/*
 * Copyright (c) 2020, the SerenityOS developers.
 * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/ByteBuffer.h>
#include <AK/Optional.h>
#include <AK/Time.h>
#include <AK/Variant.h>
#include <Kernel/API/KeyCode.h>
#include <LibGfx/Rect.h>
#include <LibJS/Heap/MarkedVector.h>
#include <LibJS/SafeFunction.h>
#include <LibWeb/DOM/DocumentLoadEventDelayer.h>
#include <LibWeb/HTML/CORSSettingAttribute.h>
#include <LibWeb/HTML/EventLoop/Task.h>
#include <LibWeb/HTML/HTMLElement.h>
#include <LibWeb/PixelUnits.h>
#include <LibWeb/WebIDL/DOMException.h>
#include <math.h>

namespace Web::HTML {

enum class MediaSeekMode {
    Accurate,
    ApproximateForSpeed,
};

class SourceElementSelector;

class HTMLMediaElement : public HTMLElement {
    WEB_PLATFORM_OBJECT(HTMLMediaElement, HTMLElement);

public:
    virtual ~HTMLMediaElement() override;

    virtual bool is_focusable() const override { return true; }

    void queue_a_media_element_task(JS::SafeFunction<void()> steps);

    JS::GCPtr<MediaError> error() const { return m_error; }
    WebIDL::ExceptionOr<void> set_decoder_error(String error_message);

    String const& current_src() const { return m_current_src; }
    WebIDL::ExceptionOr<void> select_resource();

    enum class NetworkState : u16 {
        Empty,
        Idle,
        Loading,
        NoSource,
    };
    NetworkState network_state() const { return m_network_state; }

    WebIDL::ExceptionOr<JS::NonnullGCPtr<TimeRanges>> buffered() const;

    WebIDL::ExceptionOr<Bindings::CanPlayTypeResult> can_play_type(DeprecatedString const& type) const;

    enum class ReadyState : u16 {
        HaveNothing,
        HaveMetadata,
        HaveCurrentData,
        HaveFutureData,
        HaveEnoughData,
    };
    ReadyState ready_state() const { return m_ready_state; }
    bool blocked() const;
    bool stalled() const;

    bool seeking() const { return m_seeking; }
    void set_seeking(bool);

    WebIDL::ExceptionOr<void> load();

    double current_time() const;
    void set_current_time(double);
    void fast_seek(double);

    double current_playback_position() const { return m_current_playback_position; }
    void set_current_playback_position(double);

    double duration() const;
    bool show_poster() const { return m_show_poster; }
    bool paused() const { return m_paused; }
    bool ended() const;
    bool potentially_playing() const;
    WebIDL::ExceptionOr<JS::NonnullGCPtr<JS::Promise>> play();
    WebIDL::ExceptionOr<void> pause();
    WebIDL::ExceptionOr<void> toggle_playback();

    double volume() const { return m_volume; }
    WebIDL::ExceptionOr<void> set_volume(double);

    bool muted() const { return m_muted; }
    void set_muted(bool);

    double effective_media_volume() const;

    JS::NonnullGCPtr<AudioTrackList> audio_tracks() const { return *m_audio_tracks; }
    JS::NonnullGCPtr<VideoTrackList> video_tracks() const { return *m_video_tracks; }

    WebIDL::ExceptionOr<void> handle_keydown(Badge<Web::EventHandler>, KeyCode);

    enum class MouseTrackingComponent {
        Timeline,
        Volume,
    };
    void set_layout_mouse_tracking_component(Badge<Painting::MediaPaintable>, Optional<MouseTrackingComponent> mouse_tracking_component) { m_mouse_tracking_component = move(mouse_tracking_component); }
    Optional<MouseTrackingComponent> const& layout_mouse_tracking_component(Badge<Painting::MediaPaintable>) const { return m_mouse_tracking_component; }

    void set_layout_mouse_position(Badge<Painting::MediaPaintable>, Optional<CSSPixelPoint> mouse_position) { m_mouse_position = move(mouse_position); }
    Optional<CSSPixelPoint> const& layout_mouse_position(Badge<Painting::MediaPaintable>) const { return m_mouse_position; }

    void set_layout_display_time(Badge<Painting::MediaPaintable>, Optional<double> display_time);
    double layout_display_time(Badge<Painting::MediaPaintable>) const;

    struct CachedLayoutBoxes {
        Optional<CSSPixelRect> control_box_rect;
        Optional<CSSPixelRect> playback_button_rect;
        Optional<CSSPixelRect> timeline_rect;
        Optional<CSSPixelRect> speaker_button_rect;
        Optional<CSSPixelRect> volume_rect;
    };
    CachedLayoutBoxes& cached_layout_boxes(Badge<Painting::MediaPaintable>) const { return m_layout_boxes; }

protected:
    HTMLMediaElement(DOM::Document&, DOM::QualifiedName);

    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
    virtual void visit_edges(Cell::Visitor&) override;

    virtual void attribute_changed(DeprecatedFlyString const& name, DeprecatedString const& value) override;
    virtual void removed_from(DOM::Node*) override;
    virtual void children_changed() override;

    // Override in subclasses to handle implementation-specific behavior when the element state changes
    // to playing or paused, e.g. to start/stop play timers.
    virtual void on_playing() { }
    virtual void on_paused() { }

    // Override in subclasses to handle implementation-specific seeking behavior. When seeking is complete,
    // subclasses must invoke set_current_playback_position() to unblock the user agent.
    virtual void on_seek(double, MediaSeekMode) { m_seek_in_progress = false; }

    virtual void on_volume_change() { }

private:
    friend SourceElementSelector;

    struct EntireResource { };
    using ByteRange = Variant<EntireResource>; // FIXME: This will need to include "until end" and an actual byte range.

    Task::Source media_element_event_task_source() const { return m_media_element_event_task_source.source; }

    WebIDL::ExceptionOr<void> load_element();
    WebIDL::ExceptionOr<void> fetch_resource(AK::URL const&, Function<void(String)> failure_callback);
    static bool verify_response(JS::NonnullGCPtr<Fetch::Infrastructure::Response>, ByteRange const&);
    WebIDL::ExceptionOr<void> process_media_data(Function<void(String)> failure_callback);
    WebIDL::ExceptionOr<void> handle_media_source_failure(Span<JS::NonnullGCPtr<WebIDL::Promise>> promises, String error_message);
    void forget_media_resource_specific_tracks();
    void set_ready_state(ReadyState);

    WebIDL::ExceptionOr<void> play_element();
    WebIDL::ExceptionOr<void> pause_element();
    void seek_element(double playback_position, MediaSeekMode = MediaSeekMode::Accurate);
    void notify_about_playing();
    void set_show_poster(bool);
    void set_paused(bool);
    void set_duration(double);

    void volume_or_muted_attribute_changed();

    bool is_eligible_for_autoplay() const;
    bool has_ended_playback() const;
    WebIDL::ExceptionOr<void> reached_end_of_media_playback();

    WebIDL::ExceptionOr<void> dispatch_time_update_event();

    enum class TimeMarchesOnReason {
        NormalPlayback,
        Other,
    };
    void time_marches_on(TimeMarchesOnReason = TimeMarchesOnReason::NormalPlayback);

    JS::MarkedVector<JS::NonnullGCPtr<WebIDL::Promise>> take_pending_play_promises();
    void resolve_pending_play_promises(ReadonlySpan<JS::NonnullGCPtr<WebIDL::Promise>> promises);
    void reject_pending_play_promises(ReadonlySpan<JS::NonnullGCPtr<WebIDL::Promise>> promises, JS::NonnullGCPtr<WebIDL::DOMException> error);

    // https://html.spec.whatwg.org/multipage/media.html#reject-pending-play-promises
    template<typename ErrorType>
    void reject_pending_play_promises(ReadonlySpan<JS::NonnullGCPtr<WebIDL::Promise>> promises, FlyString const& message)
    {
        auto& realm = this->realm();

        auto error = ErrorType::create(realm, message.to_deprecated_fly_string());
        reject_pending_play_promises(promises, error);
    }

    // https://html.spec.whatwg.org/multipage/media.html#media-element-event-task-source
    UniqueTaskSource m_media_element_event_task_source {};

    // https://html.spec.whatwg.org/multipage/media.html#dom-media-error
    JS::GCPtr<MediaError> m_error;

    // https://html.spec.whatwg.org/multipage/media.html#dom-media-crossorigin
    CORSSettingAttribute m_crossorigin { CORSSettingAttribute::NoCORS };

    // https://html.spec.whatwg.org/multipage/media.html#dom-media-currentsrc
    String m_current_src;

    // https://html.spec.whatwg.org/multipage/media.html#dom-media-networkstate
    NetworkState m_network_state { NetworkState::Empty };

    // https://html.spec.whatwg.org/multipage/media.html#dom-media-readystate
    ReadyState m_ready_state { ReadyState::HaveNothing };
    bool m_first_data_load_event_since_load_start { false };

    // https://html.spec.whatwg.org/multipage/media.html#dom-media-seeking
    bool m_seeking { false };

    // https://html.spec.whatwg.org/multipage/media.html#current-playback-position
    double m_current_playback_position { 0 };

    // https://html.spec.whatwg.org/multipage/media.html#official-playback-position
    double m_official_playback_position { 0 };

    // https://html.spec.whatwg.org/multipage/media.html#default-playback-start-position
    double m_default_playback_start_position { 0 };

    // https://html.spec.whatwg.org/multipage/media.html#show-poster-flag
    bool m_show_poster { true };

    // https://html.spec.whatwg.org/multipage/media.html#dom-media-duration
    double m_duration { NAN };

    // https://html.spec.whatwg.org/multipage/media.html#list-of-pending-play-promises
    JS::MarkedVector<JS::NonnullGCPtr<WebIDL::Promise>> m_pending_play_promises;

    // https://html.spec.whatwg.org/multipage/media.html#dom-media-paused
    bool m_paused { true };

    // https://html.spec.whatwg.org/multipage/media.html#dom-media-volume
    double m_volume { 1.0 };

    // https://html.spec.whatwg.org/multipage/media.html#dom-media-muted
    bool m_muted { false };

    // https://html.spec.whatwg.org/multipage/media.html#dom-media-audiotracks
    JS::GCPtr<AudioTrackList> m_audio_tracks;

    // https://html.spec.whatwg.org/multipage/media.html#dom-media-videotracks
    JS::GCPtr<VideoTrackList> m_video_tracks;

    // https://html.spec.whatwg.org/multipage/media.html#media-data
    ByteBuffer m_media_data;

    // https://html.spec.whatwg.org/multipage/media.html#can-autoplay-flag
    bool m_can_autoplay { true };

    // https://html.spec.whatwg.org/multipage/media.html#delaying-the-load-event-flag
    Optional<DOM::DocumentLoadEventDelayer> m_delaying_the_load_event;

    bool m_running_time_update_event_handler { false };
    Optional<MonotonicTime> m_last_time_update_event_time;

    JS::GCPtr<DOM::DocumentObserver> m_document_observer;

    JS::GCPtr<SourceElementSelector> m_source_element_selector;

    JS::GCPtr<Fetch::Infrastructure::FetchController> m_fetch_controller;

    bool m_seek_in_progress = false;

    // Cached state for layout.
    Optional<MouseTrackingComponent> m_mouse_tracking_component;
    bool m_tracking_mouse_position_while_playing { false };
    Optional<CSSPixelPoint> m_mouse_position;
    Optional<double> m_display_time;
    mutable CachedLayoutBoxes m_layout_boxes;
};

}