// parsers.rs

//

// Copyright 2019 Raphaël Gomès <rgomes@octobus.net>

//

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

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

//! Bindings for the `hg::dirstate::parsers` module provided by the

//! `hg-core` package.

//!

//! From Python, this will be seen as `mercurial.rustext.parsers`

use cpython::{

    exc, PyBytes, PyDict, PyErr, PyInt, PyModule, PyResult, PyTuple, Python,

    PythonObject, ToPyObject,

};

use hg::{

    dirstate::parsers::Timestamp, pack_dirstate, parse_dirstate,

    utils::hg_path::HgPathBuf, DirstateEntry, DirstateParents, FastHashMap,

    PARENT_SIZE,

};

use std::convert::TryInto;

use crate::dirstate::{extract_dirstate, make_dirstate_tuple};

fn parse_dirstate_wrapper(

    py: Python,

    dmap: PyDict,

    copymap: PyDict,

    st: PyBytes,

) -> PyResult<PyTuple> {

    match parse_dirstate(st.data(py)) {

        Ok((parents, entries, copies)) => {

            let dirstate_map: FastHashMap<HgPathBuf, DirstateEntry> = entries

                .into_iter()

                .map(|(path, entry)| (path.to_owned(), entry))

                .collect();

            let copy_map: FastHashMap<HgPathBuf, HgPathBuf> = copies

                .into_iter()

                .map(|(path, copy)| (path.to_owned(), copy.to_owned()))

                .collect();

            for (filename, entry) in &dirstate_map {

                dmap.set_item(

                    py,

                    PyBytes::new(py, filename.as_bytes()),

                    make_dirstate_tuple(py, entry)?,

                )?;

            }

            for (path, copy_path) in copy_map {

                copymap.set_item(

                    py,

                    PyBytes::new(py, path.as_bytes()),

                    PyBytes::new(py, copy_path.as_bytes()),

                )?;

            }

            Ok(dirstate_parents_to_pytuple(py, parents))

        }

        Err(e) => Err(PyErr::new::<exc::ValueError, _>(py, e.to_string())),

    }

}

fn pack_dirstate_wrapper(

    py: Python,

    dmap: PyDict,

    copymap: PyDict,

    pl: PyTuple,

    now: PyInt,

) -> PyResult<PyBytes> {

    let p1 = pl.get_item(py, 0).extract::<PyBytes>(py)?;

    let p1: &[u8] = p1.data(py);

    let p2 = pl.get_item(py, 1).extract::<PyBytes>(py)?;

    let p2: &[u8] = p2.data(py);

    let mut dirstate_map = extract_dirstate(py, &dmap)?;

    let copies: Result<FastHashMap<HgPathBuf, HgPathBuf>, PyErr> = copymap

        .items(py)

        .iter()

        .map(|(key, value)| {

            Ok((

                HgPathBuf::from_bytes(key.extract::<PyBytes>(py)?.data(py)),

                HgPathBuf::from_bytes(value.extract::<PyBytes>(py)?.data(py)),

            ))

        })

        .collect();

    if p1.len() != PARENT_SIZE || p2.len() != PARENT_SIZE {

        return Err(PyErr::new::<exc::ValueError, _>(

            py,

            "expected a 20-byte hash".to_string(),

        ));

    }

    match pack_dirstate(

        &mut dirstate_map,

        &copies?,

        DirstateParents {

            p1: p1.try_into().unwrap(),

            p2: p2.try_into().unwrap(),

        },

    ) {

        Ok(packed) => {

            for (filename, entry) in dirstate_map.iter() {

                dmap.set_item(

                    py,

                    PyBytes::new(py, filename.as_bytes()),

                    make_dirstate_tuple(py, &entry)?,

                )?;

            }

            Ok(PyBytes::new(py, &packed))

        }

        Err(error) => {

            Err(PyErr::new::<exc::ValueError, _>(py, error.to_string()))

        }

    }

}

/// Create the module, with `__package__` given from parent

pub fn init_parsers_module(py: Python, package: &str) -> PyResult<PyModule> {

    let dotted_name = &format!("{}.parsers", package);

    let m = PyModule::new(py, dotted_name)?;

    m.add(py, "__package__", package)?;

    m.add(py, "__doc__", "Parsers - Rust implementation")?;

    m.add(

        py,

        "parse_dirstate",

        py_fn!(

            py,

            parse_dirstate_wrapper(dmap: PyDict, copymap: PyDict, st: PyBytes)

        ),

    )?;

    m.add(

        py,

        "pack_dirstate",

        py_fn!(

            py,

            pack_dirstate_wrapper(

                dmap: PyDict,

                copymap: PyDict,

                pl: PyTuple,

                now: PyInt

            )

        ),

    )?;

    let sys = PyModule::import(py, "sys")?;

    let sys_modules: PyDict = sys.get(py, "modules")?.extract(py)?;

    sys_modules.set_item(py, dotted_name, &m)?;

    Ok(m)

}

pub(crate) fn dirstate_parents_to_pytuple(

    py: Python,

    parents: &DirstateParents,

) -> PyTuple {

    let p1 = PyBytes::new(py, parents.p1.as_bytes());

    let p2 = PyBytes::new(py, parents.p2.as_bytes());

    (p1, p2).to_py_object(py)

}