From 863c9aade5623f79ccfb9d3c69718bd12a8846c2 Mon Sep 17 00:00:00 2001
From: CJ van den Berg <cj@vdbonline.com>
Date: Fri, 20 Feb 2026 11:40:12 +0100
Subject: [PATCH] refactor: update project file index on watcher events

---
 src/Project.zig         | 34 ++++++++++++++++++++++++++++++++++
 src/project_manager.zig | 25 ++++++++++++++++++++++++-
 2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/src/Project.zig b/src/Project.zig
index 817ada8..6103d11 100644
--- a/src/Project.zig
+++ b/src/Project.zig
@@ -777,6 +777,40 @@ fn loaded(self: *Self, parent: tp.pid_ref) OutOfMemoryError!void {
     parent.send(.{ "PRJ", "open_done", self.name, self.longest_file_path, self.files.items.len }) catch {};
 }
 
+pub fn file_added(self: *Self, file_path: []const u8) OutOfMemoryError!void {
+    for (self.files.items) |file|
+        if (std.mem.eql(u8, file.path, file_path)) return;
+    const file_type, const file_icon, const file_color = guess_file_type(file_path);
+    (try self.files.addOne(self.allocator)).* = .{
+        .path = try self.allocator.dupe(u8, file_path),
+        .type = file_type,
+        .icon = file_icon,
+        .color = file_color,
+        .mtime = std.time.nanoTimestamp(),
+    };
+    self.longest_file_path = @max(self.longest_file_path, file_path.len);
+    self.sort_files_by_mtime();
+}
+
+pub fn file_modified(self: *Self, file_path: []const u8) void {
+    for (self.files.items) |*file| {
+        if (!std.mem.eql(u8, file.path, file_path)) continue;
+        file.mtime = std.time.nanoTimestamp();
+        self.sort_files_by_mtime();
+        return;
+    }
+}
+
+pub fn file_deleted(self: *Self, file_path: []const u8) void {
+    for (self.files.items, 0..) |file, i| {
+        if (!std.mem.eql(u8, file.path, file_path)) continue;
+        self.allocator.free(file.path);
+        _ = self.files.swapRemove(i);
+        self.sort_files_by_mtime();
+        return;
+    }
+}
+
 pub fn update_mru(self: *Self, file_path: []const u8, row: usize, col: usize) OutOfMemoryError!void {
     defer self.sort_files_by_mtime();
     try self.update_mru_internal(file_path, std.time.nanoTimestamp(), row, col);
diff --git a/src/project_manager.zig b/src/project_manager.zig
index a3e9eb5..bd56f5e 100644
--- a/src/project_manager.zig
+++ b/src/project_manager.zig
@@ -421,8 +421,11 @@ const Process = struct {
         var vcs_id: []const u8 = undefined;
 
         var eol_mode: Buffer.EolModeTag = @intFromEnum(Buffer.EolMode.lf);
+        var event_type: file_watcher.EventType = undefined;
 
-        if (try cbor.match(m.buf, .{ "walk_tree_entry", tp.extract(&project_directory), tp.more })) {
+        if (try cbor.match(m.buf, .{ "FW", "change", tp.extract(&path), tp.extract(&event_type) })) {
+            self.handle_file_watch_event(path, event_type);
+        } else if (try cbor.match(m.buf, .{ "walk_tree_entry", tp.extract(&project_directory), tp.more })) {
             if (self.projects.get(project_directory)) |project|
                 project.walk_tree_entry(m) catch |e| self.logger.err("walk_tree_entry", e);
         } else if (try cbor.match(m.buf, .{ "walk_tree_done", tp.extract(&project_directory) })) {
@@ -539,6 +542,26 @@ const Process = struct {
         }
     }
 
+    fn handle_file_watch_event(self: *Process, abs_path: []const u8, event_type: file_watcher.EventType) void {
+        std.log.debug("file_watch_event: {s} {s}", .{ @tagName(event_type), abs_path });
+        var it = self.projects.iterator();
+        while (it.next()) |entry| {
+            const dir = entry.key_ptr.*;
+            if (!std.mem.startsWith(u8, abs_path, dir)) continue;
+            if (abs_path.len <= dir.len or abs_path[dir.len] != std.fs.path.sep) continue;
+            const rel_path = abs_path[dir.len + 1 ..];
+            const project = entry.value_ptr.*;
+            switch (event_type) {
+                .created => project.file_added(rel_path) catch |e| self.logger.err("file_watcher.file_added", e),
+                .modified => project.file_modified(rel_path),
+                .deleted => project.file_deleted(rel_path),
+                .renamed => project.file_deleted(rel_path),
+            }
+            return;
+        }
+        self.parent.send(.{ "FW", "change", abs_path, event_type }) catch {};
+    }
+
     fn open(self: *Process, project_directory: []const u8) (SpawnError || std.fs.Dir.OpenError)!void {
         if (self.projects.get(project_directory)) |project| {
             project.last_used = std.time.nanoTimestamp();