immich/web/src/lib/stores/assets.store.ts

import { AssetGridState, BucketPosition } from '$lib/models/asset-grid-state';
import { api, AssetCountByTimeBucketResponseDto } from '@api';
import { flatMap, sumBy } from 'lodash-es';
import { writable } from 'svelte/store';

/**
 * The state that holds information about the asset grid
 */
export const assetGridState = writable<AssetGridState>(new AssetGridState());
export const loadingBucketState = writable<{ [key: string]: boolean }>({});

function createAssetStore() {
  let _assetGridState = new AssetGridState();
  assetGridState.subscribe((state) => {
    _assetGridState = state;
  });

  let _loadingBucketState: { [key: string]: boolean } = {};
  loadingBucketState.subscribe((state) => {
    _loadingBucketState = state;
  });

  const estimateViewportHeight = (assetCount: number, viewportWidth: number): number => {
    // Ideally we would use the average aspect ratio for the photoset, however assume
    // a normal landscape aspect ratio of 3:2, then discount for the likelihood we
    // will be scaling down and coalescing.
    const thumbnailHeight = 235;
    const unwrappedWidth = (3 / 2) * assetCount * thumbnailHeight * (7 / 10);
    const rows = Math.ceil(unwrappedWidth / viewportWidth);
    const height = rows * thumbnailHeight;
    return height;
  };

  /**
   * Set initial state
   * @param viewportHeight
   * @param viewportWidth
   * @param data
   */
  const setInitialState = (
    viewportHeight: number,
    viewportWidth: number,
    data: AssetCountByTimeBucketResponseDto,
    userId: string | undefined,
  ) => {
    assetGridState.set({
      viewportHeight,
      viewportWidth,
      timelineHeight: 0,
      buckets: data.buckets.map((bucket) => ({
        bucketDate: bucket.timeBucket,
        bucketHeight: estimateViewportHeight(bucket.count, viewportWidth),
        assets: [],
        cancelToken: new AbortController(),
        position: BucketPosition.Unknown,
      })),
      assets: [],
      userId,
    });

    // Update timeline height based on calculated bucket height
    assetGridState.update((state) => {
      state.timelineHeight = sumBy(state.buckets, (d) => d.bucketHeight);
      return state;
    });
  };

  const getAssetsByBucket = async (bucket: string, position: BucketPosition) => {
    try {
      const currentBucketData = _assetGridState.buckets.find((b) => b.bucketDate === bucket);
      if (currentBucketData?.assets && currentBucketData.assets.length > 0) {
        assetGridState.update((state) => {
          const bucketIndex = state.buckets.findIndex((b) => b.bucketDate === bucket);
          state.buckets[bucketIndex].position = position;
          return state;
        });
        return;
      }

      loadingBucketState.set({
        ..._loadingBucketState,
        [bucket]: true,
      });
      const { data: assets } = await api.assetApi.getAssetByTimeBucket(
        {
          getAssetByTimeBucketDto: {
            timeBucket: [bucket],
            userId: _assetGridState.userId,
            withoutThumbs: true,
          },
        },
        { signal: currentBucketData?.cancelToken.signal },
      );
      loadingBucketState.set({
        ..._loadingBucketState,
        [bucket]: false,
      });

      // Update assetGridState with assets by time bucket
      assetGridState.update((state) => {
        const bucketIndex = state.buckets.findIndex((b) => b.bucketDate === bucket);
        state.buckets[bucketIndex].assets = assets;
        state.buckets[bucketIndex].position = position;
        state.assets = flatMap(state.buckets, (b) => b.assets);
        return state;
      });
      // eslint-disable-next-line @typescript-eslint/no-explicit-any
    } catch (e: any) {
      if (e.name === 'CanceledError') {
        return;
      }
      console.error('Failed to get asset for bucket ', bucket);
      console.error(e);
    }
  };

  const removeAsset = (assetId: string) => {
    assetGridState.update((state) => {
      const bucketIndex = state.buckets.findIndex((b) => b.assets.some((a) => a.id === assetId));
      const assetIndex = state.buckets[bucketIndex].assets.findIndex((a) => a.id === assetId);
      state.buckets[bucketIndex].assets.splice(assetIndex, 1);

      if (state.buckets[bucketIndex].assets.length === 0) {
        _removeBucket(state.buckets[bucketIndex].bucketDate);
      }
      state.assets = flatMap(state.buckets, (b) => b.assets);
      return state;
    });
  };

  const _removeBucket = (bucketDate: string) => {
    assetGridState.update((state) => {
      const bucketIndex = state.buckets.findIndex((b) => b.bucketDate === bucketDate);
      state.buckets.splice(bucketIndex, 1);
      state.assets = flatMap(state.buckets, (b) => b.assets);
      return state;
    });
  };

  const updateBucketHeight = (bucket: string, actualBucketHeight: number): number => {
    let scrollTimeline = false;
    let heightDelta = 0;

    assetGridState.update((state) => {
      const bucketIndex = state.buckets.findIndex((b) => b.bucketDate === bucket);
      // Update timeline height based on the new bucket height
      const estimateBucketHeight = state.buckets[bucketIndex].bucketHeight;

      heightDelta = actualBucketHeight - estimateBucketHeight;
      state.timelineHeight += heightDelta;

      scrollTimeline = state.buckets[bucketIndex].position == BucketPosition.Above;

      state.buckets[bucketIndex].bucketHeight = actualBucketHeight;
      state.buckets[bucketIndex].position = BucketPosition.Unknown;

      return state;
    });

    if (scrollTimeline) {
      return heightDelta;
    }

    return 0;
  };

  const cancelBucketRequest = async (token: AbortController, bucketDate: string) => {
    token.abort();
    // set new abort controller for bucket
    assetGridState.update((state) => {
      const bucketIndex = state.buckets.findIndex((b) => b.bucketDate === bucketDate);
      state.buckets[bucketIndex].cancelToken = new AbortController();
      return state;
    });
  };

  const updateAsset = (assetId: string, isFavorite: boolean) => {
    assetGridState.update((state) => {
      const bucketIndex = state.buckets.findIndex((b) => b.assets.some((a) => a.id === assetId));
      const assetIndex = state.buckets[bucketIndex].assets.findIndex((a) => a.id === assetId);
      state.buckets[bucketIndex].assets[assetIndex].isFavorite = isFavorite;

      state.assets = flatMap(state.buckets, (b) => b.assets);
      return state;
    });
  };

  return {
    setInitialState,
    getAssetsByBucket,
    removeAsset,
    updateBucketHeight,
    cancelBucketRequest,
    updateAsset,
  };
}

export const assetStore = createAssetStore();