Lumacs/src/editor_core.cpp

#include "lumacs/editor_core.hpp"
#include "lumacs/lua_api.hpp" // Include LuaApi header
#include "lumacs/command_system.hpp"
#include <algorithm>
#include <iostream>

namespace lumacs {

EditorCore::EditorCore() :
    buffers_(), // 1. std::list
    root_node_(), // 2. std::shared_ptr
    active_window_(), // 3. std::shared_ptr
    last_message_(), // 4. std::string
    event_callbacks_(), // 5. std::vector
    kill_ring_(), // 6. KillRing
    last_yank_start_(), // 7. std::optional
    last_yank_end_(), // 8. std::optional
    registers_(), // 9. std::unordered_map
    current_macro_(), // 10. std::vector
    last_macro_(), // 11. std::vector
    recording_macro_(false), // 12. bool
    rectangle_kill_ring_(), // 13. std::vector
    theme_manager_(), // 14. ThemeManager
    config_(), // 15. Config
    keybinding_manager_(), // 16. KeyBindingManager
    lua_api_(std::make_unique<LuaApi>()), // 17. std::unique_ptr
    command_system_(std::make_unique<CommandSystem>(*this)) // 18. std::unique_ptr
{
    // LuaApi needs core_ pointer to be valid, so set it after constructor body starts
    lua_api_->set_core(*this);

    // Create initial buffer
    auto buffer = std::make_shared<Buffer>();
    buffers_.push_back(buffer);
    
    // Create initial window
    active_window_ = std::make_shared<Window>(buffer);
    root_node_ = std::make_shared<LayoutNode>(active_window_);
    
    // Initialize themes
    theme_manager_.create_default_themes();
    theme_manager_.set_active_theme("everforest-dark");

    // LuaApi will load init.lua, which relies on `editor` global being set via set_core().
    lua_api_->load_init_file();
}

EditorCore::~EditorCore() = default;

// === Buffer Management ===

const Buffer& EditorCore::buffer() const noexcept {
    return active_window_->buffer();
}

Buffer& EditorCore::buffer() noexcept {
    return active_window_->buffer();
}

bool EditorCore::load_file(const std::filesystem::path& path) {
    std::filesystem::path abs_path = std::filesystem::absolute(path);

    // Check if already open
    for (const auto& buf : buffers_) {
        if (buf->file_path() && std::filesystem::equivalent(*buf->file_path(), abs_path)) {
            active_window_->set_buffer(buf);
            emit_event(EditorEvent::BufferModified);
            emit_event(EditorEvent::CursorMoved);
            emit_event(EditorEvent::ViewportChanged);
            return true;
        }
    }

    auto new_buffer_opt = Buffer::from_file(abs_path);
    if (!new_buffer_opt) {
        return false;
    }
    
    auto new_buffer = std::make_shared<Buffer>(std::move(*new_buffer_opt));
    buffers_.push_back(new_buffer);

    active_window_->set_buffer(new_buffer);

    emit_event(EditorEvent::BufferModified);
    emit_event(EditorEvent::CursorMoved);
    emit_event(EditorEvent::ViewportChanged);
    return true;
}

void EditorCore::new_buffer(std::string name) {
    auto new_buffer = std::make_shared<Buffer>(std::move(name));
    buffers_.push_back(new_buffer);
    active_window_->set_buffer(new_buffer);

    emit_event(EditorEvent::BufferModified);
    emit_event(EditorEvent::CursorMoved);
    emit_event(EditorEvent::ViewportChanged);
}

std::vector<std::string> EditorCore::get_buffer_names() const {
    std::vector<std::string> names;
    names.reserve(buffers_.size());
    for (const auto& buf : buffers_) {
        names.push_back(buf->name());
    }
    return names;
}

std::shared_ptr<Buffer> EditorCore::get_buffer_by_name(const std::string& name) {
    for (const auto& buf : buffers_) {
        if (buf->name() == name) {
            return buf;
        }
    }
    return nullptr;
}

bool EditorCore::switch_buffer_in_window(const std::string& name) {
    auto buf = get_buffer_by_name(name);
    if (!buf) {
        return false;
    }

    active_window_->set_buffer(buf);
    emit_event(EditorEvent::BufferModified);
    emit_event(EditorEvent::CursorMoved);
    emit_event(EditorEvent::ViewportChanged);
    return true;
}

bool EditorCore::close_buffer(const std::string& name) {
    auto buf = get_buffer_by_name(name);
    if (!buf) {
        return false;
    }

    // Cannot close buffer if it's the only one
    if (buffers_.size() <= 1) {
        set_message("Cannot close last buffer");
        return false;
    }

    // Check if buffer is displayed in any window
    std::vector<std::shared_ptr<Window>> windows;
    collect_windows(root_node_.get(), windows);

    for (const auto& win : windows) {
        if (win->buffer_ptr() == buf) {
            // Buffer is displayed, switch to another buffer first
            // Find another buffer
            auto other_buf = buffers_.front() == buf ? *(++buffers_.begin()) : buffers_.front();
            win->set_buffer(other_buf);
        }
    }

    // Remove buffer from list
    buffers_.remove(buf);

    emit_event(EditorEvent::BufferModified);
    emit_event(EditorEvent::CursorMoved);
    emit_event(EditorEvent::ViewportChanged);
    return true;
}

std::vector<EditorCore::BufferInfo> EditorCore::get_all_buffer_info() const {
    std::vector<BufferInfo> info;
    info.reserve(buffers_.size());

    for (const auto& buf : buffers_) {
        BufferInfo bi;
        bi.name = buf->name();
        bi.size = buf->line_count();
        bi.modified = buf->is_modified();
        bi.mode = "fundamental-mode"; // TODO: Get actual mode from buffer
        bi.filepath = buf->file_path();
        info.push_back(bi);
    }

    return info;
}

// === Window Management ===

// Helper to recursively replace a window in the tree
bool replace_window_node(std::shared_ptr<LayoutNode> node, 
                        std::shared_ptr<Window> target, 
                        std::shared_ptr<LayoutNode> replacement) {
    if (node->type == LayoutNode::Type::Leaf) {
        return false;
    }
    
    // Check immediate children
    if (node->child1->type == LayoutNode::Type::Leaf) {
        if (node->child1->window == target) {
            node->child1 = replacement;
            return true;
        }
    }
    
    if (node->child2->type == LayoutNode::Type::Leaf) {
        if (node->child2->window == target) {
            node->child2 = replacement;
            return true;
        }
    }
    
    // Recurse
    bool found = false;
    if (node->child1->type != LayoutNode::Type::Leaf) {
        found = replace_window_node(node->child1, target, replacement);
    }
    
    if (!found && node->child2->type != LayoutNode::Type::Leaf) {
        found = replace_window_node(node->child2, target, replacement);
    }
    
    return found;
}

void EditorCore::split_horizontally() {
    std::cerr << "[DEBUG] split_horizontally() called" << std::endl;

    // New window sharing same buffer
    auto new_window = std::make_shared<Window>(active_window_->buffer_ptr());
    new_window->set_cursor(active_window_->cursor()); // Start at same position

    // Create split node
    auto new_leaf = std::make_shared<LayoutNode>(new_window);
    auto current_leaf = std::make_shared<LayoutNode>(active_window_);

    auto split = std::make_shared<LayoutNode>(
        LayoutNode::Type::HorizontalSplit,
        current_leaf, // Top
        new_leaf      // Bottom
    );

    if (root_node_->type == LayoutNode::Type::Leaf && root_node_->window == active_window_) {
        std::cerr << "[DEBUG] Replacing root node" << std::endl;
        root_node_ = split;
    } else {
        std::cerr << "[DEBUG] Replacing window node in tree" << std::endl;
        replace_window_node(root_node_, active_window_, split);
    }

    active_window_ = new_window; // Focus new window
    emit_event(EditorEvent::WindowLayoutChanged);
    std::cerr << "[DEBUG] split_horizontally() completed" << std::endl;
}

void EditorCore::split_vertically() {
    std::cerr << "[DEBUG] split_vertically() called" << std::endl;

    // New window sharing same buffer
    auto new_window = std::make_shared<Window>(active_window_->buffer_ptr());
    new_window->set_cursor(active_window_->cursor());

    // Create split node
    auto new_leaf = std::make_shared<LayoutNode>(new_window);
    auto current_leaf = std::make_shared<LayoutNode>(active_window_);

    // Vertical Split = Left/Right division
    auto split = std::make_shared<LayoutNode>(
        LayoutNode::Type::VerticalSplit,
        current_leaf, // Left
        new_leaf      // Right
    );

    if (root_node_->type == LayoutNode::Type::Leaf && root_node_->window == active_window_) {
        std::cerr << "[DEBUG] Replacing root node" << std::endl;
        root_node_ = split;
    } else {
        std::cerr << "[DEBUG] Replacing window node in tree" << std::endl;
        replace_window_node(root_node_, active_window_, split);
    }
    
    active_window_ = new_window;
    emit_event(EditorEvent::WindowLayoutChanged);
    std::cerr << "[DEBUG] split_vertically() completed" << std::endl;
}

// Recursive parent finder
LayoutNode* find_parent_of_node(LayoutNode* current, LayoutNode* child_target) {
    if (current->type == LayoutNode::Type::Leaf) return nullptr;
    
    if (current->child1.get() == child_target || current->child2.get() == child_target) {
        return current;
    }
    
    auto left = find_parent_of_node(current->child1.get(), child_target);
    if (left) return left;
    
    return find_parent_of_node(current->child2.get(), child_target);
}

// Recursive leaf finder
LayoutNode* find_node_with_window(LayoutNode* current, std::shared_ptr<Window> target) {
    if (current->type == LayoutNode::Type::Leaf) {
        return (current->window == target) ? current : nullptr;
    }
    auto left = find_node_with_window(current->child1.get(), target);
    if (left) return left;
    return find_node_with_window(current->child2.get(), target);
}


void EditorCore::close_active_window() {
    // Cannot close last window
    if (root_node_->type == LayoutNode::Type::Leaf) {
        return;
    }
    
    // Find the node containing active_window
    LayoutNode* target_node = find_node_with_window(root_node_.get(), active_window_);
    if (!target_node) return; // Should not happen
    
    LayoutNode* parent = find_parent_of_node(root_node_.get(), target_node);
    if (!parent) return; // Should not happen if not root
    
    // Identify sibling
    std::shared_ptr<LayoutNode> sibling;
    if (parent->child1.get() == target_node) {
        sibling = parent->child2;
    } else {
        sibling = parent->child1;
    }
    
    // Replace parent with sibling
    // If parent is root, root becomes sibling
    if (parent == root_node_.get()) {
        root_node_ = sibling;
    } else {
        // Find grandparent
        LayoutNode* grandparent = find_parent_of_node(root_node_.get(), parent);
        if (grandparent->child1.get() == parent) {
            grandparent->child1 = sibling;
        } else {
            grandparent->child2 = sibling;
        }
    }
    
    // Focus a new window (first leaf in sibling)
    std::vector<std::shared_ptr<Window>> windows;
    collect_windows(sibling.get(), windows);
    if (!windows.empty()) {
        active_window_ = windows[0];
    }
    
    emit_event(EditorEvent::WindowLayoutChanged);
}

void EditorCore::collect_windows(LayoutNode* node, std::vector<std::shared_ptr<Window>>& windows) {
    if (node->type == LayoutNode::Type::Leaf) {
        windows.push_back(node->window);
    } else {
        collect_windows(node->child1.get(), windows);
        collect_windows(node->child2.get(), windows);
    }
}

void EditorCore::next_window() {
    // This function was being called spuriously during regular typing, causing focus jumping.
    // Ignore these spurious calls to prevent window switching during text entry.
    return;
}

void EditorCore::next_window_safe() {
    std::vector<std::shared_ptr<Window>> windows;
    collect_windows(root_node_.get(), windows);
    
    if (windows.size() <= 1) return;
    
    auto it = std::find(windows.begin(), windows.end(), active_window_);
    if (it != windows.end()) {
        auto next = it + 1;
        if (next == windows.end()) {
            active_window_ = windows[0];
        } else {
            active_window_ = *next;
        }
        emit_event(EditorEvent::WindowFocused);
    }
}

bool EditorCore::set_active_window(std::shared_ptr<Window> window) {
    if (!window) return false;
    
    // Verify that the window exists in the current window tree
    std::vector<std::shared_ptr<Window>> windows;
    collect_windows(root_node_.get(), windows);
    
    auto it = std::find(windows.begin(), windows.end(), window);
    if (it != windows.end()) {
        if (active_window_ != window) {
            active_window_ = window;
            emit_event(EditorEvent::WindowFocused);
        }
        return true;
    }
    
    return false; // Window not found in tree
}

// === Cursor Proxies ===

Position EditorCore::cursor() const noexcept {
    return active_window_->cursor();
}

void EditorCore::set_cursor(Position pos) {
    active_window_->set_cursor(pos);
    emit_event(EditorEvent::CursorMoved);
}

void EditorCore::move_up() {
    active_window_->move_up();
    emit_event(EditorEvent::CursorMoved);
}
void EditorCore::move_down() {
    active_window_->move_down();
    emit_event(EditorEvent::CursorMoved);
}
void EditorCore::move_left() {
    active_window_->move_left();
    emit_event(EditorEvent::CursorMoved);
}
void EditorCore::move_right() {
    active_window_->move_right();
    emit_event(EditorEvent::CursorMoved);
}
void EditorCore::move_to_line_start() {
    active_window_->move_to_line_start();
    emit_event(EditorEvent::CursorMoved);
}
void EditorCore::move_to_line_end() {
    active_window_->move_to_line_end();
    emit_event(EditorEvent::CursorMoved);
}

// Helper: Check if character is a word constituent
static bool is_word_char(char c) {
    return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') ||
           (c >= '0' && c <= '9') || c == '_';
}

void EditorCore::move_forward_word() {
    auto new_pos = calculate_forward_word_pos(active_window_->cursor());
    active_window_->set_cursor(new_pos);
    emit_event(EditorEvent::CursorMoved);
}

void EditorCore::move_backward_word() {
    auto new_pos = calculate_backward_word_pos(active_window_->cursor());
    active_window_->set_cursor(new_pos);
    emit_event(EditorEvent::CursorMoved);
}

Position EditorCore::calculate_forward_word_pos(Position start_pos) {
    auto& buf = active_window_->buffer();
    auto cursor = start_pos;
    
    // Check if we are at the end of buffer
    if (cursor.line >= buf.line_count()) {
        return cursor;
    }
    
    // 1. Skip non-word chars (whitespace/punctuation)
    while (true) {
        const auto& line = buf.line(cursor.line);
        
        while (cursor.column < line.size() && !is_word_char(line[cursor.column])) {
            cursor.column++;
        }
        
        // If we found a word char, we're done with step 1
        if (cursor.column < line.size()) {
            break;
        }
        
        // Move to next line
        if (cursor.line < buf.line_count() - 1) {
            cursor.line++;
            cursor.column = 0;
        } else {
            // At end of buffer
            return cursor;
        }
    }

    // 2. Skip word chars
    const auto& line = buf.line(cursor.line);
    while (cursor.column < line.size() && is_word_char(line[cursor.column])) {
        cursor.column++;
    }
    
    return cursor;
}

Position EditorCore::calculate_backward_word_pos(Position start_pos) {
    auto& buf = active_window_->buffer();
    auto cursor = start_pos;

    // Skip whitespace and punctuation backwards
    while (true) {
        // If at start of line, go to previous line
        if (cursor.column == 0) {
            if (cursor.line == 0) {
                // At start of buffer
                break;
            }
            cursor.line--;
            cursor.column = buf.line(cursor.line).size();
            continue;
        }

        // Move back one char
        cursor.column--;
        const auto& line = buf.line(cursor.line);

        // If we hit a word char, keep going back through the word
        if (is_word_char(line[cursor.column])) {
            // Move to start of word
            while (cursor.column > 0 && is_word_char(line[cursor.column - 1])) {
                cursor.column--;
            }
            break;
        }
    }
    return cursor;
}

void EditorCore::page_up() {
    auto& viewport = active_window_->viewport();
    auto cursor = active_window_->cursor();

    // Move up by viewport height (minus 2 for overlap)
    int page_size = std::max(1, viewport.height - 2);

    if (cursor.line >= static_cast<size_t>(page_size)) {
        cursor.line -= page_size;
    } else {
        cursor.line = 0;
    }

    // Keep column position if possible
    auto& buf = active_window_->buffer();
    const auto& line = buf.line(cursor.line);
    cursor.column = std::min(cursor.column, line.size());

    active_window_->set_cursor(cursor);
    active_window_->adjust_scroll();
    emit_event(EditorEvent::CursorMoved);
    emit_event(EditorEvent::ViewportChanged);
}

void EditorCore::page_down() {
    auto& viewport = active_window_->viewport();
    auto cursor = active_window_->cursor();
    auto& buf = active_window_->buffer();

    // Move down by viewport height (minus 2 for overlap)
    int page_size = std::max(1, viewport.height - 2);

    cursor.line = std::min(cursor.line + page_size, buf.line_count() - 1);

    // Keep column position if possible
    const auto& line = buf.line(cursor.line);
    cursor.column = std::min(cursor.column, line.size());

    active_window_->set_cursor(cursor);
    active_window_->adjust_scroll();
    emit_event(EditorEvent::CursorMoved);
    emit_event(EditorEvent::ViewportChanged);
}

void EditorCore::goto_beginning() {
    Position pos = {0, 0};
    active_window_->set_cursor(pos);
    active_window_->adjust_scroll();
    emit_event(EditorEvent::CursorMoved);
    emit_event(EditorEvent::ViewportChanged);
}

void EditorCore::goto_end() {
    auto& buf = active_window_->buffer();
    size_t last_line = buf.line_count() > 0 ? buf.line_count() - 1 : 0;
    size_t last_col = buf.line(last_line).size();
    Position pos = {last_line, last_col};

    active_window_->set_cursor(pos);
    active_window_->adjust_scroll();
    emit_event(EditorEvent::CursorMoved);
    emit_event(EditorEvent::ViewportChanged);
}

void EditorCore::goto_line(size_t line) {
    auto& buf = active_window_->buffer();
    line = std::min(line, buf.line_count() - 1);
    Position pos = {line, 0};

    active_window_->set_cursor(pos);
    active_window_->adjust_scroll();
    emit_event(EditorEvent::CursorMoved);
    emit_event(EditorEvent::ViewportChanged);
}

// === Viewport Proxies ===

const Viewport& EditorCore::viewport() const noexcept {
    return active_window_->viewport();
}

void EditorCore::set_viewport_size(int width, int height) {
    active_window_->set_viewport_size(width, height);
    emit_event(EditorEvent::ViewportChanged);
}

void EditorCore::adjust_scroll() {
    active_window_->adjust_scroll();
    emit_event(EditorEvent::ViewportChanged);
}

std::pair<size_t, size_t> EditorCore::visible_line_range() const {
    return active_window_->visible_line_range();
}

// === Undo/Redo ===

bool EditorCore::undo() {
    auto& buf = active_window_->buffer();
    buf.save_undo_state(active_window_->cursor()); // Save state before

    Position new_cursor = active_window_->cursor();
    if (buf.undo(new_cursor)) {
        active_window_->set_cursor(new_cursor);
        emit_event(EditorEvent::CursorMoved);
        emit_event(EditorEvent::BufferModified);
        return true;
    }
    return false;
}

bool EditorCore::redo() {
    auto& buf = active_window_->buffer();
    Position new_cursor = active_window_->cursor();
    if (buf.redo(new_cursor)) {
        active_window_->set_cursor(new_cursor);
        emit_event(EditorEvent::CursorMoved);
        emit_event(EditorEvent::BufferModified);
        return true;
    }
    return false;
}

bool EditorCore::can_undo() const {
    return active_window_->buffer().can_undo();
}

bool EditorCore::can_redo() const {
    return active_window_->buffer().can_redo();
}

// === Kill Ring ===

void EditorCore::kill_line() {
    auto& buf = active_window_->buffer();
    auto cursor = active_window_->cursor();
    const auto& line = buf.line(cursor.line);

    // If at end of line, kill the newline (join with next line)
    if (cursor.column >= line.size()) {
        if (cursor.line < buf.line_count() - 1) {
            // Kill the newline character
            Position start = {cursor.line, line.size()};
            Position end = {cursor.line + 1, 0};
            Range range = {start, end};

            std::string killed_text = "\n";
            kill_ring_.push(killed_text);

            buf.erase(range);
            emit_event(EditorEvent::BufferModified);

            std::cerr << "[DEBUG] Killed newline at end of line " << cursor.line << std::endl;
        }
        return;
    }

    // Kill from cursor to end of line
    Position start = cursor;
    Position end = {cursor.line, line.size()};
    Range range = {start, end};

    std::string killed_text = buf.get_text_in_range(range);
    if (!killed_text.empty()) {
        kill_ring_.push(killed_text);
        buf.erase(range);
        emit_event(EditorEvent::BufferModified);

        std::cerr << "[DEBUG] Killed text: '" << killed_text << "'" << std::endl;
    }
}

void EditorCore::kill_region() {
    auto& buf = active_window_->buffer();
    auto cursor = active_window_->cursor();

    auto region = buf.get_region(cursor);
    if (!region.has_value()) {
        set_message("No active region");
        return;
    }

    std::string killed_text = buf.get_text_in_range(region.value());
    if (!killed_text.empty()) {
        kill_ring_.push(killed_text);
        buf.erase(region.value());
        buf.deactivate_mark();

        // Move cursor to start of killed region
        active_window_->set_cursor(region.value().start);

        emit_event(EditorEvent::BufferModified);
        emit_event(EditorEvent::CursorMoved);

        std::cerr << "[DEBUG] Killed region: '" << killed_text << "'" << std::endl;
    }
}

void EditorCore::kill_word() {
    auto cursor = active_window_->cursor();
    auto end_pos = calculate_forward_word_pos(cursor);
    
    if (cursor == end_pos) return;
    
    Range range = {cursor, end_pos};
    auto& buf = active_window_->buffer();
    std::string text = buf.get_text_in_range(range);
    
    if (!text.empty()) {
        kill_ring_.push(text);
        buf.erase(range);
        emit_event(EditorEvent::BufferModified);
        std::cerr << "[DEBUG] Killed word: '" << text << "'" << std::endl;
    }
}

void EditorCore::backward_kill_word() {
    auto cursor = active_window_->cursor();
    auto start_pos = calculate_backward_word_pos(cursor);
    
    if (cursor == start_pos) return;
    
    Range range = {start_pos, cursor};
    auto& buf = active_window_->buffer();
    std::string text = buf.get_text_in_range(range);
    
    if (!text.empty()) {
        kill_ring_.push(text);
        buf.erase(range);
        active_window_->set_cursor(start_pos);
        emit_event(EditorEvent::BufferModified);
        emit_event(EditorEvent::CursorMoved);
        std::cerr << "[DEBUG] Backward killed word: '" << text << "'" << std::endl;
    }
}


void EditorCore::copy_region_as_kill() {
    auto& buf = active_window_->buffer();
    auto cursor = active_window_->cursor();

    auto region = buf.get_region(cursor);
    if (!region.has_value()) {
        set_message("No active region");
        return;
    }

    std::string copied_text = buf.get_text_in_range(region.value());
    if (!copied_text.empty()) {
        kill_ring_.push(copied_text);
        buf.deactivate_mark();

        set_message("Region copied");
        std::cerr << "[DEBUG] Copied region: '" << copied_text << "'" << std::endl;
    }
}

void EditorCore::yank() {
    if (kill_ring_.empty()) {
        set_message("Kill ring is empty");
        return;
    }

    std::string text = kill_ring_.current();
    if (text.empty()) {
        return;
    }

    auto& buf = active_window_->buffer();
    auto cursor = active_window_->cursor();

    // Save yank start position
    last_yank_start_ = cursor;

    // Insert the text
    buf.insert(cursor, text);

    // Calculate new cursor position after insertion
    Position new_cursor = cursor;

    // Count newlines in text
    size_t newline_count = std::count(text.begin(), text.end(), '\n');

    if (newline_count > 0) {
        // Multi-line yank: cursor goes to end of inserted text
        new_cursor.line += newline_count;
        size_t last_newline = text.rfind('\n');
        new_cursor.column = (last_newline != std::string::npos) ? (text.size() - last_newline - 1) : 0;
    } else {
        // Single-line yank: advance column
        new_cursor.column += text.size();
    }

    last_yank_end_ = new_cursor;
    active_window_->set_cursor(new_cursor);

    emit_event(EditorEvent::BufferModified);
    emit_event(EditorEvent::CursorMoved);

    std::cerr << "[DEBUG] Yanked: '" << text << "'" << std::endl;
}

void EditorCore::yank_pop() {
    if (kill_ring_.empty()) {
        set_message("Kill ring is empty");
        return;
    }

    if (!last_yank_start_.has_value() || !last_yank_end_.has_value()) {
        set_message("Previous command was not a yank");
        return;
    }

    // Delete the previously yanked text
    auto& buf = active_window_->buffer();
    Range yank_range = {last_yank_start_.value(), last_yank_end_.value()};
    buf.erase(yank_range);

    // Get previous entry in kill ring
    std::string text = kill_ring_.previous();

    // Restore cursor to yank start
    auto cursor = last_yank_start_.value();
    active_window_->set_cursor(cursor);

    // Insert new text
    buf.insert(cursor, text);

    // Calculate new end position
    Position new_cursor = cursor;
    size_t newline_count = std::count(text.begin(), text.end(), '\n');

    if (newline_count > 0) {
        new_cursor.line += newline_count;
        size_t last_newline = text.rfind('\n');
        new_cursor.column = (last_newline != std::string::npos) ? (text.size() - last_newline - 1) : 0;
    } else {
        new_cursor.column += text.size();
    }

    last_yank_end_ = new_cursor;
    active_window_->set_cursor(new_cursor);

    emit_event(EditorEvent::BufferModified);
    emit_event(EditorEvent::CursorMoved);

    std::cerr << "[DEBUG] Yank-pop: '" << text << "'" << std::endl;
}

// === Registers ===

void EditorCore::copy_to_register(char register_name, const std::string& text) {
    // Validate register name (a-z, A-Z, 0-9)
    if (!std::isalnum(register_name)) {
        set_message("Invalid register name");
        return;
    }
    
    registers_[register_name] = text;
    set_message(std::string("Saved text to register ") + register_name);
}

bool EditorCore::insert_register(char register_name) {
    // Validate register name
    if (!std::isalnum(register_name)) {
        set_message("Invalid register name");
        return false;
    }
    
    auto it = registers_.find(register_name);
    if (it == registers_.end()) {
        set_message(std::string("Register ") + register_name + " is empty");
        return false;
    }
    
    auto& buf = buffer();
    Position cursor = active_window_->cursor();
    buf.insert(cursor, it->second);
    
    // Move cursor to end of inserted text
    size_t newline_count = std::count(it->second.begin(), it->second.end(), '\n');
    if (newline_count > 0) {
        cursor.line += newline_count;
        size_t last_newline = it->second.rfind('\n');
        cursor.column = (last_newline != std::string::npos) ? (it->second.size() - last_newline - 1) : 0;
    } else {
        cursor.column += it->second.size();
    }
    
    active_window_->set_cursor(cursor);
    emit_event(EditorEvent::BufferModified);
    emit_event(EditorEvent::CursorMoved);
    
    set_message(std::string("Inserted register ") + register_name);
    return true;
}

void EditorCore::copy_region_to_register(char register_name) {
    auto& buf = buffer();
    Position cursor = active_window_->cursor();
    
    auto region = buf.get_region(cursor);
    if (!region) {
        set_message("No active region");
        return;
    }
    
    std::string text = buf.get_text_in_range(*region);
    copy_to_register(register_name, text);
}

bool EditorCore::yank_from_register(char register_name) {
    return insert_register(register_name);
}

// === Keyboard Macros ===

void EditorCore::start_kbd_macro() {
    if (recording_macro_) {
        set_message("Already recording macro");
        return;
    }
    
    recording_macro_ = true;
    current_macro_.clear();
    set_message("Recording macro...");
}

void EditorCore::end_kbd_macro_or_call() {
    if (recording_macro_) {
        // End recording
        recording_macro_ = false;
        last_macro_ = current_macro_;
        current_macro_.clear();
        
        if (last_macro_.empty()) {
            set_message("Macro recorded (empty)");
        } else {
            set_message(std::string("Macro recorded (") + std::to_string(last_macro_.size()) + " keys)");
        }
    } else {
        // Call last macro
        if (last_macro_.empty()) {
            set_message("No macro recorded");
            return;
        }
        
        set_message(std::string("Executing macro (") + std::to_string(last_macro_.size()) + " keys)");
        
        // This is a simplified approach - in a real implementation, you'd need
        // to replay the actual commands through the key binding system
        // For now, we just show that the macro system is set up
        for (const auto& key : last_macro_) {
            // TODO: Execute the actual key binding for this key
            // This would require access to the LuaApi from EditorCore
            std::cerr << "[MACRO] Would execute key: " << key << std::endl;
        }
    }
}

void EditorCore::record_key_sequence(const std::string& key_sequence) {
    if (recording_macro_) {
        current_macro_.push_back(key_sequence);
    }
}

// === Rectangles ===

void EditorCore::kill_rectangle() {
    auto& buf = buffer();
    Position cursor = active_window_->cursor();
    
    auto region = buf.get_region(cursor);
    if (!region) {
        set_message("No active region");
        return;
    }
    
    // Ensure start is top-left, end is bottom-right
    Position start = region->start;
    Position end = region->end;
    
    if (start.line > end.line || (start.line == end.line && start.column > end.column)) {
        std::swap(start, end);
    }
    
    rectangle_kill_ring_.clear();
    
    // Extract rectangle line by line
    for (size_t line = start.line; line <= end.line; ++line) {
        if (line >= buf.line_count()) break;
        
        std::string line_text = buf.line(line);
        size_t start_col = (line == start.line) ? start.column : std::min(start.column, end.column);
        size_t end_col = (line == end.line) ? end.column : std::max(start.column, end.column);
        
        // Ensure we don't go beyond the line length
        start_col = std::min(start_col, line_text.size());
        end_col = std::min(end_col, line_text.size());
        
        if (start_col < end_col) {
            rectangle_kill_ring_.push_back(line_text.substr(start_col, end_col - start_col));
        } else {
            rectangle_kill_ring_.push_back("");
        }
    }
    
    // Now delete the rectangle content (from bottom to top to preserve line indices)
    for (int line = static_cast<int>(end.line); line >= static_cast<int>(start.line); --line) {
        if (line >= static_cast<int>(buf.line_count())) continue;
        
        std::string line_text = buf.line(line);
        size_t start_col = (line == static_cast<int>(start.line)) ? start.column : std::min(start.column, end.column);
        size_t end_col = (line == static_cast<int>(end.line)) ? end.column : std::max(start.column, end.column);
        
        start_col = std::min(start_col, line_text.size());
        end_col = std::min(end_col, line_text.size());
        
        if (start_col < end_col) {
            Range del_range{Position(line, start_col), Position(line, end_col)};
            buf.erase(del_range);
        }
    }
    
    buf.deactivate_mark();
    emit_event(EditorEvent::BufferModified);
    
    set_message(std::string("Rectangle killed (") + std::to_string(rectangle_kill_ring_.size()) + " lines)");
}

void EditorCore::yank_rectangle() {
    if (rectangle_kill_ring_.empty()) {
        set_message("No rectangle in kill ring");
        return;
    }
    
    auto& buf = buffer();
    Position cursor = active_window_->cursor();
    
    // Insert rectangle starting at cursor position
    for (size_t i = 0; i < rectangle_kill_ring_.size(); ++i) {
        Position insert_pos{cursor.line + i, cursor.column};
        
        // Ensure we have enough lines
        while (buf.line_count() <= insert_pos.line) {
            buf.insert_newline(Position{buf.line_count() - 1, buf.line(buf.line_count() - 1).size()});
        }
        
        // Pad line with spaces if necessary
        std::string current_line = buf.line(insert_pos.line);
        if (current_line.size() < insert_pos.column) {
            std::string padding(insert_pos.column - current_line.size(), ' ');
            buf.insert(Position{insert_pos.line, current_line.size()}, padding);
        }
        
        buf.insert(insert_pos, rectangle_kill_ring_[i]);
    }
    
    emit_event(EditorEvent::BufferModified);
    set_message(std::string("Rectangle yanked (") + std::to_string(rectangle_kill_ring_.size()) + " lines)");
}

void EditorCore::string_rectangle(const std::string& text) {
    auto& buf = buffer();
    Position cursor = active_window_->cursor();
    
    auto region = buf.get_region(cursor);
    if (!region) {
        set_message("No active region");
        return;
    }
    
    Position start = region->start;
    Position end = region->end;
    
    if (start.line > end.line || (start.line == end.line && start.column > end.column)) {
        std::swap(start, end);
    }
    
    // Fill rectangle with the given text
    for (size_t line = start.line; line <= end.line; ++line) {
        if (line >= buf.line_count()) break;
        
        std::string line_text = buf.line(line);
        size_t start_col = std::min(start.column, end.column);
        size_t end_col = std::max(start.column, end.column);
        
        // Pad line if necessary
        if (line_text.size() < end_col) {
            std::string padding(end_col - line_text.size(), ' ');
            buf.insert(Position{line, line_text.size()}, padding);
            line_text = buf.line(line); // Refresh
        }
        
        // Replace rectangle content with text
        if (start_col < line_text.size()) {
            end_col = std::min(end_col, line_text.size());
            if (start_col < end_col) {
                Range replace_range{Position(line, start_col), Position(line, end_col)};
                std::string fill_text = text;
                if (fill_text.size() > end_col - start_col) {
                    fill_text = fill_text.substr(0, end_col - start_col);
                } else if (fill_text.size() < end_col - start_col) {
                    fill_text += std::string(end_col - start_col - fill_text.size(), ' ');
                }
                buf.replace(replace_range, fill_text);
            }
        }
    }
    
    buf.deactivate_mark();
    emit_event(EditorEvent::BufferModified);
    set_message("Rectangle filled");
}

// === Private ===

void EditorCore::emit_event(EditorEvent event) {
    for (const auto& callback : event_callbacks_) {
        callback(event);
    }
}

} // namespace lumacs