"""
RESTful view classes for presenting Deis API objects.
"""

from django.conf import settings
from django.core.exceptions import ValidationError
from django.contrib.auth.models import User
from django.shortcuts import get_object_or_404
from guardian.shortcuts import assign_perm, get_objects_for_user, \
    get_users_with_perms, remove_perm
from rest_framework import mixins, renderers, status
from rest_framework.exceptions import PermissionDenied
from rest_framework.permissions import IsAuthenticated
from rest_framework.response import Response
from rest_framework.viewsets import GenericViewSet

from api import authentication, models, permissions, serializers, viewsets


class UserRegistrationViewSet(GenericViewSet,
                              mixins.CreateModelMixin):
    """ViewSet to handle registering new users. The logic is in the serializer."""
    authentication_classes = [authentication.AnonymousAuthentication]
    permission_classes = [permissions.IsAnonymous, permissions.HasRegistrationAuth]
    serializer_class = serializers.UserSerializer


class UserManagementViewSet(GenericViewSet,
                            mixins.DestroyModelMixin):
    serializer_class = serializers.UserSerializer

    def get_queryset(self):
        return User.objects.filter(pk=self.request.user.pk)

    def get_object(self):
        return self.get_queryset()[0]

    def passwd(self, request, **kwargs):
        obj = self.get_object()
        if not obj.check_password(request.DATA['password']):
            return Response("Current password did not match", status=status.HTTP_400_BAD_REQUEST)
        obj.set_password(request.DATA['new_password'])
        obj.save()
        return Response({'status': 'password set'})


class BaseDeisViewSet(viewsets.OwnerViewSet):
    """
    A generic ViewSet for objects related to Deis.

    To use it, at minimum you'll need to provide the `serializer_class` attribute and
    the `model` attribute shortcut.
    """
    lookup_field = 'id'
    permission_classes = [IsAuthenticated, permissions.IsAppUser]
    renderer_classes = [renderers.JSONRenderer]

    def create(self, request, *args, **kwargs):
        try:
            return super(BaseDeisViewSet, self).create(request, *args, **kwargs)
        # If the scheduler oopsie'd
        except RuntimeError as e:
            return Response(str(e), status=status.HTTP_503_SERVICE_UNAVAILABLE)


class AppResourceViewSet(BaseDeisViewSet):
    """A viewset for objects which are attached to an application."""

    def get_app(self):
        app = get_object_or_404(models.App, id=self.kwargs['id'])
        self.check_object_permissions(self.request, app)
        return app

    def get_queryset(self, **kwargs):
        app = self.get_app()
        return self.model.objects.filter(app=app)

    def get_object(self, **kwargs):
        return self.get_queryset(**kwargs).latest('created')

    def create(self, request, **kwargs):
        request.DATA['app'] = self.get_app()
        return super(AppResourceViewSet, self).create(request, **kwargs)


class ReleasableViewSet(AppResourceViewSet):
    """A viewset for application resources which affect the release cycle.

    When a resource is created, a new release is created for the application
    and it returns some success headers regarding the new release.

    To use it, at minimum you'll need to provide a `release` attribute tied to your class before
    calling post_save().
    """
    def get_object(self):
        """Retrieve the object based on the latest release's value"""
        return getattr(self.get_app().release_set.latest(), self.model.__name__.lower())

    def get_success_headers(self, data, **kwargs):
        headers = super(ReleasableViewSet, self).get_success_headers(data)
        headers.update({'X-Deis-Release': self.release.version})
        return headers


class AppViewSet(BaseDeisViewSet):
    """A viewset for interacting with App objects."""
    model = models.App
    serializer_class = serializers.AppSerializer

    def get_queryset(self, **kwargs):
        return super(AppViewSet, self).get_queryset(**kwargs) | \
            get_objects_for_user(self.request.user, 'api.use_app')

    def post_save(self, app):
        app.create()

    def scale(self, request, **kwargs):
        new_structure = {}
        try:
            for target, count in request.DATA.items():
                new_structure[target] = int(count)
        except (TypeError, ValueError):
            return Response('Invalid scaling format',
                            status=status.HTTP_400_BAD_REQUEST)
        app = self.get_object()
        try:
            models.validate_app_structure(new_structure)
            app.scale(request.user, new_structure)
        except (EnvironmentError, ValidationError) as e:
            return Response(str(e), status=status.HTTP_400_BAD_REQUEST)
        except RuntimeError as e:
            return Response(str(e), status=status.HTTP_503_SERVICE_UNAVAILABLE)
        return Response(status=status.HTTP_204_NO_CONTENT,
                        content_type='application/json')

    def logs(self, request, **kwargs):
        app = self.get_object()
        try:
            logs = app.logs()
        except EnvironmentError:
            return Response("No logs for {}".format(app.id),
                            status=status.HTTP_204_NO_CONTENT,
                            content_type='text/plain')
        return Response(logs, status=status.HTTP_200_OK,
                        content_type='text/plain')

    def run(self, request, **kwargs):
        app = self.get_object()
        command = request.DATA['command']
        try:
            output_and_rc = app.run(self.request.user, command)
        except EnvironmentError as e:
            return Response(str(e), status=status.HTTP_400_BAD_REQUEST)
        except RuntimeError as e:
            return Response(str(e), status=status.HTTP_503_SERVICE_UNAVAILABLE)
        return Response(output_and_rc, status=status.HTTP_200_OK,
                        content_type='text/plain')


class BuildViewSet(ReleasableViewSet):
    """A viewset for interacting with Build objects."""
    model = models.Build
    serializer_class = serializers.BuildSerializer

    def post_save(self, build):
        self.release = build.create(self.request.user)
        super(BuildViewSet, self).post_save(build)


class ConfigViewSet(ReleasableViewSet):
    """A viewset for interacting with Config objects."""
    model = models.Config
    serializer_class = serializers.ConfigSerializer

    def post_save(self, config):
        release = config.app.release_set.latest()
        self.release = release.new(self.request.user, config=config, build=release.build)
        try:
            config.app.deploy(self.request.user, self.release)
        except RuntimeError:
            self.release.delete()
            raise


class ContainerViewSet(AppResourceViewSet):
    """A viewset for interacting with Container objects."""
    model = models.Container
    serializer_class = serializers.ContainerSerializer

    def get_queryset(self, **kwargs):
        qs = super(ContainerViewSet, self).get_queryset(**kwargs)
        container_type = self.kwargs.get('type')
        if container_type:
            qs = qs.filter(type=container_type)
        else:
            qs = qs.exclude(type='run')
        return qs

    def get_object(self, **kwargs):
        qs = self.get_queryset(**kwargs)
        return qs.get(num=self.kwargs['num'])


class DomainViewSet(AppResourceViewSet):
    """A viewset for interacting with Domain objects."""
    model = models.Domain
    serializer_class = serializers.DomainSerializer


class KeyViewSet(BaseDeisViewSet):
    """A viewset for interacting with Key objects."""
    model = models.Key
    serializer_class = serializers.KeySerializer


class ReleaseViewSet(AppResourceViewSet):
    """A viewset for interacting with Release objects."""
    model = models.Release
    serializer_class = serializers.ReleaseSerializer

    def get_object(self, **kwargs):
        """Get release by version always"""
        return self.get_queryset(**kwargs).get(version=self.kwargs['version'])

    def rollback(self, request, **kwargs):
        """
        Create a new release as a copy of the state of the compiled slug and config vars of a
        previous release.
        """
        try:
            app = self.get_app()
            release = app.release_set.latest()
            version_to_rollback_to = release.version - 1
            if request.DATA.get('version'):
                version_to_rollback_to = int(request.DATA['version'])
            new_release = release.rollback(request.user, version_to_rollback_to)
            response = {'version': new_release.version}
            return Response(response, status=status.HTTP_201_CREATED)
        except EnvironmentError as e:
            return Response(str(e), status=status.HTTP_400_BAD_REQUEST)
        except RuntimeError:
            new_release.delete()
            raise


class BaseHookViewSet(BaseDeisViewSet):
    permission_classes = [permissions.HasBuilderAuth]


class PushHookViewSet(BaseHookViewSet):
    """API hook to create new :class:`~api.models.Push`"""
    model = models.Push
    serializer_class = serializers.PushSerializer

    def create(self, request, *args, **kwargs):
        app = get_object_or_404(models.App, id=request.data['receive_repo'])
        self.user = get_object_or_404(User, username=request.data['receive_user'])
        # check the user is authorized for this app
        if self.user == app.owner or \
           self.user in get_users_with_perms(app) or \
           self.user.is_superuser:
                request.data['app'] = app
                request.data['owner'] = self.user
                return super(PushHookViewSet, self).create(request, *args, **kwargs)
        raise PermissionDenied()

    def perform_create(self, serializer, **kwargs):
        serializer.save(owner=self.user)


class BuildHookViewSet(BaseHookViewSet):
    """API hook to create new :class:`~api.models.Build`"""
    model = models.Build
    serializer_class = serializers.BuildSerializer

    def create(self, request, *args, **kwargs):
        app = get_object_or_404(models.App, id=request.data['receive_repo'])
        self.user = get_object_or_404(User, username=request.data['receive_user'])
        # check the user is authorized for this app
        if self.user == app.owner or \
           self.user in get_users_with_perms(app) or \
           self.user.is_superuser:
            request._data = request.data.copy()
            request.data['app'] = app
            request.data['owner'] = self.user
            super(BuildHookViewSet, self).create(request, *args, **kwargs)
            # return the application databag
            response = {'release': {'version': app.release_set.latest().version},
                        'domains': ['.'.join([app.id, settings.DEIS_DOMAIN])]}
            return Response(response, status=status.HTTP_200_OK)
        raise PermissionDenied()

    def perform_create(self, serializer, **kwargs):
        build = serializer.save(owner=self.user)
        self.post_save(build)

    def post_save(self, build):
        build.create(self.user)


class ConfigHookViewSet(BaseHookViewSet):
    """API hook to grab latest :class:`~api.models.Config`"""
    model = models.Config
    serializer_class = serializers.ConfigSerializer

    def create(self, request, *args, **kwargs):
        app = get_object_or_404(models.App, id=request.DATA['receive_repo'])
        user = get_object_or_404(User, username=request.DATA['receive_user'])
        # check the user is authorized for this app
        if user == app.owner or \
           user in get_users_with_perms(app) or \
           user.is_superuser:
            config = app.release_set.latest().config
            serializer = self.get_serializer(config)
            return Response(serializer.data, status=status.HTTP_200_OK)
        raise PermissionDenied()


class AppPermsViewSet(BaseDeisViewSet):
    """RESTful views for sharing apps with collaborators."""

    model = models.App  # models class
    perm = 'use_app'    # short name for permission

    def list(self, request, **kwargs):
        app = get_object_or_404(self.model, id=kwargs['id'])
        perm_name = "api.{}".format(self.perm)
        if request.user != app.owner and \
                not request.user.has_perm(perm_name, app) and \
                not request.user.is_superuser:
            return Response(status=status.HTTP_403_FORBIDDEN)
        usernames = [u.username for u in get_users_with_perms(app)
                     if u.has_perm(perm_name, app)]
        return Response({'users': usernames})

    def create(self, request, **kwargs):
        app = get_object_or_404(self.model, id=kwargs['id'])
        if request.user != app.owner and not request.user.is_superuser:
            return Response(status=status.HTTP_403_FORBIDDEN)
        user = get_object_or_404(User, username=request.DATA['username'])
        assign_perm(self.perm, user, app)
        models.log_event(app, "User {} was granted access to {}".format(user, app))
        return Response(status=status.HTTP_201_CREATED)

    def destroy(self, request, **kwargs):
        app = get_object_or_404(self.model, id=kwargs['id'])
        if request.user != app.owner and not request.user.is_superuser:
            return Response(status=status.HTTP_403_FORBIDDEN)
        user = get_object_or_404(User, username=kwargs['username'])
        if user.has_perm(self.perm, app):
            remove_perm(self.perm, user, app)
            models.log_event(app, "User {} was revoked access to {}".format(user, app))
            return Response(status=status.HTTP_204_NO_CONTENT)
        else:
            return Response(status=status.HTTP_403_FORBIDDEN)


class AdminPermsViewSet(BaseDeisViewSet):
    """RESTful views for sharing admin permissions with other users."""

    model = User
    serializer_class = serializers.AdminUserSerializer
    permission_classes = (permissions.IsAdmin,)

    def get_queryset(self, **kwargs):
        self.check_object_permissions(self.request, self.request.user)
        return self.model.objects.filter(is_active=True, is_superuser=True)

    def create(self, request, **kwargs):
        user = get_object_or_404(User, username=request.DATA['username'])
        user.is_superuser = user.is_staff = True
        user.save(update_fields=['is_superuser', 'is_staff'])
        return Response(status=status.HTTP_201_CREATED)

    def destroy(self, request, **kwargs):
        user = get_object_or_404(User, username=kwargs['username'])
        user.is_superuser = user.is_staff = False
        user.save(update_fields=['is_superuser', 'is_staff'])
        return Response(status=status.HTTP_204_NO_CONTENT)