from .database import DatabaseManager
import falcon


class RootResource:
    def on_get(self, req, resp):
        resp.status = falcon.HTTP_200
        resp.content_type = 'text/html'
        with open('dspace_statistics_api/docs/index.html', 'r') as f:
            resp.body = f.read()


class AllItemsResource:
    def on_get(self, req, resp):
        """Handles GET requests"""
        # Return HTTPBadRequest if id parameter is not present and valid
        limit = req.get_param_as_int("limit", min=0, max=100) or 100
        page = req.get_param_as_int("page", min=0) or 0
        offset = limit * page

        with DatabaseManager() as db:
            db.set_session(readonly=True)

            with db.cursor() as cursor:
                # get total number of items so we can estimate the pages
                cursor.execute('SELECT COUNT(id) FROM items')
                pages = round(cursor.fetchone()[0] / limit)

                # get statistics, ordered by id, and use limit and offset to page through results
                cursor.execute('SELECT id, views, downloads FROM items ORDER BY id ASC LIMIT {} OFFSET {}'.format(limit, offset))

                # create a list to hold dicts of item stats
                statistics = list()

                # iterate over results and build statistics object
                for item in cursor:
                    statistics.append({'id': item['id'], 'views': item['views'], 'downloads': item['downloads']})

        message = {
            'currentPage': page,
            'totalPages': pages,
            'limit': limit,
            'statistics': statistics
        }

        resp.media = message


class ItemResource:
    def on_get(self, req, resp, item_id):
        """Handles GET requests"""

        with DatabaseManager() as db:
            db.set_session(readonly=True)

            with db.cursor() as cursor:
                cursor = db.cursor()
                cursor.execute('SELECT views, downloads FROM items WHERE id={}'.format(item_id))
                if cursor.rowcount == 0:
                    raise falcon.HTTPNotFound(
                        title='Item not found',
                        description='The item with id "{}" was not found.'.format(item_id)
                    )
                else:
                    results = cursor.fetchone()

                    statistics = {
                        'id': item_id,
                        'views': results['views'],
                        'downloads': results['downloads']
                    }

                    resp.media = statistics


api = application = falcon.API()
api.add_route('/', RootResource())
api.add_route('/items', AllItemsResource())
api.add_route('/item/{item_id:int}', ItemResource())

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