#!/usr/bin/env python3
import sys

try:
    import requests
except ImportError as e:
    sys.exit(f"Error: {str(e)}. Try 'python3 -m pip install <module-name>'")

def is_dependency_edge_blacklisted(*, parent_pkg: str, dep: str) -> bool:
    """Sometimes a package declares a hard dependency
    for some niche functionality that we really do not care about.
    """
    dep = dep.lower()
    parent_pkg = parent_pkg.lower()
    return (parent_pkg, dep) in {
        ("qrcode", "colorama"),  # only needed for using qrcode-CLI on Windows.
        ("click",  "colorama"),  # 'click' is a CLI tool, and it only needs colorama on Windows.
                                 # In fact, we should blacklist 'click' itself, but that should be done elsewhere.
    }


def check_restriction(*, dep: str, restricted: str, parent_pkg: str):
    # See: https://www.python.org/dev/peps/pep-0496/
    # Hopefully we don't need to parse the whole microlanguage
    if is_dependency_edge_blacklisted(dep=dep, parent_pkg=parent_pkg):
        return False
    if "extra" in restricted and "[" not in dep:
        return False
    for marker in ["os_name", "platform_release", "sys_platform", "platform_system"]:
        if marker in restricted:
            return True
    return False


def main():
    for p in sys.stdin.read().split():
        p = p.strip()
        if not p:
            continue
        assert "==" in p, "This script expects a list of packages with pinned version, e.g. package==1.2.3, not {}".format(p)
        p, v = p.rsplit("==", 1)
        try:
            data = requests.get("https://pypi.org/pypi/{}/{}/json".format(p, v)).json()["info"]
        except ValueError:
            raise Exception("Package could not be found: {}=={}".format(p, v))
        try:
            for r in data["requires_dist"]:  # type: str
                if ";" not in r:
                    continue
                # example value for "r" at this point: "pefile (>=2017.8.1) ; sys_platform == \"win32\""
                dep, restricted = r.split(";", 1)
                dep = dep.strip()
                restricted = restricted.strip()
                dep_basename = dep.split(" ")[0]
                if check_restriction(dep=dep, restricted=restricted, parent_pkg=p):
                    print(dep_basename, sep=" ")
                    print("Installing {} from {} although it is only needed for {}".format(dep, p, restricted), file=sys.stderr)
        except TypeError:
            # Has no dependencies at all
            continue

if __name__ == "__main__":
    main()