// revlog/index.rs

//

// Copyright 2019-2020 Georges Racinet <georges.racinet@octobus.net>

//           2020-2024 Raphaël Gomès <raphael.gomes@octobus.net>

//           2024 Georges Racinet <georges.racinet@cloudcrane.io>

//

// This software may be used and distributed according to the terms of the

// GNU General Public License version 2 or any later version.

//! Utilities for dealing with the index at the Python boundary

use pyo3::prelude::*;

use pyo3::types::{PyBytes, PyTuple};

use hg::revlog::{

    index::{Index, RevisionDataParams},

    Node, Revision, RevlogIndex,

};

pub struct PySharedIndex {

    /// The underlying hg-core index

    inner: &'static Index,

}

impl PySharedIndex {

    /// Return a reference to the inner index, bound by `self`

    pub fn inner(&self) -> &Index {

        self.inner

    }

    /// Return an unsafe "faked" `'static` reference to the inner index, for

    /// the purposes of Python <-> Rust memory sharing.

    pub unsafe fn static_inner(&self) -> &'static Index {

        self.inner

    }

}

impl RevlogIndex for PySharedIndex {

    fn len(&self) -> usize {

        self.inner.len()

    }

    fn node(&self, rev: Revision) -> Option<&Node> {

        self.inner.node(rev)

    }

}

pub fn py_tuple_to_revision_data_params(

    tuple: &Bound<'_, PyTuple>,

) -> PyResult<RevisionDataParams> {

    // no need to check length: in PyO3 tup.get_item() does return

    // proper errors

    let offset_or_flags: u64 = tuple.get_item(0)?.extract()?;

    let node_id = tuple

        .get_item(7)?

        .downcast::<PyBytes>()?

        .as_bytes()

        .try_into()

        .expect("nodeid should be set");

    let flags = (offset_or_flags & 0xFFFF) as u16;

    let data_offset = offset_or_flags >> 16;

    Ok(RevisionDataParams {

        flags,

        data_offset,

        data_compressed_length: tuple.get_item(1)?.extract()?,

        data_uncompressed_length: tuple.get_item(2)?.extract()?,

        data_delta_base: tuple.get_item(3)?.extract()?,

        link_rev: tuple.get_item(4)?.extract()?,

        parent_rev_1: tuple.get_item(5)?.extract()?,

        parent_rev_2: tuple.get_item(6)?.extract()?,

        node_id,

        ..Default::default()

    })

}

pub fn revision_data_params_to_py_tuple(

    py: Python<'_>,

    params: RevisionDataParams,

) -> PyResult<Bound<'_, PyTuple>> {

    PyTuple::new(

        py,

        &[

            params.data_offset.into_pyobject(py)?.into_any(),

            params.data_compressed_length.into_pyobject(py)?.into_any(),

            params

                .data_uncompressed_length

                .into_pyobject(py)?

                .into_any(),

            params.data_delta_base.into_pyobject(py)?.into_any(),

            params.link_rev.into_pyobject(py)?.into_any(),

            params.parent_rev_1.into_pyobject(py)?.into_any(),

            params.parent_rev_2.into_pyobject(py)?.into_any(),

            PyBytes::new(py, &params.node_id).into_any().into_any(),

            params._sidedata_offset.into_pyobject(py)?.into_any(),

            params

                ._sidedata_compressed_length

                .into_pyobject(py)?

                .into_any(),

            params.data_compression_mode.into_pyobject(py)?.into_any(),

            params

                ._sidedata_compression_mode

                .into_pyobject(py)?

                .into_any(),

            params._rank.into_pyobject(py)?.into_any(),

        ],

    )

}