import { defineStore } from 'pinia'
import { ref, computed } from 'vue'
import { useApi } from '../composables/useApi.js'
import { useInflightToken } from '../composables/useInflightToken.js'
import { toast } from '../utils/toast.js'

// Explore (#94): anchor on an image, walk its visual neighbours (pgvector
// SigLIP via /api/gallery/similar), keep an in-memory breadcrumb of the walked
// path. The ROUTE (`/explore/:imageId`) is the source of truth for the anchor;
// the view calls anchorOn() on every param change and the store reconciles the
// trail. The store ALSO acts as a TagPanel "host" (current/currentImageId +
// tag CRUD over the anchor) so the Explore workspace reuses the modal's tag
// rail verbatim for modal-parity tagging while rabbit-holing.
const NEIGHBOR_LIMIT = 24

export const useExploreStore = defineStore('explore', () => {
  const api = useApi()

  const anchor = ref(null)       // /api/gallery/image/<id> payload
  const neighbors = ref([])      // [{id, thumbnail_url, ...}]
  const breadcrumb = ref([])     // [{id, thumbnail_url}] walked path
  const loading = ref(false)
  const error = ref(null)

  const inflight = useInflightToken()

  async function anchorOn (id) {
    const numId = Number(id)
    if (!Number.isInteger(numId) || numId <= 0) return
    inflight.cancel()
    const t = inflight.claim()
    loading.value = true
    error.value = null
    try {
      const detail = await api.get(`/api/gallery/image/${numId}`)
      if (!t.isCurrent()) return
      anchor.value = detail
      _reconcileTrail(numId, detail.thumbnail_url)
      // Videos / not-yet-embedded images have no neighbours — leave the grid
      // empty and let the view explain why (anchor.has_embedding === false).
      if (detail.has_embedding) {
        const body = await api.get('/api/gallery/similar', {
          params: { similar_to: numId, limit: NEIGHBOR_LIMIT },
        })
        if (!t.isCurrent()) return
        neighbors.value = body.images || []
      } else {
        neighbors.value = []
      }
    } catch (e) {
      if (t.isCurrent()) { error.value = e.message; neighbors.value = [] }
    } finally {
      if (t.isCurrent()) loading.value = false
    }
  }

  // Forward walk appends; navigating to an id already in the trail (a
  // breadcrumb click, or a loop back) TRIMS to it — so the route stays the
  // single source of truth and the crumb bar never grows stale branches.
  function _reconcileTrail (id, thumbnailUrl) {
    const idx = breadcrumb.value.findIndex((c) => c.id === id)
    if (idx >= 0) breadcrumb.value = breadcrumb.value.slice(0, idx + 1)
    else breadcrumb.value = [...breadcrumb.value, { id, thumbnail_url: thumbnailUrl }]
  }

  function reset () {
    inflight.cancel()
    anchor.value = null
    neighbors.value = []
    breadcrumb.value = []
    error.value = null
    loading.value = false
  }

  // --- TagPanel "host" surface ---------------------------------------------
  // The anchor IS the current image (same /api/gallery/image/<id> payload the
  // modal uses), so these mirror the modal store's tag-CRUD, targeting the
  // anchor. Kept separate from the modal store so the audited overlay flow is
  // untouched; the id is captured at call-time so a fast walk can't misroute a
  // mutation to the next anchor (same guard as the modal store).
  const current = computed(() => anchor.value)
  const currentImageId = computed(() => anchor.value?.id ?? null)

  async function reloadTags () {
    const id = anchor.value?.id
    if (!id) return
    const tags = await api.get(`/api/images/${id}/tags`)
    if (anchor.value && anchor.value.id === id) anchor.value.tags = tags
  }

  async function addExistingTag (tagId) {
    const id = anchor.value?.id
    if (!id) return
    await api.post(`/api/images/${id}/tags`, {
      body: { tag_id: tagId, source: 'manual' },
    })
    await reloadTags()
  }

  async function removeTag (tagId) {
    const id = anchor.value?.id
    if (!id) return
    const prev = anchor.value.tags
    anchor.value.tags = (anchor.value.tags || []).filter((t) => t.id !== tagId)
    try {
      await api.delete(`/api/images/${id}/tags/${tagId}`)
    } catch (e) {
      if (anchor.value && anchor.value.id === id) anchor.value.tags = prev
      toast({ text: `Failed to remove tag: ${e.message}`, type: 'error' })
      throw e
    }
    // The dismiss is best-effort — the tag is gone server-side regardless.
    try {
      await api.post(`/api/images/${id}/suggestions/dismiss`, {
        body: { tag_id: tagId },
      })
    } catch (e) {
      toast({
        text: `Tag removed, but failed to dismiss suggestion: ${e.message}`,
        type: 'warning',
      })
    }
  }

  async function createAndAdd ({ name, kind, fandom_id = null }) {
    const id = anchor.value?.id
    if (!id) return
    const tag = await api.post('/api/tags', { body: { name, kind, fandom_id } })
    if (kind === 'fandom') {
      // Mirror the modal store: a freshly-created fandom must land in the cache
      // so FandomPicker sees it without a reload.
      const { useTagStore } = await import('./tags.js')
      useTagStore().fandomCache.push({
        id: tag.id, name: tag.name, kind: 'fandom',
        fandom_id: null, fandom_name: null, image_count: 0,
      })
    }
    if (anchor.value?.id !== id) return  // walked away mid-create
    await addExistingTag(tag.id)
  }

  // No overlay to dismiss in the Explore workspace — the chip-body "show me
  // more of this tag" navigation just routes away. Present so TagPanel's
  // host.close?.() is a no-op here.
  function close () {}

  return {
    anchor, neighbors, breadcrumb, loading, error, NEIGHBOR_LIMIT,
    anchorOn, reset,
    // host surface
    current, currentImageId,
    reloadTags, addExistingTag, removeTag, createAndAdd, close,
  }
})