// Copyright 2019-2021 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only

import { isNumber, pick, reject, groupBy, values } from 'lodash';
import pMap from 'p-map';
import Queue from 'p-queue';

import { strictAssert } from '../util/assert';
import { dropNull } from '../util/dropNull';
import { makeLookup } from '../util/makeLookup';
import { maybeParseUrl } from '../util/url';
import { base64ToArrayBuffer, deriveStickerPackKey } from '../Crypto';
import type {
  StickerType,
  StickerPackType,
  StickerPackStatusType,
} from '../sql/Interface';
import Data from '../sql/Client';
import { SignalService as Proto } from '../protobuf';

export type RecentStickerType = Readonly<{
  stickerId: number;
  packId: string;
}>;

export type BlessedType = Pick<StickerPackType, 'key' | 'status'>;

export type InitialState = {
  packs: Record<string, StickerPackType>;
  recentStickers: Array<RecentStickerType>;
  blessedPacks: Record<string, boolean>;
};

export type DownloadMap = Record<
  string,
  {
    id: string;
    key: string;
    status?: StickerPackStatusType;
  }
>;

// TODO: remove once we move away from ArrayBuffers
const FIXMEU8 = Uint8Array;

export const BLESSED_PACKS: Record<string, BlessedType> = {
  '9acc9e8aba563d26a4994e69263e3b25': {
    key: 'Wm3/OUjCjvubeq+T7MN1xp/DFueAd+0mhnoU0QoPahI=',
    status: 'downloaded',
  },
  fb535407d2f6497ec074df8b9c51dd1d: {
    key: 'F+lxwTQDViJ4HS7iSeZHO3dFg3ULaMEbuCt1CcaLbf0=',
    status: 'downloaded',
  },
  e61fa0867031597467ccc036cc65d403: {
    key: 'E657GnQHMYKA6bOMEmHe044OcTi5+WSmzLtz5A9zeps=',
    status: 'downloaded',
  },
  cca32f5b905208b7d0f1e17f23fdc185: {
    key: 'i/jpX3pFver+DI9bAC7wGrlbjxtbqsQBnM1ra+Cxg3o=',
    status: 'downloaded',
  },
  ccc89a05dc077856b57351e90697976c: {
    key: 'RXMOYPCdVWYRUiN0RTemt9nqmc7qy3eh+9aAG5YH+88=',
    status: 'downloaded',
  },
};

const STICKER_PACK_DEFAULTS: StickerPackType = {
  id: '',
  key: '',

  author: '',
  coverStickerId: 0,
  createdAt: 0,
  downloadAttempts: 0,
  status: 'ephemeral',
  stickerCount: 0,
  stickers: {},
  title: '',
};

const VALID_PACK_ID_REGEXP = /^[0-9a-f]{32}$/i;

let initialState: InitialState | undefined;
let packsToDownload: DownloadMap | undefined;
const downloadQueue = new Queue({ concurrency: 1, timeout: 1000 * 60 * 2 });

export async function load(): Promise<void> {
  const [packs, recentStickers] = await Promise.all([
    getPacksForRedux(),
    getRecentStickersForRedux(),
  ]);

  const blessedPacks: Record<string, boolean> = Object.create(null);
  for (const key of Object.keys(BLESSED_PACKS)) {
    blessedPacks[key] = true;
  }

  initialState = {
    packs,
    recentStickers,
    blessedPacks,
  };

  packsToDownload = capturePacksToDownload(packs);
}

export function getDataFromLink(
  link: string
): undefined | { id: string; key: string } {
  const url = maybeParseUrl(link);
  if (!url) {
    return undefined;
  }

  const { hash } = url;
  if (!hash) {
    return undefined;
  }

  let params;
  try {
    params = new URLSearchParams(hash.slice(1));
  } catch (err) {
    return undefined;
  }

  const id = params.get('pack_id');
  if (!isPackIdValid(id)) {
    return undefined;
  }

  const key = params.get('pack_key');
  if (!key) {
    return undefined;
  }

  return { id, key };
}

export function getInstalledStickerPacks(): Array<StickerPackType> {
  const state = window.reduxStore.getState();
  const { stickers } = state;
  const { packs } = stickers;
  if (!packs) {
    return [];
  }

  const items = Object.values(packs);
  return items.filter(pack => pack.status === 'installed');
}

export function downloadQueuedPacks(): void {
  strictAssert(packsToDownload, 'Stickers not initialized');

  const ids = Object.keys(packsToDownload);
  for (const id of ids) {
    const { key, status } = packsToDownload[id];

    // The queuing is done inside this function, no need to await here
    downloadStickerPack(id, key, { finalStatus: status });
  }

  packsToDownload = {};
}

function capturePacksToDownload(
  existingPackLookup: Record<string, StickerPackType>
): DownloadMap {
  const toDownload: DownloadMap = Object.create(null);

  // First, ensure that blessed packs are in good shape
  const blessedIds = Object.keys(BLESSED_PACKS);
  blessedIds.forEach(id => {
    const existing = existingPackLookup[id];
    if (
      !existing ||
      (existing.status !== 'downloaded' && existing.status !== 'installed')
    ) {
      toDownload[id] = {
        id,
        ...BLESSED_PACKS[id],
      };
    }
  });

  // Then, find error cases in packs we already know about
  const existingIds = Object.keys(existingPackLookup);
  existingIds.forEach(id => {
    if (toDownload[id]) {
      return;
    }

    const existing = existingPackLookup[id];

    // These packs should never end up in the database, but if they do we'll delete them
    if (existing.status === 'ephemeral') {
      deletePack(id);
      return;
    }

    // We don't automatically download these; not until a user action kicks it off
    if (existing.status === 'known') {
      return;
    }

    if (doesPackNeedDownload(existing)) {
      const status =
        existing.attemptedStatus === 'installed' ? 'installed' : undefined;
      toDownload[id] = {
        id,
        key: existing.key,
        status,
      };
    }
  });

  return toDownload;
}

function doesPackNeedDownload(pack?: StickerPackType): boolean {
  if (!pack) {
    return true;
  }

  const { status, stickerCount } = pack;
  const stickersDownloaded = Object.keys(pack.stickers || {}).length;

  if (
    (status === 'installed' || status === 'downloaded') &&
    stickerCount > 0 &&
    stickersDownloaded >= stickerCount
  ) {
    return false;
  }

  // If we don't understand a pack's status, we'll download it
  // If a pack has any other status, we'll download it
  // If a pack has zero stickers in it, we'll download it
  // If a pack doesn't have enough downloaded stickers, we'll download it

  return true;
}

async function getPacksForRedux(): Promise<Record<string, StickerPackType>> {
  const [packs, stickers] = await Promise.all([
    Data.getAllStickerPacks(),
    Data.getAllStickers(),
  ]);

  const stickersByPack = groupBy(stickers, sticker => sticker.packId);
  const fullSet: Array<StickerPackType> = packs.map(pack => ({
    ...pack,
    stickers: makeLookup(stickersByPack[pack.id] || [], 'id'),
  }));

  return makeLookup(fullSet, 'id');
}

async function getRecentStickersForRedux(): Promise<Array<RecentStickerType>> {
  const recent = await Data.getRecentStickers();
  return recent.map(sticker => ({
    packId: sticker.packId,
    stickerId: sticker.id,
  }));
}

export function getInitialState(): InitialState {
  strictAssert(initialState !== undefined, 'Stickers not initialized');
  return initialState;
}

export function isPackIdValid(packId: unknown): packId is string {
  return typeof packId === 'string' && VALID_PACK_ID_REGEXP.test(packId);
}

export function redactPackId(packId: string): string {
  return `[REDACTED]${packId.slice(-3)}`;
}

function getReduxStickerActions() {
  const actions = window.reduxActions;
  strictAssert(actions && actions.stickers, 'Redux not ready');

  return actions.stickers;
}

async function decryptSticker(
  packKey: string,
  ciphertext: ArrayBuffer
): Promise<ArrayBuffer> {
  const binaryKey = base64ToArrayBuffer(packKey);
  const derivedKey = await deriveStickerPackKey(binaryKey);
  const plaintext = await window.textsecure.crypto.decryptAttachment(
    ciphertext,
    derivedKey
  );

  return plaintext;
}

async function downloadSticker(
  packId: string,
  packKey: string,
  proto: Proto.StickerPack.ISticker,
  { ephemeral }: { ephemeral?: boolean } = {}
): Promise<Omit<StickerType, 'isCoverOnly'>> {
  const { id, emoji } = proto;
  strictAssert(id !== undefined && id !== null, "Sticker id can't be null");

  const ciphertext = await window.textsecure.messaging.getSticker(packId, id);
  const plaintext = await decryptSticker(packKey, ciphertext);

  const sticker = ephemeral
    ? await window.Signal.Migrations.processNewEphemeralSticker(plaintext)
    : await window.Signal.Migrations.processNewSticker(plaintext);

  return {
    id,
    emoji: dropNull(emoji),
    ...sticker,
    packId,
  };
}

export async function savePackMetadata(
  packId: string,
  packKey: string,
  { messageId }: { messageId?: string } = {}
): Promise<void> {
  const existing = getStickerPack(packId);
  if (existing) {
    return;
  }

  const { stickerPackAdded } = getReduxStickerActions();
  const pack = {
    ...STICKER_PACK_DEFAULTS,

    id: packId,
    key: packKey,
    status: 'known' as const,
  };
  stickerPackAdded(pack);

  await Data.createOrUpdateStickerPack(pack);
  if (messageId) {
    await Data.addStickerPackReference(messageId, packId);
  }
}

export async function removeEphemeralPack(packId: string): Promise<void> {
  const existing = getStickerPack(packId);
  strictAssert(existing, `No existing sticker pack with id: ${packId}`);
  if (
    existing.status !== 'ephemeral' &&
    !(existing.status === 'error' && existing.attemptedStatus === 'ephemeral')
  ) {
    return;
  }

  const { removeStickerPack } = getReduxStickerActions();
  removeStickerPack(packId);

  const stickers = values(existing.stickers);
  const paths = stickers.map(sticker => sticker.path);
  await pMap(paths, window.Signal.Migrations.deleteTempFile, {
    concurrency: 3,
  });

  // Remove it from database in case it made it there
  await Data.deleteStickerPack(packId);
}

export async function downloadEphemeralPack(
  packId: string,
  packKey: string
): Promise<void> {
  const {
    stickerAdded,
    stickerPackAdded,
    stickerPackUpdated,
  } = getReduxStickerActions();

  const existingPack = getStickerPack(packId);
  if (
    existingPack &&
    (existingPack.status === 'downloaded' ||
      existingPack.status === 'installed' ||
      existingPack.status === 'pending')
  ) {
    window.log.warn(
      `Ephemeral download for pack ${redactPackId(
        packId
      )} requested, we already know about it. Skipping.`
    );
    return;
  }

  try {
    // Synchronous placeholder to help with race conditions
    const placeholder = {
      ...STICKER_PACK_DEFAULTS,

      id: packId,
      key: packKey,
      status: 'ephemeral' as const,
    };
    stickerPackAdded(placeholder);

    const ciphertext = await window.textsecure.messaging.getStickerPackManifest(
      packId
    );
    const plaintext = await decryptSticker(packKey, ciphertext);
    const proto = Proto.StickerPack.decode(new FIXMEU8(plaintext));
    const firstStickerProto = proto.stickers ? proto.stickers[0] : null;
    const stickerCount = proto.stickers.length;

    const coverProto = proto.cover || firstStickerProto;
    const coverStickerId = coverProto ? coverProto.id : null;

    if (!coverProto || !isNumber(coverStickerId)) {
      throw new Error(
        `Sticker pack ${redactPackId(
          packId
        )} is malformed - it has no cover, and no stickers`
      );
    }

    const nonCoverStickers = reject(
      proto.stickers,
      sticker => !isNumber(sticker.id) || sticker.id === coverStickerId
    );

    const coverIncludedInList = nonCoverStickers.length < stickerCount;

    const pack = {
      ...STICKER_PACK_DEFAULTS,

      id: packId,
      key: packKey,
      coverStickerId,
      stickerCount,
      status: 'ephemeral' as const,
      ...pick(proto, ['title', 'author']),
    };
    stickerPackAdded(pack);

    const downloadStickerJob = async (
      stickerProto: Proto.StickerPack.ISticker
    ): Promise<void> => {
      const stickerInfo = await downloadSticker(packId, packKey, stickerProto, {
        ephemeral: true,
      });
      const sticker = {
        ...stickerInfo,
        isCoverOnly: !coverIncludedInList && stickerInfo.id === coverStickerId,
      };

      const statusCheck = getStickerPackStatus(packId);
      if (statusCheck !== 'ephemeral') {
        throw new Error(
          `Ephemeral download for pack ${redactPackId(
            packId
          )} interrupted by status change. Status is now ${statusCheck}.`
        );
      }

      stickerAdded(sticker);
    };

    // Download the cover first
    await downloadStickerJob(coverProto);

    // Then the rest
    await pMap(nonCoverStickers, downloadStickerJob, {
      concurrency: 3,
    });
  } catch (error) {
    // Because the user could install this pack while we are still downloading this
    //   ephemeral pack, we don't want to go change its status unless we're still in
    //   ephemeral mode.
    const statusCheck = getStickerPackStatus(packId);
    if (statusCheck === 'ephemeral') {
      stickerPackUpdated(packId, {
        attemptedStatus: 'ephemeral',
        status: 'error',
      });
    }
    window.log.error(
      `Ephemeral download error for sticker pack ${redactPackId(packId)}:`,
      error && error.stack ? error.stack : error
    );
  }
}

export type DownloadStickerPackOptions = Readonly<{
  messageId?: string;
  fromSync?: boolean;
  finalStatus?: StickerPackStatusType;
}>;

export async function downloadStickerPack(
  packId: string,
  packKey: string,
  options: DownloadStickerPackOptions = {}
): Promise<void> {
  // This will ensure that only one download process is in progress at any given time
  return downloadQueue.add(async () => {
    try {
      await doDownloadStickerPack(packId, packKey, options);
    } catch (error) {
      window.log.error(
        'doDownloadStickerPack threw an error:',
        error && error.stack ? error.stack : error
      );
    }
  });
}

async function doDownloadStickerPack(
  packId: string,
  packKey: string,
  {
    finalStatus = 'downloaded',
    messageId,
    fromSync = false,
  }: DownloadStickerPackOptions
): Promise<void> {
  const {
    stickerAdded,
    stickerPackAdded,
    stickerPackUpdated,
    installStickerPack,
  } = getReduxStickerActions();

  if (finalStatus !== 'downloaded' && finalStatus !== 'installed') {
    throw new Error(
      `doDownloadStickerPack: invalid finalStatus of ${finalStatus} requested.`
    );
  }

  const existing = getStickerPack(packId);
  if (!doesPackNeedDownload(existing)) {
    window.log.warn(
      `Download for pack ${redactPackId(
        packId
      )} requested, but it does not need re-download. Skipping.`
    );
    return;
  }

  // We don't count this as an attempt if we're offline
  const attemptIncrement = navigator.onLine ? 1 : 0;
  const downloadAttempts =
    (existing ? existing.downloadAttempts || 0 : 0) + attemptIncrement;
  if (downloadAttempts > 3) {
    window.log.warn(
      `Refusing to attempt another download for pack ${redactPackId(
        packId
      )}, attempt number ${downloadAttempts}`
    );

    if (existing && existing.status !== 'error') {
      await Data.updateStickerPackStatus(packId, 'error');
      stickerPackUpdated(packId, {
        status: 'error',
      });
    }

    return;
  }

  let coverProto: Proto.StickerPack.ISticker | undefined;
  let coverStickerId: number | undefined;
  let coverIncludedInList = false;
  let nonCoverStickers: Array<Proto.StickerPack.ISticker> = [];

  try {
    // Synchronous placeholder to help with race conditions
    const placeholder = {
      ...STICKER_PACK_DEFAULTS,

      id: packId,
      key: packKey,
      attemptedStatus: finalStatus,
      downloadAttempts,
      status: 'pending' as const,
    };
    stickerPackAdded(placeholder);

    const ciphertext = await window.textsecure.messaging.getStickerPackManifest(
      packId
    );
    const plaintext = await decryptSticker(packKey, ciphertext);
    const proto = Proto.StickerPack.decode(new FIXMEU8(plaintext));
    const firstStickerProto = proto.stickers ? proto.stickers[0] : undefined;
    const stickerCount = proto.stickers.length;

    coverProto = proto.cover || firstStickerProto;
    coverStickerId = dropNull(coverProto ? coverProto.id : undefined);

    if (!coverProto || !isNumber(coverStickerId)) {
      throw new Error(
        `Sticker pack ${redactPackId(
          packId
        )} is malformed - it has no cover, and no stickers`
      );
    }

    nonCoverStickers = reject(
      proto.stickers,
      sticker => !isNumber(sticker.id) || sticker.id === coverStickerId
    );

    coverIncludedInList = nonCoverStickers.length < stickerCount;

    // status can be:
    //   - 'known'
    //   - 'ephemeral' (should not hit database)
    //   - 'pending'
    //   - 'downloaded'
    //   - 'error'
    //   - 'installed'
    const pack: StickerPackType = {
      id: packId,
      key: packKey,
      attemptedStatus: finalStatus,
      coverStickerId,
      downloadAttempts,
      stickerCount,
      status: 'pending',
      createdAt: Date.now(),
      stickers: {},
      ...pick(proto, ['title', 'author']),
    };
    await Data.createOrUpdateStickerPack(pack);
    stickerPackAdded(pack);

    if (messageId) {
      await Data.addStickerPackReference(messageId, packId);
    }
  } catch (error) {
    window.log.error(
      `Error downloading manifest for sticker pack ${redactPackId(packId)}:`,
      error && error.stack ? error.stack : error
    );

    const pack = {
      ...STICKER_PACK_DEFAULTS,

      id: packId,
      key: packKey,
      attemptedStatus: finalStatus,
      downloadAttempts,
      status: 'error' as const,
    };
    await Data.createOrUpdateStickerPack(pack);
    stickerPackAdded(pack);

    return;
  }

  // We have a separate try/catch here because we're starting to download stickers here
  //   and we want to preserve more of the pack on an error.
  try {
    const downloadStickerJob = async (
      stickerProto: Proto.StickerPack.ISticker
    ): Promise<void> => {
      const stickerInfo = await downloadSticker(packId, packKey, stickerProto);
      const sticker = {
        ...stickerInfo,
        isCoverOnly: !coverIncludedInList && stickerInfo.id === coverStickerId,
      };
      await Data.createOrUpdateSticker(sticker);
      stickerAdded(sticker);
    };

    // Download the cover first
    await downloadStickerJob(coverProto);

    // Then the rest
    await pMap(nonCoverStickers, downloadStickerJob, {
      concurrency: 3,
    });

    // Allow for the user marking this pack as installed in the middle of our download;
    //   don't overwrite that status.
    const existingStatus = getStickerPackStatus(packId);
    if (existingStatus === 'installed') {
      return;
    }

    if (finalStatus === 'installed') {
      await installStickerPack(packId, packKey, { fromSync });
    } else {
      // Mark the pack as complete
      await Data.updateStickerPackStatus(packId, finalStatus);
      stickerPackUpdated(packId, {
        status: finalStatus,
      });
    }
  } catch (error) {
    window.log.error(
      `Error downloading stickers for sticker pack ${redactPackId(packId)}:`,
      error && error.stack ? error.stack : error
    );

    const errorStatus = 'error';
    await Data.updateStickerPackStatus(packId, errorStatus);
    if (stickerPackUpdated) {
      stickerPackUpdated(packId, {
        attemptedStatus: finalStatus,
        status: errorStatus,
      });
    }
  }
}

export function getStickerPack(packId: string): StickerPackType | undefined {
  const state = window.reduxStore.getState();
  const { stickers } = state;
  const { packs } = stickers;
  if (!packs) {
    return undefined;
  }

  return packs[packId];
}

export function getStickerPackStatus(
  packId: string
): StickerPackStatusType | undefined {
  const pack = getStickerPack(packId);
  if (!pack) {
    return undefined;
  }

  return pack.status;
}

export function getSticker(
  packId: string,
  stickerId: number
): StickerType | undefined {
  const pack = getStickerPack(packId);

  if (!pack || !pack.stickers) {
    return undefined;
  }

  return pack.stickers[stickerId];
}

export async function copyStickerToAttachments(
  packId: string,
  stickerId: number
): Promise<StickerType | undefined> {
  const sticker = getSticker(packId, stickerId);
  if (!sticker) {
    return undefined;
  }

  const { path } = sticker;
  const absolutePath = window.Signal.Migrations.getAbsoluteStickerPath(path);
  const newPath = await window.Signal.Migrations.copyIntoAttachmentsDirectory(
    absolutePath
  );

  return {
    ...sticker,
    path: newPath,
  };
}

// In the case where a sticker pack is uninstalled, we want to delete it if there are no
//   more references left. We'll delete a nonexistent reference, then check if there are
//   any references left, just like usual.
export async function maybeDeletePack(packId: string): Promise<void> {
  // This hardcoded string is fine because message ids are GUIDs
  await deletePackReference('NOT-USED', packId);
}

// We don't generally delete packs outright; we just remove references to them, and if
//   the last reference is deleted, we finally then remove the pack itself from database
//   and from disk.
export async function deletePackReference(
  messageId: string,
  packId: string
): Promise<void> {
  const isBlessed = Boolean(BLESSED_PACKS[packId]);
  if (isBlessed) {
    return;
  }

  // This call uses locking to prevent race conditions with other reference removals,
  //   or an incoming message creating a new message->pack reference
  const paths = await Data.deleteStickerPackReference(messageId, packId);

  // If we don't get a list of paths back, then the sticker pack was not deleted
  if (!paths) {
    return;
  }

  const { removeStickerPack } = getReduxStickerActions();
  removeStickerPack(packId);

  await pMap(paths, window.Signal.Migrations.deleteSticker, {
    concurrency: 3,
  });
}

// The override; doesn't honor our ref-counting scheme - just deletes it all.
export async function deletePack(packId: string): Promise<void> {
  const isBlessed = Boolean(BLESSED_PACKS[packId]);
  if (isBlessed) {
    return;
  }

  // This call uses locking to prevent race conditions with other reference removals,
  //   or an incoming message creating a new message->pack reference
  const paths = await Data.deleteStickerPack(packId);

  const { removeStickerPack } = getReduxStickerActions();
  removeStickerPack(packId);

  await pMap(paths, window.Signal.Migrations.deleteSticker, {
    concurrency: 3,
  });
}