import { defineStore } from 'pinia'
import { ref } from 'vue'
import { useApi } from '../composables/useApi.js'
import { useAsyncAction } from '../composables/useAsyncAction.js'
import { useInflightToken } from '../composables/useInflightToken.js'

export const usePostsStore = defineStore('posts', () => {
  const api = useApi()

  const items = ref([])
  const cursor = ref(null)
  const { loading, error, run } = useAsyncAction()
  const done = ref(false)
  const filters = ref({ artist_id: null, platform: null, q: null })

  // In-context (anchored) view: bidirectional cursors so the feed can load
  // newer posts on scroll-up and older posts on scroll-down around a post.
  const cursorOlder = ref(null)
  const cursorNewer = ref(null)
  const doneOlder = ref(false)
  const doneNewer = ref(false)
  const anchorId = ref(null)
  // loadInitial, loadMore, loadAround, loadOlder, loadNewer all share
  // one `loading` flag and previously had no inflight guard. A filter
  // change (loadInitial) racing a still-in-flight loadMore would
  // append the prior filter's items into the new filter's feed.
  // Audit 2026-06-02.
  const inflight = useInflightToken()

  function _qs() {
    const q = {}
    if (cursor.value) q.cursor = cursor.value
    if (filters.value.artist_id != null) q.artist_id = filters.value.artist_id
    if (filters.value.platform) q.platform = filters.value.platform
    if (filters.value.q) q.q = filters.value.q
    return q
  }

  function _reset() {
    items.value = []
    cursor.value = null
    done.value = false
    error.value = null
  }

  async function loadInitial(newFilters) {
    inflight.cancel()
    filters.value = {
      artist_id: newFilters?.artist_id ?? null,
      platform: newFilters?.platform ?? null,
      q: newFilters?.q ?? null,
    }
    _reset()
    await loadMore()
  }

  async function loadMore() {
    if (loading.value || done.value) return
    const t = inflight.claim()
    await run(async () => {
      const body = await api.get('/api/posts', { params: _qs() })
      if (!t.isCurrent()) return
      items.value.push(...body.items)
      cursor.value = body.next_cursor
      if (body.next_cursor == null) done.value = true
    })
  }

  async function getPostFull(id) {
    // Used by PostCard's "Show more" expand to fetch the full description.
    return await api.get(`/api/posts/${id}`)
  }

  // Set a post's sticky translation override (auto/force/original, #155) and
  // patch the loaded item in place with the endpoint's result (it translates /
  // clears immediately when the service is up), so the card reflects the change
  // without a feed reload.
  async function applyTranslationOverride(postId, override) {
    const res = await api.post(`/api/posts/${postId}/translation-override`, {
      body: { override },
    })
    const item = items.value.find((p) => p.id === postId)
    if (item) {
      item.translation_override = res.translation_override
      item.post_title_translated = res.post_title_translated
      item.description_translated = res.description_translated
      item.translated_source_lang = res.translated_source_lang
    }
    return res
  }

  // Filter overlay for the around/older/newer (in-context anchored)
  // path. Keep this distinct from `filters.value` (the down-only feed)
  // so a normal-feed filter change doesn't leak into an active anchored
  // view (or vice versa). Caller of loadAround passes the snapshot; the
  // subsequent loadOlder/loadNewer use it verbatim.
  function _aroundParams(extra) {
    const p = { ...extra }
    if (filters.value.artist_id != null) p.artist_id = filters.value.artist_id
    if (filters.value.platform) p.platform = filters.value.platform
    if (filters.value.q) p.q = filters.value.q
    return p
  }

  // Load a window centered on `postId`: newer posts above, the post, older
  // posts below. Sets both directional cursors for subsequent scrolling.
  // Accepts the same filter shape as loadInitial so the anchored view
  // stays artist/platform-scoped (operator-flagged 2026-06-01: clicking a
  // post title from the modal's Provenance card opens the post in the
  // posts feed; without this the older/newer scroll loaded unfiltered
  // global posts instead of staying in the artist's stream).
  async function loadAround(postId, newFilters) {
    inflight.cancel()
    filters.value = {
      artist_id: newFilters?.artist_id ?? null,
      platform: newFilters?.platform ?? null,
      q: newFilters?.q ?? null,
    }
    loading.value = true
    error.value = null
    anchorId.value = null
    const t = inflight.claim()
    try {
      const body = await api.get('/api/posts', {
        params: _aroundParams({ around: postId }),
      })
      if (!t.isCurrent()) return
      items.value = body.items
      cursorOlder.value = body.cursor_older
      cursorNewer.value = body.cursor_newer
      doneOlder.value = body.cursor_older == null
      doneNewer.value = body.cursor_newer == null
      anchorId.value = body.anchor_id
    } catch (e) {
      if (!t.isCurrent()) return
      error.value = e
    } finally {
      if (t.isCurrent()) loading.value = false
    }
  }

  async function loadOlder() {
    if (loading.value || doneOlder.value || cursorOlder.value == null) return
    loading.value = true
    const t = inflight.claim()
    try {
      const body = await api.get('/api/posts', {
        params: _aroundParams({
          cursor: cursorOlder.value, direction: 'older',
        }),
      })
      if (!t.isCurrent()) return
      items.value.push(...body.items)
      cursorOlder.value = body.next_cursor
      if (body.next_cursor == null) doneOlder.value = true
    } catch (e) {
      if (!t.isCurrent()) return
      error.value = e
    } finally {
      if (t.isCurrent()) loading.value = false
    }
  }

  async function loadNewer() {
    if (loading.value || doneNewer.value || cursorNewer.value == null) return
    loading.value = true
    const t = inflight.claim()
    try {
      const body = await api.get('/api/posts', {
        params: _aroundParams({
          cursor: cursorNewer.value, direction: 'newer',
        }),
      })
      if (!t.isCurrent()) return
      items.value.unshift(...body.items)
      cursorNewer.value = body.next_cursor
      if (body.next_cursor == null) doneNewer.value = true
    } catch (e) {
      if (!t.isCurrent()) return
      error.value = e
    } finally {
      if (t.isCurrent()) loading.value = false
    }
  }

  return {
    items, cursor, loading, done, error, filters,
    cursorOlder, cursorNewer, doneOlder, doneNewer, anchorId,
    loadInitial, loadMore, getPostFull, applyTranslationOverride,
    loadAround, loadOlder, loadNewer,
  }
})
