empty));
-        assert_eq!(fx.files.len(), 1);
-    }
-
-    #[test]
-    fn test_produce_sees_current_state() {
-        let mut fx = Fixture::new();
-        let a = named("a");
-        produce(&mut fx.state(), |_| vec![a]);
-        produce(&mut fx.state(), |state| {
-            assert_eq!(state.files.len(), 1);
-            vec![]
-        });
-    }
-
-    #[test]
-    fn test_update_each_selected_file_only_touches_selection() {
-        let mut fx = Fixture::new();
-        let (a, b, c) = (named("a"), named("b"), named("c"));
-        let ids = [a.id, b.id, c.id];
-        for file in [a, b, c] {
-            fx.files.insert(file.id, Rc::new(file));
-        }
-        let untouched = fx.files[&ids[2]].clone();
-        fx.selection = Selection::File {
-            file_ids: HashSet::from([ids[0], ids[1]]),
-        };
-
-        let mut calls = 0;
-        update_each_selected_file(&mut fx.state(), &mut |file| {
-            calls += 1;
-            let mut next = file.clone();
-            next.info.name.push('!');
-            next
-        });
-
-        assert_eq!(calls, 2);
-        assert_eq!(fx.files[&ids[0]].info.name, "a!");
-        assert_eq!(fx.files[&ids[1]].info.name, "b!");
-        assert!(Rc::ptr_eq(&fx.files[&ids[2]], &untouched));
-    }
-
-    #[test]
-    fn test_update_each_selected_file_ignores_missing_and_other_selections() {
-        let mut fx = Fixture::new();
-        let a = named("a");
-        let id = a.id;
-        fx.files.insert(id, Rc::new(a));
-
-        let mut calls = 0;
-        let mut count = |file: &File| {
-            calls += 1;
-            file.clone()
-        };
-        fx.selection = Selection::File {
-            file_ids: HashSet::from([FileId::default()]),
-        };
-        update_each_selected_file(&mut fx.state(), &mut count);
-        fx.selection = Selection::Waypoints { file_id: id };
-        update_each_selected_file(&mut fx.state(), &mut count);
-        fx.selection = Selection::Empty;
-        update_each_selected_file(&mut fx.state(), &mut count);
-        assert_eq!(calls, 0);
-    }
-}

gpx-rs/engine/src/engine/command/pattern/mod.rs

@@ -0,0 +1,5 @@
+mod produce;
+mod update_selected;
+
+pub use produce::*;
+pub use update_selected::*;

gpx-rs/engine/src/engine/command/pattern/produce.rs

@@ -0,0 +1,81 @@
+use std::rc::Rc;
+
+use crate::{File, Selection, State};
+
+/// Pure producer: adds the files returned by `f` to the state and selects the first one.
+pub fn produce<F>(state: &mut State, f: F)
+where
+    F: FnOnce(&State) -> Vec<File>,
+{
+    *state.selection = Selection::Empty;
+    for file in f(state) {
+        let file_id = file.id;
+        state.files.insert(file_id, Rc::new(file));
+        state.order.0.push(file_id);
+        if matches!(*state.selection, Selection::Empty) {
+            *state.selection = Selection::File {
+                file_ids: [file_id].into(),
+            };
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::collections::HashSet;
+
+    use crate::engine::command::fixture::Fixture;
+
+    use super::*;
+
+    fn named(name: &str) -> File {
+        let mut file = File::default();
+        file.info.name = name.to_string();
+        file
+    }
+
+    #[test]
+    fn test_produce_adds_orders_and_selects_first() {
+        let mut fx = Fixture::default();
+        let (a, b) = (named("a"), named("b"));
+        let (id_a, id_b) = (a.id, b.id);
+        produce(&mut fx.state(), |_| vec![a, b]);
+
+        assert_eq!(fx.files.len(), 2);
+        assert_eq!(fx.order.0, vec![id_a, id_b]);
+        assert_eq!(fx.selected_files(), HashSet::from([id_a]));
+    }
+
+    #[test]
+    fn test_produce_replaces_selection_and_keeps_order() {
+        let mut fx = Fixture::default();
+        let a = named("a");
+        let id_a = a.id;
+        produce(&mut fx.state(), |_| vec![a]);
+        let b = named("b");
+        let id_b = b.id;
+        produce(&mut fx.state(), |_| vec![b]);
+
+        assert_eq!(fx.order.0, vec![id_a, id_b]);
+        assert_eq!(fx.selected_files(), HashSet::from([id_b]));
+    }
+
+    #[test]
+    fn test_produce_nothing_clears_selection() {
+        let mut fx = Fixture::default();
+        produce(&mut fx.state(), |_| vec![named("a")]);
+        produce(&mut fx.state(), |_| vec![]);
+        assert!(matches!(fx.selection, Selection::Empty));
+        assert_eq!(fx.files.len(), 1);
+    }
+
+    #[test]
+    fn test_produce_sees_current_state() {
+        let mut fx = Fixture::default();
+        produce(&mut fx.state(), |_| vec![named("a")]);
+        produce(&mut fx.state(), |state| {
+            assert_eq!(state.files.len(), 1);
+            vec![]
+        });
+    }
+}

gpx-rs/engine/src/engine/command/pattern/update_selected.rs

@@ -0,0 +1,266 @@
+use std::rc::Rc;
+
+use crate::{File, FileId, Selection, StackEntry, State, Track, TrackSegment};
+
+/// What an [`Editor`] hook did to the element it was given.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Edit {
+    Unchanged,
+    Changed,
+}
+
+impl Edit {
+    fn merge(self, other: Edit) -> Edit {
+        if self == Edit::Changed || other == Edit::Changed {
+            Edit::Changed
+        } else {
+            Edit::Unchanged
+        }
+    }
+}
+
+/// Independent edit of each selected element, without needing the rest of the state.
+///
+/// A selected file, track or segment is passed to the hook of its own level. By default a
+/// file is forwarded to its tracks and a track to its segments, so an editor only overrides
+/// the level(s) it cares about (metadata: file and track, style: track, reverse: segment).
+pub trait Editor {
+    fn file(&mut self, file: &mut File) -> Edit {
+        edit_each(&mut file.trk, |trk| self.track(trk))
+    }
+
+    fn track(&mut self, track: &mut Track) -> Edit {
+        edit_each(&mut track.trkseg, |seg| edit_segment(self, seg))
+    }
+
+    fn segment(&mut self, _segment: &mut TrackSegment) -> Edit {
+        Edit::Unchanged
+    }
+}
+
+/// Calls the segment hook and gives the segment a new revision id if it changed, so that
+/// derived data (statistics) is recomputed.
+fn edit_segment<E: Editor + ?Sized>(editor: &mut E, segment: &mut TrackSegment) -> Edit {
+    let edit = editor.segment(segment);
+    if edit == Edit::Changed {
+        segment.rev_id = Default::default();
+    }
+    edit
+}
+
+fn edit_each<T>(items: &mut [T], f: impl FnMut(&mut T) -> Edit) -> Edit {
+    edit_where(items, |_| true, f)
+}
+
+fn edit_where<T>(
+    items: &mut [T],
+    filter: impl Fn(&T) -> bool,
+    mut f: impl FnMut(&mut T) -> Edit,
+) -> Edit {
+    items
+        .iter_mut()
+        .filter(|item| filter(item))
+        .fold(Edit::Unchanged, |acc, item| acc.merge(f(item)))
+}
+
+/// Edits a copy of the file (cheap, track points are shared chunks) and stores it back as a
+/// new snapshot only if something changed.
+fn update_file(files: &mut StackEntry, id: FileId, f: impl FnOnce(&mut File) -> Edit) {
+    let Some(current) = files.get(&id) else {
+        return;
+    };
+    let mut file = (**current).clone();
+    if f(&mut file) == Edit::Changed {
+        files.insert(id, Rc::new(file));
+    }
+}
+
+/// Applies the editor to every selected file, track or segment.
+pub fn update_selected<E: Editor>(state: &mut State, editor: &mut E) {
+    match &*state.selection {
+        Selection::File { file_ids } => {
+            for id in file_ids {
+                update_file(state.files, *id, |file| editor.file(file));
+            }
+        }
+        Selection::Track { file_id, trk_ids } => {
+            update_file(state.files, *file_id, |file| {
+                edit_where(
+                    &mut file.trk,
+                    |trk| trk_ids.contains(&trk.id),
+                    |trk| editor.track(trk),
+                )
+            });
+        }
+        Selection::TrackSegment {
+            file_id,
+            trk_id,
+            trkseg_ids,
+        } => {
+            update_file(state.files, *file_id, |file| {
+                edit_where(
+                    &mut file.trk,
+                    |trk| trk.id == *trk_id,
+                    |trk| {
+                        edit_where(
+                            &mut trk.trkseg,
+                            |seg| trkseg_ids.contains(&seg.id),
+                            |seg| edit_segment(editor, seg),
+                        )
+                    },
+                )
+            });
+        }
+        // TODO waypoint-level hooks
+        Selection::Empty | Selection::Waypoints { .. } | Selection::Waypoint { .. } => {}
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::collections::HashSet;
+
+    use crate::engine::command::fixture::Fixture;
+
+    use super::*;
+
+    struct Rename;
+
+    impl Editor for Rename {
+        fn file(&mut self, file: &mut File) -> Edit {
+            file.info.name.push('!');
+            Edit::Changed
+        }
+
+        fn track(&mut self, track: &mut Track) -> Edit {
+            track.info.name = Some("track".to_string());
+            Edit::Changed
+        }
+
+        fn segment(&mut self, _: &mut TrackSegment) -> Edit {
+            Edit::Changed
+        }
+    }
+
+    struct Nothing;
+    impl Editor for Nothing {}
+
+    fn fixture_with_tracks() -> (Fixture, FileId) {
+        let mut fx = Fixture::default();
+        let data = std::fs::read("data/with_tracks_and_segments.gpx").unwrap();
+        let file = Rc::new(crate::parse(&data).unwrap());
+        let id = file.id;
+        fx.files.insert(id, file);
+        (fx, id)
+    }
+
+    #[test]
+    fn test_only_selected_files_are_updated() {
+        let mut fx = Fixture::default();
+        let (a, b, c) = (File::default(), File::default(), File::default());
+        let ids = [a.id, b.id, c.id];
+        for file in [a, b, c] {
+            fx.files.insert(file.id, Rc::new(file));
+        }
+        let untouched = fx.files[&ids[2]].clone();
+        fx.selection = Selection::File {
+            file_ids: HashSet::from([ids[0], ids[1]]),
+        };
+
+        update_selected(&mut fx.state(), &mut Rename);
+
+        assert_eq!(fx.files[&ids[0]].info.name, "!");
+        assert_eq!(fx.files[&ids[1]].info.name, "!");
+        assert!(Rc::ptr_eq(&fx.files[&ids[2]], &untouched));
+    }
+
+    #[test]
+    fn test_unchanged_file_keeps_its_snapshot() {
+        let (mut fx, id) = fixture_with_tracks();
+        fx.selection = Selection::File {
+            file_ids: HashSet::from([id]),
+        };
+        let before = fx.files[&id].clone();
+        update_selected(&mut fx.state(), &mut Nothing);
+        assert!(Rc::ptr_eq(&fx.files[&id], &before));
+    }
+
+    #[test]
+    fn test_track_selection_uses_track_hook() {
+        let (mut fx, id) = fixture_with_tracks();
+        let trk_id = fx.files[&id].trk[0].id;
+        fx.selection = Selection::Track {
+            file_id: id,
+            trk_ids: HashSet::from([trk_id]),
+        };
+        update_selected(&mut fx.state(), &mut Rename);
+
+        let file = &fx.files[&id];
+        assert_eq!(file.info.name, "with_tracks_and_segments");
+        assert_eq!(file.trk[0].info.name.as_deref(), Some("track"));
+        assert_ne!(file.trk[1].info.name.as_deref(), Some("track"));
+    }
+
+    #[test]
+    fn test_segment_selection_bumps_revision_id() {
+        let (mut fx, id) = fixture_with_tracks();
+        let before = fx.files[&id].clone();
+        let trk = &before.trk[0];
+        fx.selection = Selection::TrackSegment {
+            file_id: id,
+            trk_id: trk.id,
+            trkseg_ids: HashSet::from([trk.trkseg[0].id]),
+        };
+        update_selected(&mut fx.state(), &mut Rename);
+
+        let after = &fx.files[&id];
+        assert_ne!(after.trk[0].trkseg[0].rev_id, trk.trkseg[0].rev_id);
+        assert_eq!(after.trk[0].trkseg[1].rev_id, trk.trkseg[1].rev_id);
+        assert_eq!(
+            after.trk[1].trkseg[0].rev_id,
+            before.trk[1].trkseg[0].rev_id
+        );
+    }
+
+    #[test]
+    fn test_file_selection_cascades_to_segments() {
+        struct SegmentsOnly;
+        impl Editor for SegmentsOnly {
+            fn segment(&mut self, _: &mut TrackSegment) -> Edit {
+                Edit::Changed
+            }
+        }
+        let (mut fx, id) = fixture_with_tracks();
+        let before = fx.files[&id].clone();
+        fx.selection = Selection::File {
+            file_ids: HashSet::from([id]),
+        };
+        update_selected(&mut fx.state(), &mut SegmentsOnly);
+        for (b, a) in before.trk.iter().zip(fx.files[&id].trk.iter()) {
+            for (b, a) in b.trkseg.iter().zip(a.trkseg.iter()) {
+                assert_ne!(b.rev_id, a.rev_id);
+            }
+        }
+    }
+
+    #[test]
+    fn test_missing_files_and_other_selections_are_ignored() {
+        let mut fx = Fixture::default();
+        let file = File::default();
+        let id = file.id;
+        fx.files.insert(id, Rc::new(file));
+        let before = fx.files[&id].clone();
+
+        for selection in [
+            Selection::File {
+                file_ids: HashSet::from([FileId::default()]),
+            },
+            Selection::Waypoints { file_id: id },
+            Selection::Empty,
+        ] {
+            fx.selection = selection;
+            update_selected(&mut fx.state(), &mut Rename);
+            assert!(Rc::ptr_eq(&fx.files[&id], &before));
+        }
+    }
+}

gpx-rs/engine/src/engine/command/tools/append.rs

@@ -0,0 +1,15 @@
+use crate::{Apply, CommandError, State};
+
+#[derive(Debug)]
+pub struct Append<'a> {
+    pub lng: &'a [f64],
+    pub lat: &'a [f64],
+    pub ele: &'a [f64],
+}
+
+impl Apply for Append<'_> {
+    fn apply(self, _state: &mut State) -> Result<(), CommandError> {
+        // TODO
+        Err(CommandError::NotImplemented("append"))
+    }
+}

gpx-rs/engine/src/engine/command/tools/clean.rs

@@ -0,0 +1,22 @@
+use crate::{Apply, CommandError, LngLatBounds, State};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum CleanType {
+    Inside,
+    Outside,
+}
+
+#[derive(Debug)]
+pub struct Clean {
+    pub bounds: LngLatBounds,
+    pub type_: CleanType,
+    pub trkpt: bool,
+    pub wpt: bool,
+}
+
+impl Apply for Clean {
+    fn apply(self, _state: &mut State) -> Result<(), CommandError> {
+        // TODO
+        Err(CommandError::NotImplemented("clean"))
+    }
+}

gpx-rs/engine/src/engine/command/tools/crop.rs

@@ -0,0 +1,14 @@
+use crate::{Apply, CommandError, State};
+
+#[derive(Debug)]
+pub struct Crop {
+    pub start: u32,
+    pub end: u32,
+}
+
+impl Apply for Crop {
+    fn apply(self, _state: &mut State) -> Result<(), CommandError> {
+        // TODO
+        Err(CommandError::NotImplemented("crop"))
+    }
+}

gpx-rs/engine/src/engine/command/tools/elevation.rs

@@ -0,0 +1,13 @@
+use crate::{Apply, CommandError, State};
+
+#[derive(Debug)]
+pub struct Elevation<'a> {
+    pub ele: &'a [f64],
+}
+
+impl Apply for Elevation<'_> {
+    fn apply(self, _state: &mut State) -> Result<(), CommandError> {
+        // TODO
+        Err(CommandError::NotImplemented("elevation"))
+    }
+}

gpx-rs/engine/src/engine/command/tools/extract.rs

@@ -0,0 +1,11 @@
+use crate::{Apply, CommandError, State};
+
+#[derive(Debug)]
+pub struct Extract;
+
+impl Apply for Extract {
+    fn apply(self, _state: &mut State) -> Result<(), CommandError> {
+        // TODO
+        Err(CommandError::NotImplemented("extract"))
+    }
+}

gpx-rs/engine/src/engine/command/tools/merge.rs

@@ -0,0 +1,19 @@
+use crate::{Apply, CommandError, State};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum MergeType {
+    Connect,
+    Group,
+}
+
+#[derive(Debug)]
+pub struct Merge {
+    pub type_: MergeType,
+}
+
+impl Apply for Merge {
+    fn apply(self, _state: &mut State) -> Result<(), CommandError> {
+        // TODO
+        Err(CommandError::NotImplemented("merge"))
+    }
+}

gpx-rs/engine/src/engine/command/tools/mod.rs

@@ -0,0 +1,25 @@
+mod append;
+mod clean;
+mod crop;
+mod elevation;
+mod extract;
+mod merge;
+mod move_waypoint;
+mod new_waypoint;
+mod replace;
+mod reverse;
+mod split;
+mod time;
+
+pub use append::*;
+pub use clean::*;
+pub use crop::*;
+pub use elevation::*;
+pub use extract::*;
+pub use merge::*;
+pub use move_waypoint::*;
+pub use new_waypoint::*;
+pub use replace::*;
+pub use reverse::*;
+pub use split::*;
+pub use time::*;

gpx-rs/engine/src/engine/command/tools/move_waypoint.rs

@@ -0,0 +1,15 @@
+use crate::{Apply, CommandError, State};
+
+#[derive(Debug)]
+pub struct MoveWaypoint {
+    pub lng: f64,
+    pub lat: f64,
+    pub ele: f64,
+}
+
+impl Apply for MoveWaypoint {
+    fn apply(self, _state: &mut State) -> Result<(), CommandError> {
+        // TODO
+        Err(CommandError::NotImplemented("move waypoint"))
+    }
+}

gpx-rs/engine/src/engine/command/tools/new_waypoint.rs

@@ -0,0 +1,19 @@
+use crate::{Apply, CommandError, State};
+
+#[derive(Debug)]
+pub struct NewWaypoint<'a> {
+    pub lng: f64,
+    pub lat: f64,
+    pub ele: f64,
+    pub name: &'a str,
+    pub desc: &'a str,
+    pub icon: &'a str,
+    pub link: &'a str,
+}
+
+impl Apply for NewWaypoint<'_> {
+    fn apply(self, _state: &mut State) -> Result<(), CommandError> {
+        // TODO
+        Err(CommandError::NotImplemented("new waypoint"))
+    }
+}

gpx-rs/engine/src/engine/command/tools/replace.rs

@@ -0,0 +1,17 @@
+use crate::{Apply, CommandError, State};
+
+#[derive(Debug)]
+pub struct Replace<'a> {
+    pub start: u32,
+    pub end: u32,
+    pub lng: &'a [f64],
+    pub lat: &'a [f64],
+    pub ele: &'a [f64],
+}
+
+impl Apply for Replace<'_> {
+    fn apply(self, _state: &mut State) -> Result<(), CommandError> {
+        // TODO
+        Err(CommandError::NotImplemented("replace"))
+    }
+}

gpx-rs/engine/src/engine/command/tools/reverse.rs

@@ -0,0 +1,11 @@
+use crate::{Apply, CommandError, State};
+
+#[derive(Debug)]
+pub struct Reverse;
+
+impl Apply for Reverse {
+    fn apply(self, _state: &mut State) -> Result<(), CommandError> {
+        // TODO
+        Err(CommandError::NotImplemented("reverse"))
+    }
+}

gpx-rs/engine/src/engine/command/tools/split.rs

@@ -0,0 +1,13 @@
+use crate::{Apply, CommandError, State};
+
+#[derive(Debug)]
+pub struct Split {
+    pub at: u32,
+}
+
+impl Apply for Split {
+    fn apply(self, _state: &mut State) -> Result<(), CommandError> {
+        // TODO
+        Err(CommandError::NotImplemented("split"))
+    }
+}

gpx-rs/engine/src/engine/command/tools/time.rs

@@ -0,0 +1,11 @@
+use crate::{Apply, CommandError, State};
+
+#[derive(Debug)]
+pub struct Time;
+
+impl Apply for Time {
+    fn apply(self, _state: &mut State) -> Result<(), CommandError> {
+        // TODO
+        Err(CommandError::NotImplemented("time"))
+    }
+}

gpx-rs/engine/src/engine/engine.rs

@@ -1,8 +1,10 @@
 // TODO license in every file
 
+use std::collections::HashSet;
+
 use crate::{
-    Command, FileOrder, Selection, Stack, State, StatisticsBuffer, StatisticsCache, create_file,
-    load_file, update_metadata,
+    Action, Apply, Command, FileId, FileOrder, Selection, Stack, State, StatisticsBuffer,
+    StatisticsCache,
 };
 
 #[derive(Debug, Default)]
@@ -19,97 +21,116 @@ impl Engine {
         &self.statistics_buffer
     }
 
-    // pub fn delete_file(&mut self, id: &[u8]) -> bool {
-    //     self.event_loop(|entry| {
-    //         if let Ok(id) = Uuid::from_slice(id) {
-    //             let id = FileId(id);
-    //             entry.remove(&id).is_some()
-    //         } else {
-    //             false
-    //         }
-    //     })
-    // }
-
-    /// Single entry point for every user action coming from the frontend.
-    pub fn execute(&mut self, command: Command) -> bool {
-        if let Some(diff) = self.stack.create_and_push_next(|files| {
-            let mut state = State {
-                files,
-                selection: &mut self.selection,
-                order: &mut self.order,
-            };
-            match command {
-                Command::New { name } => create_file(&mut state, name),
-                Command::Load { data } => load_file(&mut state, data),
-                Command::Metadata { name, desc } => update_metadata(&mut state, name, desc),
-                Command::Delete
-                | Command::DeleteAll
-                | Command::Duplicate
-                | Command::Style { .. }
-                | Command::NewTrack
-                | Command::NewTrackSegment
-                | Command::Reverse
-                | Command::Append { .. }
-                | Command::Replace { .. }
-                | Command::NewWaypoint { .. }
-                | Command::MoveWaypoint { .. }
-                | Command::Crop { .. }
-                | Command::Split { .. }
-                | Command::Time
-                | Command::Merge { .. }
-                | Command::Extract
-                | Command::Elevation { .. }
-                | Command::Clean { .. }
-                | Command::Undo
-                | Command::Redo
-                | Command::Select { .. }
-                | Command::AddSelect { .. }
-                | Command::SelectAll => todo!("command not implemented yet"),
+    /// Single entry point for every action coming from the frontend. Returns whether anything
+    /// changed.
+    pub fn execute(&mut self, action: Action) -> bool {
+        let changed = match action {
+            Action::Edit(command) => self.edit(command),
+            Action::Undo => self.stack.undo().is_some(),
+            Action::Redo => self.stack.redo().is_some(),
+            Action::Select { file_ids } => {
+                self.selection = Selection::File {
+                    file_ids: file_ids.into_iter().collect(),
+                };
+                true
             }
-        }) {
-            self.statistics_cache.update(self.stack.current());
-            self.statistics_buffer.update(
-                &self
-                    .statistics_cache
-                    .get(self.stack.current(), &self.selection),
-            );
-            true
-        } else {
-            false
+            Action::AddSelect { file_ids } => {
+                match &mut self.selection {
+                    Selection::File { file_ids: ids } => ids.extend(file_ids),
+                    selection => {
+                        *selection = Selection::File {
+                            file_ids: file_ids.into_iter().collect(),
+                        }
+                    }
+                }
+                true
+            }
+            Action::SelectAll => {
+                self.selection = Selection::File {
+                    file_ids: self.order.0.iter().copied().collect(),
+                };
+                true
+            }
+        };
+        if changed {
+            self.refresh();
         }
+        changed
+    }
+
+    fn edit(&mut self, command: Command) -> bool {
+        self.stack
+            .create_and_push_next(|files| {
+                let mut state = State {
+                    files,
+                    selection: &mut self.selection,
+                    order: &mut self.order,
+                };
+                command.apply(&mut state).map_err(|err| err.to_string())
+            })
+            .is_some()
+    }
+
+    /// Brings everything derived from the files back in line with the current stack entry.
+    fn refresh(&mut self) {
+        let current = self.stack.current();
+        match current {
+            Some(files) => {
+                self.order.0.retain(|id| files.contains_key(id));
+                let known: HashSet<FileId> = self.order.0.iter().copied().collect();
+                self.order
+                    .0
+                    .extend(files.keys().filter(|id| !known.contains(id)).copied());
+                self.selection.retain_existing(files);
+            }
+            None => {
+                self.order.0.clear();
+                self.selection = Selection::Empty;
+            }
+        }
+        self.statistics_cache.update(current);
+        self.statistics_buffer
+            .update(&self.statistics_cache.get(current, &self.selection));
     }
 }
 
 #[cfg(test)]
 mod tests {
-    use std::{fs::File, io::Read};
+    use crate::{Load, Metadata, New, NewTrack, Style};
 
     use super::*;
 
-    #[test]
-    fn test_load_file() {
-        let mut engine = Engine::default();
+    fn edit(engine: &mut Engine, command: Command) -> bool {
+        engine.execute(Action::Edit(command))
+    }
 
-        let mut f = File::open("data/simple.gpx").unwrap();
-        let mut data = String::new();
-        let _ = f.read_to_string(&mut data);
-
-        engine.execute(Command::Load {
-            data: data.as_bytes(),
-        });
-
-        assert_eq!(engine.statistics_buffer.total_distance.len(), 80);
+    fn new(engine: &mut Engine, name: &str) -> bool {
+        edit(engine, Command::New(New { name }))
     }
 
     fn load(engine: &mut Engine, path: &str) -> bool {
         let data = std::fs::read(path).unwrap();
-        engine.execute(Command::Load { data: &data })
+        edit(engine, Command::Load(Load { data: &data }))
+    }
+
+    fn selected(engine: &Engine) -> Vec<FileId> {
+        match &engine.selection {
+            Selection::File { file_ids } => file_ids.iter().copied().collect(),
+            _ => vec![],
+        }
+    }
+
+    #[test]
+    fn test_load_file() {
+        let mut engine = Engine::default();
+        assert!(load(&mut engine, "data/simple.gpx"));
+        assert_eq!(engine.statistics_buffer.total_distance.len(), 80);
     }
 
     #[test]
     fn test_new_file_has_no_statistics() {
         let mut engine = Engine::default();
-        assert!(engine.execute(Command::New { name: "empty" }));
+        assert!(new(&mut engine, "empty"));
         assert_eq!(engine.stack.current().unwrap().len(), 1);
         assert_eq!(engine.order.0.len(), 1);
         assert!(engine.statistics().total_distance.is_empty());
@@ -123,7 +144,7 @@ mod tests {
         assert!(n > 0);
 
         // a newly created (empty) file becomes the selection
-        assert!(engine.execute(Command::New { name: "empty" }));
+        assert!(new(&mut engine, "empty"));
         assert!(engine.statistics().total_distance.is_empty());
         assert_eq!(engine.stack.current().unwrap().len(), 2);
 
@@ -135,39 +156,142 @@ mod tests {
     #[test]
     fn test_invalid_load_is_rejected() {
         let mut engine = Engine::default();
-        assert!(!engine.execute(Command::Load {
-            data: b"<gpx><trk></gpx>"
-        }));
+        assert!(!edit(
+            &mut engine,
+            Command::Load(Load {
+                data: b"<gpx><trk></gpx>"
+            })
+        ));
         assert!(engine.stack.current().is_none());
         assert!(!engine.stack.can_undo());
         assert!(engine.order.0.is_empty());
     }
 
+    #[test]
+    fn test_not_implemented_command_is_rejected() {
+        let mut engine = Engine::default();
+        new(&mut engine, "file");
+        assert!(!edit(&mut engine, Command::Reverse(crate::Reverse)));
+        assert!(!engine.stack.can_redo());
+        assert_eq!(engine.stack.current().unwrap().len(), 1);
+    }
+
     #[test]
     fn test_metadata_renames_selected_file() {
         let mut engine = Engine::default();
-        engine.execute(Command::New { name: "before" });
-        assert!(engine.execute(Command::Metadata {
-            name: "after",
-            desc: "about",
-        }));
-        let state = engine.stack.current().unwrap();
-        let file = state.values().next().unwrap();
+        new(&mut engine, "before");
+        assert!(edit(
+            &mut engine,
+            Command::Metadata(Metadata {
+                name: "after",
+                desc: "about",
+            })
+        ));
+        let file = engine.stack.current().unwrap().values().next().unwrap();
         assert_eq!(file.info.name, "after");
         assert_eq!(file.info.desc.as_deref(), Some("about"));
-        assert!(engine.stack.can_undo());
     }
 
     #[test]
     fn test_metadata_without_selection_does_not_modify_files() {
         let mut engine = Engine::default();
-        engine.execute(Command::New { name: "file" });
+        new(&mut engine, "file");
         engine.selection = Selection::Empty;
-        engine.execute(Command::Metadata {
-            name: "renamed",
-            desc: "",
-        });
-        let state = engine.stack.current().unwrap();
-        assert_eq!(state.values().next().unwrap().info.name, "file");
+        edit(
+            &mut engine,
+            Command::Metadata(Metadata {
+                name: "renamed",
+                desc: "",
+            }),
+        );
+        let file = engine.stack.current().unwrap().values().next().unwrap();
+        assert_eq!(file.info.name, "file");
+    }
+
+    #[test]
+    fn test_edit_changes_statistics_when_segments_change() {
+        let mut engine = Engine::default();
+        load(&mut engine, "data/simple.gpx");
+        let before = engine
+            .statistics_cache
+            .get(engine.stack.current(), &engine.selection)[0] as *const _;
+        edit(&mut engine, Command::NewTrack(NewTrack));
+        edit(
+            &mut engine,
+            Command::Style(Style {
+                color: Some("ff0000"),
+                opacity: None,
+                width: None,
+            }),
+        );
+        // styling does not touch the segments: their statistics are reused
+        let after = engine
+            .statistics_cache
+            .get(engine.stack.current(), &engine.selection)[0] as *const _;
+        assert!(std::ptr::eq(before, after));
+    }
+
+    #[test]
+    fn test_undo_redo_keep_selection_and_order_consistent() {
+        let mut engine = Engine::default();
+        new(&mut engine, "a");
+        let a = selected(&engine)[0];
+        new(&mut engine, "b");
+        let b = selected(&engine)[0];
+        assert_eq!(engine.order.0, vec![a, b]);
+
+        assert!(engine.execute(Action::Undo));
+        assert_eq!(engine.order.0, vec![a]);
+        assert!(selected(&engine).is_empty());
+
+        assert!(engine.execute(Action::Redo));
+        assert_eq!(engine.order.0, vec![a, b]);
+
+        assert!(engine.execute(Action::Undo));
+        assert!(engine.execute(Action::Undo));
+        assert!(engine.order.0.is_empty());
+        assert!(!engine.execute(Action::Undo));
+        assert!(engine.stack.current().is_none());
+    }
+
+    #[test]
+    fn test_undo_updates_statistics() {
+        let mut engine = Engine::default();
+        load(&mut engine, "data/simple.gpx");
+        assert!(!engine.statistics().total_distance.is_empty());
+        engine.execute(Action::Undo);
+        assert!(engine.statistics().total_distance.is_empty());
+        engine.execute(Action::Redo);
+        engine.execute(Action::SelectAll);
+        assert_eq!(engine.statistics().total_distance.len(), 80);
+    }
+
+    #[test]
+    fn test_selection_actions() {
+        let mut engine = Engine::default();
+        new(&mut engine, "a");
+        let a = selected(&engine)[0];
+        new(&mut engine, "b");
+        let b = selected(&engine)[0];
+        assert_eq!(selected(&engine), vec![b]);
+
+        assert!(engine.execute(Action::Select { file_ids: vec![a] }));
+        assert_eq!(selected(&engine), vec![a]);
+
+        assert!(engine.execute(Action::AddSelect { file_ids: vec![b] }));
+        assert_eq!(selected(&engine).len(), 2);
+
+        engine.execute(Action::Select { file_ids: vec![] });
+        assert!(engine.execute(Action::SelectAll));
+        assert_eq!(selected(&engine).len(), 2);
+    }
+
+    #[test]
+    fn test_selection_does_not_create_undo_steps() {
+        let mut engine = Engine::default();
+        new(&mut engine, "a");
+        engine.execute(Action::SelectAll);
+        engine.execute(Action::Undo);
+        assert!(engine.stack.current().is_none());
     }
 }

gpx-rs/engine/src/engine/mod.rs

@@ -1,8 +1,10 @@
+mod action;
 mod command;
 mod derived;
 mod engine;
 mod state;
 
+pub use action::*;
 pub use command::*;
 pub use derived::*;
 pub use engine::*;

gpx-rs/engine/src/engine/state/selection.rs

@@ -1,6 +1,6 @@
 use std::collections::HashSet;
 
-use crate::{FileId, TrackId, TrackSegmentId, WaypointId};
+use crate::{FileId, StackEntry, TrackId, TrackSegmentId, WaypointId};
 
 #[derive(Debug, Default)]
 pub enum Selection {
@@ -26,3 +26,64 @@ pub enum Selection {
         wpt_ids: HashSet<WaypointId>,
     },
 }
+
+impl Selection {
+    /// Drops the files that do not exist anymore (e.g. after an undo).
+    pub fn retain_existing(&mut self, files: &StackEntry) {
+        match self {
+            Selection::Empty => {}
+            Selection::File { file_ids } => {
+                file_ids.retain(|id| files.contains_key(id));
+                if file_ids.is_empty() {
+                    *self = Selection::Empty;
+                }
+            }
+            Selection::Track { file_id, .. }
+            | Selection::TrackSegment { file_id, .. }
+            | Selection::Waypoints { file_id }
+            | Selection::Waypoint { file_id, .. } => {
+                if !files.contains_key(file_id) {
+                    *self = Selection::Empty;
+                }
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::rc::Rc;
+
+    use crate::File;
+
+    use super::*;
+
+    #[test]
+    fn test_retain_existing() {
+        let file = File::default();
+        let (kept, gone) = (file.id, FileId::default());
+        let mut files = StackEntry::default();
+        files.insert(kept, Rc::new(file));
+
+        let mut selection = Selection::File {
+            file_ids: [kept, gone].into(),
+        };
+        selection.retain_existing(&files);
+        assert!(
+            matches!(&selection, Selection::File { file_ids } if file_ids.len() == 1 && file_ids.contains(&kept))
+        );
+
+        let mut selection = Selection::File {
+            file_ids: [gone].into(),
+        };
+        selection.retain_existing(&files);
+        assert!(matches!(selection, Selection::Empty));
+
+        let mut selection = Selection::Waypoints { file_id: kept };
+        selection.retain_existing(&files);
+        assert!(matches!(selection, Selection::Waypoints { .. }));
+        let mut selection = Selection::Waypoints { file_id: gone };
+        selection.retain_existing(&files);
+        assert!(matches!(selection, Selection::Empty));
+    }
+}

gpx-rs/wasm/src/lib.rs

@@ -11,7 +11,7 @@ use std::cell::RefCell;
 
 use wasm_bindgen::prelude::*;
 
-use gpx_engine::{self as engine, Command, Engine, FileId, LngLat, LngLatBounds};
+use gpx_engine::{self as engine, Action, Command, Engine, FileId, LngLat, LngLatBounds};
 use js_sys::{Float64Array, Int32Array};
 
 #[wasm_bindgen]
@@ -50,13 +50,17 @@ thread_local! {
     static ENGINE: RefCell<Option<Engine>> = RefCell::new(None);
 }
 
-fn execute(command: Command) -> bool {
+fn execute(action: Action) -> bool {
     ENGINE.with(|engine| match engine.borrow_mut().as_mut() {
-        Some(engine) => engine.execute(command),
+        Some(engine) => engine.execute(action),
         None => false,
     })
 }
 
+fn edit(command: Command) -> bool {
+    execute(Action::Edit(command))
+}
+
 /// Decodes concatenated 16-byte UUIDs.
 fn file_ids(bytes: &[u8]) -> Option<Vec<FileId>> {
     if bytes.len() % 16 != 0 {
@@ -114,78 +118,78 @@ stats_getter!(slope_segment_distance, Float64Array);
 
 #[wasm_bindgen]
 pub fn new_file(name: &str) -> bool {
-    execute(Command::New { name })
+    edit(Command::New(engine::New { name }))
 }
 
 #[wasm_bindgen]
 pub fn load_file(data: &[u8]) -> bool {
-    execute(Command::Load { data })
+    edit(Command::Load(engine::Load { data }))
 }
 
 #[wasm_bindgen]
 pub fn duplicate() -> bool {
-    execute(Command::Duplicate)
+    edit(Command::Duplicate(engine::Duplicate))
 }
 
 #[wasm_bindgen]
 pub fn delete() -> bool {
-    execute(Command::Delete)
+    edit(Command::Delete(engine::Delete))
 }
 
 #[wasm_bindgen]
 pub fn delete_all() -> bool {
-    execute(Command::DeleteAll)
+    edit(Command::DeleteAll(engine::DeleteAll))
 }
 
 // Edit commands
 
 #[wasm_bindgen]
 pub fn metadata(name: &str, desc: &str) -> bool {
-    execute(Command::Metadata { name, desc })
+    edit(Command::Metadata(engine::Metadata { name, desc }))
 }
 
 #[wasm_bindgen]
 pub fn style(color: Option<String>, opacity: Option<f64>, width: Option<f64>) -> bool {
-    execute(Command::Style {
+    edit(Command::Style(engine::Style {
         color: color.as_deref(),
         opacity,
         width,
-    })
+    }))
 }
 
 #[wasm_bindgen]
 pub fn new_track() -> bool {
-    execute(Command::NewTrack)
+    edit(Command::NewTrack(engine::NewTrack))
 }
 
 #[wasm_bindgen]
 pub fn new_track_segment() -> bool {
-    execute(Command::NewTrackSegment)
+    edit(Command::NewTrackSegment(engine::NewTrackSegment))
 }
 
 // Tools
 
 #[wasm_bindgen]
 pub fn reverse() -> bool {
-    execute(Command::Reverse)
+    edit(Command::Reverse(engine::Reverse))
 }
 
 #[wasm_bindgen]
 pub fn append(lng: &[f64], lat: &[f64], ele: &[f64]) -> bool {
-    same_len(lng, lat, ele) && execute(Command::Append { lng, lat, ele })
+    same_len(lng, lat, ele) && edit(Command::Append(engine::Append { lng, lat, ele }))
 }
 
 #[wasm_bindgen]
 pub fn replace(start: u32, end: u32, lng: &[f64], lat: &[f64], ele: &[f64]) -> bool {
     start <= end
         && same_len(lng, lat, ele)
-        && execute(Command::Replace {
+        && edit(Command::Replace(engine::Replace {
             start,
             end,
             lng,
             lat,
             ele,
-        })
+        }))
 }
 
 #[wasm_bindgen]
@@ -198,7 +202,7 @@ pub fn new_waypoint(
     icon: &str,
     link: &str,
 ) -> bool {
-    execute(Command::NewWaypoint {
+    edit(Command::NewWaypoint(engine::NewWaypoint {
         lng,
         lat,
         ele,
@@ -206,44 +210,48 @@ pub fn new_waypoint(
         desc,
         icon,
         link,
-    })
+    }))
 }
 
 #[wasm_bindgen]
 pub fn move_waypoint(lng: f64, lat: f64, ele: f64) -> bool {
-    execute(Command::MoveWaypoint { lng, lat, ele })
+    edit(Command::MoveWaypoint(engine::MoveWaypoint {
+        lng,
+        lat,
+        ele,
+    }))
 }
 
 #[wasm_bindgen]
 pub fn crop(start: u32, end: u32) -> bool {
-    start <= end && execute(Command::Crop { start, end })
+    start <= end && edit(Command::Crop(engine::Crop { start, end }))
 }
 
 #[wasm_bindgen]
 pub fn split(at: u32) -> bool {
-    execute(Command::Split { at })
+    edit(Command::Split(engine::Split { at }))
 }
 
 #[wasm_bindgen]
 pub fn time() -> bool {
-    execute(Command::Time)
+    edit(Command::Time(engine::Time))
 }
 
 #[wasm_bindgen]
 pub fn merge(type_: MergeType) -> bool {
-    execute(Command::Merge {
+    edit(Command::Merge(engine::Merge {
         type_: type_.into(),
-    })
+    }))
 }
 
 #[wasm_bindgen]
 pub fn extract() -> bool {
-    execute(Command::Extract)
+    edit(Command::Extract(engine::Extract))
 }
 
 #[wasm_bindgen]
 pub fn elevation(ele: &[f64]) -> bool {
-    execute(Command::Elevation { ele })
+    edit(Command::Elevation(engine::Elevation { ele }))
 }
 
 #[wasm_bindgen]
@@ -256,7 +264,7 @@ pub fn clean(
     trkpt: bool,
     wpt: bool,
 ) -> bool {
-    execute(Command::Clean {
+    edit(Command::Clean(engine::Clean {
         bounds: LngLatBounds {
             sw: LngLat {
                 lng: west,
@@ -270,42 +278,42 @@ pub fn clean(
         type_: type_.into(),
         trkpt,
         wpt,
-    })
+    }))
 }
 
 // Undo-redo
 
 #[wasm_bindgen]
 pub fn undo() -> bool {
-    execute(Command::Undo)
+    execute(Action::Undo)
 }
 
 #[wasm_bindgen]
 pub fn redo() -> bool {
-    execute(Command::Redo)
+    execute(Action::Redo)
 }
 
 // Selection
 
-/// `file_ids`: concatenated 16-byte UUIDs.
+/// `file_ids_bytes`: concatenated 16-byte UUIDs.
 #[wasm_bindgen]
 pub fn select(file_ids_bytes: &[u8]) -> bool {
     match file_ids(file_ids_bytes) {
-        Some(file_ids) => execute(Command::Select { file_ids }),
+        Some(file_ids) => execute(Action::Select { file_ids }),
         None => false,
     }
 }
 
-/// `file_ids`: concatenated 16-byte UUIDs.
+/// `file_ids_bytes`: concatenated 16-byte UUIDs.
 #[wasm_bindgen]
 pub fn add_select(file_ids_bytes: &[u8]) -> bool {
     match file_ids(file_ids_bytes) {
-        Some(file_ids) => execute(Command::AddSelect { file_ids }),
+        Some(file_ids) => execute(Action::AddSelect { file_ids }),
         None => false,
     }
 }
 
 #[wasm_bindgen]
 pub fn select_all() -> bool {
-    execute(Command::SelectAll)
+    execute(Action::SelectAll)
 }