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

6 files changed, 234 insertions, 21 deletions

diff --git a/zellij-utils/src/plugin_api/event.proto b/zellij-utils/src/plugin_api/event.proto
index 52c1801c..f5059131 100644
--- a/zellij-utils/src/plugin_api/event.proto
+++ b/zellij-utils/src/plugin_api/event.proto
@@ -58,6 +58,7 @@ enum EventType {
     BeforeClose = 32;
     FailedToStartWebServer = 34;
     InterceptedKeyPress = 35;
+    PaneRenderReport = 36;
 }
 
 message EventNameList {
@@ -95,6 +96,7 @@ message Event {
     WebServerStatusPayload web_server_status_payload = 27;
     FailedToStartWebServerPayload failed_to_start_web_server_payload = 28;
     key.Key intercepted_key_payload = 29;
+    PaneRenderReportPayload pane_render_report_payload = 30;
   }
 }
 
@@ -388,3 +390,31 @@ message KeyBind {
   key.Key key = 1;
   repeated action.Action action = 2;
 }
+
+message PaneRenderReportPayload {
+  repeated PaneContentsEntry pane_contents = 1;
+}
+
+message PaneContentsEntry {
+  PaneId pane_id = 1;
+  PaneContents pane_contents = 2;
+}
+
+message PaneContents {
+  repeated string viewport = 1;
+  optional SelectedText selected_text = 2;
+  repeated string lines_above_viewport = 3;
+  repeated string lines_below_viewport = 4;
+}
+
+message PaneScrollbackResponse {
+  oneof response {
+    PaneContents ok = 1;
+    string err = 2;
+  }
+}
+
+message SelectedText {
+  action.Position start = 1;
+  action.Position end = 2;
+}
diff --git a/zellij-utils/src/plugin_api/event.rs b/zellij-utils/src/plugin_api/event.rs
index fe8822e4..02ef1842 100644
--- a/zellij-utils/src/plugin_api/event.rs
+++ b/zellij-utils/src/plugin_api/event.rs
@@ -1,18 +1,21 @@
 pub use super::generated_api::api::{
     action::{Action as ProtobufAction, Position as ProtobufPosition},
     event::{
-        event::Payload as ProtobufEventPayload, ClientInfo as ProtobufClientInfo,
-        ClientTabHistory as ProtobufClientTabHistory, CopyDestination as ProtobufCopyDestination,
-        Event as ProtobufEvent, EventNameList as ProtobufEventNameList,
-        EventType as ProtobufEventType, FileMetadata as ProtobufFileMetadata,
-        InputModeKeybinds as ProtobufInputModeKeybinds, KeyBind as ProtobufKeyBind,
-        LayoutInfo as ProtobufLayoutInfo, ModeUpdatePayload as ProtobufModeUpdatePayload,
-        PaneId as ProtobufPaneId, PaneInfo as ProtobufPaneInfo,
-        PaneManifest as ProtobufPaneManifest, PaneType as ProtobufPaneType,
+        event::Payload as ProtobufEventPayload, pane_scrollback_response,
+        ClientInfo as ProtobufClientInfo, ClientTabHistory as ProtobufClientTabHistory,
+        CopyDestination as ProtobufCopyDestination, Event as ProtobufEvent,
+        EventNameList as ProtobufEventNameList, EventType as ProtobufEventType,
+        FileMetadata as ProtobufFileMetadata, InputModeKeybinds as ProtobufInputModeKeybinds,
+        KeyBind as ProtobufKeyBind, LayoutInfo as ProtobufLayoutInfo,
+        ModeUpdatePayload as ProtobufModeUpdatePayload, PaneContents as ProtobufPaneContents,
+        PaneContentsEntry as ProtobufPaneContentsEntry, PaneId as ProtobufPaneId,
+        PaneInfo as ProtobufPaneInfo, PaneManifest as ProtobufPaneManifest,
+        PaneRenderReportPayload as ProtobufPaneRenderReportPayload,
+        PaneScrollbackResponse as ProtobufPaneScrollbackResponse, PaneType as ProtobufPaneType,
         PluginInfo as ProtobufPluginInfo, ResurrectableSession as ProtobufResurrectableSession,
-        SessionManifest as ProtobufSessionManifest, TabInfo as ProtobufTabInfo,
-        WebServerStatusPayload as ProtobufWebServerStatusPayload, WebSharing as ProtobufWebSharing,
-        *,
+        SelectedText as ProtobufSelectedText, SessionManifest as ProtobufSessionManifest,
+        TabInfo as ProtobufTabInfo, WebServerStatusPayload as ProtobufWebServerStatusPayload,
+        WebSharing as ProtobufWebSharing, *,
     },
     input_mode::InputMode as ProtobufInputMode,
     key::Key as ProtobufKey,
@@ -21,8 +24,9 @@ pub use super::generated_api::api::{
 #[allow(hidden_glob_reexports)]
 use crate::data::{
     ClientInfo, CopyDestination, Event, EventType, FileMetadata, InputMode, KeyWithModifier,
-    LayoutInfo, ModeInfo, Mouse, PaneId, PaneInfo, PaneManifest, PermissionStatus,
-    PluginCapabilities, PluginInfo, SessionInfo, Style, TabInfo, WebServerStatus, WebSharing,
+    LayoutInfo, ModeInfo, Mouse, PaneContents, PaneId, PaneInfo, PaneManifest,
+    PaneScrollbackResponse, PermissionStatus, PluginCapabilities, PluginInfo, SelectedText,
+    SessionInfo, Style, TabInfo, WebServerStatus, WebSharing,
 };
 
 use crate::errors::prelude::*;
@@ -387,6 +391,12 @@ impl TryFrom<ProtobufEvent> for Event {
                 },
                 _ => Err("Malformed payload for the InterceptedKeyPress Event"),
             },
+            Some(ProtobufEventType::PaneRenderReport) => match protobuf_event.payload {
+                Some(ProtobufEventPayload::PaneRenderReportPayload(protobuf_payload)) => {
+                    Ok(Event::PaneRenderReport(protobuf_payload.try_into()?))
+                },
+                _ => Err("Malformed payload for the PaneRenderReport Event"),
+            },
             None => Err("Unknown Protobuf Event"),
         }
     }
@@ -781,6 +791,12 @@ impl TryFrom<Event> for ProtobufEvent {
                 name: ProtobufEventType::InterceptedKeyPress as i32,
                 payload: Some(event::Payload::KeyPayload(key.try_into()?)),
             }),
+            Event::PaneRenderReport(pane_contents_map) => Ok(ProtobufEvent {
+                name: ProtobufEventType::PaneRenderReport as i32,
+                payload: Some(event::Payload::PaneRenderReportPayload(
+                    pane_contents_map.try_into()?,
+                )),
+            }),
         }
     }
 }
@@ -1459,6 +1475,7 @@ impl TryFrom<ProtobufEventType> for EventType {
             ProtobufEventType::BeforeClose => EventType::BeforeClose,
             ProtobufEventType::FailedToStartWebServer => EventType::FailedToStartWebServer,
             ProtobufEventType::InterceptedKeyPress => EventType::InterceptedKeyPress,
+            ProtobufEventType::PaneRenderReport => EventType::PaneRenderReport,
         })
     }
 }
@@ -1502,6 +1519,7 @@ impl TryFrom<EventType> for ProtobufEventType {
             EventType::BeforeClose => ProtobufEventType::BeforeClose,
             EventType::FailedToStartWebServer => ProtobufEventType::FailedToStartWebServer,
             EventType::InterceptedKeyPress => ProtobufEventType::InterceptedKeyPress,
+            EventType::PaneRenderReport => ProtobufEventType::PaneRenderReport,
         })
     }
 }
@@ -2243,3 +2261,134 @@ impl TryFrom<ProtobufWebServerStatusPayload> for WebServerStatus {
         }
     }
 }
+
+impl TryFrom<ProtobufPaneRenderReportPayload> for HashMap<PaneId, PaneContents> {
+    type Error = &'static str;
+    fn try_from(protobuf_payload: ProtobufPaneRenderReportPayload) -> Result<Self, &'static str> {
+        let mut pane_contents_map = HashMap::new();
+
+        for entry in protobuf_payload.pane_contents {
+            let pane_id = entry
+                .pane_id
+                .ok_or("Missing pane_id in PaneContentsEntry")?
+                .try_into()?;
+            let pane_contents = entry
+                .pane_contents
+                .ok_or("Missing pane_contents in PaneContentsEntry")?
+                .try_into()?;
+            pane_contents_map.insert(pane_id, pane_contents);
+        }
+
+        Ok(pane_contents_map)
+    }
+}
+
+impl TryFrom<HashMap<PaneId, PaneContents>> for ProtobufPaneRenderReportPayload {
+    type Error = &'static str;
+    fn try_from(pane_contents_map: HashMap<PaneId, PaneContents>) -> Result<Self, &'static str> {
+        let mut pane_contents_vec = vec![];
+
+        for (pane_id, pane_contents) in pane_contents_map {
+            pane_contents_vec.push(ProtobufPaneContentsEntry {
+                pane_id: Some(pane_id.try_into()?),
+                pane_contents: Some(pane_contents.try_into()?),
+            });
+        }
+
+        Ok(ProtobufPaneRenderReportPayload {
+            pane_contents: pane_contents_vec,
+        })
+    }
+}
+
+impl TryFrom<ProtobufPaneContents> for PaneContents {
+    type Error = &'static str;
+    fn try_from(protobuf_contents: ProtobufPaneContents) -> Result<Self, &'static str> {
+        let selected_text = protobuf_contents
+            .selected_text
+            .map(|st| st.try_into())
+            .transpose()?;
+
+        Ok(PaneContents {
+            viewport: protobuf_contents.viewport,
+            selected_text,
+            lines_above_viewport: protobuf_contents.lines_above_viewport,
+            lines_below_viewport: protobuf_contents.lines_below_viewport,
+        })
+    }
+}
+
+impl TryFrom<PaneContents> for ProtobufPaneContents {
+    type Error = &'static str;
+    fn try_from(pane_contents: PaneContents) -> Result<Self, &'static str> {
+        let selected_text = pane_contents
+            .selected_text
+            .map(|st| st.try_into())
+            .transpose()?;
+
+        Ok(ProtobufPaneContents {
+            viewport: pane_contents.viewport,
+            selected_text,
+            lines_above_viewport: pane_contents.lines_above_viewport,
+            lines_below_viewport: pane_contents.lines_below_viewport,
+        })
+    }
+}
+
+impl TryFrom<ProtobufPaneScrollbackResponse> for PaneScrollbackResponse {
+    type Error = &'static str;
+    fn try_from(protobuf_response: ProtobufPaneScrollbackResponse) -> Result<Self, &'static str> {
+        match protobuf_response.response {
+            Some(pane_scrollback_response::Response::Ok(pane_contents)) => {
+                Ok(PaneScrollbackResponse::Ok(pane_contents.try_into()?))
+            },
+            Some(pane_scrollback_response::Response::Err(error_msg)) => {
+                Ok(PaneScrollbackResponse::Err(error_msg))
+            },
+            None => Err("PaneScrollbackResponse missing response field"),
+        }
+    }
+}
+
+impl TryFrom<PaneScrollbackResponse> for ProtobufPaneScrollbackResponse {
+    type Error = &'static str;
+    fn try_from(response: PaneScrollbackResponse) -> Result<Self, &'static str> {
+        let response_field = match response {
+            PaneScrollbackResponse::Ok(pane_contents) => {
+                pane_scrollback_response::Response::Ok(pane_contents.try_into()?)
+            },
+            PaneScrollbackResponse::Err(error_msg) => {
+                pane_scrollback_response::Response::Err(error_msg)
+            },
+        };
+        Ok(ProtobufPaneScrollbackResponse {
+            response: Some(response_field),
+        })
+    }
+}
+
+impl TryFrom<ProtobufSelectedText> for SelectedText {
+    type Error = &'static str;
+    fn try_from(protobuf_selected_text: ProtobufSelectedText) -> Result<Self, &'static str> {
+        Ok(SelectedText {
+            start: protobuf_selected_text
+                .start
+                .ok_or("Missing start in SelectedText")?
+                .try_into()?,
+            end: protobuf_selected_text
+                .end
+                .ok_or("Missing end in SelectedText")?
+                .try_into()?,
+        })
+    }
+}
+
+impl TryFrom<SelectedText> for ProtobufSelectedText {
+    type Error = &'static str;
+    fn try_from(selected_text: SelectedText) -> Result<Self, &'static str> {
+        Ok(ProtobufSelectedText {
+            start: Some(selected_text.start.try_into()?),
+            end: Some(selected_text.end.try_into()?),
+        })
+    }
+}
diff --git a/zellij-utils/src/plugin_api/plugin_command.proto b/zellij-utils/src/plugin_api/plugin_command.proto
index 49ab98c6..7ffe2fc1 100644
--- a/zellij-utils/src/plugin_api/plugin_command.proto
+++ b/zellij-utils/src/plugin_api/plugin_command.proto
@@ -159,6 +159,7 @@ enum CommandName {
   InterceptKeyPresses = 143;
   ClearKeyPressesIntercepts = 144;
   ReplacePaneWithExistingPane = 155;
+  GetPaneScrollback = 163;
 }
 
 message PluginCommand {
@@ -266,6 +267,7 @@ message PluginCommand {
     RenameWebLoginTokenPayload rename_web_login_token_payload = 110;
     ReplacePaneWithExistingPanePayload replace_pane_with_existing_pane_payload = 111;
     NewTabPayload new_tab_payload = 112;
+    GetPaneScrollbackPayload get_pane_scrollback_payload = 113;
   }
 }
 
@@ -703,3 +705,8 @@ message RenameWebTokenResponse {
   bool successfully_renamed = 1;
   optional string error = 2;
 }
+
+message GetPaneScrollbackPayload {
+  PaneId pane_id = 1;
+  bool get_full_scrollback = 2;
+}
diff --git a/zellij-utils/src/plugin_api/plugin_command.rs b/zellij-utils/src/plugin_api/plugin_command.rs
index 4fc9d939..c1ba877e 100644
--- a/zellij-utils/src/plugin_api/plugin_command.rs
+++ b/zellij-utils/src/plugin_api/plugin_command.rs
@@ -12,14 +12,14 @@ pub use super::generated_api::api::{
         FixedOrPercent as ProtobufFixedOrPercent,
         FixedOrPercentValue as ProtobufFixedOrPercentValue, FloatMultiplePanesPayload,
         FloatingPaneCoordinates as ProtobufFloatingPaneCoordinates, GenerateWebLoginTokenPayload,
-        GroupAndUngroupPanesPayload, HidePaneWithIdPayload, HighlightAndUnhighlightPanesPayload,
-        HttpVerb as ProtobufHttpVerb, IdAndNewName, KeyToRebind, KeyToUnbind, KillSessionsPayload,
-        ListTokensResponse, LoadNewPluginPayload, MessageToPluginPayload,
-        MovePaneWithPaneIdInDirectionPayload, MovePaneWithPaneIdPayload, MovePayload,
-        NewPluginArgs as ProtobufNewPluginArgs, NewTabPayload, NewTabsWithLayoutInfoPayload,
-        OpenCommandPaneFloatingNearPluginPayload, OpenCommandPaneInPlaceOfPluginPayload,
-        OpenCommandPaneNearPluginPayload, OpenCommandPanePayload,
-        OpenFileFloatingNearPluginPayload, OpenFileInPlaceOfPluginPayload,
+        GetPaneScrollbackPayload, GroupAndUngroupPanesPayload, HidePaneWithIdPayload,
+        HighlightAndUnhighlightPanesPayload, HttpVerb as ProtobufHttpVerb, IdAndNewName,
+        KeyToRebind, KeyToUnbind, KillSessionsPayload, ListTokensResponse, LoadNewPluginPayload,
+        MessageToPluginPayload, MovePaneWithPaneIdInDirectionPayload, MovePaneWithPaneIdPayload,
+        MovePayload, NewPluginArgs as ProtobufNewPluginArgs, NewTabPayload,
+        NewTabsWithLayoutInfoPayload, OpenCommandPaneFloatingNearPluginPayload,
+        OpenCommandPaneInPlaceOfPluginPayload, OpenCommandPaneNearPluginPayload,
+        OpenCommandPanePayload, OpenFileFloatingNearPluginPayload, OpenFileInPlaceOfPluginPayload,
         OpenFileNearPluginPayload, OpenFilePayload, OpenTerminalFloatingNearPluginPayload,
         OpenTerminalInPlaceOfPluginPayload, OpenTerminalNearPluginPayload,
         PageScrollDownInPaneIdPayload, PageScrollUpInPaneIdPayload, PaneId as ProtobufPaneId,
@@ -1109,6 +1109,18 @@ impl TryFrom<ProtobufPluginCommand> for PluginCommand {
                 },
                 _ => Err("Mismatched payload for EditScrollback"),
             },
+            Some(CommandName::GetPaneScrollback) => match protobuf_plugin_command.payload {
+                Some(Payload::GetPaneScrollbackPayload(get_pane_scrollback_payload)) => {
+                    match get_pane_scrollback_payload.pane_id {
+                        Some(pane_id) => Ok(PluginCommand::GetPaneScrollback {
+                            pane_id: pane_id.try_into()?,
+                            get_full_scrollback: get_pane_scrollback_payload.get_full_scrollback,
+                        }),
+                        _ => Err("Malformed get_pane_scrollback_payload"),
+                    }
+                },
+                _ => Err("Mismatched payload for GetPaneScrollback"),
+            },
             Some(CommandName::WriteToPaneId) => match protobuf_plugin_command.payload {
                 Some(Payload::WriteToPaneIdPayload(write_to_pane_id_payload)) => {
                     match write_to_pane_id_payload.pane_id {
@@ -2373,6 +2385,18 @@ impl TryFrom<PluginCommand> for ProtobufPluginCommand {
                     },
                 )),
             }),
+            PluginCommand::GetPaneScrollback {
+                pane_id,
+                get_full_scrollback,
+            } => Ok(ProtobufPluginCommand {
+                name: CommandName::GetPaneScrollback as i32,
+                payload: Some(Payload::GetPaneScrollbackPayload(
+                    GetPaneScrollbackPayload {
+                        pane_id: Some(pane_id.try_into()?),
+                        get_full_scrollback,
+                    },
+                )),
+            }),
             PluginCommand::WriteToPaneId(bytes_to_write, pane_id) => Ok(ProtobufPluginCommand {
                 name: CommandName::WriteToPaneId as i32,
                 payload: Some(Payload::WriteToPaneIdPayload(WriteToPaneIdPayload {
diff --git a/zellij-utils/src/plugin_api/plugin_permission.proto b/zellij-utils/src/plugin_api/plugin_permission.proto
index 0f53bb55..85126830 100644
--- a/zellij-utils/src/plugin_api/plugin_permission.proto
+++ b/zellij-utils/src/plugin_api/plugin_permission.proto
@@ -16,4 +16,5 @@ enum PermissionType {
   FullHdAccess = 10;
   StartWebServer = 11;
   InterceptInput = 12;
+  ReadPaneContents = 13;
 }
diff --git a/zellij-utils/src/plugin_api/plugin_permission.rs b/zellij-utils/src/plugin_api/plugin_permission.rs
index 926f993f..307d3576 100644
--- a/zellij-utils/src/plugin_api/plugin_permission.rs
+++ b/zellij-utils/src/plugin_api/plugin_permission.rs
@@ -28,6 +28,7 @@ impl TryFrom<ProtobufPermissionType> for PermissionType {
             ProtobufPermissionType::FullHdAccess => Ok(PermissionType::FullHdAccess),
             ProtobufPermissionType::StartWebServer => Ok(PermissionType::StartWebServer),
             ProtobufPermissionType::InterceptInput => Ok(PermissionType::InterceptInput),
+            ProtobufPermissionType::ReadPaneContents => Ok(PermissionType::ReadPaneContents),
         }
     }
 }
@@ -57,6 +58,7 @@ impl TryFrom<PermissionType> for ProtobufPermissionType {
             PermissionType::FullHdAccess => Ok(ProtobufPermissionType::FullHdAccess),
             PermissionType::StartWebServer => Ok(ProtobufPermissionType::StartWebServer),
             PermissionType::InterceptInput => Ok(ProtobufPermissionType::InterceptInput),
+            PermissionType::ReadPaneContents => Ok(ProtobufPermissionType::ReadPaneContents),
         }
     }
 }