6 files changed, 312 insertions, 24 deletions

diff --git a/crates/vcs_data/src/constants.rs b/crates/vcs_data/src/constants.rs
index cd6eaa3..1d17927 100644
--- a/crates/vcs_data/src/constants.rs
+++ b/crates/vcs_data/src/constants.rs
@@ -42,6 +42,7 @@ pub const SERVER_FILE_README: &str = "./README.md";
 
 // Client
 pub const CLIENT_PATH_WORKSPACE_ROOT: &str = "./.jv/";
+pub const CLIENT_FOLDER_WORKSPACE_ROOT_NAME: &str = ".jv";
 
 // Client - Workspace (Main)
 pub const CLIENT_FILE_WORKSPACE: &str = "./.jv/workspace.toml";
@@ -52,6 +53,9 @@ pub const CLIENT_FILE_LATEST_INFO: &str = "./.jv/latest.json";
 // Client - Sheets
 pub const CLIENT_FILE_SHEET_COPY: &str = "./.jv/sheets/{sheet_name}.copy.json";
 
+// Client - Local Draft
+pub const CLIENT_PATH_LOCAL_DRAFT: &str = "./.jv/drafts/{sheet_name}/";
+
 // Client - Other
 pub const CLIENT_FILE_IGNOREFILES: &str = "IGNORE_RULES.toml";
 pub const CLIENT_FILE_README: &str = "./README.md";
diff --git a/crates/vcs_data/src/data/local/config.rs b/crates/vcs_data/src/data/local/config.rs
index 338d01b..3dc5248 100644
--- a/crates/vcs_data/src/data/local/config.rs
+++ b/crates/vcs_data/src/data/local/config.rs
@@ -1,12 +1,24 @@
 use cfg_file::ConfigFile;
+use cfg_file::config::ConfigFile;
 use serde::{Deserialize, Serialize};
 use std::net::SocketAddr;
+use std::path::Path;
+use std::path::PathBuf;
+use string_proc::snake_case;
 
 use crate::constants::CLIENT_FILE_WORKSPACE;
+use crate::constants::CLIENT_FOLDER_WORKSPACE_ROOT_NAME;
+use crate::constants::CLIENT_PATH_LOCAL_DRAFT;
+use crate::constants::CLIENT_PATH_WORKSPACE_ROOT;
 use crate::constants::PORT;
+use crate::current::current_local_path;
+use crate::data::local::latest_info::LatestInfo;
 use crate::data::member::MemberId;
+use crate::data::sheet::SheetName;
 use crate::data::vault::config::VaultUuid;
 
+const SHEET_NAME: &str = "{sheet_name}";
+
 #[derive(Serialize, Deserialize, ConfigFile)]
 #[cfg_file(path = CLIENT_FILE_WORKSPACE)]
 pub struct LocalConfig {
@@ -25,6 +37,9 @@ pub struct LocalConfig {
     /// If the value is None, it means not stained;
     /// otherwise, it contains the stain identifier (i.e., the upstream vault's unique ID)
     stained_uuid: Option<VaultUuid>,
+
+    /// The name of the sheet currently in use.
+    sheet_in_use: Option<SheetName>,
 }
 
 impl Default for LocalConfig {
@@ -36,6 +51,7 @@ impl Default for LocalConfig {
             )),
             using_account: "unknown".to_string(),
             stained_uuid: None,
+            sheet_in_use: None,
         }
     }
 }
@@ -56,6 +72,208 @@ impl LocalConfig {
         self.using_account = account;
     }
 
+    /// Set the currently used sheet
+    pub async fn use_sheet(&mut self, sheet: SheetName) -> Result<(), std::io::Error> {
+        let sheet = snake_case!(sheet);
+
+        // Check if the sheet is already in use
+        if self.sheet_in_use().is_some() {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::AlreadyExists,
+                "Sheet already in use",
+            ));
+        };
+
+        // Check if the local path exists
+        let local_path = self.get_local_path().await?;
+
+        // Get latest info
+        let Ok(latest_info) = LatestInfo::read().await else {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::NotFound,
+                "No latest info found",
+            ));
+        };
+
+        // Check if the sheet exists
+        if !latest_info.my_sheets.contains(&sheet) {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::NotFound,
+                "Sheet not found",
+            ));
+        }
+
+        // Check if there are any files or folders other than .jv
+        self.check_local_path_empty(&local_path).await?;
+
+        // Get the draft folder path
+        let draft_folder = self.draft_folder(&sheet, &local_path);
+
+        if draft_folder.exists() {
+            // Exists
+            // Move the contents of the draft folder to the local path with rollback support
+            self.move_draft_to_local(&draft_folder, &local_path).await?;
+        }
+
+        self.sheet_in_use = Some(sheet);
+        LocalConfig::write(&self).await?;
+
+        Ok(())
+    }
+
+    /// Exit the currently used sheet
+    pub async fn exit_sheet(&mut self) -> Result<(), std::io::Error> {
+        // Check if the sheet is already in use
+        if self.sheet_in_use().is_none() {
+            return Ok(());
+        }
+
+        // Check if the local path exists
+        let local_path = self.get_local_path().await?;
+
+        // Get the current sheet name
+        let sheet_name = self.sheet_in_use().as_ref().unwrap().clone();
+
+        // Get the draft folder path
+        let draft_folder = self.draft_folder(&sheet_name, &local_path);
+
+        // Create the draft folder if it doesn't exist
+        if !draft_folder.exists() {
+            std::fs::create_dir_all(&draft_folder)
+                .map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e))?;
+        }
+
+        // Move all files and folders (except .jv folder) to the draft folder with rollback support
+        self.move_local_to_draft(&local_path, &draft_folder).await?;
+
+        // Clear the sheet in use
+        self.sheet_in_use = None;
+        LocalConfig::write(&self).await?;
+
+        Ok(())
+    }
+
+    /// Get local path or return error
+    async fn get_local_path(&self) -> Result<PathBuf, std::io::Error> {
+        current_local_path().ok_or_else(|| {
+            std::io::Error::new(std::io::ErrorKind::NotFound, "Fail to get local path")
+        })
+    }
+
+    /// Check if local path is empty (except for .jv folder)
+    async fn check_local_path_empty(&self, local_path: &Path) -> Result<(), std::io::Error> {
+        let jv_folder = local_path.join(CLIENT_PATH_WORKSPACE_ROOT);
+        let mut entries = std::fs::read_dir(local_path)
+            .map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e))?;
+
+        if entries.any(|entry| {
+            if let Ok(entry) = entry {
+                let path = entry.path();
+                path != jv_folder
+                    && path.file_name().and_then(|s| s.to_str())
+                        != Some(CLIENT_FOLDER_WORKSPACE_ROOT_NAME)
+            } else {
+                false
+            }
+        }) {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::DirectoryNotEmpty,
+                "Local path is not empty!",
+            ));
+        }
+
+        Ok(())
+    }
+
+    /// Move contents from draft folder to local path with rollback support
+    async fn move_draft_to_local(
+        &self,
+        draft_folder: &Path,
+        local_path: &Path,
+    ) -> Result<(), std::io::Error> {
+        let draft_entries: Vec<_> = std::fs::read_dir(draft_folder)
+            .map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e))?
+            .collect::<Result<Vec<_>, _>>()
+            .map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e))?;
+
+        let mut moved_items: Vec<MovedItem> = Vec::new();
+
+        for entry in &draft_entries {
+            let entry_path = entry.path();
+            let target_path = local_path.join(entry_path.file_name().unwrap());
+
+            // Move each file/directory from draft folder to local path
+            std::fs::rename(&entry_path, &target_path).map_err(|e| {
+                // Rollback all previously moved items
+                for moved_item in &moved_items {
+                    let _ = std::fs::rename(&moved_item.target, &moved_item.source);
+                }
+                std::io::Error::new(std::io::ErrorKind::Other, e)
+            })?;
+
+            moved_items.push(MovedItem {
+                source: entry_path.clone(),
+                target: target_path.clone(),
+            });
+        }
+
+        // Remove the now-empty draft folder
+        std::fs::remove_dir(draft_folder).map_err(|e| {
+            // Rollback all moved items if folder removal fails
+            for moved_item in &moved_items {
+                let _ = std::fs::rename(&moved_item.target, &moved_item.source);
+            }
+            std::io::Error::new(std::io::ErrorKind::Other, e)
+        })?;
+
+        Ok(())
+    }
+
+    /// Move contents from local path to draft folder with rollback support (except .jv folder)
+    async fn move_local_to_draft(
+        &self,
+        local_path: &Path,
+        draft_folder: &Path,
+    ) -> Result<(), std::io::Error> {
+        let jv_folder = local_path.join(CLIENT_PATH_WORKSPACE_ROOT);
+        let entries: Vec<_> = std::fs::read_dir(local_path)
+            .map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e))?
+            .collect::<Result<Vec<_>, _>>()
+            .map_err(|e| std::io::Error::new(std::io::ErrorKind::Other, e))?;
+
+        let mut moved_items: Vec<MovedItem> = Vec::new();
+
+        for entry in &entries {
+            let entry_path = entry.path();
+
+            // Skip the .jv folder
+            if entry_path == jv_folder
+                || entry_path.file_name().and_then(|s| s.to_str())
+                    == Some(CLIENT_FOLDER_WORKSPACE_ROOT_NAME)
+            {
+                continue;
+            }
+
+            let target_path = draft_folder.join(entry_path.file_name().unwrap());
+
+            // Move each file/directory from local path to draft folder
+            std::fs::rename(&entry_path, &target_path).map_err(|e| {
+                // Rollback all previously moved items
+                for moved_item in &moved_items {
+                    let _ = std::fs::rename(&moved_item.target, &moved_item.source);
+                }
+                std::io::Error::new(std::io::ErrorKind::Other, e)
+            })?;
+
+            moved_items.push(MovedItem {
+                source: entry_path.clone(),
+                target: target_path.clone(),
+            });
+        }
+
+        Ok(())
+    }
+
     /// Get the currently used account
     pub fn current_account(&self) -> MemberId {
         self.using_account.clone()
@@ -66,6 +284,11 @@ impl LocalConfig {
         self.stained_uuid.is_some()
     }
 
+    /// Get the UUID of the vault that the local workspace is stained with.
+    pub fn stained_uuid(&self) -> Option<VaultUuid> {
+        self.stained_uuid
+    }
+
     /// Stain the local workspace with the given UUID.
     pub fn stain(&mut self, uuid: VaultUuid) {
         self.stained_uuid = Some(uuid);
@@ -75,4 +298,44 @@ impl LocalConfig {
     pub fn unstain(&mut self) {
         self.stained_uuid = None;
     }
+
+    /// Get the upstream address.
+    pub fn upstream_addr(&self) -> SocketAddr {
+        self.upstream_addr
+    }
+
+    /// Get the currently used sheet
+    pub fn sheet_in_use(&self) -> &Option<SheetName> {
+        &self.sheet_in_use
+    }
+
+    /// Get draft folder
+    pub fn draft_folder(
+        &self,
+        sheet_name: &SheetName,
+        local_workspace_path: impl Into<PathBuf>,
+    ) -> PathBuf {
+        let sheet_name_str = snake_case!(sheet_name.as_str());
+        let draft_path = CLIENT_PATH_LOCAL_DRAFT.replace(SHEET_NAME, &sheet_name_str);
+        local_workspace_path.into().join(draft_path)
+    }
+
+    /// Get current draft folder
+    pub fn current_draft_folder(&self) -> Option<PathBuf> {
+        let Some(sheet_name) = self.sheet_in_use() else {
+            return None;
+        };
+
+        let Some(current_dir) = current_local_path() else {
+            return None;
+        };
+
+        Some(self.draft_folder(sheet_name, current_dir))
+    }
+}
+
+#[derive(Clone)]
+struct MovedItem {
+    source: PathBuf,
+    target: PathBuf,
 }
diff --git a/crates/vcs_data/src/data/local/latest_info.rs b/crates/vcs_data/src/data/local/latest_info.rs
index 5a76277..6b116d8 100644
--- a/crates/vcs_data/src/data/local/latest_info.rs
+++ b/crates/vcs_data/src/data/local/latest_info.rs
@@ -4,7 +4,7 @@ use serde::{Deserialize, Serialize};
 use crate::{
     constants::CLIENT_FILE_LATEST_INFO,
     data::{
-        member::Member,
+        member::{Member, MemberId},
         sheet::{SheetData, SheetName},
     },
 };
@@ -16,7 +16,7 @@ pub struct LatestInfo {
     /// My sheets, indicating which sheets I can edit
     pub my_sheets: Vec<SheetName>,
     /// Other sheets, indicating which sheets I can export files to (these sheets are not readable to me)
-    pub other_sheets: Vec<SheetName>,
+    pub other_sheets: Vec<SheetInfo>,
     /// Reference sheet data, indicating what files I can get from the reference sheet
     pub ref_sheet_content: SheetData,
 
@@ -26,3 +26,9 @@ pub struct LatestInfo {
 }
 
 impl LatestInfo {}
+
+#[derive(Default, Serialize, Deserialize)]
+pub struct SheetInfo {
+    pub sheet_name: SheetName,
+    pub holder_name: Option<MemberId>,
+}
diff --git a/crates/vcs_data/src/data/sheet.rs b/crates/vcs_data/src/data/sheet.rs
index b558c0d..ce450a6 100644
--- a/crates/vcs_data/src/data/sheet.rs
+++ b/crates/vcs_data/src/data/sheet.rs
@@ -51,7 +51,7 @@ pub struct Sheet<'a> {
 #[derive(Default, Serialize, Deserialize, ConfigFile, Clone)]
 pub struct SheetData {
     /// The holder of the current sheet, who has full operation rights to the sheet mapping
-    pub(crate) holder: MemberId,
+    pub(crate) holder: Option<MemberId>,
 
     /// Inputs
     pub(crate) inputs: Vec<InputPackage>,
@@ -66,8 +66,8 @@ impl<'a> Sheet<'a> {
     }
 
     /// Get the holder of this sheet
-    pub fn holder(&self) -> &MemberId {
-        &self.data.holder
+    pub fn holder(&self) -> Option<&MemberId> {
+        self.data.holder.as_ref()
     }
 
     /// Get the inputs of this sheet
@@ -143,10 +143,11 @@ impl<'a> Sheet<'a> {
     /// Add (or Edit) a mapping entry to the sheet
     ///
     /// This operation performs safety checks to ensure the member has the right to add the mapping:
-    /// 1. If the virtual file ID doesn't exist in the vault, the mapping is added directly
-    /// 2. If the virtual file exists, check if the member has edit rights to the virtual file
-    /// 3. If member has edit rights, the mapping is not allowed to be modified and returns an error
-    /// 4. If member doesn't have edit rights, the mapping is allowed (member is giving up the file)
+    /// 1. The sheet must have a holder (member) to perform this operation
+    /// 2. If the virtual file ID doesn't exist in the vault, the mapping is added directly
+    /// 3. If the virtual file exists, check if the member has edit rights to the virtual file
+    /// 4. If member has edit rights, the mapping is not allowed to be modified and returns an error
+    /// 5. If member doesn't have edit rights, the mapping is allowed (member is giving up the file)
     ///
     /// Note: Full validation adds overhead - avoid frequent calls
     pub async fn add_mapping(
@@ -161,10 +162,18 @@ impl<'a> Sheet<'a> {
             return Ok(());
         }
 
+        // Check if the sheet has a holder
+        let Some(holder) = self.holder() else {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::PermissionDenied,
+                "This sheet has no holder",
+            ));
+        };
+
         // Check if the holder has edit rights to the virtual file
         match self
             .vault_reference
-            .has_virtual_file_edit_right(self.holder(), &virtual_file_id)
+            .has_virtual_file_edit_right(holder, &virtual_file_id)
             .await
         {
             Ok(false) => {
@@ -191,9 +200,10 @@ impl<'a> Sheet<'a> {
     /// Remove a mapping entry from the sheet
     ///
     /// This operation performs safety checks to ensure the member has the right to remove the mapping:
-    /// 1. Member must NOT have edit rights to the virtual file to release it (ensuring clear ownership)
-    /// 2. If the virtual file doesn't exist, the mapping is removed but no ID is returned
-    /// 3. If member has no edit rights and the file exists, returns the removed virtual file ID
+    /// 1. The sheet must have a holder (member) to perform this operation
+    /// 2. Member must NOT have edit rights to the virtual file to release it (ensuring clear ownership)
+    /// 3. If the virtual file doesn't exist, the mapping is removed but no ID is returned
+    /// 4. If member has no edit rights and the file exists, returns the removed virtual file ID
     ///
     /// Note: Full validation adds overhead - avoid frequent calls
     pub async fn remove_mapping(&mut self, sheet_path: &SheetPathBuf) -> Option<VirtualFileId> {
@@ -212,10 +222,15 @@ impl<'a> Sheet<'a> {
             return None;
         }
 
+        // Check if the sheet has a holder
+        let Some(holder) = self.holder() else {
+            return None;
+        };
+
         // Check if the holder has edit rights to the virtual file
         match self
             .vault_reference
-            .has_virtual_file_edit_right(self.holder(), virtual_file_id)
+            .has_virtual_file_edit_right(holder, virtual_file_id)
             .await
         {
             Ok(false) => {
diff --git a/crates/vcs_data/src/data/vault/sheets.rs b/crates/vcs_data/src/data/vault/sheets.rs
index 0bba4f5..1407350 100644
--- a/crates/vcs_data/src/data/vault/sheets.rs
+++ b/crates/vcs_data/src/data/vault/sheets.rs
@@ -130,7 +130,7 @@ impl Vault {
 
         // Create the sheet file
         let sheet_data = SheetData {
-            holder: holder.clone(),
+            holder: Some(holder.clone()),
             inputs: Vec::new(),
             mapping: HashMap::new(),
         };
diff --git a/crates/vcs_data/vcs_data_test/src/test_sheet_creation_management_and_persistence.rs b/crates/vcs_data/vcs_data_test/src/test_sheet_creation_management_and_persistence.rs
index 7484e4b..f256436 100644
--- a/crates/vcs_data/vcs_data_test/src/test_sheet_creation_management_and_persistence.rs
+++ b/crates/vcs_data/vcs_data_test/src/test_sheet_creation_management_and_persistence.rs
@@ -36,8 +36,8 @@ async fn test_sheet_creation_management_and_persistence() -> Result<(), std::io:
     let sheet = vault.create_sheet(&sheet_name, &member_id).await?;
 
     // Verify sheet properties
-    assert_eq!(sheet.holder(), &member_id);
-    assert_eq!(sheet.holder(), &member_id);
+    assert_eq!(sheet.holder(), Some(&member_id));
+    assert_eq!(sheet.holder(), Some(&member_id));
     assert!(sheet.inputs().is_empty());
     assert!(sheet.mapping().is_empty());
 
@@ -100,7 +100,7 @@ async fn test_sheet_creation_management_and_persistence() -> Result<(), std::io:
 
     // Verify persistence by reloading the sheet
     let reloaded_sheet = vault.sheet(&sheet_name).await?;
-    assert_eq!(reloaded_sheet.holder(), &member_id);
+    assert_eq!(reloaded_sheet.holder(), Some(&member_id));
     assert_eq!(reloaded_sheet.inputs().len(), 1);
     assert_eq!(reloaded_sheet.mapping().len(), 3);
 
@@ -129,16 +129,16 @@ async fn test_sheet_creation_management_and_persistence() -> Result<(), std::io:
     // One sheet should be the test sheet, the other should be the ref sheet with host as holder
     let test_sheet_holder = all_sheets
         .iter()
-        .find(|s| s.holder() == &member_id)
+        .find(|s| s.holder() == Some(&member_id))
         .map(|s| s.holder())
         .unwrap();
     let ref_sheet_holder = all_sheets
         .iter()
-        .find(|s| s.holder() == &"host".to_string())
+        .find(|s| s.holder() == Some(&"host".to_string()))
         .map(|s| s.holder())
         .unwrap();
-    assert_eq!(test_sheet_holder, &member_id);
-    assert_eq!(ref_sheet_holder, &"host".to_string());
+    assert_eq!(test_sheet_holder, Some(&member_id));
+    assert_eq!(ref_sheet_holder, Some(&"host".to_string()));
 
     // Test 8: Safe deletion (move to trash)
     vault.delete_sheet_safely(&sheet_name).await?;
@@ -150,8 +150,8 @@ async fn test_sheet_creation_management_and_persistence() -> Result<(), std::io:
 
     // Test 9: Restore sheet from trash
     let restored_sheet = vault.sheet(&sheet_name).await?;
-    assert_eq!(restored_sheet.holder(), &member_id);
-    assert_eq!(restored_sheet.holder(), &member_id);
+    assert_eq!(restored_sheet.holder(), Some(&member_id));
+    assert_eq!(restored_sheet.holder(), Some(&member_id));
 
     // Verify sheet is back in normal listing
     let sheet_names_after_restore = vault.sheet_names()?;