/*
 * Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/Function.h>
#include <AK/Noncopyable.h>
#include <AK/RefPtr.h>
#include <AK/WeakPtr.h>
#include <LibCore/Timer.h>
#include <LibGfx/Bitmap.h>
#include <LibGfx/Rect.h>
#include <LibGfx/Size.h>
#include <LibWeb/DOM/Position.h>
#include <LibWeb/HTML/BrowsingContextContainer.h>
#include <LibWeb/HTML/SessionHistoryEntry.h>
#include <LibWeb/Loader/FrameLoader.h>
#include <LibWeb/Page/EventHandler.h>
#include <LibWeb/TreeNode.h>

namespace Web::HTML {

class BrowsingContext : public TreeNode<BrowsingContext> {
public:
    static NonnullRefPtr<BrowsingContext> create_nested(Page& page, HTML::BrowsingContextContainer& container) { return adopt_ref(*new BrowsingContext(page, &container)); }
    static NonnullRefPtr<BrowsingContext> create(Page& page) { return adopt_ref(*new BrowsingContext(page, nullptr)); }
    ~BrowsingContext();

    class ViewportClient {
    public:
        virtual ~ViewportClient() = default;
        virtual void browsing_context_did_set_viewport_rect(Gfx::IntRect const&) = 0;
    };
    void register_viewport_client(ViewportClient&);
    void unregister_viewport_client(ViewportClient&);

    bool is_top_level() const;
    bool is_focused_context() const;

    DOM::Document const* active_document() const { return m_active_document; }
    DOM::Document* active_document() { return m_active_document; }

    void set_active_document(DOM::Document*);

    Page* page() { return m_page; }
    Page const* page() const { return m_page; }

    Gfx::IntSize const& size() const { return m_size; }
    void set_size(Gfx::IntSize const&);

    void set_needs_display();
    void set_needs_display(Gfx::IntRect const&);

    Gfx::IntPoint const& viewport_scroll_offset() const { return m_viewport_scroll_offset; }
    Gfx::IntRect viewport_rect() const { return { m_viewport_scroll_offset, m_size }; }
    void set_viewport_rect(Gfx::IntRect const&);

    FrameLoader& loader() { return m_loader; }
    FrameLoader const& loader() const { return m_loader; }

    Web::EventHandler& event_handler() { return m_event_handler; }
    Web::EventHandler const& event_handler() const { return m_event_handler; }

    void scroll_to(Gfx::IntPoint const&);
    void scroll_to_anchor(String const&);

    BrowsingContext& top_level_browsing_context()
    {
        BrowsingContext* context = this;
        while (context->parent())
            context = context->parent();
        return *context;
    }

    BrowsingContext const& top_level_browsing_context() const { return const_cast<BrowsingContext*>(this)->top_level_browsing_context(); }

    BrowsingContext* choose_a_browsing_context(StringView name, bool noopener);

    HTML::BrowsingContextContainer* container() { return m_container; }
    HTML::BrowsingContextContainer const* container() const { return m_container; }

    Gfx::IntPoint to_top_level_position(Gfx::IntPoint const&);
    Gfx::IntRect to_top_level_rect(Gfx::IntRect const&);

    DOM::Position const& cursor_position() const { return m_cursor_position; }
    void set_cursor_position(DOM::Position);
    bool increment_cursor_position_offset();
    bool decrement_cursor_position_offset();

    bool cursor_blink_state() const { return m_cursor_blink_state; }

    String selected_text() const;
    void select_all();

    void did_edit(Badge<EditEventHandler>);

    void register_frame_nesting(AK::URL const&);
    bool is_frame_nesting_allowed(AK::URL const&) const;

    void set_frame_nesting_levels(HashMap<AK::URL, size_t> frame_nesting_levels) { m_frame_nesting_levels = move(frame_nesting_levels); };
    HashMap<AK::URL, size_t> const& frame_nesting_levels() const { return m_frame_nesting_levels; }

    DOM::Document* container_document();
    DOM::Document const* container_document() const;

    bool has_a_rendering_opportunity() const;

    RefPtr<DOM::Node> currently_focused_area();

    String const& name() const { return m_name; }
    void set_name(String const& name) { m_name = name; }

    Vector<SessionHistoryEntry>& session_history() { return m_session_history; }
    Vector<SessionHistoryEntry> const& session_history() const { return m_session_history; }

private:
    explicit BrowsingContext(Page&, HTML::BrowsingContextContainer*);

    void reset_cursor_blink_cycle();

    WeakPtr<Page> m_page;

    FrameLoader m_loader;
    Web::EventHandler m_event_handler;

    // https://html.spec.whatwg.org/multipage/history.html#session-history
    Vector<SessionHistoryEntry> m_session_history;

    WeakPtr<HTML::BrowsingContextContainer> m_container;
    RefPtr<DOM::Document> m_active_document;
    Gfx::IntSize m_size;
    Gfx::IntPoint m_viewport_scroll_offset;

    DOM::Position m_cursor_position;
    RefPtr<Core::Timer> m_cursor_blink_timer;
    bool m_cursor_blink_state { false };

    HashTable<ViewportClient*> m_viewport_clients;

    HashMap<AK::URL, size_t> m_frame_nesting_levels;
    String m_name;
};

}