import hasProperty from '@uppy/utils/lib/hasProperty'
import ErrorWithCause from '@uppy/utils/lib/ErrorWithCause'
import { RateLimitedQueue } from '@uppy/utils/lib/RateLimitedQueue'
import BasePlugin from '@uppy/core/lib/BasePlugin.js'
import type { DefinePluginOpts, PluginOpts } from '@uppy/core/lib/BasePlugin.js'
import Tus, { type TusDetailedError } from '@uppy/tus'
import type { Body, Meta, UppyFile } from '@uppy/utils/lib/UppyFile'
import type { Uppy } from '@uppy/core'
import Assembly from './Assembly.ts'
import Client, { AssemblyError } from './Client.ts'
import AssemblyOptionsBuilder, {
  validateParams,
  type OptionsWithRestructuredFields,
} from './AssemblyOptions.ts'
import AssemblyWatcher from './AssemblyWatcher.ts'

import locale from './locale.ts'
// eslint-disable-next-line @typescript-eslint/ban-ts-comment
// @ts-ignore We don't want TS to generate types for the package.json
import packageJson from '../package.json'

export interface AssemblyFile {
  id: string
  name: string
  basename: string
  ext: string
  size: number
  mime: string
  type: string
  field: string
  md5hash: string
  is_tus_file: boolean
  original_md5hash: string
  original_id: string
  original_name: string
  original_basename: string
  original_path: string
  url: string
  ssl_url: string
  tus_upload_url: string
  meta: Record<string, any>
}

export interface AssemblyResult extends AssemblyFile {
  cost: number
  execTime: number
  queue: string
  queueTime: number
  localId: string | null
}

export interface AssemblyResponse {
  ok: string
  message?: string
  assembly_id: string
  parent_id?: string
  account_id: string
  template_id?: string
  instance: string
  assembly_url: string
  assembly_ssl_url: string
  uppyserver_url: string
  companion_url: string
  websocket_url: string
  tus_url: string
  bytes_received: number
  bytes_expected: number
  upload_duration: number
  client_agent?: string
  client_ip?: string
  client_referer?: string
  transloadit_client: string
  start_date: string
  upload_meta_data_extracted: boolean
  warnings: any[]
  is_infinite: boolean
  has_dupe_jobs: boolean
  execution_start: string
  execution_duration: number
  queue_duration: number
  jobs_queue_duration: number
  notify_start?: any
  notify_url?: string
  notify_status?: any
  notify_response_code?: any
  notify_duration?: any
  last_job_completed?: string
  fields: Record<string, any>
  running_jobs: any[]
  bytes_usage: number
  executing_jobs: any[]
  started_jobs: string[]
  parent_assembly_status: any
  params: string
  template?: any
  merged_params: string
  uploads: AssemblyFile[]
  results: Record<string, AssemblyResult[]>
  build_id: string
  error?: string
  stderr?: string
  stdout?: string
  reason?: string
}

const sendErrorToConsole = (originalErr: Error) => (err: Error) => {
  const error = new ErrorWithCause('Failed to send error to the client', {
    cause: err,
  })
  // eslint-disable-next-line no-console
  console.error(error, originalErr)
}

const COMPANION_URL = 'https://api2.transloadit.com/companion'
// Regex matching acceptable postMessage() origins for authentication feedback from companion.
const COMPANION_ALLOWED_HOSTS = /\.transloadit\.com$/
// Regex used to check if a Companion address is run by Transloadit.
const TL_COMPANION = /https?:\/\/api2(?:-\w+)?\.transloadit\.com\/companion/

export interface AssemblyParameters {
  auth: {
    key: string
    expires?: string
  }
  template_id?: string
  steps?: { [step: string]: Record<string, unknown> }
  fields?: { [name: string]: number | string }
  notify_url?: string
}

export interface AssemblyOptions {
  params?: AssemblyParameters | null
  fields?: Record<string, string | number> | string[] | null
  signature?: string | null
}

interface BaseOptions extends PluginOpts {
  service?: string
  errorReporting?: boolean
  waitForEncoding?: boolean
  waitForMetadata?: boolean
  importFromUploadURLs?: boolean
  alwaysRunAssembly?: boolean
  limit?: number
  clientName?: string | null
  retryDelays?: number[]
}

export type TransloaditOptions<M extends Meta, B extends Body> = BaseOptions &
  (
    | {
        assemblyOptions?:
          | AssemblyOptions
          | ((
              file?: UppyFile<M, B> | null,
              options?: AssemblyOptions,
            ) => Promise<AssemblyOptions> | AssemblyOptions)
        /** @deprecated use `assemblyOptions` instead */
        getAssemblyOptions?: never | null
        /** @deprecated use `assemblyOptions` instead */
        params?: never | null
        /** @deprecated use `assemblyOptions` instead */
        fields?: never | null
        /** @deprecated use `assemblyOptions` instead */
        signature?: never | null
      }
    | {
        /** @deprecated use `assemblyOptions` instead */
        getAssemblyOptions?: (
          file?: UppyFile<M, B> | null,
        ) => AssemblyOptions | Promise<AssemblyOptions>
        assemblyOptions?: never
        /** @deprecated use `assemblyOptions` instead */
        params?: never | null
        /** @deprecated use `assemblyOptions` instead */
        fields?: never | null
        /** @deprecated use `assemblyOptions` instead */
        signature?: never | null
      }
    | {
        /** @deprecated use `assemblyOptions` instead */
        params?: AssemblyParameters | null
        /** @deprecated use `assemblyOptions` instead */
        fields?: { [name: string]: number | string } | string[] | null
        /** @deprecated use `assemblyOptions` instead */
        signature?: string | null
        /** @deprecated use `assemblyOptions` instead */
        getAssemblyOptions?: never | null
        assemblyOptions?: never
      }
  )

const defaultOptions = {
  service: 'https://api2.transloadit.com',
  errorReporting: true,
  waitForEncoding: false,
  waitForMetadata: false,
  alwaysRunAssembly: false,
  importFromUploadURLs: false,
  /** @deprecated use `assemblyOptions` instead */
  signature: null,
  /** @deprecated use `assemblyOptions` instead */
  params: null,
  /** @deprecated use `assemblyOptions` instead */
  fields: null,
  /** @deprecated use `assemblyOptions` instead */
  getAssemblyOptions: null,
  limit: 20,
  retryDelays: [7_000, 10_000, 15_000, 20_000],
  clientName: null,
} satisfies TransloaditOptions<any, any>

export type Opts<M extends Meta, B extends Body> = DefinePluginOpts<
  TransloaditOptions<M, B>,
  keyof typeof defaultOptions
>

type TransloaditState = {
  assemblies: Record<string, AssemblyResponse>
  files: Record<
    string,
    { assembly: string; id: string; uploadedFile: AssemblyFile }
  >
  results: Array<{
    result: AssemblyResult
    stepName: string
    id: string
    assembly: string
  }>
  uploadsAssemblies: Record<string, string[]>
}

declare module '@uppy/core' {
  // eslint-disable-next-line @typescript-eslint/no-unused-vars
  export interface UppyEventMap<M extends Meta, B extends Body> {
    // We're also overriding the `restored` event as it is now populated with Transloadit state.
    restored: (pluginData: Record<string, TransloaditState>) => void
    'restore:get-data': (
      setData: (
        arg: Record<
          string,
          Pick<TransloaditState, 'assemblies' | 'uploadsAssemblies'>
        >,
      ) => void,
    ) => void
    'transloadit:assembly-created': (
      assembly: AssemblyResponse,
      fileIDs: string[],
    ) => void
    'transloadit:assembly-cancel': (assembly: AssemblyResponse) => void
    'transloadit:import-error': (
      assembly: AssemblyResponse,
      fileID: string,
      error: Error,
    ) => void
    'transloadit:assembly-error': (
      assembly: AssemblyResponse,
      error: Error,
    ) => void
    'transloadit:assembly-executing': (assembly: AssemblyResponse) => void
    'transloadit:assembly-cancelled': (assembly: AssemblyResponse) => void
    'transloadit:upload': (
      file: AssemblyFile,
      assembly: AssemblyResponse,
    ) => void
    'transloadit:result': (
      stepName: string,
      result: AssemblyResult,
      assembly: AssemblyResponse,
    ) => void
    'transloadit:complete': (assembly: AssemblyResponse) => void
    'transloadit:execution-progress': (details: {
      progress_combined?: number
    }) => void
  }
}

declare module '@uppy/utils/lib/UppyFile' {
  // eslint-disable-next-line no-shadow, @typescript-eslint/no-unused-vars
  export interface UppyFile<M extends Meta, B extends Body> {
    transloadit?: { assembly: string }
    tus?: { uploadUrl?: string | null }
  }
}

/**
 * Upload files to Transloadit using Tus.
 */
export default class Transloadit<
  M extends Meta,
  B extends Body,
> extends BasePlugin<Opts<M, B>, M, B, TransloaditState> {
  static VERSION = packageJson.version

  /** @deprecated use `import { COMPANION_URL } from '@uppy/transloadit'` instead. */
  static COMPANION = COMPANION_URL

  /** @deprecated use `import { COMPANION_ALLOWED_HOSTS } from '@uppy/transloadit'` instead. */
  static COMPANION_PATTERN = COMPANION_ALLOWED_HOSTS

  #rateLimitedQueue: RateLimitedQueue

  client: Client<M, B>

  activeAssemblies: Record<string, Assembly>

  assemblyWatchers: Record<string, AssemblyWatcher<M, B>>

  completedFiles: Record<string, boolean>

  restored: Promise<void> | null

  constructor(uppy: Uppy<M, B>, opts: TransloaditOptions<M, B>) {
    super(uppy, { ...defaultOptions, ...opts })
    this.type = 'uploader'
    this.id = this.opts.id || 'Transloadit'

    this.defaultLocale = locale

    // TODO: remove this fallback in the next major
    this.opts.assemblyOptions ??= this.opts.getAssemblyOptions ?? {
      params: this.opts.params,
      signature: this.opts.signature,
      fields: this.opts.fields,
    }

    // TODO: remove this check in the next major (validating params when creating the assembly should be enough)
    if (
      opts?.params != null &&
      opts.getAssemblyOptions == null &&
      opts.assemblyOptions == null
    ) {
      validateParams((this.opts.assemblyOptions as AssemblyOptions).params)
    }

    this.#rateLimitedQueue = new RateLimitedQueue(this.opts.limit)

    this.i18nInit()

    this.client = new Client({
      service: this.opts.service,
      client: this.#getClientVersion(),
      errorReporting: this.opts.errorReporting,
      rateLimitedQueue: this.#rateLimitedQueue,
    })
    // Contains Assembly instances for in-progress Assemblies.
    this.activeAssemblies = {}
    // Contains a mapping of uploadID to AssemblyWatcher
    this.assemblyWatchers = {}
    // Contains a file IDs that have completed postprocessing before the upload
    // they belong to has entered the postprocess stage.
    this.completedFiles = Object.create(null)
  }

  #getClientVersion() {
    const list = [
      // @ts-expect-error VERSION comes from babel, TS does not understand
      `uppy-core:${this.uppy.constructor.VERSION}`,
      // @ts-expect-error VERSION comes from babel, TS does not understand
      `uppy-transloadit:${this.constructor.VERSION}`,
      `uppy-tus:${Tus.VERSION}`,
    ]

    const addPluginVersion = (pluginName: string, versionName: string) => {
      const plugin = this.uppy.getPlugin(pluginName)
      if (plugin) {
        // @ts-expect-error VERSION comes from babel, TS does not understand
        list.push(`${versionName}:${plugin.constructor.VERSION}`)
      }
    }

    if (this.opts.importFromUploadURLs) {
      addPluginVersion('XHRUpload', 'uppy-xhr-upload')
      addPluginVersion('AwsS3', 'uppy-aws-s3')
      addPluginVersion('AwsS3Multipart', 'uppy-aws-s3-multipart')
    }

    addPluginVersion('Dropbox', 'uppy-dropbox')
    addPluginVersion('Box', 'uppy-box')
    addPluginVersion('Facebook', 'uppy-facebook')
    addPluginVersion('GoogleDrive', 'uppy-google-drive')
    addPluginVersion('GooglePhotos', 'uppy-google-photos')
    addPluginVersion('Instagram', 'uppy-instagram')
    addPluginVersion('OneDrive', 'uppy-onedrive')
    addPluginVersion('Zoom', 'uppy-zoom')
    addPluginVersion('Url', 'uppy-url')

    if (this.opts.clientName != null) {
      list.push(this.opts.clientName)
    }

    return list.join(',')
  }

  /**
   * Attach metadata to files to configure the Tus plugin to upload to Transloadit.
   * Also use Transloadit's Companion
   *
   * See: https://github.com/tus/tusd/wiki/Uploading-to-Transloadit-using-tus#uploading-using-tus
   */
  #attachAssemblyMetadata(file: UppyFile<M, B>, status: AssemblyResponse) {
    // Add the metadata parameters Transloadit needs.
    const meta = {
      ...file.meta,
      assembly_url: status.assembly_url,
      filename: file.name,
      fieldname: 'file',
    }
    // Add Assembly-specific Tus endpoint.
    const tus = {
      ...file.tus,
      endpoint: status.tus_url,
      // Include X-Request-ID headers for better debugging.
      addRequestId: true,
    }

    // Set Companion location. We only add this, if 'file' has the attribute
    // remote, because this is the criteria to identify remote files.
    // We only replace the hostname for Transloadit's companions, so that
    // people can also self-host them while still using Transloadit for encoding.
    let { remote } = file

    if (file.remote && TL_COMPANION.test(file.remote.companionUrl)) {
      const newHost = status.companion_url.replace(/\/$/, '')
      const path = file.remote.url
        .replace(file.remote.companionUrl, '')
        .replace(/^\//, '')

      remote = {
        ...file.remote,
        companionUrl: newHost,
        url: `${newHost}/${path}`,
      }
    }

    // Store the Assembly ID this file is in on the file under the `transloadit` key.
    const newFile = {
      ...file,
      transloadit: {
        assembly: status.assembly_id,
      },
    }
    // Only configure the Tus plugin if we are uploading straight to Transloadit (the default).
    if (!this.opts.importFromUploadURLs) {
      Object.assign(newFile, { meta, tus, remote })
    }
    return newFile
  }

  #createAssembly(
    fileIDs: string[],
    uploadID: string,
    assemblyOptions: OptionsWithRestructuredFields,
  ) {
    this.uppy.log('[Transloadit] Create Assembly')

    return this.client
      .createAssembly({
        ...assemblyOptions,
        expectedFiles: fileIDs.length,
      })
      .then(async (newAssembly) => {
        const files = this.uppy
          .getFiles()
          .filter(({ id }) => fileIDs.includes(id))

        if (files.length === 0 && fileIDs.length !== 0) {
          // All files have been removed, cancelling.
          await this.client.cancelAssembly(newAssembly)
          return null
        }

        const assembly = new Assembly(newAssembly, this.#rateLimitedQueue)
        const { status } = assembly
        const assemblyID = status.assembly_id

        const { assemblies, uploadsAssemblies } = this.getPluginState()
        this.setPluginState({
          // Store the Assembly status.
          assemblies: {
            ...assemblies,
            [assemblyID]: status,
          },
          // Store the list of Assemblies related to this upload.
          uploadsAssemblies: {
            ...uploadsAssemblies,
            [uploadID]: [...uploadsAssemblies[uploadID], assemblyID],
          },
        })

        const updatedFiles: Record<string, UppyFile<M, B>> = {}
        files.forEach((file) => {
          updatedFiles[file.id] = this.#attachAssemblyMetadata(file, status)
        })

        this.uppy.setState({
          files: {
            ...this.uppy.getState().files,
            ...updatedFiles,
          },
        })

        // TODO: this should not live inside a `file-removed` event but somewhere more deterministic.
        // Such as inside the function where the assembly has succeeded or cancelled.
        // For the use case of cancelling the assembly when needed, we should try to do that with just `cancel-all`.
        const fileRemovedHandler = (
          fileRemoved: UppyFile<M, B>,
          reason?: string,
        ) => {
          // If the assembly has successfully completed, we do not need these checks.
          // Otherwise we may cancel an assembly after it already succeeded
          if (assembly.status?.ok === 'ASSEMBLY_COMPLETED') {
            this.uppy.off('file-removed', fileRemovedHandler)
            return
          }
          if (reason === 'cancel-all') {
            assembly.close()
            this.uppy.off('file-removed', fileRemovedHandler)
          }
        }
        this.uppy.on('file-removed', fileRemovedHandler)

        this.uppy.emit('transloadit:assembly-created', status, fileIDs)

        this.uppy.log(`[Transloadit] Created Assembly ${assemblyID}`)
        return assembly
      })
      .catch((err) => {
        // TODO: use AssemblyError?
        const wrapped = new ErrorWithCause(
          `${this.i18n('creatingAssemblyFailed')}: ${err.message}`,
          { cause: err },
        )
        if ('details' in err) {
          // @ts-expect-error details is not in the Error type
          wrapped.details = err.details
        }
        if ('assembly' in err) {
          // @ts-expect-error assembly is not in the Error type
          wrapped.assembly = err.assembly
        }
        throw wrapped
      })
  }

  #createAssemblyWatcher(idOrArrayOfIds: string | string[], uploadID: string) {
    // AssemblyWatcher tracks completion states of all Assemblies in this upload.
    const ids =
      Array.isArray(idOrArrayOfIds) ? idOrArrayOfIds : [idOrArrayOfIds]
    const watcher = new AssemblyWatcher(this.uppy, ids)

    watcher.on('assembly-complete', (id: string) => {
      const files = this.getAssemblyFiles(id)
      files.forEach((file) => {
        this.completedFiles[file.id] = true
        this.uppy.emit('postprocess-complete', file)
      })
    })

    watcher.on('assembly-error', (id: string, error: Error) => {
      // Clear postprocessing state for all our files.
      const filesFromAssembly = this.getAssemblyFiles(id)
      filesFromAssembly.forEach((file) => {
        // TODO Maybe make a postprocess-error event here?

        this.uppy.emit('upload-error', file, error)
        this.uppy.emit('postprocess-complete', file)
      })

      // Reset `tus` key in the file state, so when the upload is retried,
      // old tus upload is not re-used — Assebmly expects a new upload, can't currently
      // re-use the old one. See: https://github.com/transloadit/uppy/issues/4412
      // and `onReceiveUploadUrl` in @uppy/tus
      const files = { ...this.uppy.getState().files }
      filesFromAssembly.forEach((file) => delete files[file.id].tus)
      this.uppy.setState({ files })

      this.uppy.emit('error', error)
    })

    this.assemblyWatchers[uploadID] = watcher
  }

  #shouldWaitAfterUpload() {
    return this.opts.waitForEncoding || this.opts.waitForMetadata
  }

  /**
   * Used when `importFromUploadURLs` is enabled: reserves all files in
   * the Assembly.
   */
  #reserveFiles(assembly: Assembly, fileIDs: string[]) {
    return Promise.all(
      fileIDs.map((fileID) => {
        const file = this.uppy.getFile(fileID)
        return this.client.reserveFile(assembly.status, file)
      }),
    )
  }

  /**
   * Used when `importFromUploadURLs` is enabled: adds files to the Assembly
   * once they have been fully uploaded.
   */
  #onFileUploadURLAvailable = (rawFile: UppyFile<M, B> | undefined) => {
    const file = this.uppy.getFile(rawFile!.id)
    if (!file?.transloadit?.assembly) {
      return
    }

    const { assemblies } = this.getPluginState()
    const assembly = assemblies[file.transloadit.assembly]

    this.client.addFile(assembly, file).catch((err) => {
      this.uppy.log(err)
      this.uppy.emit('transloadit:import-error', assembly, file.id, err)
    })
  }

  #findFile(uploadedFile: AssemblyFile) {
    const files = this.uppy.getFiles()
    for (let i = 0; i < files.length; i++) {
      const file = files[i]
      // Completed file upload.
      if (file.uploadURL === uploadedFile.tus_upload_url) {
        return file
      }
      // In-progress file upload.
      if (file.tus && file.tus.uploadUrl === uploadedFile.tus_upload_url) {
        return file
      }
      if (!uploadedFile.is_tus_file) {
        // Fingers-crossed check for non-tus uploads, eg imported from S3.
        if (
          file.name === uploadedFile.name &&
          file.size === uploadedFile.size
        ) {
          return file
        }
      }
    }
    return undefined
  }

  #onFileUploadComplete(assemblyId: string, uploadedFile: AssemblyFile) {
    const state = this.getPluginState()
    const file = this.#findFile(uploadedFile)
    if (!file) {
      this.uppy.log(
        '[Transloadit] Couldn’t find the file, it was likely removed in the process',
      )
      return
    }
    this.setPluginState({
      files: {
        ...state.files,
        [uploadedFile.id]: {
          assembly: assemblyId,
          id: file.id,
          uploadedFile,
        },
      },
    })
    this.uppy.emit(
      'transloadit:upload',
      uploadedFile,
      this.getAssembly(assemblyId),
    )
  }

  #onResult(assemblyId: string, stepName: string, result: AssemblyResult) {
    const state = this.getPluginState()
    const file = state.files[result.original_id]
    // The `file` may not exist if an import robot was used instead of a file upload.
    result.localId = file ? file.id : null // eslint-disable-line no-param-reassign

    const entry = {
      result,
      stepName,
      id: result.id,
      assembly: assemblyId,
    }

    this.setPluginState({
      results: [...state.results, entry],
    })
    const assembly = this.activeAssemblies[assemblyId].status
    this.uppy.emit('transloadit:result', stepName, result, assembly)
  }

  /**
   * When an Assembly has finished processing, get the final state
   * and emit it.
   */
  #onAssemblyFinished(status: AssemblyResponse) {
    const url = status.assembly_ssl_url
    this.client.getAssemblyStatus(url).then((finalStatus) => {
      const assemblyId = finalStatus.assembly_id
      const state = this.getPluginState()
      this.setPluginState({
        assemblies: {
          ...state.assemblies,
          [assemblyId]: finalStatus,
        },
      })
      this.uppy.emit('transloadit:complete', finalStatus)
    })
  }

  async #cancelAssembly(assembly: AssemblyResponse) {
    await this.client.cancelAssembly(assembly)
    // TODO bubble this through AssemblyWatcher so its event handlers can clean up correctly
    this.uppy.emit('transloadit:assembly-cancelled', assembly)
  }

  /**
   * When all files are removed, cancel in-progress Assemblies.
   */
  #onCancelAll = async ({ reason }: { reason?: string } = {}) => {
    try {
      if (reason !== 'user') return

      const { uploadsAssemblies } = this.getPluginState()
      const assemblyIDs = Object.values(uploadsAssemblies).flat(1)
      const assemblies = assemblyIDs.map((assemblyID) =>
        this.getAssembly(assemblyID),
      )

      await Promise.all(
        assemblies.map((assembly) => this.#cancelAssembly(assembly)),
      )
    } catch (err) {
      this.uppy.log(err)
    }
  }

  /**
   * Custom state serialization for the Golden Retriever plugin.
   * It will pass this back to the `_onRestored` function.
   */
  #getPersistentData = (
    setData: (
      arg: Record<
        string,
        Pick<TransloaditState, 'assemblies' | 'uploadsAssemblies'>
      >,
    ) => void,
  ) => {
    const { assemblies, uploadsAssemblies } = this.getPluginState()

    setData({
      [this.id]: {
        assemblies,
        uploadsAssemblies,
      },
    })
  }

  #onRestored = (pluginData: Record<string, TransloaditState>) => {
    const savedState =
      pluginData && pluginData[this.id] ? pluginData[this.id] : {}
    const previousAssemblies = (savedState as TransloaditState).assemblies || {}
    const uploadsAssemblies =
      (savedState as TransloaditState).uploadsAssemblies || {}

    if (Object.keys(uploadsAssemblies).length === 0) {
      // Nothing to restore.
      return
    }

    // Convert loaded Assembly statuses to a Transloadit plugin state object.
    const restoreState = (assemblies: TransloaditState['assemblies']) => {
      const files: Record<
        string,
        { id: string; assembly: string; uploadedFile: AssemblyFile }
      > = {}
      const results: {
        result: AssemblyResult
        stepName: string
        id: string
        assembly: string
      }[] = []
      for (const [id, status] of Object.entries(assemblies)) {
        status.uploads.forEach((uploadedFile) => {
          const file = this.#findFile(uploadedFile)
          files[uploadedFile.id] = {
            id: file!.id,
            assembly: id,
            uploadedFile,
          }
        })

        const state = this.getPluginState()
        Object.keys(status.results).forEach((stepName) => {
          for (const result of status.results[stepName]) {
            const file = state.files[result.original_id]
            result.localId = file ? file.id : null
            results.push({
              id: result.id,
              result,
              stepName,
              assembly: id,
            })
          }
        })
      }

      this.setPluginState({
        assemblies,
        files,
        results,
        uploadsAssemblies,
      })
    }

    // Set up the Assembly instances and AssemblyWatchers for existing Assemblies.
    const restoreAssemblies = () => {
      // eslint-disable-next-line no-shadow
      const { assemblies, uploadsAssemblies } = this.getPluginState()

      // Set up the assembly watchers again for all the ongoing uploads.
      Object.keys(uploadsAssemblies).forEach((uploadID) => {
        const assemblyIDs = uploadsAssemblies[uploadID]
        this.#createAssemblyWatcher(assemblyIDs, uploadID)
      })

      const allAssemblyIDs = Object.keys(assemblies)
      allAssemblyIDs.forEach((id) => {
        const assembly = new Assembly(assemblies[id], this.#rateLimitedQueue)
        this.#connectAssembly(assembly)
      })
    }

    // Force-update all Assemblies to check for missed events.
    const updateAssemblies = () => {
      const { assemblies } = this.getPluginState()
      return Promise.all(
        Object.keys(assemblies).map((id) => {
          return this.activeAssemblies[id].update()
        }),
      )
    }

    // Restore all Assembly state.
    this.restored = Promise.resolve().then(() => {
      restoreState(previousAssemblies)
      restoreAssemblies()
      updateAssemblies()
    })

    this.restored.then(() => {
      this.restored = null
    })
  }

  #connectAssembly(assembly: Assembly) {
    const { status } = assembly
    const id = status.assembly_id
    this.activeAssemblies[id] = assembly

    // Sync local `assemblies` state
    assembly.on('status', (newStatus: AssemblyResponse) => {
      const { assemblies } = this.getPluginState()
      this.setPluginState({
        assemblies: {
          ...assemblies,
          [id]: newStatus,
        },
      })
    })

    assembly.on('upload', (file: AssemblyFile) => {
      this.#onFileUploadComplete(id, file)
    })
    assembly.on('error', (error: AssemblyError) => {
      error.assembly = assembly.status // eslint-disable-line no-param-reassign
      this.uppy.emit('transloadit:assembly-error', assembly.status, error)
    })

    assembly.on('executing', () => {
      this.uppy.emit('transloadit:assembly-executing', assembly.status)
    })

    assembly.on(
      'execution-progress',
      (details: { progress_combined?: number }) => {
        this.uppy.emit('transloadit:execution-progress', details)

        if (details.progress_combined != null) {
          // TODO: Transloadit emits progress information for the entire Assembly combined
          // (progress_combined) and for each imported/uploaded file (progress_per_original_file).
          // Uppy's current design requires progress to be set for each file, which is then
          // averaged to get the total progress (see calculateProcessingProgress.js).
          // Therefore, we currently set the combined progres for every file, so that this is
          // the same value that is displayed to the end user, although we have more accurate
          // per-file progress as well. We cannot use this here or otherwise progress from
          // imported files would not be counted towards the total progress because imported
          // files are not registered with Uppy.
          for (const file of this.uppy.getFiles()) {
            this.uppy.emit('postprocess-progress', file, {
              mode: 'determinate',
              value: details.progress_combined / 100,
              message: this.i18n('encoding'),
            })
          }
        }
      },
    )

    if (this.opts.waitForEncoding) {
      assembly.on('result', (stepName: string, result: AssemblyResult) => {
        this.#onResult(id, stepName, result)
      })
    }

    if (this.opts.waitForEncoding) {
      assembly.on('finished', () => {
        this.#onAssemblyFinished(assembly.status)
      })
    } else if (this.opts.waitForMetadata) {
      assembly.on('metadata', () => {
        this.#onAssemblyFinished(assembly.status)
      })
    }

    // No need to connect to the socket if the Assembly has completed by now.
    // @ts-expect-error ok does not exist on Assembly?
    if (assembly.ok === 'ASSEMBLY_COMPLETE') {
      return assembly
    }

    assembly.connect()
    return assembly
  }

  #prepareUpload = async (fileIDs: string[], uploadID: string) => {
    const files = fileIDs.map((id) => this.uppy.getFile(id))
    const filesWithoutErrors = files.filter((file) => {
      if (!file.error) {
        this.uppy.emit('preprocess-progress', file, {
          mode: 'indeterminate',
          message: this.i18n('creatingAssembly'),
        })
        return true
      }
      return false
    })

    const createAssembly = async ({
      // eslint-disable-next-line no-shadow
      fileIDs,
      options,
    }: {
      fileIDs: string[]
      options: OptionsWithRestructuredFields
    }) => {
      try {
        const assembly = (await this.#createAssembly(
          fileIDs,
          uploadID,
          options,
        )) as Assembly
        if (this.opts.importFromUploadURLs) {
          await this.#reserveFiles(assembly, fileIDs)
        }
        fileIDs.forEach((fileID) => {
          const file = this.uppy.getFile(fileID)
          this.uppy.emit('preprocess-complete', file)
        })
        return assembly
      } catch (err) {
        fileIDs.forEach((fileID) => {
          const file = this.uppy.getFile(fileID)
          // Clear preprocessing state when the Assembly could not be created,
          // otherwise the UI gets confused about the lingering progress keys
          this.uppy.emit('preprocess-complete', file)
          this.uppy.emit('upload-error', file, err)
        })
        throw err
      }
    }

    const { uploadsAssemblies } = this.getPluginState()
    this.setPluginState({
      uploadsAssemblies: {
        ...uploadsAssemblies,
        [uploadID]: [],
      },
    })

    const assemblyOptions = new AssemblyOptionsBuilder(
      filesWithoutErrors,
      this.opts,
    )

    await assemblyOptions
      .build()
      .then((assemblies) => Promise.all(assemblies.map(createAssembly)))
      .then((maybeCreatedAssemblies) => {
        const createdAssemblies = maybeCreatedAssemblies.filter(Boolean)
        const assemblyIDs = createdAssemblies.map(
          (assembly) => assembly.status.assembly_id,
        )
        this.#createAssemblyWatcher(assemblyIDs, uploadID)
        return Promise.all(
          createdAssemblies.map((assembly) => this.#connectAssembly(assembly)),
        )
      })
      // If something went wrong before any Assemblies could be created,
      // clear all processing state.
      .catch((err) => {
        filesWithoutErrors.forEach((file) => {
          this.uppy.emit('preprocess-complete', file)
          this.uppy.emit('upload-error', file, err)
        })
        throw err
      })
  }

  #afterUpload = (fileIDs: string[], uploadID: string): Promise<void> => {
    const files = fileIDs.map((fileID) => this.uppy.getFile(fileID))
    // Only use files without errors
    const filteredFileIDs = files
      .filter((file) => !file.error)
      .map((file) => file.id)

    const state = this.getPluginState()

    // If we're still restoring state, wait for that to be done.
    if (this.restored) {
      return this.restored.then(() => {
        return this.#afterUpload(filteredFileIDs, uploadID)
      })
    }

    const assemblyIDs = state.uploadsAssemblies[uploadID]

    const closeSocketConnections = () => {
      assemblyIDs.forEach((assemblyID) => {
        const assembly = this.activeAssemblies[assemblyID]
        assembly.close()
        delete this.activeAssemblies[assemblyID]
      })
    }

    // If we don't have to wait for encoding metadata or results, we can close
    // the socket immediately and finish the upload.
    if (!this.#shouldWaitAfterUpload()) {
      closeSocketConnections()
      const assemblies = assemblyIDs.map((id) => this.getAssembly(id))
      this.uppy.addResultData(uploadID, { transloadit: assemblies })
      return Promise.resolve()
    }

    // If no Assemblies were created for this upload, we also do not have to wait.
    // There's also no sockets or anything to close, so just return immediately.
    if (assemblyIDs.length === 0) {
      this.uppy.addResultData(uploadID, { transloadit: [] })
      return Promise.resolve()
    }

    const incompleteFiles = files.filter(
      (file) => !hasProperty(this.completedFiles, file.id),
    )
    incompleteFiles.forEach((file) => {
      this.uppy.emit('postprocess-progress', file, {
        mode: 'indeterminate',
        message: this.i18n('encoding'),
      })
    })

    const watcher = this.assemblyWatchers[uploadID]
    return watcher.promise.then(() => {
      closeSocketConnections()

      const assemblies = assemblyIDs.map((id) => this.getAssembly(id))

      // Remove the Assembly ID list for this upload,
      // it's no longer going to be used anywhere.
      const uploadsAssemblies = { ...this.getPluginState().uploadsAssemblies }
      delete uploadsAssemblies[uploadID]
      this.setPluginState({ uploadsAssemblies })

      this.uppy.addResultData(uploadID, {
        transloadit: assemblies,
      })
    })
  }

  #closeAssemblyIfExists = (assemblyID?: string) => {
    if (!assemblyID) return
    this.activeAssemblies[assemblyID]?.close()
  }

  #onError = (err: { name: string; message: string; details?: string }) => {
    // TODO: uploadID is not accessible here. The state in core has many upload IDs,
    // so we don't know which one to get. This code never worked and no one complained.
    // See if we run into problems with this.
    // const state = this.getPluginState()
    // const assemblyIDs = state.uploadsAssemblies[uploadID]
    // assemblyIDs?.forEach(this.#closeAssemblyIfExists)

    this.client
      .submitError(err)
      // if we can't report the error that sucks
      .catch(sendErrorToConsole(err))
  }

  #onTusError = (file: UppyFile<M, B> | undefined, err: Error) => {
    this.#closeAssemblyIfExists(file?.transloadit?.assembly)
    if (err?.message?.startsWith('tus: ')) {
      const endpoint = (
        err as TusDetailedError
      ).originalRequest?.getUnderlyingObject()?.responseURL as string
      this.client
        .submitError(err, { endpoint })
        // if we can't report the error that sucks
        .catch(sendErrorToConsole(err))
    }
  }

  install(): void {
    this.uppy.addPreProcessor(this.#prepareUpload)
    this.uppy.addPostProcessor(this.#afterUpload)

    // We may need to close socket.io connections on error.
    this.uppy.on('error', this.#onError)

    // Handle cancellation.
    this.uppy.on('cancel-all', this.#onCancelAll)

    this.uppy.on('upload-error', this.#onTusError)

    if (this.opts.importFromUploadURLs) {
      // No uploader needed when importing; instead we take the upload URL from an existing uploader.
      this.uppy.on('upload-success', this.#onFileUploadURLAvailable)
    } else {
      // @ts-expect-error endpoint has to be required for @uppy/tus but for some reason
      // we don't need it here.
      this.uppy.use(Tus, {
        // Disable tus-js-client fingerprinting, otherwise uploading the same file at different times
        // will upload to an outdated Assembly, and we won't get socket events for it.
        //
        // To resume a Transloadit upload, we need to reconnect to the websocket, and the state that's
        // required to do that is not saved by tus-js-client's fingerprinting. We need the tus URL,
        // the Assembly URL, and the WebSocket URL, at least. We also need to know _all_ the files that
        // were added to the Assembly, so we can properly complete it. All that state is handled by
        // Golden Retriever. So, Golden Retriever is required to do resumability with the Transloadit plugin,
        // and we disable Tus's default resume implementation to prevent bad behaviours.
        storeFingerprintForResuming: false,
        // Only send Assembly metadata to the tus endpoint.
        allowedMetaFields: ['assembly_url', 'filename', 'fieldname'],
        // Pass the limit option to @uppy/tus
        limit: this.opts.limit,
        rateLimitedQueue: this.#rateLimitedQueue,
        retryDelays: this.opts.retryDelays,
      })
    }

    this.uppy.on('restore:get-data', this.#getPersistentData)
    this.uppy.on('restored', this.#onRestored)

    this.setPluginState({
      // Contains Assembly status objects, indexed by their ID.
      assemblies: {},
      // Contains arrays of Assembly IDs, indexed by the upload ID that they belong to.
      uploadsAssemblies: {},
      // Contains file data from Transloadit, indexed by their Transloadit-assigned ID.
      files: {},
      // Contains result data from Transloadit.
      results: [],
    })

    // We cannot cancel individual files because Assemblies tend to contain many files.
    const { capabilities } = this.uppy.getState()
    this.uppy.setState({
      capabilities: {
        ...capabilities,
        individualCancellation: false,
      },
    })
  }

  uninstall(): void {
    this.uppy.removePreProcessor(this.#prepareUpload)
    this.uppy.removePostProcessor(this.#afterUpload)
    this.uppy.off('error', this.#onError)

    if (this.opts.importFromUploadURLs) {
      this.uppy.off('upload-success', this.#onFileUploadURLAvailable)
    }

    const { capabilities } = this.uppy.getState()
    this.uppy.setState({
      capabilities: {
        ...capabilities,
        individualCancellation: true,
      },
    })
  }

  getAssembly(id: string): AssemblyResponse {
    const { assemblies } = this.getPluginState()
    return assemblies[id]
  }

  getAssemblyFiles(assemblyID: string): UppyFile<M, B>[] {
    return this.uppy.getFiles().filter((file) => {
      return file?.transloadit?.assembly === assemblyID
    })
  }
}

export { COMPANION_URL, COMPANION_ALLOWED_HOSTS }