use std::cell::RefCell;
use std::rc::Rc;
use crate::keys::Keyring;

/// The game-global player state: stats that follow the player across boards.
///
/// Owned by [`GameState::player`](crate::game::GameState) (a single value, not
/// per-board), so health, gems, and keys persist through board transitions.
/// Distinct from [`PlayerPos`](crate::utils::PlayerPos), which is the player's
/// position *on a particular board*. A `Copy` snapshot is handed to each script
/// hook and exposed to Rhai (read-only) as the `Player` constant.
#[derive(Copy, Clone)]
pub struct Player {
    /// The player's current health. Game-global (not per-board), so it persists
    /// across board transitions. Scripts change it via `alter_health(dh)`, which
    /// clamps to `[0, max_health]`. Front-ends display it via the status sidebar.
    pub health: i64,

    /// The maximum health the player can have. Scripts clamp `alter_health` to
    /// this ceiling; the status sidebar uses it to size the heart row.
    pub max_health: i64,

    /// The player's key inventory. Game-global; persists across board transitions.
    pub keys: Keyring,

    /// The number of gems the player has collected. Game-global like
    /// [`health`](Player::health); starts at `0`.
    pub gems: i64,
}

pub type PlayerRef = Rc<RefCell<Player>>;

impl Player {
    /// Create a new PlayerRef from a default player
    pub fn new_ref() -> PlayerRef {
        Rc::new(RefCell::from(Player::default()))
    }

    /// Attempt to modify the gem total by the given amount, but maintain a minimum of zero.
    /// If the modification would take up below zero, leave it alone and return false.
    pub fn alter_gems(&mut self, delta: i64) -> bool {
        if delta + self.gems < 0 {
            false
        } else {
            self.gems += delta;
            true
        }
    }

    /// Modify the player's health by the given delta, clamped to within the range `[0, max_health]`
    pub fn alter_health(&mut self, delta: i64) {
        self.health = (self.health + delta).clamp(0, self.max_health);
    }
}

impl Default for Player {
    fn default() -> Player {
        Self {
            health: 5,
            max_health: 5,
            gems: 0,
            keys: Keyring::default(),
        }
    }
}