use crate::{HeaderTagFlag, HeaderTagHeader, HeaderTagType};
use core::mem;
use multiboot2_common::{MaybeDynSized, Tag};

/// Specifies the preferred graphics mode. If this tag
/// is present the bootloader assumes that the payload
/// has framebuffer support. Note: This is only a
/// recommended mode. Only relevant on legacy BIOS.
#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(C, align(8))]
pub struct FramebufferHeaderTag {
    header: HeaderTagHeader,
    width: u32,
    height: u32,
    depth: u32,
}

impl FramebufferHeaderTag {
    /// Constructs a new tag.
    #[must_use]
    pub const fn new(flags: HeaderTagFlag, width: u32, height: u32, depth: u32) -> Self {
        let header =
            HeaderTagHeader::new(HeaderTagType::Framebuffer, flags, Self::BASE_SIZE as u32);
        Self {
            header,
            width,
            height,
            depth,
        }
    }

    /// 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()
    }

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

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

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

impl MaybeDynSized for FramebufferHeaderTag {
    type Header = HeaderTagHeader;

    const BASE_SIZE: usize = mem::size_of::<HeaderTagHeader>() + 3 * mem::size_of::<u32>();

    fn dst_len(_header: &Self::Header) -> Self::Metadata {}
}

impl Tag for FramebufferHeaderTag {
    type IDType = HeaderTagType;
    const ID: HeaderTagType = HeaderTagType::Framebuffer;
}