use pyo3::exceptions::PyValueError;

use pyo3::prelude::*;

use pyo3::types::PyBytes;

use hg::revlog::RevlogIndex;

use hg::{

    revlog::index::Index, revlog::node::NODE_BYTES_LENGTH, Node, NodePrefix,

    Revision,

};

#[derive(Debug, Copy, Clone, PartialEq, derive_more::From)]

pub struct PyNode(Node);

/// Copy incoming Python binary Node ID into [`Node`]

///

/// # Python exceptions

/// Raises `ValueError` if length is not as expected

pub fn node_from_py_bytes(bytes: &Bound<'_, PyBytes>) -> PyResult<Node> {

    Node::try_from(bytes.as_bytes()).map_err(|_| {

        PyValueError::new_err(format!(

            "{}-byte hash required",

            NODE_BYTES_LENGTH

        ))

    })

}

/// Convert Python hexadecimal Node ID node or prefix given as `bytes` into

/// [`NodePrefix`].

///

/// # Python exceptions

/// Raises `ValueError` if the incoming `bytes` is invalid.

pub fn node_prefix_from_py_bytes(

    bytes: &Bound<'_, PyBytes>,

) -> PyResult<NodePrefix> {

    let as_bytes = bytes.as_bytes();

    NodePrefix::from_hex(as_bytes).map_err(|_| {

        PyValueError::new_err(format!(

            "Invalid node or prefix '{}'",

            String::from_utf8_lossy(as_bytes)

        ))

    })

}

/// Return the binary node from a checked revision

///

/// This is meant to be used on revisions already checked to exist,

/// typically obtained from a NodeTree lookup.

///

/// # Panics

/// Panics if the revision does not exist

pub fn py_node_for_rev<'py>(

    py: Python<'py>,

    idx: &Index,

    rev: Revision,

) -> Bound<'py, PyBytes> {

    PyBytes::new(py, idx.node(rev).expect("node should exist").as_bytes())

}