import itertools

from django.contrib.auth import get_user_model

from django.core.management.base import NoArgsCommand, CommandError

from django.db.models import Q

from ldt.ldt_utils.models  import Project, Content

from ldt.ldt_utils.modelsutils  import ProjectMerger

class Command(NoArgsCommand):

    """

    Merge projects.

    Beware this version of the command correctly support merging projects from only one content.

    Usage:

        -p <project_id>: project id, can have more than one

        -c <content_id>: content id, can have more than one

        -t <title>: project title (default merge of "projects title")

        -u <user>: user for project (defaut admin)

        --only-visible: only visible cuttings (default false)

        --exclude-shot-by-shot: remove shot by shot (default false)

        --all-published: merge all projects published or not (default false)

    """

    help = 'Merge projects'

    def add_arguments(self, parser):

        # Named (optional) arguments

        parser.add_argument(

            '--only-visible',

            action='store_true',

            dest='visible',

            default=False,

            help='merge only visible cuttings')

        parser.add_argument(

            '--exclude-shot-by-shot',

            action='store_true',

            dest='exclude_shot_by_shot',

            default=False,

            help='exclude shot by shot cuttings')

        parser.add_argument(

            '--all-published',

            action='store_true',

            dest='all_published',

            default=False,

            help='merge all projects published or not')

        parser.add_argument(

            '-p', '--project',

            action='append',

            dest='projects',

            metavar='PROJECT_ID',

            default=[],

            help='project id to concatenate')

        parser.add_argument(

            '-c', '--content',

            action='store',

            dest='contents',

            default=None,

            metavar='CONTENT_ID',

            help='content id to concatenate')

        parser.add_argument(

            '-t', '--title',

            action='store',

            dest='title',

            metavar='TITLE',

            help='The title for the merged project. defaut "merged: title1, title2,..."'

        )

        parser.add_argument(

            '-u', '--user',

            action='store',

            dest='user',

            metavar='USER',

            help='The user creator of the merged project'

        )

    def handle_noargs(self, **options):

        # pylint: disable=C0103

        User = get_user_model()

        username = options.get('user', None)

        if not username:

            users = User.objects.filter(is_superuser=True).order_by('date_joined')

            if len(users) > 0:

                user = users[0]

                username = user.username

            else:

                raise CommandError("No username given and can not fond a superuser")

        else:

            user = User.objects.get(username=username)

        # filter projects

        project_filter = Q()

        projects_ids = options.get('projects', None)

        if projects_ids:

            project_filter &= Q(ldt_id__in=projects_ids)

        content_id = options.get('contents', None)

        if content_id:

            project_filter = Q(contents__iri_id__in=[content_id,])

        if not projects_ids and not content_id:

            raise CommandError("At least one content or project must be specified")

        if not options.get('all_published', False):

            project_filter &= Q(state=Project.PUBLISHED)

        projects = Project.objects.filter(project_filter)

        if len(projects) == 0:

            raise CommandError("No project found, aborting")

        title = options.get('title', "")

        if not title:

            title = "Merged: " + ", ".join([p.title.strip() for p in projects])

        contents = set(itertools.chain(*[proj.contents.all() for proj in projects]))

        if len(contents) == 0:

            raise CommandError("Content not found")

        if len(contents) > 1 and not content_id:

            raise CommandError("Too many contents %d" % len(contents))

        if content_id:

            content = Content.objects.get(iri_id=content_id)

        else:

            content = contents[0]

        if options.get('verbosity', 1) > 0:

            print("Merging %d projects in \'%s\'" % (len(projects), title))

        pmerger = ProjectMerger(content, projects)

        proj = pmerger.get_merged_project(

            only_visible=not options.get('visible', False),

            shot_by_shot=not options.get('exclude_shot_by_shot', False))

        proj.created_by = username

        proj.changed_by = username

        proj.owner = user

        proj.title = title

        proj.save()

        if options.get('verbosity', 1) > 0: