use crate::FileId;

#[derive(Clone, Debug, Eq, PartialEq, serde::Serialize, serde::Deserialize)]
pub struct Span {
    pub file: FileId,
    pub start: u32, // byte offset
    pub end: u32,   // byte offset, exclusive
}

impl Span {
    #[inline]
    pub fn new(file: FileId, start: u32, end: u32) -> Self {
        Self { file, start, end }
    }

    #[inline]
    pub fn none() -> Self {
        Self {
            file: FileId::NONE,
            start: 0,
            end: 0,
        }
    }

    #[inline]
    pub fn is_none(&self) -> bool {
        self.file.is_none()
    }

    #[inline]
    pub fn len(&self) -> u32 {
        self.end.saturating_sub(self.start)
    }

    #[inline]
    pub fn contains(&self, byte: u32) -> bool {
        self.start <= byte && byte < self.end
    }
}