""" Task definitions for invoke command line utility for python bindings
    overview article.
"""
import cffi
import invoke
import pathlib
import sys
import os
import shutil
import re
import glob

on_win = sys.platform.startswith("win")


@invoke.task
def clean(c):
    """Remove any built objects"""
    for file_pattern in (
        "*.o",
        "*.so",
        "*.obj",
        "*.dll",
        "*.exp",
        "*.lib",
        "*.pyd",
        "cffi_example*",  # Is this a dir?
        "cython_wrapper.cpp",
    ):
        for file in glob.glob(file_pattern):
            os.remove(file)
    for dir_pattern in "Release":
        for dir in glob.glob(dir_pattern):
            shutil.rmtree(dir)


def print_banner(msg):
    print("==================================================")
    print("= {} ".format(msg))


@invoke.task()
def build_cmult(c, path=None):
    """Build the shared library for the sample C code"""
    # Moving this type hint into signature causes an error (???)
    c: invoke.Context
    if on_win:
        if not path:
            print("Path is missing")
        else:
            # Using c.cd didn't work with paths that have spaces :/
            path = f'"{path}vcvars32.bat" x86'  # Enter the VS venv
            path += f'&& cd "{os.getcwd()}"'  # Change to current dir
            path += "&& cl /LD cmult.c"  # Compile
            # Uncomment line below, to suppress stdout
            # path = path.replace("&&", " >nul &&") + " >nul"
            c.run(path)
    else:
        print_banner("Building C Library")
        cmd = "gcc -c -Wall -Werror -fpic cmult.c -I /usr/include/python3.7"
        invoke.run(cmd)
        invoke.run("gcc -shared -o libcmult.so cmult.o")
        print("* Complete")


@invoke.task()
def test_ctypes(c):
    """Run the script to test ctypes"""
    print_banner("Testing ctypes Module for C")
    # pty and python3 didn't work for me (win).
    if on_win:
        invoke.run("python ctypes_c_test.py")
    else:
        invoke.run("python3 ctypes_c_test.py", pty=True)


@invoke.task()
def test_ctypes_cpp(c):
    """Run the script to test ctypes"""
    print_banner("Testing ctypes Module for C++")
    # pty and python3 didn't work for me (win).
    if on_win:
        invoke.run("python ctypes_cpp_test.py")
    else:
        invoke.run("python3 ctypes_cpp_test.py", pty=True)


@invoke.task()
def build_cffi(c):
    """Build the CFFI Python bindings"""
    print_banner("Building CFFI Module")
    ffi = cffi.FFI()

    this_dir = pathlib.Path().resolve()
    h_file_name = this_dir / "cmult.h"
    with open(h_file_name) as h_file:
        # cffi does not like our preprocessor directives, so we remove them
        lns = h_file.read().splitlines()
        flt = filter(lambda ln: not re.match(r" *#", ln), lns)
        flt = map(lambda ln: ln.replace("EXPORT_SYMBOL ", ""), flt)
        ffi.cdef(str("\n").join(flt))

    ffi.set_source(
        "cffi_example",
        # Since we are calling a fully built library directly no custom source
        # is necessary. We need to include the .h files, though, because behind
        # the scenes cffi generates a .c file which contains a Python-friendly
        # wrapper around each of the functions.
        '#include "cmult.h"',
        # The important thing is to include the pre-built lib in the list of
        # libraries we are linking against:
        libraries=["cmult"],
        library_dirs=[this_dir.as_posix()],
        extra_link_args=["-Wl,-rpath,."],
    )

    ffi.compile()
    print("* Complete")


@invoke.task()
def test_cffi(c):
    """Run the script to test CFFI"""
    print_banner("Testing CFFI Module")
    invoke.run("python cffi_test.py", pty=not on_win)


@invoke.task()
def build_cppmult(c):
    """Build the shared library for the sample C++ code"""
    print_banner("Building C++ Library")
    invoke.run(
        "g++ -O3 -Wall -Werror -shared -std=c++11 -fPIC cppmult.cpp "
        "-o libcppmult.so "
    )
    print("* Complete")


def compile_python_module(cpp_name, extension_name):
    invoke.run(
        "g++ -O3 -Wall -Werror -shared -std=c++11 -fPIC "
        "`python3 -m pybind11 --includes` "
        "-I /usr/include/python3.7 -I .  "
        "{0} "
        "-o {1}`python3.7-config --extension-suffix` "
        "-L. -lcppmult -Wl,-rpath,.".format(cpp_name, extension_name)
    )


@invoke.task(build_cppmult)
def build_pybind11(c):
    """Build the pybind11 wrapper library"""
    print_banner("Building PyBind11 Module")
    compile_python_module("pybind11_wrapper.cpp", "pybind11_example")
    print("* Complete")


@invoke.task()
def test_pybind11(c):
    """Run the script to test PyBind11"""
    print_banner("Testing PyBind11 Module")
    invoke.run("python3 pybind11_test.py", pty=True)


@invoke.task(build_cppmult)
def build_cython(c):
    """Build the cython extension module"""
    print_banner("Building Cython Module")
    # Run cython on the pyx file to create a .cpp file
    invoke.run("cython --cplus -3 cython_example.pyx -o cython_wrapper.cpp")

    # Compile and link the cython wrapper library
    compile_python_module("cython_wrapper.cpp", "cython_example")
    print("* Complete")


@invoke.task()
def test_cython(c):
    """Run the script to test Cython"""
    print_banner("Testing Cython Module")
    invoke.run("python3 cython_test.py", pty=True)


@invoke.task(
    clean,
    build_cmult,
    build_cppmult,
    test_ctypes,
    test_ctypes_cpp,
    build_cffi,
    test_cffi,
    build_pybind11,
    test_pybind11,
    build_cython,
    test_cython,
)
def all(c):
    """Build and run all tests"""
    pass