from operator import attrgetter

from main.models import Arch, Package
from main.utils import cache_function, groupby_preserve_order, PackageStandin

class RecentUpdate(object):
    def __init__(self, packages):
        if len(packages) == 0:
            raise Exception
        first = packages[0]
        self.pkgbase = first.pkgbase
        self.repo = first.repo
        self.version = ''

        packages = sorted(packages, key=attrgetter('arch', 'pkgname'))
        # split the packages into two lists. we need to prefer packages
        # matching pkgbase as our primary, and group everything else in other.
        self.packages = [pkg for pkg in packages if pkg.pkgname == pkg.pkgbase]
        self.others = [pkg for pkg in packages if pkg.pkgname != pkg.pkgbase]

        if self.packages:
            version = self.packages[0].full_version
            if all(version == pkg.full_version for pkg in self.packages):
                self.version = version
        elif self.others:
            version = self.others[0].full_version
            if all(version == pkg.full_version for pkg in self.others):
                self.version = version

    def package_links(self):
        '''Returns either actual packages or package-standins for virtual
        pkgbase packages.'''
        if self.packages:
            # we have real packages- just yield each in sequence
            for package in self.packages:
                yield package
        else:
            # fake out the template- this is slightly hacky but yields one
            # 'package-like' object per arch which is what the normal loop does
            arches = set()
            for package in self.others:
                if package.arch not in arches and not arches.add(package.arch):
                    yield PackageStandin(package)

@cache_function(300)
def get_recent_updates(number=15):
    # This is a bit of magic. We are going to show 15 on the front page, but we
    # want to try and eliminate cross-architecture wasted space. Pull enough
    # packages that we can later do some screening and trim out the fat.
    pkgs = []
    # grab a few extra so we can hopefully catch everything we need
    fetch = number * 6
    for arch in Arch.objects.all():
        pkgs += list(Package.objects.normal().filter(
            arch=arch).order_by('-last_update')[:fetch])
    pkgs.sort(key=attrgetter('last_update'), reverse=True)

    same_pkgbase_key = lambda x: (x.repo.name, x.pkgbase)
    grouped = groupby_preserve_order(pkgs, same_pkgbase_key)

    updates = []
    for group in grouped:
        update = RecentUpdate(group)
        updates.append(update)

    return updates[:number]

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