//! The current song title and artist
//!
//! Also provides buttons for play/pause, previous and next.
//!
//! Supports all music players that implement the [MediaPlayer2 Interface]. This includes:
//!
//! - Spotify
//! - VLC
//! - mpd (via [mpDris2](https://github.com/eonpatapon/mpDris2))
//!
//! and many others.
//!
//! By default the block tracks all players available on the MPRIS bus. Right clicking on the block
//! will cycle it to the next player. You can pin the widget to a given player via the "player"
//! setting.
//!
//! # Configuration
//!
//! Key | Values | Default
//! ----|--------|--------
//! `format` | A string to customise the output of this block. See below for available placeholders. | <code>\" $icon {$combo.str(max_w:25,rot_interval:0.5) $play \|}\"</code>
//! `format_alt` | If set, block will switch between `format` and `format_alt` on every click | `None`
//! `player` | Name(s) of the music player(s) MPRIS interface. This can be either a music player name or an array of music player names. Run <code>busctl \--user list \| grep \"org.mpris.MediaPlayer2.\" \| cut -d\' \' -f1</code> and the name is the part after "org.mpris.MediaPlayer2.". | `None`
//! `interface_name_exclude` | A list of regex patterns for player MPRIS interface names to ignore. | `["playerctld"]`
//! `separator` | String to insert between artist and title. | `" - "`
//! `seek_step_secs` | Positive number of seconds to seek forward/backward when scrolling on the bar. Does not need to be an integer. | `1`
//! `seek_forward_step_secs` | Positive number of seconds to seek forward when scrolling on the bar. Does not need to be an integer. | `seek_step_secs`
//! `seek_backward_step_secs` | Positive number of seconds to seek backward when scrolling on the bar. Does not need to be an integer. | `seek_step_secs`
//! `volume_step` | The percent volume level is increased/decreased for the selected audio device when scrolling. Capped automatically at 50. | `5`
//!
//! Note: All placeholders except `icon` can be absent. See the examples below to learn how to handle this.
//!
//! Placeholder   | Value          | Type
//! --------------|----------------|------
//! `icon`        | A static icon  | Icon
//! `artist`      | Current artist | Text
//! `title`       | Current title  | Text
//! `url`         | Current song url | Text
//! `combo`       | Resolves to "`$artist[sep]$title"`, `"$artist"`, `"$title"`, or `"$url"` depending on what information is available. `[sep]` is set by `separator` option. | Text
//! `player`      | Name of the current player (taken from the last part of its MPRIS bus name) | Text
//! `avail`       | Total number of players available to switch between | Number
//! `cur`         | The current player index of the available players | Number
//! `play`        | Play/Pause button | Clickable icon
//! `next`        | Next button | Clickable icon
//! `prev`        | Previous button | Clickable icon
//! `volume_icon` | Icon based on volume. Missing if unsupported.    | Icon
//! `volume`      | Current volume. Missing if muted or unsupported. | Number
//!
//! Action          | Default button
//! ----------------|------------------
//! `play_pause`    | Left on `$play`
//! `next`          | Left on `$next`
//! `prev`          | Left on `$prev`
//! `next_player`   | Right
//! `seek_forward`  | Wheel Up
//! `seek_backward` | Wheel Down
//! `volume_up`     | -
//! `volume_down`   | -
//! `toggle_format` | Left
//!
//! # Examples
//!
//! Show the currently playing song on Spotify only, with play & next buttons and limit the width
//! to 20 characters:
//!
//! ```toml
//! [[block]]
//! block = "music"
//! format = " $icon {$combo.str(max_w:20) $play $next |}"
//! player = "spotify"
//! ```
//!
//! Same thing for any compatible player, takes the first active on the bus, but ignores "mpd" or anything with "kdeconnect" in the name:
//!
//! ```toml
//! [[block]]
//! block = "music"
//! format = " $icon {$combo.str(max_w:20) $play $next |}"
//! interface_name_exclude = [".*kdeconnect.*", "mpd"]
//! ```
//!
//! Same as above, but displays with rotating text
//!
//! ```toml
//! [[block]]
//! block = "music"
//! format = " $icon {$combo.str(max_w:20,rot_interval:0.5) $play $next |}"
//! interface_name_exclude = [".*kdeconnect.*", "mpd"]
//! ```
//!
//! Click anywhere to play/pause, middle click to toggle format:
//!
//! ```toml
//! [[block]]
//! block = "music"
//! format = " format 1 "
//! format_alt = " format 2 "
//! [[block.click]]
//! button = "left"
//! action = "play_pause"
//! [[block.click]]
//! button = "middle"
//! widget = "."
//! action = "toggle_format"
//! ```
//!
//! Scroll to change the player volume, use the forward and back buttons to seek:
//!
//! ```toml
//! [[block]]
//! block = "music"
//! format = " $icon $volume_icon $combo $play $next| "
//! seek_step_secs = 10
//! [[block.click]]
//! button = "up"
//! action = "volume_up"
//! [[block.click]]
//! button = "down"
//! action = "volume_down"
//! [[block.click]]
//! button = "forward"
//! action = "seek_forward"
//! [[block.click]]
//! button = "back"
//! action = "seek_backward"
//! ```
//!
//! # Icons Used
//! - `music`
//! - `music_next`
//! - `music_play`
//! - `music_prev`
//! - `volume_muted`
//! - `volume` (as a progression)
//!
//! [MediaPlayer2 Interface]: https://specifications.freedesktop.org/mpris-spec/latest/Player_Interface.html

use super::prelude::*;
use crate::wrappers::DisplaySlice;

use regex::Regex;
use std::fmt;
use zbus::fdo::{DBusProxy, NameOwnerChanged, PropertiesChanged};
use zbus::names::{OwnedBusName, OwnedUniqueName};
use zbus::{MatchRule, MessageStream};

mod zbus_mpris;
mod zbus_playerctld;

make_log_macro!(debug, "music");

const PLAY_PAUSE_BTN: &str = "play_pause_btn";
const NEXT_BTN: &str = "next_btn";
const PREV_BTN: &str = "prev_btn";

#[derive(Deserialize, Debug, SmartDefault)]
#[serde(deny_unknown_fields, default)]
pub struct Config {
    pub format: FormatConfig,
    pub format_alt: Option<FormatConfig>,
    pub player: PlayerName,
    #[default(vec!["playerctld".into()])]
    pub interface_name_exclude: Vec<String>,
    #[default(" - ".into())]
    pub separator: String,
    #[default(1.into())]
    pub seek_step_secs: Seconds<false>,
    pub seek_forward_step_secs: Option<Seconds<false>>,
    pub seek_backward_step_secs: Option<Seconds<false>>,
    #[default(5.0)]
    pub volume_step: f64,
}

#[derive(Deserialize, Debug, Clone, SmartDefault)]
#[serde(untagged)]
pub enum PlayerName {
    Single(String),
    #[default]
    Multiple(Vec<String>),
}

pub async fn run(config: &Config, api: &CommonApi) -> Result<()> {
    let mut actions = api.get_actions()?;
    api.set_default_actions(&[
        (MouseButton::Left, Some(PLAY_PAUSE_BTN), "play_pause"),
        (MouseButton::Left, Some(NEXT_BTN), "next"),
        (MouseButton::Left, Some(PREV_BTN), "prev"),
        (MouseButton::Right, None, "next_player"),
        (MouseButton::WheelUp, None, "seek_forward"),
        (MouseButton::WheelDown, None, "seek_backward"),
        (MouseButton::Left, None, "toggle_format"),
    ])?;

    let dbus_conn = new_dbus_connection().await?;

    let mut format = config
        .format
        .with_default(" $icon {$combo.str(max_w:25,rot_interval:0.5) $play |}")?;
    let mut format_alt = match &config.format_alt {
        Some(f) => Some(f.with_default("")?),
        None => None,
    };

    let volume_step = config.volume_step.clamp(0.0, 50.0) / 100.0;

    let seek_forward_step = config
        .seek_forward_step_secs
        .unwrap_or(config.seek_step_secs)
        .0
        .as_micros() as i64;
    let seek_backward_step = -(config
        .seek_backward_step_secs
        .unwrap_or(config.seek_step_secs)
        .0
        .as_micros() as i64);

    let new_btn = |icon: &str, instance: &'static str| -> Result<Value> {
        Ok(Value::icon(icon.to_string()).with_instance(instance))
    };

    let values = map! {
        "icon" => Value::icon("music"),
        "next" => new_btn("music_next", NEXT_BTN)?,
        "prev" => new_btn("music_prev", PREV_BTN)?,
    };

    let preferred_players = match config.player.clone() {
        PlayerName::Single(name) => vec![name],
        PlayerName::Multiple(names) => names,
    };
    let exclude_regex = config
        .interface_name_exclude
        .iter()
        .map(|r| Regex::new(r))
        .collect::<Result<Vec<_>, _>>()
        .error("Invalid regex")?;

    let playerctld_proxy = zbus_playerctld::PlayerctldProxy::new(&dbus_conn)
        .await
        .error("Failed to create PlayerctldProxy")?;

    let mut players = get_players(&dbus_conn, &preferred_players, &exclude_regex).await?;
    let mut cur_player = None;
    if let Ok(playerctld_players) = playerctld_proxy.player_names().await {
        // If we can get the list of players from playerctld then we should
        // take the first matching player (this is the most recently active player)
        for playerctld_player in playerctld_players {
            if let Some(pos) = players
                .iter()
                .position(|p| p.bus_name.as_str() == playerctld_player)
            {
                cur_player = Some(pos);
                break;
            }
        }
    } else {
        // If we couldn't get the players from playerctld then fall back to walking over
        // the players and select the first one found playing something, or the last one
        // in the list (the most recently opened)
        for (i, player) in players.iter().enumerate() {
            cur_player = Some(i);
            if player.status == Some(PlaybackStatus::Playing) {
                break;
            }
        }
    }

    let mut properties_stream = MessageStream::for_match_rule(
        MatchRule::builder()
            .msg_type(zbus::message::Type::Signal)
            .interface("org.freedesktop.DBus.Properties")
            .and_then(|x| x.member("PropertiesChanged"))
            .and_then(|x| x.path("/org/mpris/MediaPlayer2"))
            .unwrap()
            .build(),
        &dbus_conn,
        None,
    )
    .await
    .error("Failed to add match rule")?;

    let mut name_owner_changed_stream = MessageStream::for_match_rule(
        MatchRule::builder()
            .msg_type(zbus::message::Type::Signal)
            .interface("org.freedesktop.DBus")
            .and_then(|x| x.member("NameOwnerChanged"))
            .and_then(|x| x.arg0ns("org.mpris.MediaPlayer2"))
            .unwrap()
            .build(),
        &dbus_conn,
        None,
    )
    .await
    .error("Failed to add match rule")?;

    let mut active_player_change_end_stream = playerctld_proxy
        .receive_active_player_change_end()
        .await
        .error("Failed to create ActivePlayerChangeEndStream")?;

    loop {
        debug!("available players: {}", DisplaySlice(&players));

        let avail = players.len();
        let player = cur_player.map(|c| players.get_mut(c).unwrap());
        match player {
            Some(player) => {
                let mut values = values.clone();
                values.insert("avail".into(), Value::number(avail));
                values.insert("cur".into(), Value::number(cur_player.unwrap() + 1));
                values.insert(
                    "player".into(),
                    Value::text(
                        extract_player_name(player.bus_name.as_str())
                            .unwrap()
                            .into(),
                    ),
                );
                let (state, play_icon) = match player.status {
                    Some(PlaybackStatus::Playing) => (State::Info, "music_pause"),
                    _ => (State::Idle, "music_play"),
                };
                values.insert("play".into(), new_btn(play_icon, PLAY_PAUSE_BTN)?);
                if let Some(url) = &player.metadata.url {
                    values.insert("url".into(), Value::text(url.clone()));
                }
                match (
                    &player.metadata.title,
                    &player.metadata.artist,
                    &player.metadata.url,
                ) {
                    (Some(t), None, _) => {
                        values.insert("combo".into(), Value::text(t.clone()));
                        values.insert("title".into(), Value::text(t.clone()));
                    }
                    (None, Some(a), _) => {
                        values.insert("combo".into(), Value::text(a.clone()));
                        values.insert("artist".into(), Value::text(a.clone()));
                    }
                    (Some(t), Some(a), _) => {
                        values.insert(
                            "combo".into(),
                            Value::text(format!("{t}{}{a}", config.separator)),
                        );
                        values.insert("title".into(), Value::text(t.clone()));
                        values.insert("artist".into(), Value::text(a.clone()));
                    }
                    (None, None, Some(url)) => {
                        values.insert("combo".into(), Value::text(url.clone()));
                    }
                    _ => (),
                }
                if let Some(volume) = player.volume {
                    values.insert(
                        "volume_icon".into(),
                        Value::icon_progression("volume", volume),
                    );
                    values.insert("volume".into(), Value::percents(volume * 100.0));
                }
                let mut widget = Widget::new().with_format(format.clone());
                widget.set_values(values);
                widget.state = state;
                api.set_widget(widget)?;
            }
            None => {
                let mut widget = Widget::new().with_format(format.clone());
                widget.set_values(map!("icon" => Value::icon("music")));
                api.set_widget(widget)?;
            }
        }

        loop {
            select! {
                Some(msg) = properties_stream.next() => {
                    let msg = msg.unwrap();
                    let msg = PropertiesChanged::from_message(msg).unwrap();
                    let args = msg.args().unwrap();
                    let header = msg.message().header();
                    let sender = header.sender().unwrap();
                    if let Some((pos, player)) = players.iter_mut().enumerate().find(|p| &*p.1.owner == sender) {
                        let props = args.changed_properties;
                        if let Some(status) = props.get("PlaybackStatus") {
                            let status: &str = status.downcast_ref().unwrap();
                            player.status = PlaybackStatus::from_str(status);
                        }
                        if let Some(metadata) = props.get("Metadata") {
                            player.metadata =
                                zbus_mpris::PlayerMetadata::try_from(metadata.try_to_owned().unwrap()).unwrap();
                        }
                        if let Some(volume) = props.get("Volume") {
                            player.volume = Some(*volume.downcast_ref::<&f64>().unwrap());
                        }
                        if player.status == Some(PlaybackStatus::Playing)
                        && (
                            player.metadata.title.is_some()
                            || player.metadata.artist.is_some()
                            || player.metadata.url.is_some()
                        ) {
                            cur_player = Some(pos);
                        }
                        break;
                    }
                }
                Some(msg) = name_owner_changed_stream.next() => {
                    let msg = msg.unwrap();
                    let msg = NameOwnerChanged::from_message(msg).unwrap();
                    let args = msg.args().unwrap();
                    match (args.old_owner.as_ref(), args.new_owner.as_ref()) {
                        (None, Some(new)) => {
                            debug!("new player {} owned by {new}", args.name);
                            if player_matches(args.name.as_str(), &preferred_players, &exclude_regex) {
                                match Player::new(&dbus_conn, args.name.to_owned().into(), new.to_owned().into()).await {
                                    Ok(player) => players.push(player),
                                    Err(e) => {
                                        debug!("{e}");
                                    },
                                }
                            }
                        }
                        (Some(old), None) => {
                            if let Some(pos) = players.iter().position(|p| &*p.owner == old) {
                                debug!("removed player {} owned by {old}", args.name);
                                players.remove(pos);
                                if let Some(cur) = cur_player {
                                    if players.is_empty() {
                                        cur_player = None;
                                    } else if pos == cur {
                                        cur_player = Some(0);
                                    } else if pos < cur {
                                        cur_player = Some(cur - 1);
                                    }
                                }
                            }
                        }
                        _ => (),
                    }
                    break;
                }
                Some(msg) = active_player_change_end_stream.next() => {
                    let args = msg.args().unwrap();
                    if let Some(pos) = players.iter().position(|p| p.bus_name == args.name){
                        cur_player = Some(pos);
                    }
                    else{
                        // We must have shifted to a player we wanted to skip (on the interface_name_exclude list).
                        // Let's shift again
                        if let Err(e) = playerctld_proxy.shift().await{
                            debug!("{e}");
                        }
                    }
                    break;
                }
                Some(action) = actions.recv() => {
                    if let Some(i) = cur_player {
                        let player = &players[i];
                        match action.as_ref() {
                            "play_pause" => {
                                player.play_pause().await?;
                            }
                            "next" => {
                                player.next().await?;
                            }
                            "prev" => {
                                player.prev().await?;
                            }
                            "next_player" => {
                                cur_player = Some((i + 1) % players.len());
                                if let Err(e) = playerctld_proxy.shift().await{
                                    debug!("{e}");
                                }
                                break;
                            }
                            "seek_forward" => {
                                player.seek(seek_forward_step).await?;
                            }
                            "seek_backward" => {
                                player.seek(seek_backward_step).await?;
                            }
                            "volume_up" => {
                                player.set_volume(volume_step).await?;
                            }
                            "volume_down" => {
                                player.set_volume(-volume_step).await?;
                            }
                            "toggle_format" => {
                                if let Some(format_alt) = &mut format_alt {
                                    std::mem::swap(format_alt, &mut format);
                                    break;
                                }
                            }
                            _ => (),
                        }
                    }
                }
            }
        }
    }
}

async fn get_players(
    dbus_conn: &zbus::Connection,
    preferred_players: &[String],
    exclude_regex: &[Regex],
) -> Result<Vec<Player>> {
    let proxy = DBusProxy::new(dbus_conn)
        .await
        .error("failed to create DBusProxy")?;
    let names = proxy
        .list_names()
        .await
        .error("failed to list dbus names")?;
    let mut players = Vec::new();
    for name in names {
        if player_matches(name.as_str(), preferred_players, exclude_regex) {
            let owner = proxy.get_name_owner(name.as_ref()).await.unwrap();
            match Player::new(dbus_conn, name, owner).await {
                Ok(player) => players.push(player),
                Err(e) => {
                    debug!("{e}");
                }
            }
        }
    }
    Ok(players)
}

#[derive(Debug)]
struct Player {
    status: Option<PlaybackStatus>,
    owner: OwnedUniqueName,
    bus_name: OwnedBusName,
    player_proxy: zbus_mpris::PlayerProxy<'static>,
    metadata: zbus_mpris::PlayerMetadata,
    volume: Option<f64>,
}

impl Player {
    async fn new(
        dbus_conn: &zbus::Connection,
        bus_name: OwnedBusName,
        owner: OwnedUniqueName,
    ) -> Result<Player> {
        debug!("creating Player for {bus_name}");

        let proxy = zbus_mpris::PlayerProxy::builder(dbus_conn)
            .destination(bus_name.clone())
            .error("failed to set proxy destination")?
            .build()
            .await
            .error("failed to open player proxy")?;

        // debug!("querying player info");
        // let (metadata, status, volume) =
        //     tokio::join!(proxy.metadata(), proxy.playback_status(), proxy.volume());
        debug!("querying player metadata");
        let metadata = proxy.metadata().await;
        debug!("querying player status");
        let status = proxy.playback_status().await;
        debug!("querying player volume");
        let volume = proxy.volume().await;

        let metadata = metadata.error("failed to obtain player metadata")?;
        let status = status.error("failed to obtain player status")?;

        debug!("Player created");

        Ok(Self {
            status: PlaybackStatus::from_str(&status),
            owner,
            bus_name,
            player_proxy: proxy,
            metadata,
            volume: volume.ok(),
        })
    }

    async fn play_pause(&self) -> Result<()> {
        self.player_proxy
            .play_pause()
            .await
            .error("play_pause() failed")
    }

    async fn prev(&self) -> Result<()> {
        self.player_proxy.previous().await.error("prev() failed")
    }

    async fn next(&self) -> Result<()> {
        self.player_proxy.next().await.error("next() failed")
    }

    async fn seek(&self, offset: i64) -> Result<()> {
        match self.player_proxy.seek(offset).await {
            Err(zbus::Error::MethodError(e, _, _))
                if e == "org.freedesktop.DBus.Error.NotSupported" =>
            {
                // TODO show this error somehow
                Ok(())
            }
            other => dbg!(other).error("seek() failed"),
        }
    }

    async fn set_volume(&self, step_size: f64) -> Result<()> {
        if let Some(volume) = self.volume {
            self.player_proxy
                .set_volume(volume + step_size)
                .await
                .error("set_volume() failed")?;
        }
        Ok(())
    }
}

impl fmt::Display for Player {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        extract_player_name(&self.bus_name).unwrap().fmt(f)
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum PlaybackStatus {
    Playing,
    Paused,
    Stopped,
}

impl PlaybackStatus {
    fn from_str(s: &str) -> Option<Self> {
        match s {
            "Paused" => Some(Self::Paused),
            "Playing" => Some(Self::Playing),
            "Stopped" => Some(Self::Stopped),
            _ => None,
        }
    }
}

fn extract_player_name(full_name: &str) -> Option<&str> {
    const NAME_PREFIX: &str = "org.mpris.MediaPlayer2.";
    full_name
        .starts_with(NAME_PREFIX)
        .then(|| &full_name[NAME_PREFIX.len()..])
}

fn player_matches(full_name: &str, preferred_players: &[String], exclude_regex: &[Regex]) -> bool {
    let name = match extract_player_name(full_name) {
        Some(name) => name,
        None => return false,
    };

    exclude_regex.iter().all(|r| !r.is_match(name))
        && (preferred_players.is_empty()
            || preferred_players.iter().any(|p| name.starts_with(&**p)))
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn extract_player_name_test() {
        assert_eq!(
            extract_player_name("org.mpris.MediaPlayer2.firefox.instance852"),
            Some("firefox.instance852")
        );
        assert_eq!(
            extract_player_name("not.org.mpris.MediaPlayer2.firefox.instance852"),
            None,
        );
        assert_eq!(
            extract_player_name("org.mpris.MediaPlayer3.firefox.instance852"),
            None,
        );
    }

    #[test]
    fn player_matches_test() {
        let exclude = vec![Regex::new("mpd").unwrap(), Regex::new("firefox.*").unwrap()];
        assert!(player_matches(
            "org.mpris.MediaPlayer2.playerctld",
            &[],
            &exclude
        ));
        assert!(!player_matches(
            "org.mpris.MediaPlayer2.playerctld",
            &["spotify".into()],
            &exclude
        ));
        assert!(!player_matches(
            "org.mpris.MediaPlayer2.firefox.instance852",
            &[],
            &exclude
        ));
    }
}