#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
This module loads a `requirements.txt` and uses `virtualenv`/`pip` to
install the required Python packages into the specified directory.

Inspired by: https://github.com/awslabs/chalice

Author: Logan Raarup <logan@logan.dk>
"""
import os
import platform
import shlex
import shutil
import subprocess
import sys

try:
    import virtualenv
except ImportError:  # pragma: no cover
    sys.exit("Unable to load virtualenv, please install")


def package(req_files, target_dir, pip_args=""):
    venv_dir = os.path.join(target_dir, ".venv")
    tmp_dir = os.path.join(target_dir, ".tmp")

    for req_file in req_files:
        if not os.path.isfile(req_file):
            sys.exit("No requirements file found in: {}".format(req_file))

    if os.path.exists(target_dir):
        if not os.path.isdir(target_dir):
            sys.exit("Existing non-directory found at: {}".format(target_dir))
        shutil.rmtree(target_dir)
    os.mkdir(target_dir)

    if os.path.exists(venv_dir):
        shutil.rmtree(venv_dir)

    if os.path.exists(tmp_dir):
        shutil.rmtree(tmp_dir)

    if hasattr(virtualenv, "main"):
        original = sys.argv
        sys.argv = ["", venv_dir, "--quiet", "-p", sys.executable]
        try:
            virtualenv.main()
        finally:
            sys.argv = original
    else:
        virtualenv.cli_run([venv_dir, "--quiet", "-p", sys.executable])

    if platform.system() == "Windows":
        pip_exe = os.path.join(venv_dir, "Scripts", "pip.exe")
        deps_dir = os.path.join(venv_dir, "Lib", "site-packages")
    else:
        pip_exe = os.path.join(venv_dir, "bin", "pip")
        lib_path = os.path.join(venv_dir, "lib")
        libs_dir_path_items = os.listdir(lib_path)
        directories = [
            d for d in libs_dir_path_items if os.path.isdir(os.path.join(lib_path, d))
        ]
        if len(directories) > 0:
            python_dir = directories[0]
        else:
            sys.exit("No python directory")
        deps_dir = os.path.join(venv_dir, "lib", python_dir, "site-packages")

    if not os.path.isfile(pip_exe):
        sys.exit("Pip not found in: {}".format(pip_exe))

    for req_file in req_files:
        p = subprocess.Popen(
            [pip_exe, "install", "-r", req_file] + shlex.split(pip_args),
            stdout=subprocess.PIPE,
        )
        p.communicate()
        if p.returncode != 0:
            sys.exit("Failed to install requirements from: {}".format(req_file))

    if not os.path.isdir(deps_dir):
        sys.exit("Installed packages not found in: {}".format(deps_dir))

    blacklist = [
        "pip",
        "pip-*",
        "wheel",
        "wheel-*",
        "setuptools",
        "setuptools-*",
        "*.dist-info",
        "easy_install.*",
        "*.pyc",
        "__pycache__",
        "_virtualenv.*",
        "distutils-precedence.pth",
        "six.py",
        "zipp.py"
    ]

    shutil.copytree(
        deps_dir, tmp_dir, symlinks=False, ignore=shutil.ignore_patterns(*blacklist)
    )
    for f in os.listdir(tmp_dir):
        target = os.path.join(target_dir, f)
        if os.path.isdir(target):
            shutil.rmtree(target)
        elif os.path.exists(target):
            os.remove(target)
        shutil.move(os.path.join(tmp_dir, f), target_dir)
    shutil.rmtree(venv_dir)
    shutil.rmtree(tmp_dir)


if __name__ == "__main__":  # pragma: no cover
    args = sys.argv
    pip_args = ""

    if len(args) > 3 and args[1] == "--pip-args":
        pip_args = args[2]
        args = args[3:]
    else:
        args = args[1:]

    if len(args) < 2:
        sys.exit(
            "Usage: {} --pip-args '--no-deps' REQ_FILE... TARGET_DIR".format(
                os.path.basename(sys.argv[0])
            )
        )

    package(args[:-1], args[-1], pip_args)