par-term 0.39.0

//! Layout-change tmux notification handler.
//!
//! `handle_tmux_layout_change` parses the tmux layout string, reconciles it
//! with the current native pane tree, and delegates to one of four case
//! handlers in `layout_apply`:
//!
//! - same panes (geometry only)
//! - panes removed
//! - panes added
//! - full recreation
//!
//! `request_pane_refresh` and `log_layout_node` are helpers used exclusively
//! by the layout handler.

use crate::app::window_state::WindowState;
use crate::tmux::{TmuxLayout, TmuxWindowId};

/// Render bounds info passed through layout helper methods.
///
/// Fields: (physical_size, scale_factor, viewport_x, viewport_y, cell_width, cell_height, line_height)
pub(super) type BoundsInfo = Option<(winit::dpi::PhysicalSize<u32>, f32, f32, f32, f32, f32, f32)>;

impl WindowState {
    /// Request content refresh for specific panes
    ///
    /// After learning about panes from a layout change, we ask tmux to refresh
    /// the client view so that existing pane content is re-sent via %output.
    /// We deliberately avoid sending C-l (Ctrl+L) to individual panes because
    /// doing so causes TUI apps (vim, htop, etc.) to re-emit their full escape
    /// sequence initialisation (alt-screen, mouse-tracking, etc.), which would
    /// corrupt par-term's local virtual terminal state and break mouse focus.
    pub(super) fn request_pane_refresh(&self, pane_ids: &[crate::tmux::TmuxPaneId]) {
        // Request client refresh so tmux re-sends current pane content
        let refresh_cmd = "refresh-client\n";
        if self.write_to_gateway(refresh_cmd) {
            crate::debug_info!(
                "TMUX",
                "Requested client refresh for {} panes",
                pane_ids.len()
            );
        }
    }

    /// Handle layout change notification - updates pane arrangement
    pub(super) fn handle_tmux_layout_change(&mut self, window_id: TmuxWindowId, layout_str: &str) {
        crate::debug_info!(
            "TMUX",
            "Layout changed for window @{}: {}",
            window_id,
            layout_str
        );

        // Parse the layout string
        let parsed_layout = match TmuxLayout::parse(layout_str) {
            Some(layout) => layout,
            None => {
                crate::debug_error!(
                    "TMUX",
                    "Failed to parse layout string for window @{}: {}",
                    window_id,
                    layout_str
                );
                return;
            }
        };

        // Log the parsed layout structure
        let pane_ids = parsed_layout.pane_ids();
        crate::debug_info!(
            "TMUX",
            "Parsed layout for window @{}: {} panes (IDs: {:?})",
            window_id,
            pane_ids.len(),
            pane_ids
        );

        // Log the layout structure for debugging
        Self::log_layout_node(&parsed_layout.root, 0);

        // Update focused pane in session if we have one
        if !pane_ids.is_empty()
            && let Some(session) = &mut self.tmux_state.tmux_session
        {
            // Default to first pane if no focused pane set
            if session.focused_pane().is_none() {
                session.set_focused_pane(Some(pane_ids[0]));
            }
        }

        // Find the corresponding tab and create window mapping if needed
        let tab_id = if let Some(id) = self.tmux_state.tmux_sync.get_tab(window_id) {
            Some(id)
        } else {
            // No window mapping exists - try to find a tab that has one of our panes
            // This happens when we connect to an existing session and receive layout before window-add
            let mut found_tab_id = None;
            for pane_id in &pane_ids {
                // Check if any tab has this tmux_pane_id set
                for tab in self.tab_manager.tabs() {
                    if tab.tmux.tmux_pane_id == Some(*pane_id) {
                        found_tab_id = Some(tab.id);
                        crate::debug_info!(
                            "TMUX",
                            "Found existing tab {} with pane %{} for window @{}",
                            tab.id,
                            pane_id,
                            window_id
                        );
                        break;
                    }
                }
                if found_tab_id.is_some() {
                    break;
                }
            }

            // If we found a tab, create the window mapping
            if let Some(tid) = found_tab_id {
                self.tmux_state.tmux_sync.map_window(window_id, tid);
                crate::debug_info!(
                    "TMUX",
                    "Created window mapping: @{} -> tab {}",
                    window_id,
                    tid
                );
            }

            found_tab_id
        };

        // Get bounds info from renderer for proper pane sizing (needed for both paths)
        // Calculate status bar height for proper content area
        let is_tmux_connected = self.is_tmux_connected();
        let status_bar_height = crate::tmux_status_bar_ui::TmuxStatusBarUI::height(
            &self.config.load(),
            is_tmux_connected,
        );
        let custom_status_bar_height = self
            .status_bar_ui
            .height(&self.config.load(), self.is_fullscreen);

        let bounds_info = self.renderer.as_ref().map(|r| {
            let size = r.size();
            let padding = r.window_padding();
            let content_offset_y = r.content_offset_y();
            let content_inset_right = r.content_inset_right();
            let cell_width = r.cell_width();
            let cell_height = r.cell_height();
            // Scale status_bar_height from logical to physical pixels
            let physical_status_bar_height =
                (status_bar_height + custom_status_bar_height) * r.scale_factor();
            (
                size,
                padding,
                content_offset_y,
                content_inset_right,
                cell_width,
                cell_height,
                physical_status_bar_height,
            )
        });

        if let Some(tab_id) = tab_id {
            self.apply_layout_to_existing_tab(
                tab_id,
                window_id,
                &parsed_layout,
                &pane_ids,
                bounds_info,
            );
        } else {
            // No tab mapping found - create a new tab for this tmux window
            self.create_tab_for_layout(window_id, &parsed_layout, &pane_ids, bounds_info);
        }
    }

    /// Apply a parsed tmux layout to an already-mapped tab.
    ///
    /// Handles four cases in priority order — delegates to helpers in `layout_apply`:
    /// 1. Same panes — preserve terminals, update layout structure.
    /// 2. Panes removed — incrementally close removed native panes, update layout.
    /// 3. Panes added — rebuild tree preserving existing terminals, add new ones.
    /// 4. Full recreation — completely replace the pane tree.
    fn apply_layout_to_existing_tab(
        &mut self,
        tab_id: crate::tab::TabId,
        window_id: TmuxWindowId,
        parsed_layout: &TmuxLayout,
        pane_ids: &[crate::tmux::TmuxPaneId],
        bounds_info: BoundsInfo,
    ) {
        crate::debug_info!(
            "TMUX",
            "Layout change for window @{} on tab {} - {} panes: {:?}",
            window_id,
            tab_id,
            pane_ids.len(),
            pane_ids
        );

        let Some(tab) = self.tab_manager.get_tab_mut(tab_id) else {
            return;
        };

        // Initialize pane manager if needed
        tab.init_pane_manager();

        // Set pane bounds before applying layout
        if let Some((
            size,
            padding,
            content_offset_y,
            content_inset_right,
            _cell_width,
            _cell_height,
            status_bar_height,
        )) = bounds_info
            && let Some(pm) = tab.pane_manager_mut()
        {
            // Tmux layouts always have multiple panes; hide window padding if configured
            let effective_padding = if self.config.load().window.hide_window_padding_on_split {
                0.0
            } else {
                padding
            };
            let content_width = size.width as f32 - effective_padding * 2.0 - content_inset_right;
            let content_height =
                size.height as f32 - content_offset_y - effective_padding - status_bar_height;
            let bounds = crate::pane::PaneBounds::new(
                effective_padding,
                content_offset_y,
                content_width,
                content_height,
            );
            pm.set_bounds(bounds);
            crate::debug_info!(
                "TMUX",
                "Set pane manager bounds: {}x{} at ({}, {})",
                content_width,
                content_height,
                effective_padding,
                content_offset_y
            );
        }

        // Compute set deltas between existing and new tmux pane IDs
        let existing_tmux_ids: std::collections::HashSet<_> = self
            .tmux_state
            .tmux_pane_to_native_pane
            .keys()
            .copied()
            .collect();
        let new_tmux_ids: std::collections::HashSet<_> = pane_ids.iter().copied().collect();

        if existing_tmux_ids == new_tmux_ids && !existing_tmux_ids.is_empty() {
            // Same panes - preserve terminals but update layout structure
            self.handle_same_pane_layout_update(tab_id, parsed_layout, bounds_info);
            return;
        }

        let panes_to_keep: std::collections::HashSet<_> = existing_tmux_ids
            .intersection(&new_tmux_ids)
            .copied()
            .collect();
        let panes_to_remove: Vec<_> = existing_tmux_ids
            .difference(&new_tmux_ids)
            .copied()
            .collect();
        let panes_to_add: Vec<_> = new_tmux_ids
            .difference(&existing_tmux_ids)
            .copied()
            .collect();

        if !panes_to_keep.is_empty() && !panes_to_remove.is_empty() && panes_to_add.is_empty() {
            self.handle_pane_removal(
                tab_id,
                parsed_layout,
                &panes_to_keep,
                &panes_to_remove,
                bounds_info,
            );
            return;
        }

        if !panes_to_keep.is_empty() && !panes_to_add.is_empty() && panes_to_remove.is_empty() {
            self.handle_pane_addition(
                tab_id,
                parsed_layout,
                &panes_to_keep,
                &panes_to_add,
                bounds_info,
            );
            return;
        }

        // Full layout recreation needed (complete replacement or complex changes)
        self.handle_full_layout_recreation(tab_id, window_id, parsed_layout, pane_ids, bounds_info);
    }

    /// Log a layout node and its children recursively for debugging
    pub(super) fn log_layout_node(node: &crate::tmux::LayoutNode, depth: usize) {
        let indent = "  ".repeat(depth);
        match node {
            crate::tmux::LayoutNode::Pane {
                id,
                width,
                height,
                x,
                y,
            } => {
                crate::debug_trace!(
                    "TMUX",
                    "{}Pane %{}: {}x{} at ({}, {})",
                    indent,
                    id,
                    width,
                    height,
                    x,
                    y
                );
            }
            crate::tmux::LayoutNode::VerticalSplit {
                width,
                height,
                x,
                y,
                children,
            } => {
                crate::debug_trace!(
                    "TMUX",
                    "{}VerticalSplit: {}x{} at ({}, {}) with {} children",
                    indent,
                    width,
                    height,
                    x,
                    y,
                    children.len()
                );
                for child in children {
                    Self::log_layout_node(child, depth + 1);
                }
            }
            crate::tmux::LayoutNode::HorizontalSplit {
                width,
                height,
                x,
                y,
                children,
            } => {
                crate::debug_trace!(
                    "TMUX",
                    "{}HorizontalSplit: {}x{} at ({}, {}) with {} children",
                    indent,
                    width,
                    height,
                    x,
                    y,
                    children.len()
                );
                for child in children {
                    Self::log_layout_node(child, depth + 1);
                }
            }
        }
    }
}