refactor: extract editor dnd helpers

rust/spikes/leptos-tiptap-spike/src/editor_runtime/block_dnd.rs

@@ -0,0 +1,92 @@
+//! Block handle 拖拽命中的纯几何 helper。
+//!
+//! 本模块不查询 DOM、不处理 Leptos signal，也不分发 editor command；
+//! 调用方负责传入已经从页面中读取的坐标。
+
+use crate::editor_runtime::block_hover_state::DropPlacement;
+
+pub(crate) struct HandleCorridorGeometry {
+    pub(crate) stage_left: f64,
+    pub(crate) stage_top: f64,
+    pub(crate) block_left: f64,
+    pub(crate) block_top: f64,
+    pub(crate) block_bottom: f64,
+    pub(crate) handle_left: f64,
+    pub(crate) handle_right: f64,
+}
+
+pub(crate) fn pointer_in_handle_corridor_geometry(
+    client_x: i32,
+    client_y: i32,
+    geometry: &HandleCorridorGeometry,
+) -> bool {
+    let x = f64::from(client_x) - geometry.stage_left;
+    let y = f64::from(client_y) - geometry.stage_top;
+    let corridor_left = (geometry.handle_left - 12.0).min(geometry.block_left);
+    let corridor_right = (geometry.block_left + 18.0).max(geometry.handle_right + 12.0);
+
+    x >= corridor_left
+        && x <= corridor_right
+        && y >= geometry.block_top - 18.0
+        && y <= geometry.block_bottom + 18.0
+}
+
+pub(crate) fn drop_placement_from_block_point(
+    client_y: i32,
+    block_top: f64,
+    block_height: f64,
+) -> DropPlacement {
+    let midpoint = block_top + (block_height / 2.0);
+    if f64::from(client_y) <= midpoint {
+        DropPlacement::Before
+    } else {
+        DropPlacement::After
+    }
+}
+
+pub(crate) fn drop_indicator_top(
+    stage_top: f64,
+    block_top: f64,
+    block_bottom: f64,
+    placement: DropPlacement,
+) -> f64 {
+    match placement {
+        DropPlacement::Before => block_top - stage_top,
+        DropPlacement::After => block_bottom - stage_top,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn pointer_corridor_accepts_handle_lane_and_block_edge() {
+        let geometry = HandleCorridorGeometry {
+            stage_left: 100.0,
+            stage_top: 20.0,
+            block_left: 140.0,
+            block_top: 40.0,
+            block_bottom: 80.0,
+            handle_left: 108.0,
+            handle_right: 130.0,
+        };
+
+        assert!(pointer_in_handle_corridor_geometry(118, 80, &geometry));
+        assert!(pointer_in_handle_corridor_geometry(250, 80, &geometry));
+        assert!(!pointer_in_handle_corridor_geometry(90, 80, &geometry));
+        assert!(!pointer_in_handle_corridor_geometry(118, 28, &geometry));
+    }
+
+    #[test]
+    fn drop_placement_splits_block_at_midpoint() {
+        assert_eq!(
+            drop_placement_from_block_point(50, 40.0, 20.0),
+            DropPlacement::Before
+        );
+        assert_eq!(
+            drop_placement_from_block_point(51, 40.0, 20.0),
+            DropPlacement::After
+        );
+    }
+}

rust/spikes/leptos-tiptap-spike/src/editor_runtime/mod.rs

@@ -1,5 +1,6 @@
 pub(crate) mod attachment_links;
 pub(crate) mod attachment_upload;
+pub(crate) mod block_dnd;
 pub(crate) mod block_hover_state;
 pub(crate) mod block_menu_document;
 pub(crate) mod block_menu_overlay;