//! This file deals with updating the active player. 
//! It also updates the prefix, which kind of breaks seperation of concerns, but this saves me a lot of headache so I'm not changing it.
use std::collections::BTreeMap;

use log::trace;
use mpris::{PlayerFinder, Player};
use crate::structs::{data::Data, config::Config};


/// This function updates the current prefix.
/// If no entry is found in config containing the active player, a default value is used instead ('>').
/// 
/// Input:
/// cfg: Config struct for the program, containing the hashmap of prefixes.
/// data: mutable char containing the active prefix.
/// name: name of active player, to fetch the appropriate prefix from cfg.
fn update_prefix(cfg: &Config, data: &mut char, name: &str) {
  if let Some(char) = cfg.player_prefixes.get(name) {
    *data = char.clone();
    trace!("updated prefix to {}", data);
  } else {
    *data = cfg.player_prefixes.get("default").unwrap_or(&'>').clone();
    trace!("set prefix to default ({})", data);
  }
}

/// This function updates which player is selected as 'active'.
/// It only considers players present in the config.player_priorities field to be valid candidates, then selects the active one with the highest rating.
/// If none of the acceptable players are available, current_player is set to None instead.
/// 
/// Input:
/// pf: PlayerFinder instance of the program.
/// cfg: Config struct of the program, containing the list of acceptable players.
/// data: mutable Data struct of the program, containing a marker for the currently active player.
pub fn update_players(pf: &PlayerFinder, cfg: &Config, mut data: &mut Data) {
  // get all acceptable players
  let players = pf.find_all().unwrap_or(Vec::new());
  if players.is_empty() {
    data.current_player = None;
  } else {
    let mut active: BTreeMap<i32, Player> = BTreeMap::new();
    for player in players {
      if let Ok(mpris::PlaybackStatus::Playing) = player.get_playback_status() {
        let idx = cfg.find_player_priorities_idx(player.identity());
        active.insert(idx, player);
      }
    }

    // select the player with the highest priority.
    if let Some((_, player)) = active.pop_first() {
      update_prefix(cfg, &mut data.prefix, player.identity());
      data.current_player = Some(player);
    } else {
      data.current_player = None;
    }
  }
}