import type { Helpers, Task } from "graphile-worker"
import { configs } from "../config"
import type { Stream } from '@futureporn/types'
import createVod from "../fetchers/createVod"
import getVod from "../fetchers/getVod"

interface Payload {
  vod_id: string;
}

function assertPayload(payload: any): asserts payload is Payload {
  if (typeof payload !== "object" || !payload) throw new Error("invalid payload (it must be an object)");
  if (typeof payload.vod_id !== "string") throw new Error("payload.vod_id was not a string");
}




/**
 * 
 * # process_video
 * 
 * We just recorded a livestream. Now what?
 * process_video takes a /vods record and runs a bunch of processes to get it ready for publishing.
 * 
 * The following are graphile-worker tasks which process_video is responsible for adding to the job queue.
 * Some of these tasks are run conditionally based on the structure of the /vods record.
 * For example, combine_video_segments is only useful on a vod recording which ended up with multiple segments.
 * 
 *   - combine_video_segments
 *   - remux_video
 *   - generate_thumbnail
 *   - queue_moderator_review
 *   - create_mux_asset
 *   - create_torrent
 * 
 * Some of the above Tasks are dependent on others. generate_thumbnail and everything following it depends on combine_video_segments.
 * graphile-worker doesn't have support for dependent tasks, 
 * thus our solution is to invoke ALL the above jobs immediately, and build those jobs to fail if pre-conditions are unmet.
 * all listed jobs are also idempotent, which means if they don't need to run (previously already performed their tasks), they will exit without doing anything.
 * 
 */
const process_video: Task = async function (payload: unknown, helpers: Helpers) {
  assertPayload(payload)
  const { vod_id } = payload
  helpers.logger.info(`process_video task has begun for vod_id=${vod_id}`)

  
  const vod = await getVod(vod_id, helpers)
  if (!vod) throw new Error(`failed to get vod from database.`);
  if (!vod.segments) throw new Error(`vod ${vod_id} fetched from database lacked any segments.`);

  const isCombinationNeeded = (vod.segments.length > 1)
  if (isCombinationNeeded) {
    const s3_manifest = vod.segments.map((segment) => ({ key: segment.s3_key, bytes: segment.bytes }))
    helpers.logger.info(`There are ${vod.segments.length} segments; Concatenation is needed.`)
    helpers.addJob('combine_video_segments', { s3_manifest, vod_id })
  } else {
    helpers.addJob('remux_video', { vod_id })
  }

  helpers.addJob('generate_thumbnail', { vod_id })
  // helpers.addJob('queue_moderator_review', { })
  // helpers.addJob('create_mux_asset', { })
  // helpers.addJob('create_torrent', { })
  // helpers.addJob('create_ipfs', { })


  

  
}

export default process_video;