from __future__ import unicode_literals

from django.core.exceptions import ObjectDoesNotExist
from djblets.util.decorators import augment_method_from
from djblets.webapi.decorators import (webapi_login_required,
                                       webapi_response_errors,
                                       webapi_request_fields)
from djblets.webapi.errors import (DOES_NOT_EXIST, INVALID_FORM_DATA,
                                   NOT_LOGGED_IN, PERMISSION_DENIED)

from reviewboard.diffviewer.models import FileDiff
from reviewboard.webapi.decorators import webapi_check_local_site
from reviewboard.webapi.resources import resources
from reviewboard.webapi.resources.base_diff_comment import \
    BaseDiffCommentResource


class ReviewDiffCommentResource(BaseDiffCommentResource):
    """Provides information on diff comments made on a review.

    If the review is a draft, then comments can be added, deleted, or
    changed on this list. However, if the review is already published,
    then no changes can be made.
    """
    allowed_methods = ('GET', 'POST', 'PUT', 'DELETE')
    policy_id = 'review_diff_comment'
    model_parent_key = 'review'

    mimetype_list_resource_name = 'review-diff-comments'
    mimetype_item_resource_name = 'review-diff-comment'

    def get_queryset(self, request, review_id, *args, **kwargs):
        q = super(ReviewDiffCommentResource, self).get_queryset(
            request, *args, **kwargs)
        return q.filter(review=review_id)

    @webapi_check_local_site
    @webapi_login_required
    @webapi_response_errors(DOES_NOT_EXIST, INVALID_FORM_DATA,
                            NOT_LOGGED_IN, PERMISSION_DENIED)
    @webapi_request_fields(
        required=dict({
            'filediff_id': {
                'type': int,
                'description': 'The ID of the file diff the comment is on.',
            },
            'first_line': {
                'type': int,
                'description': 'The line number the comment starts at.',
            },
            'num_lines': {
                'type': int,
                'description': 'The number of lines the comment spans.',
            },
        }, **BaseDiffCommentResource.REQUIRED_CREATE_FIELDS),
        optional=dict({
            'interfilediff_id': {
                'type': int,
                'description': 'The ID of the second file diff in the '
                               'interdiff the comment is on.',
            },
        }, **BaseDiffCommentResource.OPTIONAL_CREATE_FIELDS),
        allow_unknown=True,
    )
    def create(self, request, filediff_id, interfilediff_id=None,
               *args, **kwargs):
        """Creates a new diff comment.

        This will create a new diff comment on this review. The review
        must be a draft review.

        Extra data can be stored later lookup. See
        :ref:`webapi2.0-extra-data` for more information.
        """
        try:
            review_request = \
                resources.review_request.get_object(request, *args, **kwargs)
            review = resources.review.get_object(request, *args, **kwargs)
        except ObjectDoesNotExist:
            return DOES_NOT_EXIST

        if not resources.review.has_modify_permissions(request, review):
            return self.get_no_access_error(request)

        filediff = None
        interfilediff = None
        invalid_fields = {}

        try:
            filediff = FileDiff.objects.get(
                pk=filediff_id,
                diffset__history__review_request=review_request)
        except ObjectDoesNotExist:
            invalid_fields['filediff_id'] = \
                ['This is not a valid filediff ID']

        if filediff and interfilediff_id:
            if interfilediff_id == filediff.id:
                invalid_fields['interfilediff_id'] = \
                    ['This cannot be the same as filediff_id']
            else:
                try:
                    interfilediff = FileDiff.objects.get(
                        pk=interfilediff_id,
                        diffset__history=filediff.diffset.history)
                except ObjectDoesNotExist:
                    invalid_fields['interfilediff_id'] = \
                        ['This is not a valid interfilediff ID']

        if invalid_fields:
            return INVALID_FORM_DATA, {
                'fields': invalid_fields,
            }

        return self.create_comment(
            review=review,
            comments_m2m=review.comments,
            filediff=filediff,
            interfilediff=interfilediff,
            fields=('filediff', 'interfilediff', 'first_line', 'num_lines'),
            **kwargs)

    @webapi_check_local_site
    @webapi_login_required
    @webapi_response_errors(DOES_NOT_EXIST, NOT_LOGGED_IN, PERMISSION_DENIED)
    @webapi_request_fields(
        optional=dict({
            'first_line': {
                'type': int,
                'description': 'The line number the comment starts at.',
            },
            'num_lines': {
                'type': int,
                'description': 'The number of lines the comment spans.',
            },
        }, **BaseDiffCommentResource.OPTIONAL_UPDATE_FIELDS),
        allow_unknown=True,
    )
    def update(self, request, *args, **kwargs):
        """Updates a diff comment.

        This can update the text or line range of an existing comment.

        Extra data can be stored later lookup. See
        :ref:`webapi2.0-extra-data` for more information.
        """
        try:
            resources.review_request.get_object(request, *args, **kwargs)
            review = resources.review.get_object(request, *args, **kwargs)
            diff_comment = self.get_object(request, *args, **kwargs)
        except ObjectDoesNotExist:
            return DOES_NOT_EXIST

        return self.update_comment(request=request,
                                   review=review,
                                   comment=diff_comment,
                                   update_fields=('first_line', 'num_lines'),
                                   **kwargs)

    @webapi_check_local_site
    @augment_method_from(BaseDiffCommentResource)
    def delete(self, *args, **kwargs):
        """Deletes the comment.

        This will remove the comment from the review. This cannot be undone.

        Only comments on draft reviews can be deleted. Attempting to delete
        a published comment will return a Permission Denied error.

        Instead of a payload response, this will return :http:`204`.
        """
        pass

    @webapi_check_local_site
    @augment_method_from(BaseDiffCommentResource)
    def get_list(self, *args, **kwargs):
        """Returns the list of comments made on a review.

        This list can be filtered down by using the ``?line=`` and
        ``?interdiff-revision=``.

        To filter for comments that start on a particular line in the file,
        using ``?line=``.

        To filter for comments that span revisions of diffs, you can specify
        the second revision in the range using ``?interdiff-revision=``.
        """
        pass


review_diff_comment_resource = ReviewDiffCommentResource()
