# Copyright 2018 New Vector Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

swagger: '2.0'
info:
  title: "Matrix Federation Events API"
  version: "1.0.0"
host: localhost:8448
schemes:
  - https
basePath: /_matrix/federation/v1
produces:
  - application/json
paths:
  "/backfill/{roomId}":
    get:
      summary: Retrieves the events which precede the given event
      description: |-
        Retreives a sliding-window history of previous PDUs that occurred in the given room.
        Starting from the PDU ID(s) given in the ``v`` argument, the PDUs that preceded it
        are retrieved, up to the total number given by the ``limit``.
      operationId: backfillRoom
      parameters:
        - in: path
          name: roomId
          type: string
          description: The room ID to backfill.
          required: true
          x-example: "!SomeRoom:matrix.org"
        - in: query
          name: v
          type: array
          items:
            type: string
          description: The event IDs to backfill from. 
          required: true
          x-example: ["$abc123:matrix.org"]
        - in: query
          name: limit
          type: integer
          description: The maximum number of PDUs to retrieve, including the given events.
          required: true
          x-example: 2
      responses:
        200:
          description: |-
            A transaction containing the PDUs that preceded the given event(s), including the given
            event(s), up to the given limit.
          schema:
            $ref: "definitions/transaction.yaml"
          # Override the example to show the response of the request a bit better
          examples:
            application/json: {
              "$ref": "examples/transaction.json",
              "pdus": [
                {
                  "$ref": "pdu.json",
                  "room_id": "!SomeRoom:matrix.org",
                  "event_id": "$abc123:matrix.org"
                },
                {
                  "$ref": "pdu.json",
                  "room_id": "!SomeRoom:matrix.org"
                },
              ]
            }