from io import BytesIO
from os import path
from zipfile import ZipFile
import json
import urllib.request
import sys

ROOT_DIRNAME = path.dirname(path.dirname(path.abspath(__file__)))
REQUIREMENTS_PATH = path.join(ROOT_DIRNAME, "requirements.txt")
PYTHONFILES_PATH = path.join(ROOT_DIRNAME, "pythonFiles", "lib", "python")
PYPI_PTVSD_URL = "https://pypi.org/pypi/ptvsd/json"


def install_ptvsd():
    # If we are in CI use the packaging module installed in PYTHONFILES_PATH.
    if len(sys.argv) == 2 and sys.argv[1] == "--ci":
        sys.path.insert(0, PYTHONFILES_PATH)
    from packaging.requirements import Requirement

    with open(REQUIREMENTS_PATH, "r", encoding="utf-8") as requirements:
        for line in requirements:
            package_requirement = Requirement(line)
            if package_requirement.name != "ptvsd":
                continue
            requirement_specifier = package_requirement.specifier
            ptvsd_version = next(requirement_specifier.__iter__()).version

    # Response format: https://warehouse.readthedocs.io/api-reference/json/#project
    with urllib.request.urlopen(PYPI_PTVSD_URL) as response:
        json_response = json.loads(response.read())
    releases = json_response["releases"]

    # Release metadata format: https://github.com/pypa/interoperability-peps/blob/master/pep-0426-core-metadata.rst
    for wheel_info in releases[ptvsd_version]:
        # Download only if it's a 3.7 wheel.
        if not wheel_info["python_version"].endswith(("37", "3.7")):
            continue
        filename = wheel_info["filename"].rpartition(".")[0]  # Trim the file extension.
        ptvsd_path = path.join(PYTHONFILES_PATH, filename)

        with urllib.request.urlopen(wheel_info["url"]) as wheel_response:
            wheel_file = BytesIO(wheel_response.read())
        # Extract only the contents of the ptvsd subfolder.
        prefix = path.join(f"ptvsd-{ptvsd_version}.data", "purelib", "ptvsd")

        with ZipFile(wheel_file, "r") as wheel:
            for zip_info in wheel.infolist():
                if not zip_info.filename.startswith(prefix):
                    continue
                # Flatten the folder structure.
                zip_info.filename = zip_info.filename.split(prefix)[-1]
                wheel.extract(zip_info, ptvsd_path)


if __name__ == "__main__":
    install_ptvsd()