from collections import namedtuple

from django.db import models
from django.db.models.signals import pre_save
from django.contrib.auth.models import User

from main.models import Arch, Repo, Package
from main.utils import set_created_field

class PackageRelation(models.Model):
    '''
    Represents maintainership (or interest) in a package by a given developer.
    It is not a true foreign key to packages as we want to key off
    pkgbase/pkgname instead, as well as preserve this information across
    package deletes, adds, and in all repositories.
    '''
    MAINTAINER = 1
    WATCHER = 2
    TYPE_CHOICES = (
            (MAINTAINER, 'Maintainer'),
            (WATCHER, 'Watcher'),
    )
    pkgbase = models.CharField(max_length=255)
    user = models.ForeignKey(User, related_name="package_relations")
    type = models.PositiveIntegerField(choices=TYPE_CHOICES, default=MAINTAINER)
    created = models.DateTimeField(editable=False)

    def get_associated_packages(self):
        return Package.objects.normal().filter(pkgbase=self.pkgbase)

    def repositories(self):
        packages = self.get_associated_packages()
        return sorted(set([p.repo for p in packages]))

    def __unicode__(self):
        return u'%s: %s (%s)' % (
                self.pkgbase, self.user, self.get_type_display())

    class Meta:
        unique_together = (('pkgbase', 'user', 'type'),)


class SignoffSpecificationManager(models.Manager):
    def get_from_package(self, pkg):
        '''Utility method to pull all relevant name-version fields from a
        package and get a matching signoff specification.'''
        return self.get(
                pkgbase=pkg.pkgbase, pkgver=pkg.pkgver, pkgrel=pkg.pkgrel,
                epoch=pkg.epoch, arch=pkg.arch, repo=pkg.repo)

    def get_or_default_from_package(self, pkg):
        '''utility method to pull all relevant name-version fields from a
        package and get a matching signoff specification, or return the default
        base case.'''
        try:
            return self.get(
                    pkgbase=pkg.pkgbase, pkgver=pkg.pkgver, pkgrel=pkg.pkgrel,
                    epoch=pkg.epoch, arch=pkg.arch, repo=pkg.repo)
        except SignoffSpecification.DoesNotExist:
            return DEFAULT_SIGNOFF_SPEC

class SignoffSpecification(models.Model):
    '''
    A specification for the signoff policy for this particular revision of a
    package. The default is requiring two signoffs for a given package. These
    are created only if necessary; e.g., if one wanted to override the
    required=2 attribute, otherwise a sane default object is used.
    '''
    pkgbase = models.CharField(max_length=255, db_index=True)
    pkgver = models.CharField(max_length=255)
    pkgrel = models.CharField(max_length=255)
    epoch = models.PositiveIntegerField(default=0)
    arch = models.ForeignKey(Arch)
    repo = models.ForeignKey(Repo)
    user = models.ForeignKey(User, null=True)
    created = models.DateTimeField(editable=False)
    required = models.PositiveIntegerField(default=2,
        help_text="How many signoffs are required for this package?")
    enabled = models.BooleanField(default=True,
        help_text="Is this package eligible for signoffs?")
    known_bad = models.BooleanField(default=False,
        help_text="Is package is known to be broken in some way?")
    comments = models.TextField(null=True, blank=True)

    objects = SignoffSpecificationManager()

    @property
    def full_version(self):
        if self.epoch > 0:
            return u'%d:%s-%s' % (self.epoch, self.pkgver, self.pkgrel)
        return u'%s-%s' % (self.pkgver, self.pkgrel)

    def __unicode__(self):
        return u'%s-%s' % (self.pkgbase, self.full_version)


# fake default signoff spec when we don't have a persisted one in the database
FakeSignoffSpecification = namedtuple('FakeSignoffSpecification',
        ('required', 'enabled', 'known_bad', 'comments'))
DEFAULT_SIGNOFF_SPEC = FakeSignoffSpecification(2, True, False, u'')


class SignoffManager(models.Manager):
    def get_from_package(self, pkg, user, revoked=False):
        '''Utility method to pull all relevant name-version fields from a
        package and get a matching signoff.'''
        not_revoked = not revoked
        return self.get(
                pkgbase=pkg.pkgbase, pkgver=pkg.pkgver, pkgrel=pkg.pkgrel,
                epoch=pkg.epoch, arch=pkg.arch, repo=pkg.repo,
                revoked__isnull=not_revoked, user=user)

    def get_or_create_from_package(self, pkg, user):
        '''Utility method to pull all relevant name-version fields from a
        package and get or create a matching signoff.'''
        return self.get_or_create(
                pkgbase=pkg.pkgbase, pkgver=pkg.pkgver, pkgrel=pkg.pkgrel,
                epoch=pkg.epoch, arch=pkg.arch, repo=pkg.repo,
                revoked=None, user=user)

    def for_package(self, pkg):
        return self.select_related('user').filter(
                pkgbase=pkg.pkgbase, pkgver=pkg.pkgver, pkgrel=pkg.pkgrel,
                epoch=pkg.epoch, arch=pkg.arch, repo=pkg.repo)

class Signoff(models.Model):
    '''
    A signoff for a package (by pkgbase) at a given point in time. These are
    not keyed directly to a Package object so they don't ever get deleted when
    Packages come and go from testing repositories.
    '''
    pkgbase = models.CharField(max_length=255, db_index=True)
    pkgver = models.CharField(max_length=255)
    pkgrel = models.CharField(max_length=255)
    epoch = models.PositiveIntegerField(default=0)
    arch = models.ForeignKey(Arch)
    repo = models.ForeignKey(Repo)
    user = models.ForeignKey(User, related_name="package_signoffs")
    created = models.DateTimeField(editable=False)
    revoked = models.DateTimeField(null=True)
    comments = models.TextField(null=True, blank=True)

    objects = SignoffManager()

    @property
    def packages(self):
        return Package.objects.normal().filter(pkgbase=self.pkgbase,
                pkgver=self.pkgver, pkgrel=self.pkgrel, epoch=self.epoch,
                arch=self.arch, repo=self.repo)

    @property
    def full_version(self):
        if self.epoch > 0:
            return u'%d:%s-%s' % (self.epoch, self.pkgver, self.pkgrel)
        return u'%s-%s' % (self.pkgver, self.pkgrel)

    def __unicode__(self):
        revoked = u''
        if self.revoked:
            revoked = u' (revoked)'
        return u'%s-%s: %s%s' % (
                self.pkgbase, self.full_version, self.user, revoked)


class FlagRequest(models.Model):
    '''
    A notification the package is out-of-date submitted through the web site.
    '''
    user = models.ForeignKey(User, blank=True, null=True)
    user_email = models.EmailField('email address')
    created = models.DateTimeField(editable=False)
    # Great work, Django... https://code.djangoproject.com/ticket/18212
    ip_address = models.GenericIPAddressField(verbose_name='IP address',
            unpack_ipv4=True)
    pkgbase = models.CharField(max_length=255, db_index=True)
    version = models.CharField(max_length=255, default='')
    repo = models.ForeignKey(Repo)
    num_packages = models.PositiveIntegerField('number of packages', default=1)
    message = models.TextField('message to developer', blank=True)
    is_spam = models.BooleanField(default=False,
            help_text="Is this comment from a real person?")
    is_legitimate = models.BooleanField(default=True,
            help_text="Is this actually an out-of-date flag request?")

    class Meta:
        get_latest_by = 'created'

    def who(self):
        if self.user:
            return self.user.get_full_name()
        return self.user_email

    def __unicode__(self):
        return u'%s from %s on %s' % (self.pkgbase, self.who(), self.created)

class PackageGroup(models.Model):
    '''
    Represents a group a package is in. There is no actual group entity,
    only names that link to given packages.
    '''
    pkg = models.ForeignKey(Package, related_name='groups')
    name = models.CharField(max_length=255, db_index=True)

    def __unicode__(self):
        return "%s: %s" % (self.name, self.pkg)


class License(models.Model):
    pkg = models.ForeignKey(Package, related_name='licenses')
    name = models.CharField(max_length=255)

    def __unicode__(self):
        return self.name

    class Meta:
        ordering = ['name']


class RelatedToBase(models.Model):
    '''A base class for conflicts/provides/replaces/etc.'''
    name = models.CharField(max_length=255, db_index=True)
    version = models.CharField(max_length=255, default='')

    def get_best_satisfier(self):
        '''Find a satisfier for this related package that best matches the
        given criteria. It will not search provisions, but will find packages
        named and matching repo characteristics if possible.'''
        pkgs = Package.objects.normal().filter(pkgname=self.name)
        if not self.pkg.arch.agnostic:
            # make sure we match architectures if possible
            arches = self.pkg.applicable_arches()
            pkgs = pkgs.filter(arch__in=arches)
        if len(pkgs) == 0:
            # couldn't find a package in the DB
            # it should be a virtual depend (or a removed package)
            return None
        if len(pkgs) == 1:
            return pkgs[0]
        # more than one package, see if we can't shrink it down
        # grab the first though in case we fail
        pkg = pkgs[0]
        # prevents yet more DB queries, these lists should be short;
        # after each grab the best available in case we remove all entries
        pkgs = [p for p in pkgs if p.repo.staging == self.pkg.repo.staging]
        if len(pkgs) > 0:
            pkg = pkgs[0]

        pkgs = [p for p in pkgs if p.repo.testing == self.pkg.repo.testing]
        if len(pkgs) > 0:
            pkg = pkgs[0]

        return pkg

    def get_providers(self):
        '''Return providers of this related package. Does *not* include exact
        matches as it checks the Provision names only, use get_best_satisfier()
        instead for exact matches.'''
        pkgs = Package.objects.normal().filter(
                provides__name=self.name).order_by().distinct()
        if not self.pkg.arch.agnostic:
            # make sure we match architectures if possible
            arches = self.pkg.applicable_arches()
            pkgs = pkgs.filter(arch__in=arches)

        # Logic here is to filter out packages that are in multiple repos if
        # they are not requested. For example, if testing is False, only show a
        # testing package if it doesn't exist in a non-testing repo.
        filtered = {}
        for package in pkgs:
            if package.pkgname not in filtered or \
                    package.repo.staging == self.pkg.repo.staging:
                filtered[package.pkgname] = package
        pkgs = filtered.values()

        filtered = {}
        for package in pkgs:
            if package.pkgname not in filtered or \
                    package.repo.testing == self.pkg.repo.testing:
                filtered[package.pkgname] = package
        pkgs = filtered.values()

        return pkgs

    def __unicode__(self):
        if self.version:
            return u'%s%s%s' % (self.name, self.comparison, self.version)
        return self.name

    class Meta:
        abstract = True
        ordering = ['name']


class Depend(RelatedToBase):
    pkg = models.ForeignKey(Package, related_name='depends')
    comparison = models.CharField(max_length=255, default='')
    optional = models.BooleanField(default=False)
    description = models.TextField(null=True, blank=True)


class Conflict(RelatedToBase):
    pkg = models.ForeignKey(Package, related_name='conflicts')
    comparison = models.CharField(max_length=255, default='')


class Provision(RelatedToBase):
    pkg = models.ForeignKey(Package, related_name='provides')
    # comparison must be '=' for provides

    @property
    def comparison(self):
        if self.version is not None and self.version != '':
            return '='
        return None


class Replacement(RelatedToBase):
    pkg = models.ForeignKey(Package, related_name='replaces')
    comparison = models.CharField(max_length=255, default='')


# hook up some signals
for sender in (PackageRelation, SignoffSpecification, Signoff):
    pre_save.connect(set_created_field, sender=sender,
            dispatch_uid="packages.models")

# vim: set ts=4 sw=4 et: