Create module boundaries for `pane_grid` logic

1 files changed, 227 insertions, 0 deletions

diff --git a/native/src/widget/pane_grid/state.rs b/native/src/widget/pane_grid/state.rs
new file mode 100644
index 00000000..130c7e34
--- /dev/null
+++ b/native/src/widget/pane_grid/state.rs
@@ -0,0 +1,227 @@
+use crate::{
+    input::keyboard,
+    pane_grid::{node::Node, Direction, Pane, Split},
+    Hasher, Point, Rectangle, Size,
+};
+
+use std::collections::HashMap;
+
+#[derive(Debug)]
+pub struct State<T> {
+    pub(super) panes: HashMap<Pane, T>,
+    pub(super) internal: Internal,
+    pub(super) modifiers: keyboard::ModifiersState,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Focus {
+    Idle,
+    Dragging,
+}
+
+impl<T> State<T> {
+    pub fn new(first_pane_state: T) -> (Self, Pane) {
+        let first_pane = Pane(0);
+
+        let mut panes = HashMap::new();
+        let _ = panes.insert(first_pane, first_pane_state);
+
+        (
+            State {
+                panes,
+                internal: Internal {
+                    layout: Node::Pane(first_pane),
+                    last_pane: 0,
+                    focused_pane: FocusedPane::None,
+                },
+                modifiers: keyboard::ModifiersState::default(),
+            },
+            first_pane,
+        )
+    }
+
+    pub fn len(&self) -> usize {
+        self.panes.len()
+    }
+
+    pub fn get_mut(&mut self, pane: &Pane) -> Option<&mut T> {
+        self.panes.get_mut(pane)
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = (&Pane, &T)> {
+        self.panes.iter()
+    }
+
+    pub fn iter_mut(&mut self) -> impl Iterator<Item = (&Pane, &mut T)> {
+        self.panes.iter_mut()
+    }
+
+    pub fn focused_pane(&self) -> Option<Pane> {
+        match self.internal.focused_pane {
+            FocusedPane::Some {
+                pane,
+                focus: Focus::Idle,
+            } => Some(pane),
+            FocusedPane::Some {
+                focus: Focus::Dragging,
+                ..
+            } => None,
+            FocusedPane::None => None,
+        }
+    }
+
+    pub fn adjacent_pane(
+        &self,
+        pane: &Pane,
+        direction: Direction,
+    ) -> Option<Pane> {
+        let regions =
+            self.internal.layout.regions(0.0, Size::new(4096.0, 4096.0));
+
+        let current_region = regions.get(pane)?;
+
+        let target = match direction {
+            Direction::Left => {
+                Point::new(current_region.x - 1.0, current_region.y + 1.0)
+            }
+            Direction::Right => Point::new(
+                current_region.x + current_region.width + 1.0,
+                current_region.y + 1.0,
+            ),
+            Direction::Up => {
+                Point::new(current_region.x + 1.0, current_region.y - 1.0)
+            }
+            Direction::Down => Point::new(
+                current_region.x + 1.0,
+                current_region.y + current_region.height + 1.0,
+            ),
+        };
+
+        let mut colliding_regions =
+            regions.iter().filter(|(_, region)| region.contains(target));
+
+        let (pane, _) = colliding_regions.next()?;
+
+        Some(*pane)
+    }
+
+    pub fn focus(&mut self, pane: &Pane) {
+        self.internal.focus(pane);
+    }
+
+    pub fn split_vertically(&mut self, pane: &Pane, state: T) -> Option<Pane> {
+        self.split(Split::Vertical, pane, state)
+    }
+
+    pub fn split_horizontally(
+        &mut self,
+        pane: &Pane,
+        state: T,
+    ) -> Option<Pane> {
+        self.split(Split::Horizontal, pane, state)
+    }
+
+    pub fn split(
+        &mut self,
+        kind: Split,
+        pane: &Pane,
+        state: T,
+    ) -> Option<Pane> {
+        let node = self.internal.layout.find(pane)?;
+
+        let new_pane = {
+            self.internal.last_pane = self.internal.last_pane.checked_add(1)?;
+
+            Pane(self.internal.last_pane)
+        };
+
+        node.split(kind, new_pane);
+
+        let _ = self.panes.insert(new_pane, state);
+        self.focus(&new_pane);
+
+        Some(new_pane)
+    }
+
+    pub fn swap(&mut self, a: &Pane, b: &Pane) {
+        self.internal.layout.update(&|node| match node {
+            Node::Split { .. } => {}
+            Node::Pane(pane) => {
+                if pane == a {
+                    *node = Node::Pane(*b);
+                } else if pane == b {
+                    *node = Node::Pane(*a);
+                }
+            }
+        });
+    }
+
+    pub fn close(&mut self, pane: &Pane) -> Option<T> {
+        if let Some(sibling) = self.internal.layout.remove(pane) {
+            self.focus(&sibling);
+            self.panes.remove(pane)
+        } else {
+            None
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct Internal {
+    layout: Node,
+    last_pane: usize,
+    focused_pane: FocusedPane,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum FocusedPane {
+    None,
+    Some { pane: Pane, focus: Focus },
+}
+
+impl Internal {
+    pub fn focused(&self) -> FocusedPane {
+        self.focused_pane
+    }
+    pub fn dragged(&self) -> Option<Pane> {
+        match self.focused_pane {
+            FocusedPane::Some {
+                pane,
+                focus: Focus::Dragging,
+            } => Some(pane),
+            _ => None,
+        }
+    }
+
+    pub fn regions(
+        &self,
+        spacing: f32,
+        size: Size,
+    ) -> HashMap<Pane, Rectangle> {
+        self.layout.regions(spacing, size)
+    }
+
+    pub fn focus(&mut self, pane: &Pane) {
+        self.focused_pane = FocusedPane::Some {
+            pane: *pane,
+            focus: Focus::Idle,
+        };
+    }
+
+    pub fn drag(&mut self, pane: &Pane) {
+        self.focused_pane = FocusedPane::Some {
+            pane: *pane,
+            focus: Focus::Dragging,
+        };
+    }
+
+    pub fn unfocus(&mut self) {
+        self.focused_pane = FocusedPane::None;
+    }
+
+    pub fn hash_layout(&self, hasher: &mut Hasher) {
+        use std::hash::Hash;
+
+        self.layout.hash(hasher);
+    }
+}