text: /*
   * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright notice, this
   *    list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright notice,
   *    this list of conditions and the following disclaimer in the documentation
   *    and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include <LibGUI/Event.h>
  #include <LibGUI/Window.h>
  #include <LibJS/Runtime/Value.h>
  #include <LibWeb/DOM/Document.h>
  #include <LibWeb/DOM/HTMLAnchorElement.h>
  #include <LibWeb/DOM/HTMLIFrameElement.h>
  #include <LibWeb/DOM/MouseEvent.h>
  #include <LibWeb/Frame/EventHandler.h>
  #include <LibWeb/Frame/Frame.h>
  #include <LibWeb/Layout/LayoutDocument.h>
  #include <LibWeb/PageView.h>
  
  namespace Web {
  
  static Gfx::IntPoint compute_mouse_event_offset(const Gfx::IntPoint& position, const LayoutNode& layout_node)
  {
      auto top_left_of_layout_node = layout_node.box_type_agnostic_position();
      return {
          position.x() - static_cast<int>(top_left_of_layout_node.x()),
          position.y() - static_cast<int>(top_left_of_layout_node.y())
      };
  }
  
  EventHandler::EventHandler(Badge<Frame>, Frame& frame)
      : m_frame(frame)
  {
  }
  
  EventHandler::~EventHandler()
  {
  }
  
  const LayoutDocument* EventHandler::layout_root() const
  {
      if (!m_frame.document())
          return nullptr;
      return static_cast<LayoutDocument*>(m_frame.document()->layout_node());
  }
  
  LayoutDocument* EventHandler::layout_root()
  {
      if (!m_frame.document())
          return nullptr;
      return const_cast<LayoutDocument*>(m_frame.document()->layout_node());
  }
  
  bool EventHandler::handle_mouseup(const Gfx::IntPoint& position, unsigned button, unsigned modifiers)
  {
      auto* layout_root_ptr = this->layout_root();
      if (!layout_root_ptr)
          return false;
      auto& layout_root = *layout_root_ptr;
      bool handled_event = false;
  
      auto result = layout_root.hit_test(position);
      if (result.layout_node && result.layout_node->node()) {
          RefPtr<Node> node = result.layout_node->node();
          if (is<HTMLIFrameElement>(*node)) {
              if (auto* subframe = to<HTMLIFrameElement>(*node).hosted_frame())
                  return subframe->event_handler().handle_mouseup(position.translated(compute_mouse_event_offset({}, *result.layout_node)), button, modifiers);
              return false;
          }
          auto offset = compute_mouse_event_offset(position, *result.layout_node);
          node->dispatch_event(MouseEvent::create("mouseup", offset.x(), offset.y()));
          handled_event = true;
      }
  
      if (button == GUI::MouseButton::Left) {
          dump_selection("MouseUp");
          m_in_mouse_selection = false;
      }
      return handled_event;
  }
  
  bool EventHandler::handle_mousedown(const Gfx::IntPoint& position, unsigned button, unsigned modifiers)
  {
      auto* layout_root_ptr = this->layout_root();
      if (!layout_root_ptr)
          return false;
      auto& layout_root = *layout_root_ptr;
      auto& document = *m_frame.document();
      auto& page_client = m_frame.page().client();
  
      auto result = layout_root.hit_test(position);
      if (!result.layout_node)
          return false;
  
      RefPtr<Node> node = result.layout_node->node();
      document.set_hovered_node(node);
      if (!node)
          return false;
  
      if (is<HTMLIFrameElement>(*node)) {
          if (auto* subframe = to<HTMLIFrameElement>(*node).hosted_frame())
              return subframe->event_handler().handle_mousedown(position.translated(compute_mouse_event_offset({}, *result.layout_node)), button, modifiers);
          return false;
      }
  
      auto offset = compute_mouse_event_offset(position, *result.layout_node);
      node->dispatch_event(MouseEvent::create("mousedown", offset.x(), offset.y()));
      if (RefPtr<HTMLAnchorElement> link = node->enclosing_link_element()) {
          dbg() << "Web::EventHandler: Clicking on a link to " << link->href();
  
          if (button == GUI::MouseButton::Left) {
              auto href = link->href();
              if (href.starts_with("javascript:")) {
                  document.run_javascript(href.substring_view(11, href.length() - 11));
              } else {
                  if (m_frame.is_main_frame()) {
                      page_client.page_did_click_link(link->href(), link->target(), modifiers);
                  } else {
                      // FIXME: Handle different targets!
                      m_frame.loader().load(document.complete_url(link->href()));
                  }
              }
          } else if (button == GUI::MouseButton::Right) {
              page_client.page_did_request_link_context_menu(m_frame.to_main_frame_position(position), link->href(), link->target(), modifiers);
          } else if (button == GUI::MouseButton::Middle) {
              page_client.page_did_middle_click_link(link->href(), link->target(), modifiers);
          }
      } else {
          if (button == GUI::MouseButton::Left) {
              layout_root.selection().set({ result.layout_node, result.index_in_node }, {});
              dump_selection("MouseDown");
              m_in_mouse_selection = true;
          }
      }
      return true;
  }
  
  bool EventHandler::handle_mousemove(const Gfx::IntPoint& position, unsigned buttons, unsigned modifiers)
  {
      auto* layout_root_ptr = this->layout_root();
      if (!layout_root_ptr)
          return false;
      auto& layout_root = *layout_root_ptr;
      auto& document = *m_frame.document();
      auto& page_client = m_frame.page().client();
  
      bool hovered_node_changed = false;
      bool is_hovering_link = false;
      bool was_hovering_link = document.hovered_node() && document.hovered_node()->is_link();
      auto result = layout_root.hit_test(position);
      const HTMLAnchorElement* hovered_link_element = nullptr;
      if (result.layout_node) {
          RefPtr<Node> node = result.layout_node->node();
  
          if (node && is<HTMLIFrameElement>(*node)) {
              if (auto* subframe = to<HTMLIFrameElement>(*node).hosted_frame())
                  return subframe->event_handler().handle_mousemove(position.translated(compute_mouse_event_offset({}, *result.layout_node)), buttons, modifiers);
              return false;
          }
  
          hovered_node_changed = node != document.hovered_node();
          document.set_hovered_node(node);
          if (node) {
              hovered_link_element = node->enclosing_link_element();
              if (hovered_link_element) {
  #ifdef HTML_DEBUG
                  dbg() << "PageView: hovering over a link to " << hovered_link_element->href();
  #endif
                  is_hovering_link = true;
              }
              auto offset = compute_mouse_event_offset(position, *result.layout_node);
              node->dispatch_event(MouseEvent::create("mousemove", offset.x(), offset.y()));
          }
          if (m_in_mouse_selection) {
              layout_root.selection().set_end({ result.layout_node, result.index_in_node });
              dump_selection("MouseMove");
              page_client.page_did_change_selection();
          }
      }
      page_client.page_did_request_cursor_change(is_hovering_link ? GUI::StandardCursor::Hand : GUI::StandardCursor::None);
      if (hovered_node_changed) {
          RefPtr<HTMLElement> hovered_html_element = document.hovered_node() ? document.hovered_node()->enclosing_html_element() : nullptr;
          if (hovered_html_element && !hovered_html_element->title().is_null()) {
              page_client.page_did_enter_tooltip_area(m_frame.to_main_frame_position(position), hovered_html_element->title());
          } else {
              page_client.page_did_leave_tooltip_area();
          }
      }
      if (is_hovering_link != was_hovering_link) {
          if (is_hovering_link)
              page_client.page_did_hover_link(document.complete_url(hovered_link_element->href()));
          else
              page_client.page_did_unhover_link();
      }
      return true;
  }
  
  void EventHandler::dump_selection(const char* event_name) const
  {
      UNUSED_PARAM(event_name);
  #ifdef SELECTION_DEBUG
      dbg() << event_name << " selection start: "
            << layout_root()->selection().start().layout_node << ":" << layout_root()->selection().start().index_in_node << ", end: "
            << layout_root()->selection().end().layout_node << ":" << layout_root()->selection().end().index_in_node;
  #endif
  }
  
  }
  