use gst::bus::BusWatchGuard;
use gst::prelude::*;
use gst_play::{Play, PlayMessage, PlayVideoOverlayVideoRenderer};
use gtk::gdk;
use gtk::glib::{self, clone};
use gtk::prelude::*;
use relm4::{ComponentParts, ComponentSender, RelmWidgetExt, SimpleComponent};

#[allow(dead_code)]
pub struct Player {
    // GStreamer-related
    gtksink: gst::Element,
    renderer: PlayVideoOverlayVideoRenderer,
    player: Play,
    bus_watch: BusWatchGuard,
    // UI state
    is_playing: bool,
    duration: gst::ClockTime,
    position: gst::ClockTime,
    seeking: bool,
}

#[derive(Debug)]
pub enum PlayerMsg {
    SetUrl(String),
    PlayPause,
    Play,
    Pause,
    SeekTo(gst::ClockTime),
    StartSeeking,
    StopSeeking,
    // messages from GStreamer
    UpdatePosition(gst::ClockTime),
    UpdateDuration(gst::ClockTime),
}

#[derive(Debug)]
pub enum PlayerOutput {
    PositionUpdate(gst::ClockTime),
    SubtitleSelectionButtonPressed,
}

fn format_time(time: gst::ClockTime) -> String {
    let seconds = time.seconds();
    let minutes = seconds / 60;
    let hours = minutes / 60;

    if hours > 0 {
        format!("{}:{:02}:{:02}", hours, minutes % 60, seconds % 60)
    } else {
        format!("{}:{:02}", minutes, seconds % 60)
    }
}

#[relm4::component(pub)]
impl SimpleComponent for Player {
    type Input = PlayerMsg;
    type Output = PlayerOutput;
    type Init = ();

    view! {
        gtk::Box {
            set_orientation: gtk::Orientation::Vertical,

            // Video area
            gtk::Picture {
                set_paintable: Some(&paintable),
                set_vexpand: true,
            },

            // Control bar
            gtk::Box {
                set_orientation: gtk::Orientation::Horizontal,
                set_spacing: 10,
                set_margin_all: 10,

                // Play/Pause button
                gtk::Button {
                    #[watch]
                    set_icon_name: if model.is_playing { "media-playback-pause-symbolic" } else { "media-playback-start-symbolic" },
                    connect_clicked => PlayerMsg::PlayPause,
                },

                // Current time label
                gtk::Label {
                    #[watch]
                    set_text: &format_time(model.position),
                    set_width_chars: 8,
                },

                // Seek slider
                #[name = "seek_scale"]
                gtk::Scale {
                    set_hexpand: true,
                    set_orientation: gtk::Orientation::Horizontal,
                    #[watch]
                    set_range: (0.0, model.duration.mseconds() as f64),
                    #[watch]
                    set_value?: if !model.seeking {
                        Some(model.position.mseconds() as f64)
                    } else {
                        None
                    },
                    connect_change_value[sender] => move |_, _, value| {
                        let position = gst::ClockTime::from_mseconds(value as u64);
                        sender.input(PlayerMsg::SeekTo(position));
                        glib::Propagation::Proceed
                    },
                },

                // Duration label
                #[name = "duration_label"]
                gtk::Label {
                    #[watch]
                    set_text: &format_time(model.duration),
                    set_width_chars: 8,
                },

                // Subtitle selection button
                gtk::Button {
                    set_icon_name: "media-view-subtitles-symbolic",
                    connect_clicked[sender] => move |_| {
                        sender.output(PlayerOutput::SubtitleSelectionButtonPressed).unwrap();
                    },
                },
            }
        }
    }

    fn init(
        _init: Self::Init,
        _window: Self::Root,
        sender: ComponentSender<Self>,
    ) -> ComponentParts<Self> {
        let gtksink = gst::ElementFactory::make("gtk4paintablesink")
            .build()
            .expect("Failed to create gtk4paintablesink");

        // Need to set state to Ready to get a GL context
        gtksink
            .set_state(gst::State::Ready)
            .expect("Failed to set GTK sink state to ready");

        let paintable = gtksink.property::<gdk::Paintable>("paintable");

        let sink = if paintable
            .property::<Option<gdk::GLContext>>("gl-context")
            .is_some()
        {
            gst::ElementFactory::make("glsinkbin")
                .property("sink", &gtksink)
                .build()
                .expect("Failed to build glsinkbin")
        } else {
            gtksink.clone()
        };

        let renderer = PlayVideoOverlayVideoRenderer::with_sink(&sink);

        let player = Play::new(Some(
            renderer.clone().upcast::<gst_play::PlayVideoRenderer>(),
        ));

        let mut config = player.config();
        config.set_position_update_interval(5);
        player.set_config(config).unwrap();

        // 100MiB ring buffer to improve seek performance
        player
            .pipeline()
            .set_property("ring-buffer-max-size", 100 * 1024 * 1024 as u64);

        let bus_watch = player
            .message_bus()
            .add_watch_local(clone!(
                #[strong]
                sender,
                move |_, message| {
                    let play_message = if let Ok(msg) = PlayMessage::parse(message) {
                        msg
                    } else {
                        return glib::ControlFlow::Continue;
                    };

                    match play_message {
                        PlayMessage::Error(error_msg) => {
                            eprintln!("Playback error: {:?}", error_msg.error());
                            if let Some(details) = error_msg.details() {
                                eprintln!("Error details: {:?}", details);
                            }
                        }
                        PlayMessage::PositionUpdated(pos) => {
                            if let Some(position) = pos.position() {
                                sender.input(PlayerMsg::UpdatePosition(position));
                                sender
                                    .output(PlayerOutput::PositionUpdate(position))
                                    .unwrap();
                            }
                        }
                        PlayMessage::DurationChanged(dur) => {
                            if let Some(duration) = dur.duration() {
                                sender.input(PlayerMsg::UpdateDuration(duration));
                            }
                        }
                        PlayMessage::Buffering(_) => {
                            // TODO
                        }
                        _ => {}
                    }

                    glib::ControlFlow::Continue
                }
            ))
            .expect("Failed to add message bus watch");

        let model = Player {
            gtksink,
            renderer,
            player,
            bus_watch,
            is_playing: false,
            duration: gst::ClockTime::ZERO,
            position: gst::ClockTime::ZERO,
            seeking: false,
        };

        let widgets = view_output!();

        // find the existing GestureClick controller in the Scale widget
        // instead of adding a new one to avoid this bug:
        // https://gitlab.gnome.org/GNOME/gtk/-/issues/4939
        let gesture = widgets
            .seek_scale
            .observe_controllers()
            .into_iter()
            .find_map(|controller| controller.unwrap().downcast::<gtk::GestureClick>().ok())
            .unwrap();

        gesture.connect_pressed(clone!(
            #[strong]
            sender,
            move |_, _, _, _| {
                sender.input(PlayerMsg::StartSeeking);
            }
        ));
        gesture.connect_released(clone!(
            #[strong]
            sender,
            move |_, _, _, _| {
                sender.input(PlayerMsg::StopSeeking);
            }
        ));

        ComponentParts { model, widgets }
    }

    fn update(&mut self, msg: Self::Input, _sender: ComponentSender<Self>) {
        match msg {
            PlayerMsg::SetUrl(url) => {
                self.player.set_uri(Some(&url));
                self.play();
            }
            PlayerMsg::PlayPause => {
                if self.is_playing {
                    self.pause();
                } else {
                    self.play();
                }
            }
            PlayerMsg::Play => self.play(),
            PlayerMsg::Pause => self.pause(),
            PlayerMsg::SeekTo(position) => {
                //self.seek_position = position_ms;
                self.player.seek(position);
                self.position = position;
            }
            PlayerMsg::StartSeeking => {
                self.seeking = true;
            }
            PlayerMsg::StopSeeking => {
                self.seeking = false;
            }
            PlayerMsg::UpdatePosition(position) => {
                if !self.seeking {
                    self.position = position;
                }
            }
            PlayerMsg::UpdateDuration(duration) => {
                self.duration = duration;
            }
        }
    }
}

impl Player {
    fn play(&mut self) {
        self.player.play();
        self.is_playing = true;
    }

    fn pause(&mut self) {
        self.player.pause();
        self.is_playing = false;
    }
}