Give plugins the ability to read pane contents (#4465)

* initial implementation

* add Selection and better types

* event to plugins

* only send viewport diff

* simplify data structure sent over the wire

* cleanups

* rustfmt

* remove dead code and fix tests

* commit tests

* get pane scrollback plugin command without implementation

* add lines above and lines below to pane contents

* implement get scrollback plugin command

* selection => selected_text

* add convenience method to get the selected text

* move Selection back to zellij-server

* rustfmt

* bring back client id to get contents command

* rustfmt

* add pr

1 files changed, 41 insertions, 0 deletions

diff --git a/zellij-tile/src/shim.rs b/zellij-tile/src/shim.rs
index 7afe0186..6030dcc7 100644
--- a/zellij-tile/src/shim.rs
+++ b/zellij-tile/src/shim.rs
@@ -8,6 +8,7 @@ use zellij_utils::data::*;
 use zellij_utils::errors::prelude::*;
 use zellij_utils::input::actions::Action;
 pub use zellij_utils::plugin_api;
+use zellij_utils::plugin_api::event::ProtobufPaneScrollbackResponse;
 use zellij_utils::plugin_api::plugin_command::{
     CreateTokenResponse, ListTokensResponse, ProtobufPluginCommand, RenameWebTokenResponse,
     RevokeAllWebTokensResponse, RevokeTokenResponse,
@@ -1045,6 +1046,46 @@ pub fn edit_scrollback_for_pane_with_id(pane_id: PaneId) {
     unsafe { host_run_plugin_command() };
 }
 
+/// Retrieves the scrollback contents from the specified pane
+///
+/// # Arguments
+/// * `pane_id` - The ID of the pane to get scrollback from
+/// * `get_full_scrollback` - Whether to retrieve the full scrollback buffer (including lines above and below viewport)
+///
+/// # Returns
+/// * `Ok(PaneContents)` - The pane contents if successful
+/// * `Err(String)` - An error message if the pane was not found, timed out, or another error occurred
+pub fn get_pane_scrollback(
+    pane_id: PaneId,
+    get_full_scrollback: bool,
+) -> Result<PaneContents, String> {
+    let plugin_command = PluginCommand::GetPaneScrollback {
+        pane_id,
+        get_full_scrollback,
+    };
+    let protobuf_plugin_command: ProtobufPluginCommand = plugin_command.try_into().unwrap();
+    object_to_stdout(&protobuf_plugin_command.encode_to_vec());
+    unsafe { host_run_plugin_command() };
+
+    // Read response from stdin
+    let response_bytes =
+        bytes_from_stdin().map_err(|e| format!("Failed to read response from stdin: {:?}", e))?;
+
+    // Decode protobuf response
+    let protobuf_response = ProtobufPaneScrollbackResponse::decode(response_bytes.as_slice())
+        .map_err(|e| format!("Failed to decode protobuf response: {}", e))?;
+
+    // Convert to Rust type
+    let response = PaneScrollbackResponse::try_from(protobuf_response)
+        .map_err(|e| format!("Failed to convert protobuf response: {}", e))?;
+
+    // Convert Result enum to actual Result type
+    match response {
+        PaneScrollbackResponse::Ok(contents) => Ok(contents),
+        PaneScrollbackResponse::Err(error_msg) => Err(error_msg),
+    }
+}
+
 /// Write bytes to the `STDIN` of the specified pane
 pub fn write_to_pane_id(bytes: Vec<u8>, pane_id: PaneId) {
     let plugin_command = PluginCommand::WriteToPaneId(bytes, pane_id);