from django.db import models


class PackageURLMixin(models.Model):
    """
    Abstract Model for Package URL "purl" fields support.
    """
    type = models.CharField(
        max_length=16,
        blank=True,
        null=True,
        help_text=_(
            'A short code to identify the type of this package. '
            'For example: gem for a Rubygem, docker for a container, '
            'pypi for a Python Wheel or Egg, maven for a Maven Jar, '
            'deb for a Debian package, etc.'
        )
    )

    namespace = models.CharField(
        max_length=255,
        blank=True,
        null=True,
        help_text=_(
            'Package name prefix, such as Maven groupid, Docker image owner, '
            'GitHub user or organization, etc.'
        ),
    )

    name = models.CharField(
        max_length=100,
        blank=True,
        null=True,
        help_text=_('Name of the package.'),
    )

    version = models.CharField(
        max_length=50,
        blank=True,
        null=True,
        help_text=_('Version of the package.'),
    )

    qualifiers = models.CharField(
        max_length=1024,
        blank=True,
        null=True,
        help_text=_(
            'Extra qualifying data for a package such as the name of an OS, '
            'architecture, distro, etc.'
        ),
    )

    subpath = models.CharField(
        max_length=200,
        blank=True,
        null=True,
        help_text=_(
            'Extra subpath within a package, relative to the package root.'
        ),
    )

    class Meta:
        abstract = True

    @property
    def package_url(self):
        """
        Return a compact Package URL "purl" string.
        """
        try:
            purl = PackageURL(
                self.type, self.namespace, self.name,
                self.version, self.qualifiers, self.subpath
            )
        except ValueError:
            return ''
        return str(purl)