# -*- coding: utf-8 -*-
"""
reporead command

Parses a repo.db.tar.gz file and updates the Arch database with the relevant
changes.

Usage: ./manage.py reporead ARCH PATH
 ARCH:  architecture to update; must be available in the database
 PATH:  full path to the repo.db.tar.gz file.

Example:
  ./manage.py reporead i686 /tmp/core.db.tar.gz
"""

from django.core.management.base import BaseCommand, CommandError
from django.contrib.auth.models import User
from django.db import transaction

from collections import defaultdict
import io
import os
import re
import sys
import tarfile
import logging
from datetime import datetime
from optparse import make_option

from devel.utils import UserFinder
from main.models import Arch, Package, PackageDepend, PackageFile, Repo
from packages.models import Conflict, Provision, Replacement

logging.basicConfig(
    level=logging.WARNING,
    format='%(asctime)s -> %(levelname)s: %(message)s',
    datefmt='%Y-%m-%d %H:%M:%S',
    stream=sys.stderr)
logger = logging.getLogger()

class Command(BaseCommand):
    option_list = BaseCommand.option_list + (
        make_option('-f', '--force', action='store_true', dest='force', default=False,
            help='Force a re-import of data for all packages instead of only new ones. Will not touch the \'last updated\' value.'),
        make_option('--filesonly', action='store_true', dest='filesonly', default=False,
            help='Load filelists if they are outdated, but will not add or remove any packages. Will not touch the \'last updated\' value.'),
    )
    help = "Runs a package repository import for the given arch and file."
    args = "<arch> <filename>"

    def handle(self, arch=None, filename=None, **options):
        if not arch:
            raise CommandError('Architecture is required.')
        if not validate_arch(arch):
            raise CommandError('Specified architecture %s is not currently known.' % arch)
        if not filename:
            raise CommandError('Package database file is required.')
        filename = os.path.normpath(filename)
        if not os.path.exists(filename) or not os.path.isfile(filename):
            raise CommandError('Specified package database file does not exist.')

        v = int(options.get('verbosity', 0))
        if v == 0:
            logger.level = logging.ERROR
        elif v == 1:
            logger.level = logging.INFO
        elif v == 2:
            logger.level = logging.DEBUG

        return read_repo(arch, filename, options)


class Pkg(object):
    """An interim 'container' object for holding Arch package data."""
    bare = ( 'name', 'base', 'arch', 'desc', 'filename',
            'md5sum', 'sha256sum', 'pgpsig', 'url', 'packager' )
    number = ( 'csize', 'isize' )
    collections = ( 'depends', 'optdepends', 'conflicts',
            'provides', 'replaces', 'groups', 'license', 'files' )

    version_re = re.compile(r'^((\d+):)?(.+)-([^-]+)$')

    def __init__(self, repo):
        self.repo = repo
        self.ver = None
        self.rel = None
        self.epoch = 0
        for k in self.bare + self.number:
            setattr(self, k, None)
        for k in self.collections:
            setattr(self, k, ())
        self.files = None
        self.has_files = False

    def populate(self, values):
        for k, v in values.iteritems():
            # ensure we stay under our DB character limit
            if k in self.bare:
                setattr(self, k, v[0][:254])
            elif k in self.number:
                setattr(self, k, long(v[0]))
            elif k == 'version':
                match = self.version_re.match(v[0])
                self.ver = match.group(3)
                self.rel = match.group(4)
                if match.group(2):
                    self.epoch = int(match.group(2))
            elif k == 'builddate':
                try:
                    self.builddate = datetime.utcfromtimestamp(int(v[0]))
                except ValueError:
                    try:
                        self.builddate = datetime.strptime(v[0],
                                '%a %b %d %H:%M:%S %Y')
                    except ValueError:
                        logger.warning('Package %s had unparsable build date %s',
                                self.name, v[0])
            elif k == 'files':
                self.files = tuple(v)
                self.has_files = True
            else:
                # anything left in collections
                setattr(self, k, tuple(v))

    @property
    def full_version(self):
        '''Very similar to the main.models.Package method.'''
        if self.epoch > 0:
            return u'%d:%s-%s' % (self.epoch, self.ver, self.rel)
        return u'%s-%s' % (self.ver, self.rel)


DEPEND_RE = re.compile(r"^(.+?)((>=|<=|=|>|<)(.*))?$")

def create_depend(package, dep_str, optional=False):
    depend = PackageDepend(pkg=package, optional=optional)
    # lop off any description first
    parts = dep_str.split(':', 1)
    if len(parts) > 1:
        depend.description = parts[1].strip()
    match = DEPEND_RE.match(parts[0].strip())
    if match:
        depend.depname = match.group(1)
        if match.group(2):
            depend.depvcmp = match.group(2)
    else:
        logger.warning('Package %s had unparsable depend string %s',
                package.pkgname, dep_str)
        return None
    depend.save(force_insert=True)
    return depend

def create_related(model, package, rel_str, equals_only=False):
    related = model(pkg=package)
    match = DEPEND_RE.match(rel_str)
    if match:
        related.name = match.group(1)
        if match.group(3):
            comp = match.group(3)
            if not equals_only:
                related.comparison = comp
            elif comp != '=':
                logger.warning(
                        'Package %s had unexpected comparison operator %s for %s in %s',
                        package.pkgname, comp, model.__name__, rel_str)
        if match.group(4):
            related.version = match.group(4)
    else:
        logger.warning('Package %s had unparsable %s string %s',
                package.pkgname, model.___name__, rel_str)
        return None
    related.save(force_insert=True)
    return related

def create_multivalued(dbpkg, repopkg, db_attr, repo_attr):
    '''Populate the simplest of multivalued attributes. These are those that
    only deal with a 'name' attribute, such as licenses, groups, etc. The input
    and output objects and attribute names are specified, and everything is
    done via getattr().'''
    collection = getattr(dbpkg, db_attr)
    collection.all().delete()
    for name in getattr(repopkg, repo_attr):
        collection.create(name=name)

finder = UserFinder()

def populate_pkg(dbpkg, repopkg, force=False, timestamp=None):
    db_score = 1

    if repopkg.base:
        dbpkg.pkgbase = repopkg.base
    else:
        dbpkg.pkgbase = repopkg.name
    dbpkg.pkgver = repopkg.ver
    dbpkg.pkgrel = repopkg.rel
    dbpkg.epoch = repopkg.epoch
    dbpkg.pkgdesc = repopkg.desc
    dbpkg.url = repopkg.url
    dbpkg.filename = repopkg.filename
    dbpkg.compressed_size = repopkg.csize
    dbpkg.installed_size = repopkg.isize
    dbpkg.build_date = repopkg.builddate
    dbpkg.packager_str = repopkg.packager
    # attempt to find the corresponding django user for this string
    dbpkg.packager = finder.find(repopkg.packager)

    if timestamp:
        dbpkg.flag_date = None
        dbpkg.last_update = timestamp
    dbpkg.save()

    db_score += populate_files(dbpkg, repopkg, force=force)

    dbpkg.packagedepend_set.all().delete()
    for y in repopkg.depends:
        create_depend(dbpkg, y)
    for y in repopkg.optdepends:
        create_depend(dbpkg, y, True)

    dbpkg.conflicts.all().delete()
    for y in repopkg.conflicts:
        create_related(Conflict, dbpkg, y)
    dbpkg.provides.all().delete()
    for y in repopkg.provides:
        create_related(Provision, dbpkg, y, equals_only=True)
    dbpkg.replaces.all().delete()
    for y in repopkg.replaces:
        create_related(Replacement, dbpkg, y)

    create_multivalued(dbpkg, repopkg, 'groups', 'groups')
    create_multivalued(dbpkg, repopkg, 'licenses', 'license')

    related_score = (len(repopkg.depends) + len(repopkg.optdepends)
            + len(repopkg.conflicts) + len(repopkg.provides)
            + len(repopkg.replaces) + len(repopkg.groups)
            + len(repopkg.license))
    if related_score:
        db_score += (related_score / 20) + 1

    return db_score


def populate_files(dbpkg, repopkg, force=False):
    if not force:
        if dbpkg.pkgver != repopkg.ver or dbpkg.pkgrel != repopkg.rel \
                or dbpkg.epoch != repopkg.epoch:
            logger.info("DB version (%s) didn't match repo version "
                    "(%s) for package %s, skipping file list addition",
                    dbpkg.full_version, repopkg.full_version, dbpkg.pkgname)
            return 0
        if not dbpkg.files_last_update or not dbpkg.last_update:
            pass
        elif dbpkg.files_last_update > dbpkg.last_update:
            return 0
    # only delete files if we are reading a DB that contains them
    if repopkg.has_files:
        dbpkg.packagefile_set.all().delete()
        logger.info("adding %d files for package %s",
                len(repopkg.files), dbpkg.pkgname)
        for f in repopkg.files:
            dirname, filename = f.rsplit('/', 1)
            if filename == '':
                filename = None
            # this is basically like calling dbpkg.packagefile_set.create(),
            # but much faster as we can skip a lot of the repeated code paths
            pkgfile = PackageFile(pkg=dbpkg,
                    is_directory=(filename is None),
                    directory=dirname + '/',
                    filename=filename)
            pkgfile.save(force_insert=True)
        dbpkg.files_last_update = datetime.utcnow()
        dbpkg.save()
        return (len(repopkg.files) / 50) + 1
    return 0


class Batcher(object):
    def __init__(self, threshold, start=0):
        self.threshold = threshold
        self.meter = start

    def batch_commit(self, score):
        """
        Track updates to the database and perform a commit if the batch
        becomes sufficiently large. "Large" is defined by waiting for the
        sum of scores to exceed the arbitrary threshold value; once it is
        hit a commit is issued.
        """
        self.meter += score
        if self.meter > self.threshold:
            logger.debug("Committing transaction, batch threshold hit")
            transaction.commit()
            self.meter = 0


@transaction.commit_on_success
def db_update(archname, reponame, pkgs, options):
    """
    Parses a list and updates the Arch dev database accordingly.

    Arguments:
      pkgs -- A list of Pkg objects.

    """
    logger.info('Updating Arch: %s', archname)
    force = options.get('force', False)
    filesonly = options.get('filesonly', False)
    repository = Repo.objects.get(name__iexact=reponame)
    architecture = Arch.objects.get(name__iexact=archname)
    # no-arg order_by() removes even the default ordering; we don't need it
    dbpkgs = Package.objects.filter(
            arch=architecture, repo=repository).order_by()
    # This makes our inner loop where we find packages by name *way* more
    # efficient by not having to go to the database for each package to
    # SELECT them by name.
    dbdict = dict([(pkg.pkgname, pkg) for pkg in dbpkgs])

    logger.debug("Creating sets")
    dbset = set(dbdict.keys())
    syncset = set([pkg.name for pkg in pkgs])
    logger.info("%d packages in current web DB", len(dbset))
    logger.info("%d packages in new updating db", len(syncset))
    in_sync_not_db = syncset - dbset
    logger.info("%d packages in sync not db", len(in_sync_not_db))

    # Try to catch those random package deletions that make Eric so unhappy.
    if len(dbset):
        dbpercent = 100.0 * len(syncset) / len(dbset)
    else:
        dbpercent = 0.0
    logger.info("DB package ratio: %.1f%%", dbpercent)

    # Fewer than 20 packages makes the percentage check unreliable, but it also
    # means we expect the repo to fluctuate a lot.
    msg = "Package database has %.1f%% the number of packages in the " \
            "web database" % dbpercent
    if len(dbset) == 0 and len(syncset) == 0:
        pass
    elif not filesonly and \
            len(dbset) > 20 and dbpercent < 50.0 and \
            not repository.testing and not repository.staging:
        logger.error(msg)
        raise Exception(msg)
    elif dbpercent < 75.0:
        logger.warning(msg)

    batcher = Batcher(100)

    if not filesonly:
        # packages in syncdb and not in database (add to database)
        for p in [x for x in pkgs if x.name in in_sync_not_db]:
            logger.info("Adding package %s", p.name)
            pkg = Package(pkgname=p.name, arch=architecture, repo=repository)
            score = populate_pkg(pkg, p, timestamp=datetime.utcnow())
            batcher.batch_commit(score)

        # packages in database and not in syncdb (remove from database)
        in_db_not_sync = dbset - syncset
        for p in in_db_not_sync:
            logger.info("Removing package %s", p)
            dbp = dbdict[p]
            dbp.delete()
            batcher.batch_commit(1)

    # packages in both database and in syncdb (update in database)
    pkg_in_both = syncset & dbset
    for p in [x for x in pkgs if x.name in pkg_in_both]:
        logger.debug("Looking for package updates")
        dbp = dbdict[p.name]
        timestamp = None
        # for a force, we don't want to update the timestamp.
        # for a non-force, we don't want to do anything at all.
        if filesonly:
            pass
        elif p.ver == dbp.pkgver and p.rel == dbp.pkgrel \
                and p.epoch == dbp.epoch:
            if not force:
                continue
        else:
            timestamp = datetime.utcnow()

        if filesonly:
            logger.debug("Checking files for package %s", p.name)
            score = populate_files(dbp, p, force=force)
        else:
            logger.info("Updating package %s", p.name)
            score = populate_pkg(dbp, p, force=force, timestamp=timestamp)

        batcher.batch_commit(score)

    logger.info('Finished updating Arch: %s', archname)


def parse_info(iofile):
    """
    Parses an Arch repo db information file, and returns variables as a list.
    """
    store = {}
    blockname = None
    for line in iofile:
        line = line.strip()
        if len(line) == 0:
            continue
        elif line.startswith('%') and line.endswith('%'):
            blockname = line[1:-1].lower()
            logger.debug("Parsing package block %s", blockname)
            store[blockname] = []
        elif blockname:
            store[blockname].append(line)
        else:
            raise Exception("Read package info outside a block: %s" % line)
    return store


def parse_repo(repopath):
    """
    Parses an Arch repo db file, and returns a list of Pkg objects.

    Arguments:
     repopath -- The path of a repository db file.

    """
    logger.info("Starting repo parsing")
    if not os.path.exists(repopath):
        logger.error("Could not read file %s", repopath)

    logger.info("Reading repo tarfile %s", repopath)
    filename = os.path.split(repopath)[1]
    m = re.match(r"^(.*)\.(db|files)\.tar(\..*)?$", filename)
    if m:
        reponame = m.group(1)
    else:
        logger.error("File does not have the proper extension")
        raise Exception("File does not have the proper extension")

    repodb = tarfile.open(repopath, "r")
    logger.debug("Starting package parsing")
    dbfiles = ('desc', 'depends', 'files')
    newpkg = lambda: Pkg(reponame)
    pkgs = defaultdict(newpkg)
    for tarinfo in repodb.getmembers():
        if tarinfo.isreg():
            pkgid, fname = os.path.split(tarinfo.name)
            if fname not in dbfiles:
                continue
            data_file = repodb.extractfile(tarinfo)
            data_file = io.TextIOWrapper(io.BytesIO(data_file.read()),
                    encoding='utf=8')
            try:
                pkgs[pkgid].populate(parse_info(data_file))
            except UnicodeDecodeError:
                logger.warn("Could not correctly decode %s, skipping file",
                        tarinfo.name)
            data_file.close()

            logger.debug("Done parsing file %s", fname)

    repodb.close()
    logger.info("Finished repo parsing, %d total packages", len(pkgs))
    return (reponame, pkgs.values())

def validate_arch(archname):
    "Check if arch is valid."
    return Arch.objects.filter(name__iexact=archname).exists()

def read_repo(primary_arch, repo_file, options):
    """
    Parses repo.db.tar.gz file and returns exit status.
    """
    repo, packages = parse_repo(repo_file)

    # group packages by arch -- to handle noarch stuff
    packages_arches = {}
    for arch in Arch.objects.filter(agnostic=True):
        packages_arches[arch.name] = []
    packages_arches[primary_arch] = []

    for package in packages:
        if package.arch in packages_arches:
            packages_arches[package.arch].append(package)
        else:
            # we don't include mis-arched packages
            logger.warning("Package %s arch = %s",
                package.name, package.arch)
    del packages

    logger.info('Starting database updates.')
    for arch in sorted(packages_arches.keys()):
        db_update(arch, repo, packages_arches[arch], options)
    logger.info('Finished database updates.')
    return 0

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