Add WebDAV sync provider (manual + auto-sync, top-bar button)

src-tauri/Cargo.lock

@@ -1861,6 +1861,7 @@ dependencies = [
  "log",
  "notify",
  "png 0.17.16",
+ "quick-xml 0.36.2",
  "rayon",
  "regex",
  "reqwest 0.12.28",
@@ -1868,6 +1869,7 @@ dependencies = [
  "serde",
  "serde_json",
  "serde_yaml",
+ "sha2",
  "sys-locale",
  "tantivy",
  "tauri",
@@ -1880,6 +1882,7 @@ dependencies = [
  "tauri-plugin-updater",
  "tauri-plugin-window-state",
  "tokio",
+ "urlencoding",
  "uuid",
  "walkdir",
  "zip 2.4.2",
@@ -3418,7 +3421,7 @@ checksum = "740ebea15c5d1428f910cd1a5f52cebf8d25006245ed8ade92702f4943d91e07"
 dependencies = [
  "base64 0.22.1",
  "indexmap 2.13.0",
- "quick-xml",
+ "quick-xml 0.38.4",
  "serde",
  "time",
 ]
@@ -3612,6 +3615,15 @@ version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a993555f31e5a609f617c12db6250dedcac1b0a85076912c436e6fc9b2c8e6a3"
 
+[[package]]
+name = "quick-xml"
+version = "0.36.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f7649a7b4df05aed9ea7ec6f628c67c9953a43869b8bc50929569b2999d443fe"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "quick-xml"
 version = "0.38.4"
@@ -5911,6 +5923,12 @@ dependencies = [
  "serde_derive",
 ]
 
+[[package]]
+name = "urlencoding"
+version = "2.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "daf8dba3b7eb870caf1ddeed7bc9d2a049f3cfdfae7cb521b087cc33ae4c49da"
+
 [[package]]
 name = "urlpattern"
 version = "0.3.0"
@@ -6222,7 +6240,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5423e94b6a63e68e439803a3e153a9252d5ead12fd853334e2ad33997e3889e3"
 dependencies = [
  "proc-macro2",
- "quick-xml",
+ "quick-xml 0.38.4",
  "quote",
 ]
 

src-tauri/Cargo.toml

@@ -38,6 +38,9 @@ zip = { version = "2", default-features = false, features = ["deflate"] }
 reqwest = { version = "0.12", default-features = false, features = ["json", "stream", "rustls-tls", "blocking"] }
 futures = "0.3"
 rayon = "1"
+quick-xml = "0.36"
+urlencoding = "2"
+sha2 = "0.10"
 rustls = { version = "0.23", default-features = false, features = ["ring", "logging", "std", "tls12"] }
 [target.'cfg(not(any(target_os = "android", target_os = "ios")))'.dependencies]
 tauri-plugin-updater = "2"

src-tauri/src/commands.rs

@@ -1742,6 +1742,128 @@ pub fn test_ai_connection(app: AppHandle) -> Result<(), String> {
     Ok(())
 }
 
+// ── Sync (WebDAV) ──
+
+fn sync_config_from(config: &AppConfig) -> Result<crate::sync::WebdavConfig, String> {
+    if config.sync_provider.as_deref() != Some("webdav") {
+        return Err("Sync is not configured".to_string());
+    }
+    let url = config
+        .webdav_url
+        .clone()
+        .filter(|u| !u.trim().is_empty())
+        .ok_or("WebDAV URL is not set")?;
+    Ok(crate::sync::WebdavConfig {
+        url,
+        username: config.webdav_username.clone().unwrap_or_default(),
+        password: config.webdav_password.clone().unwrap_or_default(),
+    })
+}
+
+#[tauri::command]
+pub fn set_sync_settings(
+    state: State<'_, AppState>,
+    provider: Option<String>,
+    url: Option<String>,
+    username: Option<String>,
+    password: Option<String>,
+    sync_on_open: bool,
+    sync_on_change: bool,
+    sync_interval_minutes: u32,
+) -> Result<(), String> {
+    let mut config = state.config.lock().map_err(|e| e.to_string())?;
+    config.sync_provider = provider.filter(|p| !p.is_empty());
+    config.webdav_url = url.filter(|u| !u.trim().is_empty());
+    config.webdav_username = username.filter(|u| !u.is_empty());
+    config.webdav_password = password.filter(|p| !p.is_empty());
+    config.sync_on_open = sync_on_open;
+    config.sync_on_change = sync_on_change;
+    config.sync_interval_minutes = sync_interval_minutes;
+    save_app_config(&config)?;
+    Ok(())
+}
+
+#[tauri::command]
+pub fn test_sync_connection(app: AppHandle) -> Result<(), String> {
+    let cfg = {
+        let state = app.state::<AppState>();
+        let config = state.config.lock().map_err(|e| e.to_string())?;
+        sync_config_from(&config)?
+    };
+    std::thread::spawn(move || {
+        use tauri::Emitter;
+        match crate::sync::test_connection(cfg) {
+            Ok(msg) => {
+                let _ = app.emit(
+                    "sync-test-result",
+                    serde_json::json!({ "success": true, "message": msg }),
+                );
+            }
+            Err(e) => {
+                let _ = app.emit(
+                    "sync-test-result",
+                    serde_json::json!({ "success": false, "error": e }),
+                );
+            }
+        }
+    });
+    Ok(())
+}
+
+#[tauri::command]
+pub fn sync_now(app: AppHandle) -> Result<(), String> {
+    use std::sync::atomic::Ordering;
+    // Guard against overlapping syncs (manual button + interval + on-change can collide).
+    if app.state::<AppState>().syncing.swap(true, Ordering::SeqCst) {
+        return Ok(()); // a sync is already running
+    }
+    let (vault, cfg) = {
+        let state = app.state::<AppState>();
+        let config = match state.config.lock() {
+            Ok(c) => c,
+            Err(e) => {
+                state.syncing.store(false, Ordering::SeqCst);
+                return Err(e.to_string());
+            }
+        };
+        let gathered = config
+            .active_vault
+            .clone()
+            .ok_or_else(|| "No active vault".to_string())
+            .and_then(|v| sync_config_from(&config).map(|c| (v, c)));
+        match gathered {
+            Ok(vc) => vc,
+            Err(e) => {
+                drop(config);
+                state.syncing.store(false, Ordering::SeqCst);
+                return Err(e);
+            }
+        }
+    };
+    std::thread::spawn(move || {
+        use tauri::Emitter;
+        let result = crate::sync::run_sync(app.clone(), vault, cfg);
+        app.state::<AppState>().syncing.store(false, Ordering::SeqCst);
+        match result {
+            Ok(summary) => {
+                let ts = chrono::Utc::now().to_rfc3339();
+                if let Ok(mut config) = app.state::<AppState>().config.lock() {
+                    config.last_sync_time = Some(ts.clone());
+                    let _ = save_app_config(&config);
+                }
+                let _ = app.emit(
+                    "sync-done",
+                    serde_json::json!({ "success": true, "summary": summary, "last_sync_time": ts }),
+                );
+            }
+            Err(e) => {
+                let _ = app.emit("sync-error", serde_json::json!({ "success": false, "error": e }));
+            }
+        }
+    });
+    Ok(())
+}
+
 #[tauri::command]
 pub fn ai_ask(
     app: AppHandle,

src-tauri/src/lib.rs

@@ -4,6 +4,7 @@ mod commands;
 mod history;
 mod search;
 mod state;
+mod sync;
 mod types;
 mod vault;
 
@@ -159,6 +160,9 @@ pub fn run() {
             commands::set_ai_settings,
             commands::test_ai_connection,
             commands::ai_ask,
+            commands::set_sync_settings,
+            commands::test_sync_connection,
+            commands::sync_now,
             commands::get_install_type,
             commands::get_pending_open_file,
         ])

src-tauri/src/state.rs

@@ -10,6 +10,7 @@ pub struct AppState {
     pub search_index: Mutex<Option<Arc<SearchIndex>>>,
     pub watcher: Mutex<Option<RecommendedWatcher>>,
     pub importing: AtomicBool,
+    pub syncing: AtomicBool,
     pub pending_open_file: Mutex<Option<String>>,
 }
 
@@ -20,6 +21,7 @@ impl AppState {
             search_index: Mutex::new(None),
             watcher: Mutex::new(None),
             importing: AtomicBool::new(false),
+            syncing: AtomicBool::new(false),
             pending_open_file: Mutex::new(None),
         }
     }

src-tauri/src/sync.rs

@@ -0,0 +1,670 @@
+// WebDAV sync provider.
+//
+// Model: the vault stays local; this mirrors it to/from a user-configured WebDAV
+// remote (Nextcloud/ownCloud/NAS). A local manifest (.helixnotes/sync_state.json)
+// records what was in sync last time, so we can do a three-way diff (local vs remote
+// vs manifest) and resolve each file as upload/download/delete, with keep-both
+// conflict copies so nothing is ever lost.
+//
+// Synced set: every `*.md` in the vault tree, plus `.helixnotes/attachments/`.
+// Everything else under `.helixnotes/` (search_index, trash, history, *.json, the
+// manifest itself) is local-only and never synced.
+
+use crate::state::AppState;
+use crate::vault::operations::helixnotes_dir;
+use serde::{Deserialize, Serialize};
+use sha2::{Digest, Sha256};
+use std::collections::{HashMap, HashSet};
+use std::fs;
+use std::path::{Path, PathBuf};
+use tauri::{Emitter, Manager};
+use walkdir::WalkDir;
+
+// ───────────────────────── config ─────────────────────────
+
+pub struct WebdavConfig {
+    pub url: String,
+    pub username: String,
+    pub password: String,
+}
+
+#[derive(Default, Clone, Serialize)]
+pub struct SyncSummary {
+    pub uploaded: u32,
+    pub downloaded: u32,
+    pub deleted_local: u32,
+    pub deleted_remote: u32,
+    pub conflicts: u32,
+}
+
+// ───────────────────────── manifest ─────────────────────────
+
+#[derive(Default, Serialize, Deserialize)]
+struct SyncManifest {
+    files: HashMap<String, ManifestEntry>, // relpath (forward-slash) -> entry
+}
+
+#[derive(Clone, Serialize, Deserialize)]
+struct ManifestEntry {
+    local_hash: String,  // sha256 of local content at last sync
+    remote_etag: String, // remote etag at last sync
+}
+
+fn manifest_path(vault: &str) -> PathBuf {
+    helixnotes_dir(vault).join("sync_state.json")
+}
+
+fn load_manifest(vault: &str) -> SyncManifest {
+    fs::read_to_string(manifest_path(vault))
+        .ok()
+        .and_then(|s| serde_json::from_str(&s).ok())
+        .unwrap_or_default()
+}
+
+fn save_manifest(vault: &str, m: &SyncManifest) {
+    if let Ok(s) = serde_json::to_string(m) {
+        let _ = fs::write(manifest_path(vault), s);
+    }
+}
+
+// ───────────────────────── helpers ─────────────────────────
+
+fn sha256_hex(bytes: &[u8]) -> String {
+    let mut h = Sha256::new();
+    h.update(bytes);
+    let digest = h.finalize();
+    let mut s = String::with_capacity(64);
+    for b in digest {
+        s.push_str(&format!("{:02x}", b));
+    }
+    s
+}
+
+fn normalize_etag(s: &str) -> String {
+    s.trim().trim_start_matches("W/").trim_matches('"').to_string()
+}
+
+/// Percent-encode each path segment, keeping the `/` separators.
+fn encode_path(relpath: &str) -> String {
+    relpath
+        .split('/')
+        .map(|seg| urlencoding::encode(seg).into_owned())
+        .collect::<Vec<_>>()
+        .join("/")
+}
+
+/// Build the conflict-copy relpath: `dir/Note (conflict <stamp>).md`.
+fn conflict_relpath(relpath: &str, stamp: &str) -> String {
+    let (dir, name) = match relpath.rfind('/') {
+        Some(i) => (&relpath[..=i], &relpath[i + 1..]),
+        None => ("", relpath),
+    };
+    let (stem, ext) = match name.rfind('.') {
+        Some(i) => (&name[..i], &name[i..]),
+        None => (name, ""),
+    };
+    format!("{}{} (conflict {}){}", dir, stem, stamp, ext)
+}
+
+fn write_local(vault: &Path, relpath: &str, bytes: &[u8]) -> Result<(), String> {
+    let target = vault.join(relpath);
+    if let Some(parent) = target.parent() {
+        fs::create_dir_all(parent).map_err(|e| e.to_string())?;
+    }
+    fs::write(&target, bytes).map_err(|e| e.to_string())
+}
+
+struct LocalFile {
+    hash: String,
+    path: PathBuf,
+}
+
+/// The synced set: `*.md` anywhere outside `.helixnotes/`, plus everything under
+/// `.helixnotes/attachments/`. Applied to BOTH local and remote so pointing at a
+/// folder with unrelated files never drags them into the vault.
+fn is_synced_relpath(rel: &str) -> bool {
+    if rel.starts_with(".helixnotes/") {
+        rel.starts_with(".helixnotes/attachments/")
+    } else {
+        rel.ends_with(".md")
+    }
+}
+
+fn scan_local(vault: &str) -> Result<HashMap<String, LocalFile>, String> {
+    let vault_path = Path::new(vault);
+    let mut map = HashMap::new();
+    for entry in WalkDir::new(vault_path).into_iter().filter_map(|e| e.ok()) {
+        let p = entry.path();
+        if !p.is_file() {
+            continue;
+        }
+        let rel = match p.strip_prefix(vault_path) {
+            Ok(r) => r.to_string_lossy().replace('\\', "/"),
+            Err(_) => continue,
+        };
+        if !is_synced_relpath(&rel) {
+            continue;
+        }
+        let bytes = match fs::read(p) {
+            Ok(b) => b,
+            Err(_) => continue,
+        };
+        map.insert(
+            rel,
+            LocalFile {
+                hash: sha256_hex(&bytes),
+                path: p.to_path_buf(),
+            },
+        );
+    }
+    Ok(map)
+}
+
+// ───────────────────────── WebDAV client ─────────────────────────
+
+struct RemoteEntry {
+    relpath: String,
+    etag: String,
+    is_dir: bool,
+}
+
+struct WebdavClient {
+    base: String,      // normalized, no trailing slash
+    base_path: String, // path component of base, no trailing slash (percent-encoded)
+    client: reqwest::blocking::Client,
+    user: String,
+    pass: String,
+}
+
+impl WebdavClient {
+    fn new(cfg: WebdavConfig) -> Result<Self, String> {
+        let base = cfg.url.trim().trim_end_matches('/').to_string();
+        if !base.starts_with("http://") && !base.starts_with("https://") {
+            return Err("WebDAV URL must start with http:// or https://".to_string());
+        }
+        let base_url = reqwest::Url::parse(&base).map_err(|e| format!("Invalid URL: {e}"))?;
+        let base_path = base_url.path().trim_end_matches('/').to_string();
+        let client = reqwest::blocking::Client::builder()
+            .timeout(std::time::Duration::from_secs(60))
+            .build()
+            .map_err(|e| e.to_string())?;
+        Ok(Self {
+            base,
+            base_path,
+            client,
+            user: cfg.username,
+            pass: cfg.password,
+        })
+    }
+
+    fn url_for(&self, relpath: &str) -> String {
+        if relpath.is_empty() {
+            self.base.clone()
+        } else {
+            format!("{}/{}", self.base, encode_path(relpath))
+        }
+    }
+
+    fn propfind(&self, relpath: &str, depth: &str) -> Result<Vec<RemoteEntry>, String> {
+        let method = reqwest::Method::from_bytes(b"PROPFIND").unwrap();
+        let body = r#"<?xml version="1.0" encoding="utf-8"?><d:propfind xmlns:d="DAV:"><d:prop><d:getetag/><d:resourcetype/></d:prop></d:propfind>"#;
+        let resp = self
+            .client
+            .request(method, self.url_for(relpath))
+            .basic_auth(&self.user, Some(&self.pass))
+            .header("Depth", depth)
+            .header("Content-Type", "application/xml; charset=utf-8")
+            .body(body)
+            .send()
+            .map_err(|e| e.to_string())?;
+        let status = resp.status();
+        if status.as_u16() == 401 {
+            return Err("Authentication failed (check username / app password)".to_string());
+        }
+        if status.as_u16() == 404 {
+            return Err("WebDAV path not found (check the URL)".to_string());
+        }
+        if !status.is_success() {
+            return Err(format!("WebDAV PROPFIND failed: HTTP {}", status.as_u16()));
+        }
+        let text = resp.text().map_err(|e| e.to_string())?;
+        parse_multistatus(&text, &self.base_path)
+    }
+
+    /// Recursively list all files (relpath -> etag) by walking collections at Depth 1
+    /// (Depth: infinity is disabled on some servers, so we walk instead).
+    fn list(&self) -> Result<HashMap<String, String>, String> {
+        let mut files = HashMap::new();
+        let mut visited: HashSet<String> = HashSet::new();
+        let mut queue: Vec<String> = vec![String::new()];
+        while let Some(dir) = queue.pop() {
+            if !visited.insert(dir.clone()) {
+                continue;
+            }
+            for e in self.propfind(&dir, "1")? {
+                if e.relpath == dir {
+                    continue; // the collection itself
+                }
+                if e.is_dir {
+                    if !visited.contains(&e.relpath) {
+                        queue.push(e.relpath);
+                    }
+                } else {
+                    files.insert(e.relpath, e.etag);
+                }
+            }
+        }
+        Ok(files)
+    }
+
+    fn get(&self, relpath: &str) -> Result<Vec<u8>, String> {
+        let resp = self
+            .client
+            .get(self.url_for(relpath))
+            .basic_auth(&self.user, Some(&self.pass))
+            .send()
+            .map_err(|e| e.to_string())?;
+        if !resp.status().is_success() {
+            return Err(format!("GET {} failed: HTTP {}", relpath, resp.status().as_u16()));
+        }
+        Ok(resp.bytes().map_err(|e| e.to_string())?.to_vec())
+    }
+
+    fn put(&self, relpath: &str, bytes: &[u8]) -> Result<Option<String>, String> {
+        let resp = self
+            .client
+            .put(self.url_for(relpath))
+            .basic_auth(&self.user, Some(&self.pass))
+            .body(bytes.to_vec())
+            .send()
+            .map_err(|e| e.to_string())?;
+        if !resp.status().is_success() {
+            return Err(format!("PUT {} failed: HTTP {}", relpath, resp.status().as_u16()));
+        }
+        Ok(resp
+            .headers()
+            .get("etag")
+            .and_then(|h| h.to_str().ok())
+            .map(normalize_etag))
+    }
+
+    fn delete(&self, relpath: &str) -> Result<(), String> {
+        let resp = self
+            .client
+            .delete(self.url_for(relpath))
+            .basic_auth(&self.user, Some(&self.pass))
+            .send()
+            .map_err(|e| e.to_string())?;
+        let s = resp.status();
+        if s.is_success() || s.as_u16() == 404 {
+            Ok(())
+        } else {
+            Err(format!("DELETE {} failed: HTTP {}", relpath, s.as_u16()))
+        }
+    }
+
+    fn mkcol(&self, relpath: &str) -> Result<(), String> {
+        let method = reqwest::Method::from_bytes(b"MKCOL").unwrap();
+        let resp = self
+            .client
+            .request(method, self.url_for(relpath))
+            .basic_auth(&self.user, Some(&self.pass))
+            .send()
+            .map_err(|e| e.to_string())?;
+        let s = resp.status().as_u16();
+        // 201 created; 405 already exists; 301 redirect-to-existing.
+        if resp.status().is_success() || s == 405 || s == 301 {
+            Ok(())
+        } else {
+            Err(format!("MKCOL {} failed: HTTP {}", relpath, s))
+        }
+    }
+
+    /// Ensure every ancestor collection of `relpath` exists on the remote.
+    fn ensure_dirs(&self, relpath: &str, created: &mut HashSet<String>) -> Result<(), String> {
+        let parts: Vec<&str> = relpath.split('/').collect();
+        if parts.len() <= 1 {
+            return Ok(());
+        }
+        let mut cur = String::new();
+        for part in &parts[..parts.len() - 1] {
+            if !cur.is_empty() {
+                cur.push('/');
+            }
+            cur.push_str(part);
+            if created.insert(cur.clone()) {
+                self.mkcol(&cur)?;
+            }
+        }
+        Ok(())
+    }
+
+    fn put_with_dirs(
+        &self,
+        relpath: &str,
+        bytes: &[u8],
+        created: &mut HashSet<String>,
+    ) -> Result<Option<String>, String> {
+        self.ensure_dirs(relpath, created)?;
+        self.put(relpath, bytes)
+    }
+}
+
+/// Map a WebDAV `href` to a vault-relative path (forward slash). Returns None for
+/// the base collection itself.
+fn href_to_relpath(href: &str, base_path: &str) -> Option<String> {
+    let path = if href.starts_with("http://") || href.starts_with("https://") {
+        reqwest::Url::parse(href).ok()?.path().to_string()
+    } else {
+        href.to_string()
+    };
+    let path = path.trim_end_matches('/');
+    let rest = path.strip_prefix(base_path)?.trim_start_matches('/');
+    if rest.is_empty() {
+        return None;
+    }
+    Some(urlencoding::decode(rest).ok()?.into_owned())
+}
+
+fn parse_multistatus(xml: &str, base_path: &str) -> Result<Vec<RemoteEntry>, String> {
+    use quick_xml::events::Event;
+    use quick_xml::reader::Reader;
+
+    #[derive(PartialEq)]
+    enum Cap {
+        None,
+        Href,
+        Etag,
+    }
+
+    let mut reader = Reader::from_str(xml);
+    let mut entries = Vec::new();
+    let mut href: Option<String> = None;
+    let mut etag: Option<String> = None;
+    let mut is_dir = false;
+    let mut cap = Cap::None;
+    let mut buf = String::new();
+
+    loop {
+        match reader.read_event() {
+            Ok(Event::Start(e)) => match e.local_name().as_ref() {
+                b"response" => {
+                    href = None;
+                    etag = None;
+                    is_dir = false;
+                }
+                b"href" => {
+                    cap = Cap::Href;
+                    buf.clear();
+                }
+                b"getetag" => {
+                    cap = Cap::Etag;
+                    buf.clear();
+                }
+                b"collection" => is_dir = true,
+                _ => {}
+            },
+            Ok(Event::Empty(e)) => {
+                if e.local_name().as_ref() == b"collection" {
+                    is_dir = true;
+                }
+            }
+            Ok(Event::Text(e)) => {
+                if cap != Cap::None {
+                    if let Ok(t) = e.unescape() {
+                        buf.push_str(&t);
+                    }
+                }
+            }
+            Ok(Event::End(e)) => match e.local_name().as_ref() {
+                b"href" => {
+                    href = Some(buf.clone());
+                    cap = Cap::None;
+                }
+                b"getetag" => {
+                    etag = Some(buf.clone());
+                    cap = Cap::None;
+                }
+                b"response" => {
+                    if let Some(h) = href.take() {
+                        if let Some(rel) = href_to_relpath(&h, base_path) {
+                            entries.push(RemoteEntry {
+                                relpath: rel,
+                                etag: etag.take().map(|s| normalize_etag(&s)).unwrap_or_default(),
+                                is_dir,
+                            });
+                        }
+                    }
+                }
+                _ => {}
+            },
+            Ok(Event::Eof) => break,
+            Err(e) => return Err(format!("XML parse error: {e}")),
+            _ => {}
+        }
+    }
+    Ok(entries)
+}
+
+// ───────────────────────── sync engine ─────────────────────────
+
+fn apply_changes(
+    client: &WebdavClient,
+    vault: &str,
+    local: &HashMap<String, LocalFile>,
+    remote: &HashMap<String, String>,
+    manifest: &SyncManifest,
+) -> Result<(SyncManifest, SyncSummary), String> {
+    let vault_path = Path::new(vault);
+    let mut new_m = SyncManifest::default();
+    let mut sum = SyncSummary::default();
+    let mut created: HashSet<String> = HashSet::new();
+    let stamp = chrono::Local::now().format("%Y-%m-%d %H-%M-%S").to_string();
+
+    let mut keys: HashSet<&String> = HashSet::new();
+    keys.extend(local.keys());
+    keys.extend(remote.keys());
+    keys.extend(manifest.files.keys());
+
+    for key in keys {
+        let l = local.get(key);
+        let r = remote.get(key);
+        let m = manifest.files.get(key);
+
+        match (l, r) {
+            (Some(lf), Some(re)) => {
+                let local_changed = m.map_or(true, |me| me.local_hash != lf.hash);
+                let remote_changed = m.map_or(true, |me| &me.remote_etag != re);
+                if !local_changed && !remote_changed {
+                    new_m.files.insert(
+                        key.clone(),
+                        ManifestEntry {
+                            local_hash: lf.hash.clone(),
+                            remote_etag: re.clone(),
+                        },
+                    );
+                } else if local_changed && !remote_changed {
+                    let bytes = fs::read(&lf.path).map_err(|e| e.to_string())?;
+                    let etag = client.put_with_dirs(key, &bytes, &mut created)?;
+                    new_m.files.insert(
+                        key.clone(),
+                        ManifestEntry {
+                            local_hash: lf.hash.clone(),
+                            remote_etag: etag.unwrap_or_else(|| re.clone()),
+                        },
+                    );
+                    sum.uploaded += 1;
+                } else if !local_changed && remote_changed {
+                    let bytes = client.get(key)?;
+                    write_local(vault_path, key, &bytes)?;
+                    new_m.files.insert(
+                        key.clone(),
+                        ManifestEntry {
+                            local_hash: sha256_hex(&bytes),
+                            remote_etag: re.clone(),
+                        },
+                    );
+                    sum.downloaded += 1;
+                } else {
+                    // both changed: compare contents; identical => no real conflict.
+                    let rbytes = client.get(key)?;
+                    let rhash = sha256_hex(&rbytes);
+                    if rhash == lf.hash {
+                        new_m.files.insert(
+                            key.clone(),
+                            ManifestEntry {
+                                local_hash: lf.hash.clone(),
+                                remote_etag: re.clone(),
+                            },
+                        );
+                    } else {
+                        // keep-both: remote becomes canonical; local saved as a conflict copy.
+                        let lbytes = fs::read(&lf.path).map_err(|e| e.to_string())?;
+                        write_local(vault_path, key, &rbytes)?;
+                        new_m.files.insert(
+                            key.clone(),
+                            ManifestEntry {
+                                local_hash: rhash,
+                                remote_etag: re.clone(),
+                            },
+                        );
+                        let ckey = conflict_relpath(key, &stamp);
+                        write_local(vault_path, &ckey, &lbytes)?;
+                        let cetag = client.put_with_dirs(&ckey, &lbytes, &mut created)?;
+                        new_m.files.insert(
+                            ckey,
+                            ManifestEntry {
+                                local_hash: sha256_hex(&lbytes),
+                                remote_etag: cetag.unwrap_or_default(),
+                            },
+                        );
+                        sum.conflicts += 1;
+                    }
+                }
+            }
+            (Some(lf), None) => match m {
+                None => {
+                    // new local -> upload
+                    let bytes = fs::read(&lf.path).map_err(|e| e.to_string())?;
+                    let etag = client.put_with_dirs(key, &bytes, &mut created)?;
+                    new_m.files.insert(
+                        key.clone(),
+                        ManifestEntry {
+                            local_hash: lf.hash.clone(),
+                            remote_etag: etag.unwrap_or_default(),
+                        },
+                    );
+                    sum.uploaded += 1;
+                }
+                Some(me) => {
+                    if me.local_hash != lf.hash {
+                        // remote deleted but local edited -> resurrect (upload)
+                        let bytes = fs::read(&lf.path).map_err(|e| e.to_string())?;
+                        let etag = client.put_with_dirs(key, &bytes, &mut created)?;
+                        new_m.files.insert(
+                            key.clone(),
+                            ManifestEntry {
+                                local_hash: lf.hash.clone(),
+                                remote_etag: etag.unwrap_or_default(),
+                            },
+                        );
+                        sum.uploaded += 1;
+                    } else {
+                        // remote deleted, local unchanged -> delete local
+                        let _ = fs::remove_file(&lf.path);
+                        sum.deleted_local += 1;
+                    }
+                }
+            },
+            (None, Some(re)) => match m {
+                None => {
+                    // new remote -> download
+                    let bytes = client.get(key)?;
+                    write_local(vault_path, key, &bytes)?;
+                    new_m.files.insert(
+                        key.clone(),
+                        ManifestEntry {
+                            local_hash: sha256_hex(&bytes),
+                            remote_etag: re.clone(),
+                        },
+                    );
+                    sum.downloaded += 1;
+                }
+                Some(me) => {
+                    if &me.remote_etag != re {
+                        // local deleted but remote changed -> resurrect (download)
+                        let bytes = client.get(key)?;
+                        write_local(vault_path, key, &bytes)?;
+                        new_m.files.insert(
+                            key.clone(),
+                            ManifestEntry {
+                                local_hash: sha256_hex(&bytes),
+                                remote_etag: re.clone(),
+                            },
+                        );
+                        sum.downloaded += 1;
+                    } else {
+                        // local deleted, remote unchanged -> delete remote
+                        client.delete(key)?;
+                        sum.deleted_remote += 1;
+                    }
+                }
+            },
+            (None, None) => {
+                // gone on both sides -> drop from manifest
+            }
+        }
+    }
+    Ok((new_m, sum))
+}
+
+/// Validate the connection (auth + URL) with a cheap PROPFIND.
+pub fn test_connection(cfg: WebdavConfig) -> Result<String, String> {
+    let client = WebdavClient::new(cfg)?;
+    client.propfind("", "0")?;
+    Ok("Connection successful".to_string())
+}
+
+/// Run a full sync. Mutes the file watcher while applying local writes, then
+/// rebuilds the search index. Returns a summary of what changed.
+pub fn run_sync(app: tauri::AppHandle, vault: String, cfg: WebdavConfig) -> Result<SyncSummary, String> {
+    use std::sync::atomic::Ordering;
+
+    let state = app.state::<AppState>();
+    let client = WebdavClient::new(cfg)?;
+
+    let _ = app.emit("sync-progress", serde_json::json!({ "status": "listing" }));
+    let remote: HashMap<String, String> = client
+        .list()?
+        .into_iter()
+        .filter(|(k, _)| is_synced_relpath(k))
+        .collect();
+    let local = scan_local(&vault)?;
+    let manifest = load_manifest(&vault);
+
+    let _ = app.emit("sync-progress", serde_json::json!({ "status": "syncing" }));
+    // Mute the watcher across local writes so a pull doesn't storm the reindex path.
+    state.importing.store(true, Ordering::Relaxed);
+    let applied = apply_changes(&client, &vault, &local, &remote, &manifest);
+    state.importing.store(false, Ordering::Relaxed);
+
+    let (new_manifest, summary) = applied?;
+    save_manifest(&vault, &new_manifest);
+
+    // Re-index after files changed (search is non-critical; ignore failures).
+    if let Ok(guard) = state.search_index.lock() {
+        if let Some(search) = guard.as_ref() {
+            let _ = search.rebuild(&vault);
+        }
+    }
+
+    // The watcher was muted during apply, so nudge the UI to refresh its lists.
+    let _ = app.emit(
+        "file-changed",
+        crate::types::FileEvent {
+            event_type: "modify".to_string(),
+            path: vault.clone(),
+        },
+    );
+    Ok(summary)
+}

src-tauri/src/types.rs

@@ -129,6 +129,23 @@ pub struct AppConfig {
     pub close_to_tray: bool,
     #[serde(default = "default_true")]
     pub enable_wiki_links: bool,
+    // WebDAV sync (opt-in; all off by default). Endpoint is fully user-configured.
+    #[serde(default)]
+    pub sync_provider: Option<String>,
+    #[serde(default)]
+    pub webdav_url: Option<String>,
+    #[serde(default)]
+    pub webdav_username: Option<String>,
+    #[serde(default)]
+    pub webdav_password: Option<String>,
+    #[serde(default)]
+    pub sync_on_open: bool,
+    #[serde(default)]
+    pub sync_on_change: bool,
+    #[serde(default)]
+    pub sync_interval_minutes: u32,
+    #[serde(default)]
+    pub last_sync_time: Option<String>,
 }
 
 fn default_true() -> bool {
@@ -199,6 +216,14 @@ impl Default for AppConfig {
             show_tray_icon: false,
             close_to_tray: false,
             enable_wiki_links: true,
+            sync_provider: None,
+            webdav_url: None,
+            webdav_username: None,
+            webdav_password: None,
+            sync_on_open: false,
+            sync_on_change: false,
+            sync_interval_minutes: 0,
+            last_sync_time: None,
         }
     }
 }

src/app.css

@@ -404,6 +404,17 @@ body.resizing {
     user-select: none;
 }
 
+/* Spinner for the sync button while a sync is running. */
+.sync-spin {
+    animation: sync-spin 1s linear infinite;
+    transform-origin: 50% 50%;
+}
+@keyframes sync-spin {
+    to {
+        transform: rotate(360deg);
+    }
+}
+
 /* ── Mobile (Android/iOS) ── */
 @media (max-width: 768px) {
     body {

src/lib/api.ts

@@ -327,6 +327,28 @@ export async function setBackupSettings(
   });
 }
 
+// ── Sync (WebDAV) ──
+
+export async function setSyncSettings(
+  provider: string | null,
+  url: string | null,
+  username: string | null,
+  password: string | null,
+  syncOnOpen: boolean,
+  syncOnChange: boolean,
+  syncIntervalMinutes: number,
+): Promise<void> {
+  return invoke("set_sync_settings", { provider, url, username, password, syncOnOpen, syncOnChange, syncIntervalMinutes });
+}
+
+export async function testSyncConnection(): Promise<void> {
+  return invoke("test_sync_connection");
+}
+
+export async function syncNow(): Promise<void> {
+  return invoke("sync_now");
+}
+
 // ── Version History ──
 
 export async function getNoteVersions(noteId: string): Promise<VersionEntry[]> {

src/lib/components/AppLayout.svelte

@@ -40,14 +40,15 @@
 		navHistory,
 		viewerNote,
 		notebookSortMode,
-		notebookOrder
+		notebookOrder,
+		syncState
 	} from '$lib/stores/app';
 
 	const appWindow = getCurrentWindow();
 	const isMac = navigator.platform.startsWith('Mac');
 	const isMobile = /android|iphone|ipad|ipod/i.test(navigator.userAgent);
 	const isAndroid = /android/i.test(navigator.userAgent);
-	import { loadVaultState, saveVaultState, readNote, createDailyNote, createBackup, getPendingOpenFile, addQuickAccess, removeQuickAccess, getQuickAccess, setTheme } from '$lib/api';
+	import { loadVaultState, saveVaultState, readNote, createDailyNote, createBackup, getPendingOpenFile, addQuickAccess, removeQuickAccess, getQuickAccess, setTheme, syncNow } from '$lib/api';
 	import { debounce } from '$lib/utils/debounce';
 	import { openNoteWindow } from '$lib/utils/window';
 	import { get } from 'svelte/store';
@@ -63,6 +64,11 @@
 	let noteRelativePath = $derived($activeNotePath && $appConfig?.active_vault ? $activeNotePath.replace($appConfig.active_vault + '/', '') : '');
 	let isQuickAccess = $derived(noteRelativePath ? $quickAccessPaths.includes(noteRelativePath) : false);
 	let backupInterval: ReturnType<typeof setInterval> | null = null;
+	let syncInterval: ReturnType<typeof setInterval> | null = null;
+	let unlistenSync: Array<() => void> = [];
+	let unsubDirty: (() => void) | null = null;
+	let onChangeSyncTimer: ReturnType<typeof setTimeout> | null = null;
+	let prevDirty = false;
 
 
 
@@ -92,6 +98,27 @@
 		}
 	}
 
+	function syncConfigured(): boolean {
+		return get(appConfig)?.sync_provider === 'webdav';
+	}
+
+	// Auto-sync on a timer (only when configured and an interval is set).
+	async function checkScheduledSync() {
+		const config = get(appConfig);
+		if (config?.sync_provider !== 'webdav') return;
+		const mins = config.sync_interval_minutes ?? 0;
+		if (!mins || get(syncState).running) return;
+		const last = config.last_sync_time ? new Date(config.last_sync_time).getTime() : 0;
+		if (Date.now() - last >= mins * 60 * 1000) {
+			try { await syncNow(); } catch (_) {}
+		}
+	}
+
+	export async function triggerSyncNow() {
+		if (!syncConfigured() || get(syncState).running) return;
+		try { await syncNow(); } catch (_) {}
+	}
+
 	// Track note navigation in history stack
 	$effect(() => {
 		const path = $activeNotePath;
@@ -486,12 +513,44 @@
 		// Scheduled backup: check on startup and every 5 minutes
 		checkScheduledBackup();
 		backupInterval = setInterval(checkScheduledBackup, 5 * 60 * 1000);
+
+		// ── WebDAV sync: global status + auto-sync triggers ──
+		unlistenSync.push(await listen('sync-progress', () => syncState.set({ running: true, error: null })));
+		unlistenSync.push(await listen('sync-done', (event: any) => {
+			syncState.set({ running: false, error: null });
+			const cur = get(appConfig);
+			if (cur && event.payload?.last_sync_time) appConfig.set({ ...cur, last_sync_time: event.payload.last_sync_time });
+		}));
+		unlistenSync.push(await listen('sync-error', (event: any) => syncState.set({ running: false, error: event.payload?.error ?? 'Sync failed' })));
+
+		// Sync when the vault opens (if enabled)
+		if (syncConfigured() && get(appConfig)?.sync_on_open) {
+			try { await syncNow(); } catch (_) {}
+		}
+
+		// Auto-sync interval: check on startup and every minute
+		checkScheduledSync();
+		syncInterval = setInterval(checkScheduledSync, 60 * 1000);
+
+		// Auto-sync on note change: a save flips editorDirty true -> false. Debounce a sync.
+		unsubDirty = editorDirty.subscribe((d) => {
+			const config = get(appConfig);
+			if (prevDirty && !d && config?.sync_provider === 'webdav' && config?.sync_on_change) {
+				if (onChangeSyncTimer) clearTimeout(onChangeSyncTimer);
+				onChangeSyncTimer = setTimeout(() => { if (!get(syncState).running) syncNow().catch(() => {}); }, 15000);
+			}
+			prevDirty = d;
+		});
 	});
 
 	onDestroy(() => {
 		unlistenFileChange?.();
 		unlistenOpenFile?.();
 		if (backupInterval) clearInterval(backupInterval);
+		if (syncInterval) clearInterval(syncInterval);
+		if (onChangeSyncTimer) clearTimeout(onChangeSyncTimer);
+		unsubDirty?.();
+		unlistenSync.forEach((u) => u());
 	});
 </script>
 
@@ -592,6 +651,13 @@
 						</svg>
 					</button>
 					{/if}
+					{#if $appConfig?.sync_provider === 'webdav'}
+					<button class="mobile-header-btn" class:active={$syncState.running} onclick={triggerSyncNow} disabled={$syncState.running} title={$syncState.error ? `Sync error: ${$syncState.error}` : ($syncState.running ? 'Syncing...' : 'Sync now')}>
+						<svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class:sync-spin={$syncState.running}>
+							<path d="M21 2v6h-6"/><path d="M3 12a9 9 0 0115-6.7L21 8"/><path d="M3 22v-6h6"/><path d="M21 12a9 9 0 01-15 6.7L3 16"/>
+						</svg>
+					</button>
+					{/if}
 					<button class="mobile-header-btn" class:active={$sourceMode} onclick={() => ($sourceMode = !$sourceMode)} title={$sourceMode ? 'Rich Editor' : 'Source Mode'}>
 						<svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
 							<polyline points="16 18 22 12 16 6" /><polyline points="8 6 2 12 8 18" />

src/lib/components/Editor.svelte

@@ -38,8 +38,8 @@
 	import { readFile } from '@tauri-apps/plugin-fs';
 	import { openFile, openUrl, copyFileTo, copyImageToClipboard as copyImageToClipboardCmd, writeBytesTo, copyPngToClipboard } from '$lib/api';
 	import { save as saveDialog } from '@tauri-apps/plugin-dialog';
-	import { activeNote, activeNotePath, appConfig, editorDirty, sourceMode, focusMode, readOnly, quickAccessPaths, notes, navHistory, canGoBack, canGoForward, viewerNote, notebooks } from '$lib/stores/app';
+	import { activeNote, activeNotePath, appConfig, editorDirty, sourceMode, focusMode, readOnly, quickAccessPaths, notes, navHistory, canGoBack, canGoForward, viewerNote, notebooks, syncState } from '$lib/stores/app';
-	import { saveNote, saveImage, saveAttachment, readClipboardImage, addQuickAccess, removeQuickAccess, getQuickAccess, getNoteVersions, getNoteVersionContent, createVersion, aiAsk, getAllNoteTitles, readNote, renameNote } from '$lib/api';
+	import { saveNote, saveImage, saveAttachment, readClipboardImage, addQuickAccess, removeQuickAccess, getQuickAccess, getNoteVersions, getNoteVersionContent, createVersion, aiAsk, getAllNoteTitles, readNote, renameNote, syncNow } from '$lib/api';
 	import type { VersionEntry, AiStreamEvent, NoteTitleEntry } from '$lib/types';
 	import { listen } from '@tauri-apps/api/event';
 	import { debounce } from '$lib/utils/debounce';
@@ -4287,6 +4287,19 @@
 					</svg>
 				</button>
 				{/if}
+				{#if $appConfig?.sync_provider === 'webdav'}
+				<button
+					class="icon-btn"
+					class:active={$syncState.running}
+					onclick={() => { if (!$syncState.running) syncNow().catch(() => {}); }}
+					disabled={$syncState.running}
+					title={$syncState.error ? `Sync error: ${$syncState.error}` : ($syncState.running ? 'Syncing...' : 'Sync now')}
+				>
+					<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class:sync-spin={$syncState.running}>
+						<path d="M21 2v6h-6"/><path d="M3 12a9 9 0 0115-6.7L21 8"/><path d="M3 22v-6h6"/><path d="M21 12a9 9 0 01-15 6.7L3 16"/>
+					</svg>
+				</button>
+				{/if}
 				<button
 					class="icon-btn"
 					class:active={$sourceMode}

src/lib/components/SettingsPanel.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
 	import { showSettings, theme, appConfig, updateAvailable as globalUpdateAvailable, updateObj as globalUpdateObj, installType, settingsTab, vaultReady, androidApkUrl, checkForUpdateMobile, notebookSortMode } from '$lib/stores/app';
-	import { setTheme, setAccentColor, setFontSize, setFontFamily, setLineHeight, setUiScale, setGeneralSettings, importObsidian, createBackup, listBackups, restoreBackup, deleteBackup, setBackupSettings, setAiSettings, testAiConnection } from '$lib/api';
+	import { setTheme, setAccentColor, setFontSize, setFontFamily, setLineHeight, setUiScale, setGeneralSettings, importObsidian, createBackup, listBackups, restoreBackup, deleteBackup, setBackupSettings, setAiSettings, testAiConnection, setSyncSettings, testSyncConnection, syncNow } from '$lib/api';
 	import { open as openDialog } from '@tauri-apps/plugin-dialog';
 	import { listen } from '@tauri-apps/api/event';
 	import { getVersion } from '@tauri-apps/api/app';
@@ -10,7 +10,7 @@
 
 	const isMobile = /android|iphone|ipad|ipod/i.test(navigator.userAgent);
 
-	type Tab = 'general' | 'editor' | 'styling' | 'import' | 'backup' | 'ai' | 'updates';
+	type Tab = 'general' | 'editor' | 'styling' | 'import' | 'backup' | 'ai' | 'sync' | 'updates';
 	let activeTab = $state<Tab>('styling');
 
 	// Updates state
@@ -300,6 +300,78 @@
 		}
 	}
 
+	// ── WebDAV sync ──
+	let syncProvider = $state<string | null>($appConfig?.sync_provider ?? null);
+	let syncUrl = $state($appConfig?.webdav_url ?? '');
+	let syncUsername = $state($appConfig?.webdav_username ?? '');
+	let syncPassword = $state($appConfig?.webdav_password ?? '');
+	let syncShowPassword = $state(false);
+	let syncTestLoading = $state(false);
+	let syncTestMessage = $state<{ type: 'success' | 'error'; text: string } | null>(null);
+	let syncRunning = $state(false);
+	let syncMessage = $state<{ type: 'success' | 'error'; text: string } | null>(null);
+	let syncOnOpen = $state($appConfig?.sync_on_open ?? false);
+	let syncOnChange = $state($appConfig?.sync_on_change ?? false);
+	let syncIntervalMinutes = $state($appConfig?.sync_interval_minutes ?? 0);
+
+	async function saveSyncSettings() {
+		await setSyncSettings(syncProvider, syncUrl || null, syncUsername || null, syncPassword || null, syncOnOpen, syncOnChange, syncIntervalMinutes);
+	}
+
+	async function handleTestSync() {
+		syncTestLoading = true;
+		syncTestMessage = null;
+		const unlisten = await listen<{ success: boolean; message?: string; error?: string }>('sync-test-result', (event) => {
+			const data = event.payload;
+			syncTestMessage = data.success
+				? { type: 'success', text: data.message ?? 'Connection successful' }
+				: { type: 'error', text: data.error ?? 'Connection failed' };
+			syncTestLoading = false;
+			unlisten();
+		});
+		try {
+			await saveSyncSettings();
+			await testSyncConnection();
+		} catch (e) {
+			syncTestMessage = { type: 'error', text: String(e) };
+			syncTestLoading = false;
+			unlisten();
+		}
+	}
+
+	async function handleSyncNow() {
+		syncRunning = true;
+		syncMessage = null;
+		const unlisteners: Array<() => void> = [];
+		const cleanup = () => { unlisteners.forEach((u) => u()); };
+		unlisteners.push(await listen<{ success: boolean; summary?: { uploaded?: number; downloaded?: number; deleted_local?: number; deleted_remote?: number; conflicts?: number }; last_sync_time?: string }>('sync-done', (event) => {
+			const s = event.payload.summary ?? {};
+			const parts: string[] = [];
+			if (s.uploaded) parts.push(`${s.uploaded} uploaded`);
+			if (s.downloaded) parts.push(`${s.downloaded} downloaded`);
+			const deleted = (s.deleted_local ?? 0) + (s.deleted_remote ?? 0);
+			if (deleted) parts.push(`${deleted} deleted`);
+			if (s.conflicts) parts.push(`${s.conflicts} conflict copies`);
+			syncMessage = { type: 'success', text: parts.length ? `Synced: ${parts.join(', ')}.` : 'Already up to date.' };
+			syncRunning = false;
+			if ($appConfig && event.payload.last_sync_time) $appConfig = { ...$appConfig, last_sync_time: event.payload.last_sync_time };
+			cleanup();
+		}));
+		unlisteners.push(await listen<{ error?: string }>('sync-error', (event) => {
+			syncMessage = { type: 'error', text: event.payload.error ?? 'Sync failed' };
+			syncRunning = false;
+			cleanup();
+		}));
+		try {
+			await saveSyncSettings();
+			await syncNow();
+		} catch (e) {
+			syncMessage = { type: 'error', text: String(e) };
+			syncRunning = false;
+			cleanup();
+		}
+	}
+
 	const darkThemes = ['dark', 'solarized-dark', 'catppuccin', 'nord', 'tokyo-night', 'github-dark', 'dracula'];
 	let isThemeDark = $derived(
 		darkThemes.includes($theme) || ($theme === 'system' && window.matchMedia('(prefers-color-scheme: dark)').matches)
@@ -638,6 +710,12 @@
 						</svg>
 						AI
 					</button>
+					<button class="tab-btn" class:active={activeTab === 'sync'} onclick={() => activeTab = 'sync'}>
+						<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+							<path d="M21 2v6h-6"/><path d="M3 12a9 9 0 0115-6.7L21 8"/><path d="M3 22v-6h6"/><path d="M21 12a9 9 0 01-15 6.7L3 16"/>
+						</svg>
+						Sync
+					</button>
 					<button class="tab-btn" class:active={activeTab === 'updates'} onclick={() => activeTab = 'updates'}>
 						<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
 							<path d="M21 12a9 9 0 00-9-9 9.75 9.75 0 00-6.74 2.74L3 8"/><path d="M3 3v5h5"/><path d="M12 7v5l3 3"/>
@@ -1299,6 +1377,117 @@
 							{/if}
 						</div>
 
+					{:else if activeTab === 'sync'}
+						<div class="tab-content">
+							<div class="settings-section">
+								<h3>Provider</h3>
+								<div class="setting-options">
+									<button class="option-btn" class:active={!syncProvider} onclick={() => { syncProvider = null; syncMessage = null; syncTestMessage = null; saveSyncSettings(); }}>Disabled</button>
+									<button class="option-btn" class:active={syncProvider === 'webdav'} onclick={() => { syncProvider = 'webdav'; syncMessage = null; syncTestMessage = null; saveSyncSettings(); }}>WebDAV</button>
+								</div>
+								<p class="setting-hint">Sync your notes to your own WebDAV server (Nextcloud, ownCloud, a NAS). Your vault stays local on each device; the server is the shared hub.</p>
+							</div>
+
+							{#if syncProvider === 'webdav'}
+								<div class="settings-section">
+									<h3>Server URL</h3>
+									<input type="text" class="ai-key-input" placeholder="https://cloud.example.com/remote.php/dav/files/USER/HelixNotes" value={syncUrl} oninput={(e) => { syncUrl = (e.target as HTMLInputElement).value; }} onblur={saveSyncSettings} />
+									<p class="setting-hint">Full WebDAV URL of the folder to sync into. On Nextcloud: <code>https://your-server/remote.php/dav/files/USERNAME/FolderName</code></p>
+								</div>
+								<div class="settings-section">
+									<h3>Username</h3>
+									<input type="text" class="ai-key-input" placeholder="your username" value={syncUsername} oninput={(e) => { syncUsername = (e.target as HTMLInputElement).value; }} onblur={saveSyncSettings} />
+								</div>
+								<div class="settings-section">
+									<h3>Password</h3>
+									<div class="ai-key-row">
+										<input type={syncShowPassword ? 'text' : 'password'} class="ai-key-input" placeholder="app password" value={syncPassword} oninput={(e) => { syncPassword = (e.target as HTMLInputElement).value; }} onblur={saveSyncSettings} />
+										<button class="ai-key-toggle" onclick={() => syncShowPassword = !syncShowPassword} title={syncShowPassword ? 'Hide' : 'Show'}>
+											{#if syncShowPassword}
+												<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M17.94 17.94A10.07 10.07 0 0112 20c-7 0-11-8-11-8a18.45 18.45 0 015.06-5.94M9.9 4.24A9.12 9.12 0 0112 4c7 0 11 8 11 8a18.5 18.5 0 01-2.16 3.19m-6.72-1.07a3 3 0 11-4.24-4.24"/><line x1="1" y1="1" x2="23" y2="23"/></svg>
+											{:else}
+												<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M1 12s4-8 11-8 11 8 11 8-4 8-11 8-11-8-11-8z"/><circle cx="12" cy="12" r="3"/></svg>
+											{/if}
+										</button>
+									</div>
+									<p class="setting-hint">Use an app password / token, not your main account password. Stored locally on this device (like AI keys).</p>
+								</div>
+
+								<div class="settings-section">
+									<h3>Connection</h3>
+									<button class="import-btn" onclick={handleTestSync} disabled={syncTestLoading || !syncUrl}>
+										{#if syncTestLoading}
+											<svg class="spinner-icon" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><circle cx="12" cy="12" r="10" opacity="0.25" /><path d="M12 2a10 10 0 019.95 9" /></svg>
+											Testing...
+										{:else}
+											<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M22 11.08V12a10 10 0 11-5.93-9.14" /><polyline points="22 4 12 14.01 9 11.01" /></svg>
+											Test Connection
+										{/if}
+									</button>
+									{#if syncTestMessage}
+										<div class="import-result {syncTestMessage.type}">
+											{#if syncTestMessage.type === 'success'}
+												<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M22 11.08V12a10 10 0 11-5.93-9.14" /><polyline points="22 4 12 14.01 9 11.01" /></svg>
+											{:else}
+												<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="10" /><line x1="15" y1="9" x2="9" y2="15" /><line x1="9" y1="9" x2="15" y2="15" /></svg>
+											{/if}
+											<span>{syncTestMessage.text}</span>
+										</div>
+									{/if}
+								</div>
+
+								<div class="settings-section">
+									<h3>Sync</h3>
+									<button class="import-btn" onclick={handleSyncNow} disabled={syncRunning || !syncUrl}>
+										{#if syncRunning}
+											<svg class="spinner-icon" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2"><circle cx="12" cy="12" r="10" opacity="0.25" /><path d="M12 2a10 10 0 019.95 9" /></svg>
+											Syncing...
+										{:else}
+											<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M21 2v6h-6"/><path d="M3 12a9 9 0 0115-6.7L21 8"/><path d="M3 22v-6h6"/><path d="M21 12a9 9 0 01-15 6.7L3 16"/></svg>
+											Sync Now
+										{/if}
+									</button>
+									{#if syncMessage}
+										<div class="import-result {syncMessage.type}">
+											{#if syncMessage.type === 'success'}
+												<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M22 11.08V12a10 10 0 11-5.93-9.14" /><polyline points="22 4 12 14.01 9 11.01" /></svg>
+											{:else}
+												<svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><circle cx="12" cy="12" r="10" /><line x1="15" y1="9" x2="9" y2="15" /><line x1="9" y1="9" x2="15" y2="15" /></svg>
+											{/if}
+											<span>{syncMessage.text}</span>
+										</div>
+									{/if}
+									{#if $appConfig?.last_sync_time}
+										<p class="setting-hint">Last sync: {new Date($appConfig.last_sync_time).toLocaleString()}</p>
+									{/if}
+									<p class="setting-hint">Manual sync. If the same note was edited on two devices, the second version is kept as a "(conflict ...)" copy so nothing is lost.</p>
+								</div>
+								<div class="settings-section">
+									<h3>Automatic Sync</h3>
+									<div class="setting-options">
+										{#each [{ v: 0, l: 'Off' }, { v: 5, l: '5 min' }, { v: 15, l: '15 min' }, { v: 30, l: '30 min' }, { v: 60, l: '60 min' }] as opt}
+											<button class="option-btn" class:active={syncIntervalMinutes === opt.v} onclick={() => { syncIntervalMinutes = opt.v; saveSyncSettings(); }}>{opt.l}</button>
+										{/each}
+									</div>
+									<p class="setting-hint">Sync automatically on this interval.</p>
+									<label class="setting-toggle" style="margin-top: 12px;">
+										<span class="setting-label">
+											<span class="setting-name">Sync when a note changes</span>
+											<span class="setting-desc">Sync a few seconds after you edit a note.</span>
+										</span>
+										<button class="toggle-switch" class:on={syncOnChange} onclick={() => { syncOnChange = !syncOnChange; saveSyncSettings(); }}><span class="toggle-knob"></span></button>
+									</label>
+									<label class="setting-toggle">
+										<span class="setting-label">
+											<span class="setting-name">Sync when the vault opens</span>
+											<span class="setting-desc">Pull the latest changes on startup.</span>
+										</span>
+										<button class="toggle-switch" class:on={syncOnOpen} onclick={() => { syncOnOpen = !syncOnOpen; saveSyncSettings(); }}><span class="toggle-knob"></span></button>
+									</label>
+								</div>
+							{/if}
+						</div>
+
 					{:else if activeTab === 'updates'}
 						<div class="tab-content">
 							<div class="settings-section">

src/lib/stores/app.ts

@@ -67,6 +67,13 @@ export const readOnly = writable(false);
 // Theme
 export const theme = writable<string>("system");
 
+// Sync (WebDAV) - global status so the top-bar button reflects any sync,
+// whoever triggered it (manual button, settings, interval, on-change).
+export const syncState = writable<{ running: boolean; error: string | null }>({
+  running: false,
+  error: null,
+});
+
 // Update state
 export const updateAvailable = writable<{
   version: string;

src/lib/types.ts

@@ -82,6 +82,14 @@ export interface AppConfig {
   default_view_mode: boolean;
   show_tray_icon: boolean;
   enable_wiki_links: boolean;
+  sync_provider: string | null;
+  webdav_url: string | null;
+  webdav_username: string | null;
+  webdav_password: string | null;
+  sync_on_open: boolean;
+  sync_on_change: boolean;
+  sync_interval_minutes: number;
+  last_sync_time: string | null;
 }
 
 export interface VaultState {