# Copyright 2014 Pants project contributors (see CONTRIBUTORS.md).
# Licensed under the Apache License, Version 2.0 (see LICENSE).

from pants.base.hash_utils import stable_json_sha1
from pants.base.payload_field import PayloadField


class PythonArtifact(PayloadField):
    """Represents a Python setup.py-based project."""

    class MissingArgument(Exception):
        pass

    class UnsupportedArgument(Exception):
        pass

    UNSUPPORTED_ARGS = frozenset({"data_files", "package_dir", "package_data", "packages",})

    def __init__(self, **kwargs):
        """
        :param kwargs: Passed to `setuptools.setup
          <https://pythonhosted.org/setuptools/setuptools.html>`_.
        """
        self._kw = kwargs
        self._binaries = {}

        def has(name):
            value = self._kw.get(name)
            if value is None:
                raise self.MissingArgument(
                    "PythonArtifact requires {} to be specified!".format(name)
                )
            return value

        def misses(name):
            if name in self._kw:
                raise self.UnsupportedArgument(
                    "PythonArtifact prohibits {} from being specified".format(name)
                )

        self._version = has("version")
        self._name = has("name")
        for arg in self.UNSUPPORTED_ARGS:
            misses(arg)

    @property
    def name(self):
        return self._name

    @property
    def version(self):
        return self._version

    @property
    def requirement(self):
        return "{}=={}".format(self._name, self._version)

    @property
    def setup_py_keywords(self):
        return self._kw

    @property
    def binaries(self):
        return self._binaries

    def __str__(self):
        return self.name

    def _compute_fingerprint(self):
        return stable_json_sha1((self._kw, self._binaries))

    def with_binaries(self, *args, **kw):
        """Add binaries tagged to this artifact.

        For example: ::

          provides = setup_py(
            name = 'my_library',
            zip_safe = True
          ).with_binaries(
            my_command = ':my_library_bin'
          )

        This adds a console_script entry_point for the python_binary target
        pointed at by :my_library_bin.  Currently only supports
        python_binaries that specify entry_point explicitly instead of source.

        Also can take a dictionary, e.g.
        with_binaries({'my-command': ':my_library_bin'})
        """
        for arg in args:
            if isinstance(arg, dict):
                self._binaries.update(arg)
        self._binaries.update(kw)
        return self