import { useState } from 'react'
import { X, Star, ShoppingBasket, Trash2 } from 'lucide-react'
import clsx from 'clsx'
import { useMutation, useQueryClient } from '@tanstack/react-query'
import { usePhotoStore } from '../../store/photoStore'
import {
  photos as photosApi,
  heaps as heapsApi,
  tags as tagsApi,
} from '../../services/api'
import type { Photo } from '../../types/photo'
import { useActiveHeapMembers } from '../../hooks/useActiveHeapMembersQuery'
import { HEAPS_QUERY_KEY } from '../../hooks/useHeapsQuery'
import { useTagsQuery, TAGS_QUERY_KEY } from '../../hooks/useTagsQuery'
import { stripPhotosFromCache } from '../../hooks/usePhotosQuery'
import { toast } from '../ToastContainer'
import { PhotoInfoPanel } from '../sidebar/PhotoInfoPanel'
import { BulkTakenAtEditor } from '../sidebar/BulkTakenAtEditor'
import { BulkTagsEditor } from '../sidebar/BulkTagsEditor'
import { COLOR_LABEL_OPTIONS } from '../../constants/colorLabels'
import { Button } from '@/components/ui/button'
import { Label } from '@/components/ui/label'
import { useBulkPhotoMutations } from '../../hooks/useBulkPhotoMutations'
import { formatApiError } from '../../lib/apiError'

/**
 * Right-hand details panel.
 *  - 1 photo selected → delegates to PhotoInfoPanel for the full editor.
 *  - 2+ photos selected → renders a slim bulk-action panel that fans out
 *    rating / color / discard / pick across the entire selection.
 */
export function RightSidebar() {
  const { selectedPhotos, activePhotoId, clearSelection } = usePhotoStore()
  const queryClient = useQueryClient()

  const {
    bulkRating: bulkRatingMutation,
    bulkColor: bulkColorMutation,
    invalidatePhotoQueries,
  } = useBulkPhotoMutations()

  const bulkDiscardMutation = useMutation({
    mutationFn: (ids: string[]) => photosApi.bulkDiscard(ids),
    // Yank the photos from the timeline before the network round-trip
    // so the grid reflows immediately. Same pattern as the X hotkey
    // path in useKeyboardShortcuts.
    onMutate: (ids) => {
      usePhotoStore.getState().removePhotosFromTimeline(ids)
      stripPhotosFromCache(queryClient, ids)
    },
    onSuccess: invalidatePhotoQueries,
  })

  // Shared report-and-invalidate tail for both bulk taken_at mutations.
  // They return a partial-apply shape (updated/skipped/errors) because
  // EXIF writes can fail per-photo (unsupported format, missing file)
  // without wrecking the rest of the batch.
  const reportBulkTakenAt = (
    data: {
      status: string
      updated: number
      skipped: number
      errors: { id: string; message: string }[]
    },
  ) => {
    const errCount = data.errors?.length ?? 0
    const detail =
      errCount > 0
        ? `${data.updated} updated · ${errCount} error${errCount === 1 ? '' : 's'}`
        : `${data.updated} updated`
    if (errCount > 0) {
      toast.error('Date update partial', detail)
    } else {
      toast.success('Dates updated', detail)
    }
    invalidatePhotoQueries()
  }

  const bulkTakenAtMutation = useMutation({
    mutationFn: ({ ids, iso }: { ids: string[]; iso: string }) =>
      photosApi.bulkSetTakenAt(ids, iso),
    onSuccess: reportBulkTakenAt,
    onError: (e: any) =>
      toast.error('Date update failed', formatApiError(e)),
  })

  const bulkTakenAtMapMutation = useMutation({
    mutationFn: (map: Record<string, string>) =>
      photosApi.bulkSetTakenAtMap(map),
    onSuccess: reportBulkTakenAt,
    onError: (e: any) =>
      toast.error('Date update failed', formatApiError(e)),
  })

  // Bulk tag mutations. Tag mutations also need to invalidate the tags
  // query so the FilterBar / sidebar tag counts stay fresh.
  const invalidateTagsAndPhotos = () => {
    invalidatePhotoQueries()
    queryClient.invalidateQueries({ queryKey: TAGS_QUERY_KEY })
  }
  const bulkAddTagsMutation = useMutation({
    mutationFn: ({ ids, tagIds }: { ids: string[]; tagIds: string[] }) =>
      photosApi.bulkAddTags(ids, tagIds),
    onSuccess: (data) => {
      const added = data?.added ?? 0
      toast.success(
        'Tags added',
        `${added} new link${added === 1 ? '' : 's'}`
      )
      invalidateTagsAndPhotos()
    },
    onError: (e: any) =>
      toast.error('Add tags failed', formatApiError(e)),
  })
  const bulkRemoveTagsMutation = useMutation({
    mutationFn: ({ ids, tagIds }: { ids: string[]; tagIds: string[] }) =>
      photosApi.bulkRemoveTags(ids, tagIds),
    onSuccess: (data) => {
      const removed = data?.removed ?? 0
      toast.success(
        'Tags removed',
        `${removed} link${removed === 1 ? '' : 's'} removed`
      )
      invalidateTagsAndPhotos()
    },
    onError: (e: any) =>
      toast.error('Remove tags failed', formatApiError(e)),
  })

  // Idempotent create-and-attach: lets the user type a brand-new tag
  // name and apply it to the whole selection in one click.
  const createAndAttachMutation = useMutation({
    mutationFn: async ({ name, ids }: { name: string; ids: string[] }) => {
      const created = await tagsApi.create(name)
      return photosApi.bulkAddTags(ids, [created.id])
    },
    onSuccess: () => {
      toast.success('Tag created and applied')
      invalidateTagsAndPhotos()
    },
    onError: (e: any) =>
      toast.error('Create tag failed', formatApiError(e)),
  })

  const { data: allTags = [] } = useTagsQuery()
  const [tagInput, setTagInput] = useState('')

  // Active heap membership for the bulk Select toggle.
  const { activeHeap, memberIds: activeHeapMembers } = useActiveHeapMembers()

  const heapMutation = useMutation({
    mutationFn: ({ ids, remove }: { ids: string[]; remove: boolean }) => {
      if (!activeHeap || ids.length === 0) return Promise.resolve(null)
      return remove
        ? heapsApi.removePhotos(activeHeap.id, ids)
        : heapsApi.addPhotos(activeHeap.id, ids)
    },
    onMutate: ({ ids, remove }) => {
      if (!activeHeap || ids.length === 0) return { previous: undefined }
      const key = ['heap-photo-ids', activeHeap.id] as const
      const previous = queryClient.getQueryData<string[]>(key)
      const set = new Set(previous ?? [])
      if (remove) ids.forEach((id) => set.delete(id))
      else ids.forEach((id) => set.add(id))
      queryClient.setQueryData<string[]>(key, Array.from(set))
      return { previous }
    },
    onError: (e: any, _vars, ctx) => {
      if (activeHeap && ctx?.previous) {
        queryClient.setQueryData(['heap-photo-ids', activeHeap.id], ctx.previous)
      }
      toast.error('Heap update failed', formatApiError(e))
    },
    onSettled: () => {
      queryClient.invalidateQueries({ queryKey: HEAPS_QUERY_KEY })
      if (activeHeap) {
        queryClient.invalidateQueries({
          queryKey: ['heap-photo-ids', activeHeap.id],
        })
      }
    },
  })

  // Unified header rendered in every branch so the collapse button is
  // always reachable regardless of selection state. Title and the
  // clear-selection X adapt to what's selected.
  const headerTitle =
    selectedPhotos.length === 0
      ? 'Metadata'
      : selectedPhotos.length === 1
        ? 'Metadata'
        : `${selectedPhotos.length} Photos Selected`

  const Header = () => (
    <div className="flex h-9 flex-shrink-0 items-center justify-between border-b border-border px-3">
      <h2 className="text-[11px] font-semibold uppercase tracking-[0.14em] text-text-muted">
        {headerTitle}
      </h2>
      <div className="flex items-center gap-0.5">
        {selectedPhotos.length > 0 && (
          <Button
            variant="ghost"
            size="icon"
            className="h-6 w-6 text-text-muted"
            onClick={clearSelection}
            title="Clear selection (Esc)"
            aria-label="Clear selection"
          >
            <X className="h-3.5 w-3.5" />
          </Button>
        )}
      </div>
    </div>
  )

  if (selectedPhotos.length === 0) {
    return (
      <div className="flex h-full flex-col bg-surface">
        <Header />
        <div className="flex flex-1 items-center justify-center p-4 text-center">
          <div className="text-text-muted">
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            <p className="text-sm">Select photos to view details</p>
          </div>
        </div>
      </div>
    )
  }

  // ── Single-photo: full editor via PhotoInfoPanel ────────────────────
  if (selectedPhotos.length === 1) {
    const id = activePhotoId ?? selectedPhotos[0]
    return (
      <div className="flex h-full flex-col bg-surface">
        <Header />
        <PhotoInfoPanel photoId={id} />
      </div>
    )
  }

  // ── Multi-photo: bulk action panel ──────────────────────────────────
  const allMembers = selectedPhotos.every((id) => activeHeapMembers.has(id))

  /** Walk the react-query cache for every selected id and return the
   *  full Photo records. Checks the standalone `['photo', id]` entry
   *  first (populated whenever a single-photo view or preview opens),
   *  then falls back to scanning every cached timeline list for the
   *  id. Any id with no cached record is skipped — the selection UI
   *  can't act on a photo the user hasn't loaded yet anyway. */
  const collectSelectedPhotos = (): Photo[] => {
    const out: Photo[] = []
    const seen = new Set<string>()
    for (const id of selectedPhotos) {
      if (seen.has(id)) continue
      const direct = queryClient.getQueryData<Photo>(['photo', id])
      if (direct) {
        out.push(direct)
        seen.add(id)
        continue
      }
      const lists = queryClient.getQueriesData<Photo[]>({ queryKey: ['photos'] })
      for (const [, list] of lists) {
        if (!list) continue
        const hit = list.find((p) => p.id === id)
        if (hit) {
          out.push(hit)
          seen.add(id)
          break
        }
      }
    }
    return out
  }

  return (
    <div className="flex h-full flex-col bg-surface">
      <Header />

      <div className="space-y-2.5 border-b border-border p-3">
        <p className="text-[11px] text-text-muted">
          Rating, color, and flag apply to all {selectedPhotos.length} selected.
        </p>

        {/* Bulk rating */}
        <div>
          <Label className="mb-1 block">Rating</Label>
          <div className="flex gap-1">
            {[1, 2, 3, 4, 5].map((value) => (
              <button
                key={value}
                onClick={() =>
                  bulkRatingMutation.mutate({ ids: selectedPhotos, rating: value })
                }
                className="p-0.5"
                title={`Set rating to ${value}`}
              >
                <Star className="h-5 w-5 text-text-muted hover:text-star" />
              </button>
            ))}
            <button
              onClick={() =>
                bulkRatingMutation.mutate({ ids: selectedPhotos, rating: 0 })
              }
              className="ml-1 rounded px-1 text-xs text-text-muted hover:text-text"
              title="Clear rating"
            >
              clear
            </button>
          </div>
        </div>

        {/* Bulk color */}
        <div>
          <Label className="mb-1 block">Color label</Label>
          <div className="flex items-center gap-1.5">
            {COLOR_LABEL_OPTIONS.map(({ value, className }) => (
              <button
                key={value}
                onClick={() =>
                  bulkColorMutation.mutate({ ids: selectedPhotos, color: value })
                }
                className={clsx(
                  'h-5 w-5 rounded-full opacity-80 ring-offset-2 ring-offset-surface transition-all hover:opacity-100',
                  className
                )}
                title={value}
              />
            ))}
            <button
              onClick={() =>
                bulkColorMutation.mutate({ ids: selectedPhotos, color: null })
              }
              className="ml-1 rounded p-0.5 text-text-muted hover:bg-surface-2 hover:text-text"
              title="Clear color label"
            >
              <X className="h-3 w-3" />
            </button>
          </div>
        </div>

        {/* Bulk flag */}
        <div>
          <Label className="mb-1 block">Flag</Label>
          <div className="flex gap-2">
            <Button
              size="sm"
              onClick={() => {
                if (!activeHeap) return
                heapMutation.mutate({ ids: selectedPhotos, remove: allMembers })
              }}
              disabled={!activeHeap || heapMutation.isPending}
              className={clsx(
                allMembers
                  ? 'bg-pick/20 text-pick hover:bg-pick/30'
                  : 'bg-surface-2 text-text-muted hover:bg-surface-offset'
              )}
              title={
                activeHeap
                  ? allMembers
                    ? `Remove all from "${activeHeap.name}"`
                    : `Add all to "${activeHeap.name}"`
                  : 'Set an active heap first'
              }
            >
              <ShoppingBasket className="mr-1 h-3 w-3" />
              {allMembers ? 'Selected' : 'Select'}
            </Button>
            <Button
              variant="secondary"
              size="sm"
              onClick={() => bulkDiscardMutation.mutate(selectedPhotos)}
              className="text-text-muted"
            >
              <Trash2 className="mr-1 h-3 w-3" />
              Discard
            </Button>
          </div>
        </div>

        {/* Bulk tags. Click an existing tag chip to apply it to the
         *  whole selection; long-press / X icon to remove. The text
         *  input adds an existing tag if it matches a name, or creates
         *  a new tag and applies it. */}
        <div>
          <Label className="mb-1 block">Tags</Label>
          <BulkTagsEditor
            allTags={allTags}
            tagInput={tagInput}
            onTagInputChange={setTagInput}
            disabled={
              bulkAddTagsMutation.isPending ||
              bulkRemoveTagsMutation.isPending ||
              createAndAttachMutation.isPending
            }
            onApply={(tagId) =>
              bulkAddTagsMutation.mutate({ ids: selectedPhotos, tagIds: [tagId] })
            }
            onRemove={(tagId) =>
              bulkRemoveTagsMutation.mutate({
                ids: selectedPhotos,
                tagIds: [tagId],
              })
            }
            onCreate={(name) => {
              createAndAttachMutation.mutate({ name, ids: selectedPhotos })
              setTagInput('')
            }}
          />
        </div>

        {/* Bulk Date Taken — lets an operator repair the capture date on
         *  a whole selection at once, either by applying one date to
         *  everything or by inferring a per-photo date from each file's
         *  folder path and filename. Useful for cameras that lost their
         *  clock (1970 epoch) and for legacy libraries where the folder
         *  structure is the only trustworthy date signal. */}
        <div>
          <Label className="mb-1 block">Date Taken</Label>
          <BulkTakenAtEditor
            disabled={
              bulkTakenAtMutation.isPending || bulkTakenAtMapMutation.isPending
            }
            selectedCount={selectedPhotos.length}
            collectPhotos={collectSelectedPhotos}
            onApplyUniform={(iso) =>
              bulkTakenAtMutation.mutate({ ids: selectedPhotos, iso })
            }
            onApplyMap={(map) => bulkTakenAtMapMutation.mutate(map)}
          />
        </div>
      </div>
    </div>
  )
}
