import type { Task, Helpers } from "graphile-worker";
import getVod from "@futureporn/fetchers/getVod.ts";
import { getStoryboard } from '@futureporn/utils/image.ts'
import { getCdnUrl, uploadFile, type S3FileArgs } from '@futureporn/storage/s3.ts'
import patchVodInDatabase from "@futureporn/fetchers/patchVodInDatabase.ts";
import { configs } from "../config";

interface Payload {
  vod_id?: string;
  video_url?: 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" && typeof payload.video_url !== "string") throw new Error("payload requires either vod_id or video_url, however both were not a string.");
}


async function doIntegratedRequest(vodId: string): Promise<void> {

  const vod = await getVod(vodId)
  const s3_file = vod?.s3_file
  if (!s3_file) throw new Error(`vod ${vodId} was missing a s3_file.`);

  // we need to get a CDN url to the vod so we can download chunks of the file in order for Prevvy to create the storyboard image.
  const cdnUrl = getCdnUrl(configs.s3MainBucket, s3_file.s3_key)

  const tmpImagePath = await getStoryboard(cdnUrl)

  
  // we need to upload the image to S3
  const uploadArgs: S3FileArgs = { 
    filePath: tmpImagePath,
    s3AccessKeyId: configs.s3AccessKeyId,
    s3SecretAccessKey: configs.s3SecretAccessKey,
    s3BucketName: configs.s3MainBucket,
    s3Endpoint: configs.s3Region,
    s3Region: configs.s3Region
  }

  const upload = await uploadFile(uploadArgs)
  if (!upload) throw new Error(`failed to upload ${tmpImagePath} to S3`);
  if (!upload.Key) throw new Error(`failed to upload ${tmpImagePath} to S3 (upload.Key was missing)`);
  
  // we need to create a S3 file in the db
  const thumbnail = getCdnUrl(configs.s3MainBucket, upload.Key)
  await patchVodInDatabase(vodId, { thumbnail })


  

}

async function doSoloRequest(videoUrl: string): Promise<string> {
  return await getThumbnailUrl(videoUrl)
}


export const generate_thumbnail: Task = async function (payload: unknown, helpers: Helpers) {
  assertPayload(payload)
  const { vod_id, video_url } = payload
  
  helpers.logger.info(`🏗️ generate_thumbnail started with vod_id=${vod_id}, video_url=${video_url}`);


  // Determine what kind of request is being made.
  // It could be one of two scenarios
  //   * Here is a VOD record in the database, please update it's thumbnail. (integratedRequest)
  //   * Here is a video URL, please give us a thumbnail URL. (soloRequest)
  // 
  const integratedRequest = (!!vod_id && !video_url)
  const soloRequest = (!!video_url && !vod_id)
  
  if (integratedRequest) {
    await doIntegratedRequest(vod_id)
  } else if (soloRequest) {
    await getThumbnailUrl(video_url)
  } else {
    throw new Error(`unsupported ambiguous request!`)
  }

}

export default generate_thumbnail