use crate::{HeaderTagFlag, HeaderTagHeader, HeaderTagType};
use core::mem::size_of;

/// This tag indicates that payload supports starting without terminating UEFI boot services.
/// Or in other words: The payload wants to use UEFI boot services.
#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(C)]
pub struct EfiBootServiceHeaderTag {
    header: HeaderTagHeader,
}

impl EfiBootServiceHeaderTag {
    /// Constructs a new tag.
    #[must_use]
    pub const fn new(flags: HeaderTagFlag) -> Self {
        let header = HeaderTagHeader::new(HeaderTagType::EfiBS, flags, size_of::<Self>() as u32);
        Self { header }
    }

    /// Returns the [`HeaderTagType`].
    #[must_use]
    pub const fn typ(&self) -> HeaderTagType {
        self.header.typ()
    }

    /// Returns the [`HeaderTagFlag`]s.
    #[must_use]
    pub const fn flags(&self) -> HeaderTagFlag {
        self.header.flags()
    }

    /// Returns the size.
    #[must_use]
    pub const fn size(&self) -> u32 {
        self.header.size()
    }
}

#[cfg(test)]
mod tests {
    use crate::EfiBootServiceHeaderTag;

    #[test]
    fn test_assert_size() {
        assert_eq!(core::mem::size_of::<EfiBootServiceHeaderTag>(), 2 + 2 + 4);
    }
}