From 7143d4017b8f2838930b40978285205034bc547a Mon Sep 17 00:00:00 2001
From: dino <dinojoaocosta@gmail.com>
Date: Tue, 4 Nov 2025 00:00:33 +0000
Subject: [PATCH] chore(vim): add projections :sunrise:

---
 crates/vim/src/projections.rs | 88 +++++++++++++++++++++++++++++++++++
 crates/vim/src/vim.rs         |  2 +
 2 files changed, 90 insertions(+)
 create mode 100644 crates/vim/src/projections.rs

diff --git a/crates/vim/src/projections.rs b/crates/vim/src/projections.rs
new file mode 100644
index 0000000000000000000000000000000000000000..9e242e66b40390b703ef297431441f15c5756913
--- /dev/null
+++ b/crates/vim/src/projections.rs
@@ -0,0 +1,88 @@
+// Projections allow users to associate files within a project as projections of
+// one another. Inspired by https://github.com/tpope/vim-projectionist .
+//
+// Take, for example, a newly generated Phoenix project. Among other files, one
+// can find the page controller module and its corresponding test file in:
+//
+// - `lib/app_web/controllers/page_controller.ex`
+// - `lib/app_web/controllers/page_controller_test.exs`
+//
+// From the point of view of the controller module, one can say that the test
+// file is a projection of the controller module, and vice versa.
+//
+// TODO!:
+// - [ ] Implement `:a` to open alternate file
+// - [ ] Implement `:as` to open alternate file in split
+// - [ ] Implement `:av` to open alternate file in vertical split
+// - [ ] Implement actually updating the state from the `projections.json` file
+// - [ ] Make this work with excerpts in multibuffers
+
+use crate::Vim;
+use editor::Editor;
+use gpui::Context;
+use gpui::Window;
+use gpui::actions;
+use project::ProjectItem;
+use project::ProjectPath;
+use util::rel_path::RelPath;
+
+actions!(
+    vim,
+    [
+        /// Opens a projection of the current file.
+        OpenProjection,
+    ]
+);
+
+pub fn register(editor: &mut Editor, cx: &mut Context<Vim>) {
+    Vim::action(editor, cx, Vim::open_projection);
+}
+
+impl Vim {
+    pub fn open_projection(
+        &mut self,
+        _: &OpenProjection,
+        window: &mut Window,
+        cx: &mut Context<Self>,
+    ) {
+        // Implementation for opening a projection
+        dbg!("[vim] attempting to open projection...");
+        self.update_editor(cx, |_vim, editor, cx| {
+            let project_path = editor
+                .buffer()
+                .read(cx)
+                .as_singleton()
+                .and_then(|buffer| buffer.read(cx).project_path(cx));
+
+            // User is editing an empty buffer, can't even find a projection.
+            if project_path.is_none() {
+                return;
+            }
+
+            if let Some(project_path) = project_path
+                && let Some(workspace) = editor.workspace()
+            {
+                dbg!(&project_path);
+                if project_path.path.as_unix_str()
+                    == "lib/phx_new_web/controllers/page_controller.ex"
+                {
+                    dbg!("[vim] opening projection...");
+                    workspace
+                        .update(cx, |workspace, cx| {
+                            let worktree_id = project_path.worktree_id;
+                            let mut project_path = ProjectPath::root_path(worktree_id);
+                            project_path.path = RelPath::unix(
+                                "test/phx_new_web/controllers/page_controller_test.exs",
+                            )
+                            .unwrap()
+                            .into_arc();
+                            dbg!(&project_path);
+
+                            workspace.open_path(project_path, None, true, window, cx)
+                        })
+                        .detach();
+                }
+            }
+        });
+    }
+}
diff --git a/crates/vim/src/vim.rs b/crates/vim/src/vim.rs
index 6ffdbcce910c10229dc7c2e6df95055c5c812f28..0e292c0769c0ca4cf82460f7dae29501f4d00a6d 100644
--- a/crates/vim/src/vim.rs
+++ b/crates/vim/src/vim.rs
@@ -13,6 +13,7 @@ mod mode_indicator;
 mod motion;
 mod normal;
 mod object;
+mod projections;
 mod replace;
 mod rewrap;
 mod state;
@@ -942,6 +943,7 @@ impl Vim {
             visual::register(editor, cx);
             change_list::register(editor, cx);
             digraph::register(editor, cx);
+            projections::register(editor, cx);
 
             if editor.is_focused(window) {
                 cx.defer_in(window, |vim, window, cx| {