use crate::mpv;
use crate::signal::{Signal, SignalEmitter};
use event_listener::EventListener;
use std::cell::{Ref, RefCell};
use url::Url;

pub trait PlaybinEntry {
    fn url(&self) -> Url;
}

impl PlaybinEntry for Url {
    fn url(&self) -> Url {
        self.clone()
    }
}

// E: generic entry type
pub struct Playbin<E> {
    mpv: mpv::Handle,
    entries: RefCell<Vec<E>>,

    volume_changed: SignalEmitter<Self, ()>,
    muted_changed: SignalEmitter<Self, ()>,
    paused_changed: SignalEmitter<Self, ()>,
    current_entry_changed: SignalEmitter<Self, ()>,

    entry_inserted: SignalEmitter<Self, usize>,
    stopped: SignalEmitter<Self, ()>,
    entry_removed: SignalEmitter<Self, usize>,

    file_started: SignalEmitter<Self, ()>,
}

impl<E> Default for Playbin<E> {
    fn default() -> Self {
        let mpv = mpv::Handle::new();
        mpv.set_property("audio-client-name", "audrey").unwrap();
        mpv.set_property("user-agent", crate::USER_AGENT).unwrap();
        mpv.set_property("video", false).unwrap();
        mpv.set_property("prefetch-playlist", true).unwrap();
        mpv.set_property("gapless-audio", true).unwrap();

        mpv.observe_property(0, "volume").unwrap();
        mpv.observe_property(1, "mute").unwrap();
        mpv.observe_property(2, "pause").unwrap();
        mpv.observe_property(3, "playlist-pos").unwrap();

        // "Useful to drain property changes before a new file is loaded."
        mpv.add_hook(0, "on_before_start_file", 0).unwrap();

        Self {
            mpv,
            entries: RefCell::new(vec![]),

            volume_changed: Default::default(),
            muted_changed: Default::default(),
            paused_changed: Default::default(),
            current_entry_changed: Default::default(),

            entry_inserted: Default::default(),
            stopped: Default::default(),
            entry_removed: Default::default(),

            file_started: Default::default(),
        }
    }
}

impl<E> Playbin<E>
where
    E: PlaybinEntry,
{
    pub fn volume(&self) -> i64 {
        self.mpv.get_property("volume").unwrap()
    }

    pub fn set_volume(&self, volume: i64) {
        self.mpv.set_property("volume", volume).unwrap();
    }

    pub fn muted(&self) -> bool {
        self.mpv.get_property("mute").unwrap()
    }

    pub fn set_muted(&self, muted: bool) {
        self.mpv.set_property("mute", muted).unwrap();
    }

    pub fn paused(&self) -> bool {
        self.mpv.get_property("pause").unwrap()
    }

    pub fn set_paused(&self, paused: bool) {
        self.mpv.set_property("pause", paused).unwrap();
    }

    pub fn position(&self) -> Option<f64> {
        todo!()
    }

    pub fn current_entry(&self) -> Option<usize> {
        self.mpv
            .get_property::<i64>("playlist-pos")
            .unwrap()
            .try_into()
            .ok()
    }

    pub fn seek(&self, _position: f64) {
        todo!()
    }

    pub fn next_entry(&self) {
        self.mpv.command(["playlist-next"]).unwrap();
    }

    pub fn prev_entry(&self) {
        self.mpv.command(["playlist-prev"]).unwrap();
    }

    pub fn play_entry(&self, index: usize) {
        self.mpv
            .command(["playlist-play-index", &index.to_string()])
            .unwrap();
    }

    pub fn entries(&self) -> Ref<'_, [E]> {
        Ref::map(self.entries.borrow(), Vec::as_ref)
    }

    pub fn push_entry(&self, entry: E) {
        let mut entries = self.entries.borrow_mut();
        self.mpv
            .command(["loadfile", entry.url().as_str(), "append-play"])
            .unwrap();
        let index = entries.len();
        entries.push(entry);

        drop(entries);
        self.entry_inserted.emit(self, index as usize);
    }

    pub fn insert_entry(&self, index: usize, entry: E) {
        let mut entries = self.entries.borrow_mut();
        self.mpv
            .command(["loadfile", entry.url().as_str(), "insert-at-play"])
            .unwrap();
        entries.insert(index as usize, entry);

        drop(entries);
        self.entry_inserted.emit(self, index);
    }

    // stop playback and clear playlist
    pub fn stop(&self) {
        let mut entries = self.entries.borrow_mut();
        self.mpv.command(["stop"]).unwrap();
        entries.clear();

        drop(entries);
        self.stopped.emit(self, ());
    }

    pub fn remove_entry(&self, index: usize) {
        let mut entries = self.entries.borrow_mut();
        self.mpv.command(["remove", &index.to_string()]).unwrap();
        entries.remove(index as usize);

        drop(entries);
        self.entry_removed.emit(self, index);
    }

    pub fn move_entry(&self, _from: usize, _to: usize) {
        todo!()
    }

    pub fn tick(&self) -> EventListener {
        let listener = self.mpv.wakeup_listener();
        while let Some(event) = self.mpv.wait_event(0.0) {
            self.handle_event(event);
        }
        listener
    }

    fn handle_event(&self, event: mpv::Event) {
        match event {
            mpv::Event::PropertyChange(event) => match event.reply_userdata {
                0 => {
                    assert_eq!(&event.name, "volume");
                    self.volume_changed.emit(self, ());
                    println!("new volume! {:?}", self.volume());
                }

                1 => {
                    assert_eq!(&event.name, "mute");
                    self.muted_changed.emit(self, ());
                    println!("new muted! {:?}", self.muted());
                }

                2 => {
                    assert_eq!(&event.name, "pause");
                    self.paused_changed.emit(self, ());
                    println!("new paused! {:?}", self.paused());
                }

                3 => {
                    assert_eq!(&event.name, "playlist-pos");
                    self.current_entry_changed.emit(self, ());
                    println!("new current_entry! {:?}", self.current_entry());
                }

                _ => unreachable!(),
            },

            mpv::Event::Hook(event) => match event.reply_userdata {
                0 => {
                    assert_eq!(&event.name, "on_before_start_file");
                    // just use this as a barrier
                    println!("on_before_start_file triggered");
                    self.mpv.continue_hook(event.id).unwrap();
                }

                _ => unreachable!(),
            },

            mpv::Event::StartFile(_) => {
                // since we set up the hook before, the current song is guaranteed not to change
                // under our feet
                self.file_started.emit(self, ());
            }

            _ => println!("mpv event {:?}", event),
        }
    }

    pub fn volume_changed(&self) -> Signal<'_, Self, ()> {
        self.volume_changed.signal()
    }

    pub fn muted_changed(&self) -> Signal<'_, Self, ()> {
        self.muted_changed.signal()
    }

    pub fn file_started(&self) -> Signal<'_, Self, ()> {
        self.file_started.signal()
    }
}

impl<E> Drop for Playbin<E> {
    fn drop(&mut self) {
        println!("dropping Playbin2");
        self.mpv.command(["quit"]).unwrap();
    }
}