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use std::marker::PhantomData;
use std::u32::MAX;

#[derive(Serialize, Deserialize)]
pub struct Id<T> {
    index: u32,
    #[serde(skip)]
    marker: PhantomData<T>,
}

impl<T> Id<T> {
    pub fn invalid() -> Self {
        Self::new(MAX)
    }

    pub fn is_invalid(&self) -> bool {
        self.index == MAX
    }

    pub fn is_valid(&self) -> bool {
        self.index != MAX
    }

    fn new(index: u32) -> Self {
        Self { index, marker: PhantomData }
    }
}

impl<T> Copy for Id<T> {}

impl<T> Clone for Id<T> {
    fn clone(&self) -> Self {
        *self
    }
}

impl<T> PartialEq for Id<T> {
    fn eq(&self, other: &Self) -> bool {
        self.index == other.index
    }
}

impl<T> Eq for Id<T> {}

impl<T> From<usize> for Id<T> {
    fn from(index: usize) -> Self {
        if index >= MAX as usize {
            Self::invalid()
        } else {
            Self::new(index as u32)
        }
    }
}

impl<T> Into<usize> for Id<T> {
    fn into(self) -> usize {
        self.index as usize
    }
}