// filepatterns.rs

//

// Copyright 2019, Georges Racinet <gracinet@anybox.fr>,

// 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::filepatterns` module provided by the

//! `hg-core` crate. From Python, this will be seen as `rustext.filepatterns`

//! and can be used as replacement for the the pure `filepatterns` Python

//! module.

//!

use crate::exceptions::{PatternError, PatternFileError};

use cpython::{

    PyBytes, PyDict, PyModule, PyObject, PyResult, PyString, PyTuple, Python,

    ToPyObject,

};

use hg::{

    build_single_regex, read_pattern_file, utils::files::get_path_from_bytes,

    LineNumber, PatternTuple,

};

use std::path::PathBuf;

/// Rust does not like functions with different return signatures.

/// The 3-tuple version is always returned by the hg-core function,

/// the (potential) conversion is handled at this level since it is not likely

/// to have any measurable impact on performance.

///

/// The Python implementation passes a function reference for `warn` instead

/// of a boolean that is used to emit warnings while parsing. The Rust

/// implementation chooses to accumulate the warnings and propagate them to

/// Python upon completion. See the `readpatternfile` function in `match.py`

/// for more details.

fn read_pattern_file_wrapper(

    py: Python,

    file_path: PyObject,

    warn: bool,

    source_info: bool,

) -> PyResult<PyTuple> {

    let bytes = file_path.extract::<PyBytes>(py)?;

    let path = get_path_from_bytes(bytes.data(py));

    match read_pattern_file(path, warn) {

        Ok((patterns, warnings)) => {

            if source_info {

                let itemgetter = |x: &PatternTuple| {

                    (PyBytes::new(py, &x.0), x.1, PyBytes::new(py, &x.2))

                };

                let results: Vec<(PyBytes, LineNumber, PyBytes)> =

                    patterns.iter().map(itemgetter).collect();

                return Ok((results, warnings_to_py_bytes(py, &warnings))

                    .to_py_object(py));

            }

            let itemgetter = |x: &PatternTuple| PyBytes::new(py, &x.0);

            let results: Vec<PyBytes> =

                patterns.iter().map(itemgetter).collect();

            Ok(

                (results, warnings_to_py_bytes(py, &warnings))

                    .to_py_object(py),

            )

        }

        Err(e) => Err(PatternFileError::pynew(py, e)),

    }

}

fn warnings_to_py_bytes(

    py: Python,

    warnings: &[(PathBuf, Vec<u8>)],

) -> Vec<(PyString, PyBytes)> {

    warnings

        .iter()

        .map(|(path, syn)| {

            (

                PyString::new(py, &path.to_string_lossy()),

                PyBytes::new(py, syn),

            )

        })

        .collect()

}

fn build_single_regex_wrapper(

    py: Python,

    kind: PyObject,

    pat: PyObject,

    globsuffix: PyObject,

) -> PyResult<PyBytes> {

    match build_single_regex(

        kind.extract::<PyBytes>(py)?.data(py),

        pat.extract::<PyBytes>(py)?.data(py),

        globsuffix.extract::<PyBytes>(py)?.data(py),

    ) {

        Ok(regex) => Ok(PyBytes::new(py, &regex)),

        Err(e) => Err(PatternError::pynew(py, e)),

    }

}

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

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

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

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

    m.add(

        py,

        "__doc__",

        "Patterns files parsing - Rust implementation",

    )?;

    m.add(

        py,

        "build_single_regex",

        py_fn!(

            py,

            build_single_regex_wrapper(

                kind: PyObject,

                pat: PyObject,

                globsuffix: PyObject

            )

        ),

    )?;

    m.add(

        py,

        "read_pattern_file",

        py_fn!(

            py,

            read_pattern_file_wrapper(

                file_path: PyObject,

                warn: bool,

                source_info: bool

            )

        ),

    )?;

    m.add(py, "PatternError", py.get_type::<PatternError>())?;

    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)

}