pub mod error {
    use thiserror::Error;

    #[derive(Debug, Error)]
    pub enum Error {
        #[error("read failed")]
        ReadFailed,
        #[error("invalid magic signature")]
        InvalidMagic,
        #[error("invalid offset")]
        InvalidOffset,
        #[error("Expected an internal node")]
        ExpectedInternalNode,
        #[error("Expected a leaf node")]
        ExpectedLeafNode,
        #[error("Failed to read with logical offset")]
        BadLogicalAddress,
        #[error("Default subvolume root could not be found")]
        NoDefaultSubvolRoot,
        #[error("Default subvolume root fs tree could not be found")]
        NoDefaultSubvolFsRoot,
        #[error("INode could not be found in FsTree")]
        INodeNotFound,
        #[error("attempted to access {index}th item out of bounds {range:?}")]
        OutOfBounds {
            range: core::ops::Range<usize>,
            index: usize,
        },
        #[error("Invalid checksum: expected {expected:#?} but got {actual:#?}")]
        InvalidChecksum {
            expected: [u8; 32],
            actual: [u8; 32],
        },
        #[error("{0}")]
        ScrollError(scroll::Error),
    }

    impl From<scroll::Error> for Error {
        fn from(value: scroll::Error) -> Self {
            Self::ScrollError(value)
        }
    }

    pub type Result<T> = core::result::Result<T, Error>;
}

pub trait Read {
    fn read(&self, dst: &mut [u8], address: u64) -> error::Result<()>;
    fn alignment(&self) -> usize {
        1
    }
}

impl Read for &[u8] {
    fn read(&self, dst: &mut [u8], address: u64) -> error::Result<()> {
        let src = self
            .get(address as usize..address as usize + dst.len())
            .ok_or(error::Error::ReadFailed)?;
        dst.copy_from_slice(src);
        Ok(())
    }
}

#[cfg(all(any(feature = "std", test), unix))]
impl Read for std::fs::File {
    fn read(&self, dst: &mut [u8], address: u64) -> error::Result<()> {
        use std::os::unix::prelude::FileExt;
        self.read_at(dst, address)
            .map_err(|_| error::Error::ReadFailed)?;
        Ok(())
    }
}

pub mod file;
pub mod tree;
pub mod volume;