import {
  type $Typed,
  AppBskyUnspeccedDefs,
  type AppBskyUnspeccedGetPostThreadV2,
  AtUri,
} from '@atproto/api'
import {type QueryClient} from '@tanstack/react-query'

import {findAllPostsInQueryData as findAllPostsInExploreFeedPreviewsQueryData} from '#/state/queries/explore-feed-previews'
import {findAllPostsInQueryData as findAllPostsInNotifsQueryData} from '#/state/queries/notifications/feed'
import {findAllPostsInQueryData as findAllPostsInFeedQueryData} from '#/state/queries/post-feed'
import {findAllPostsInQueryData as findAllPostsInQuoteQueryData} from '#/state/queries/post-quotes'
import {findAllPostsInQueryData as findAllPostsInSearchQueryData} from '#/state/queries/search-posts'
import {postThreadQueryKeyRoot} from '#/state/queries/usePostThread/types'
import {
  embedViewToThreadPlaceholder,
  postViewToThreadPlaceholder,
} from '#/state/queries/usePostThread/views'
import {didOrHandleUriMatches, getEmbeddedPost} from '#/state/queries/util'

export function getThreadPlaceholder(
  queryClient: QueryClient,
  uri: string,
): $Typed<AppBskyUnspeccedDefs.ThreadItemPost> | void {
  let partial
  for (let item of getThreadPlaceholderCandidates(queryClient, uri)) {
    /*
     * Currently, the backend doesn't send full post info in some cases (for
     * example, for quoted posts). We use missing `likeCount` as a way to
     * detect that. In the future, we should fix this on the backend, which
     * will let us always stop on the first result.
     *
     * TODO can we send in feeds and quotes?
     */
    const hasAllInfo = item.post.likeCount != null
    if (hasAllInfo) {
      return item
    } else {
      // Keep searching, we might still find a full post in the cache.
      partial = item
    }
  }
  return partial
}

export function* getThreadPlaceholderCandidates(
  queryClient: QueryClient,
  uri: string,
): Generator<$Typed<AppBskyUnspeccedDefs.ThreadItemPost>, void> {
  const atUri = new AtUri(uri)

  /*
   * Check this thread in the cache first.
   * TODO extract just this for shadowing
   */
  const queryDatas =
    queryClient.getQueriesData<AppBskyUnspeccedGetPostThreadV2.OutputSchema>({
      queryKey: [postThreadQueryKeyRoot],
    })
  for (const [_queryKey, queryData] of queryDatas) {
    if (!queryData) continue

    const {thread} = queryData

    for (const item of thread) {
      if (AppBskyUnspeccedDefs.isThreadItemPost(item)) {
        if (didOrHandleUriMatches(atUri, item.post)) {
          yield {
            ...item,
            depth: 0,
          }
        }

        const qp = getEmbeddedPost(item.post.embed)
        if (qp && didOrHandleUriMatches(atUri, qp)) {
          yield embedViewToThreadPlaceholder(qp)
        }
      }
    }
  }

  /*
   * Check notifications first. If you have a post in notifications, it's
   * often due to a like or a repost, and we want to prioritize a post object
   * with >0 likes/reposts over a stale version with no metrics in order to
   * avoid a notification->post scroll jump.
   */
  for (let post of findAllPostsInNotifsQueryData(queryClient, uri)) {
    yield postViewToThreadPlaceholder(post)
  }
  for (let post of findAllPostsInFeedQueryData(queryClient, uri)) {
    yield postViewToThreadPlaceholder(post)
  }
  for (let post of findAllPostsInQuoteQueryData(queryClient, uri)) {
    yield postViewToThreadPlaceholder(post)
  }
  for (let post of findAllPostsInSearchQueryData(queryClient, uri)) {
    yield postViewToThreadPlaceholder(post)
  }
  for (let post of findAllPostsInExploreFeedPreviewsQueryData(
    queryClient,
    uri,
  )) {
    yield postViewToThreadPlaceholder(post)
  }
}