From 1f4c96f827f34240e52a02a299625019788b7188 Mon Sep 17 00:00:00 2001
From: Nikita Galaiko <nikita@galaiko.rocks>
Date: Tue, 14 Mar 2023 11:30:58 +0100
Subject: [PATCH] add git watcher

---
 src-tauri/src/watchers/delta.rs |   2 +-
 src-tauri/src/watchers/git.rs   | 108 ++++++++++++++++++++++++++++++++
 src-tauri/src/watchers/mod.rs   |   8 ++-
 3 files changed, 116 insertions(+), 2 deletions(-)
 create mode 100644 src-tauri/src/watchers/git.rs

diff --git a/src-tauri/src/watchers/delta.rs b/src-tauri/src/watchers/delta.rs
index 8addb6734..b7c3fd00a 100644
--- a/src-tauri/src/watchers/delta.rs
+++ b/src-tauri/src/watchers/delta.rs
@@ -136,7 +136,7 @@ impl DeltaWatchers {
         Ok(())
     }
 
-    pub fn unwatch(&mut self, project: projects::Project) -> Result<()> {
+    pub fn unwatch(&mut self, project: &projects::Project) -> Result<()> {
         if let Some(mut watcher) = self.watchers.remove(&project.path) {
             watcher.unwatch(Path::new(&project.path))?;
         }
diff --git a/src-tauri/src/watchers/git.rs b/src-tauri/src/watchers/git.rs
new file mode 100644
index 000000000..d59cbd58f
--- /dev/null
+++ b/src-tauri/src/watchers/git.rs
@@ -0,0 +1,108 @@
+use crate::projects;
+use anyhow::Result;
+use notify::{Config, RecommendedWatcher, Watcher};
+use std::{
+    collections::HashMap,
+    path::Path,
+    sync::{mpsc, Arc, Mutex},
+};
+
+pub enum Event {
+    Head,
+}
+
+pub struct GitWatchers {
+    watchers: HashMap<String, RecommendedWatcher>,
+}
+
+impl GitWatchers {
+    pub fn new() -> Self {
+        Self {
+            watchers: HashMap::new(),
+        }
+    }
+
+    pub fn unwatch(&mut self, project: &projects::Project) -> Result<()> {
+        if let Some(mut watcher) = self.watchers.remove(&project.id) {
+            watcher.unwatch(&Path::new(&Path::new(&project.path).join(".git")))?;
+        }
+        Ok(())
+    }
+
+    pub fn watch(&mut self, project: projects::Project) -> Result<mpsc::Receiver<Event>> {
+        let (tx, rx) = mpsc::channel();
+        let mut watcher = RecommendedWatcher::new(tx, Config::default())?;
+
+        watcher.watch(
+            Path::new(&Path::new(&project.path).join(".git")),
+            notify::RecursiveMode::Recursive,
+        )?;
+        self.watchers.insert(project.id.clone(), watcher);
+
+        let project = Arc::new(Mutex::new(project.clone()));
+
+        let (events_sender, events_receiver) = mpsc::channel();
+        tauri::async_runtime::spawn_blocking(move || {
+            log::info!("{}: watching git", project.lock().unwrap().id);
+
+            let project = project.lock().unwrap().clone();
+            let project_path = Path::new(&project.path);
+
+            while let Ok(event) = rx.recv() {
+                if let Err(e) = event {
+                    log::error!("{}: notify event error: {:#}", project.id.clone(), e);
+                    continue;
+                }
+
+                let event = event.unwrap();
+
+                for file_path in event.paths {
+                    let relative_file_path = file_path
+                        .strip_prefix(Path::new(&project_path.join(".git")))
+                        .unwrap();
+
+                    match is_interesting_event(&event.kind) {
+                        Some(kind_string) => {
+                            log::info!(
+                                "{}: \"{}\" {}",
+                                project.id,
+                                relative_file_path.display(),
+                                kind_string
+                            );
+
+                            if relative_file_path == Path::new("HEAD") {
+                                if let Err(e) = events_sender.send(Event::Head) {
+                                    log::error!("{}: failed to send event: {:#}", project.id, e);
+                                }
+                            }
+                        }
+                        None => {
+                            // ignore
+                        }
+                    }
+                }
+            }
+            log::info!("{}: stopped watching git", project.id);
+        });
+
+        Ok(events_receiver)
+    }
+}
+
+fn is_interesting_event(kind: &notify::EventKind) -> Option<String> {
+    match kind {
+        notify::EventKind::Create(notify::event::CreateKind::File) => {
+            Some("file created".to_string())
+        }
+        notify::EventKind::Modify(notify::event::ModifyKind::Data(_)) => {
+            Some("file modified".to_string())
+        }
+        notify::EventKind::Modify(notify::event::ModifyKind::Name(_)) => {
+            Some("file renamed".to_string())
+        }
+        notify::EventKind::Remove(notify::event::RemoveKind::File) => {
+            Some("file removed".to_string())
+        }
+        _ => None,
+    }
+}
diff --git a/src-tauri/src/watchers/mod.rs b/src-tauri/src/watchers/mod.rs
index 42bfca2d4..d47e14634 100644
--- a/src-tauri/src/watchers/mod.rs
+++ b/src-tauri/src/watchers/mod.rs
@@ -1,4 +1,5 @@
 mod delta;
+mod git;
 mod session;
 
 #[cfg(test)]
@@ -16,6 +17,7 @@ use std::{
 pub struct Watcher {
     session_watcher: session::SessionWatcher,
     delta_watcher: delta::DeltaWatchers,
+    git_watcher: git::GitWatchers,
 }
 
 impl Watcher {
@@ -27,9 +29,11 @@ impl Watcher {
         let session_watcher =
             session::SessionWatcher::new(projects_storage, users_storage, deltas_searcher);
         let delta_watcher = delta::DeltaWatchers::new();
+        let git_watcher = git::GitWatchers::new();
         Self {
             session_watcher,
             delta_watcher,
+            git_watcher,
         }
     }
 
@@ -53,12 +57,14 @@ impl Watcher {
             .watch(sender.clone(), project.clone(), lock_file.clone())?;
         self.session_watcher
             .watch(sender.clone(), project.clone(), lock_file.clone())?;
+        self.git_watcher.watch(project.clone())?;
 
         Ok(())
     }
 
     pub fn unwatch(&mut self, project: projects::Project) -> Result<()> {
-        self.delta_watcher.unwatch(project)?;
+        self.delta_watcher.unwatch(&project)?;
+        self.git_watcher.unwatch(&project)?;
         // TODO: how to unwatch session ?
         Ok(())
     }