import React, { useEffect, useState } from 'react'

function tagList(item) {
  return Array.isArray(item?.tags) ? item.tags.filter(Boolean) : []
}

function categoryList(item) {
  return Array.isArray(item?.categories) ? item.categories.filter(Boolean) : []
}

function creatorName(item) {
  return item?.user?.username || item?.user?.name || 'Unknown creator'
}

function isMature(item) {
  return Boolean(item?.nsfw || item?.is_mature)
}

function formatDate(value) {
  if (!value) {
    return null
  }

  const date = new Date(value)
  if (Number.isNaN(date.getTime())) {
    return null
  }

  return date.toLocaleString()
}

function PreviewImage({ src, alt, className }) {
  const [failed, setFailed] = useState(false)

  useEffect(() => {
    setFailed(false)
  }, [src])

  if (!src || failed) {
    return (
      <div className={`flex items-center justify-center bg-white/5 text-xs text-white/40 ${className}`}>
        No preview
      </div>
    )
  }

  return (
    <img
      src={src}
      alt={alt}
      className={className}
      onError={() => setFailed(true)}
    />
  )
}

function Badge({ children, tone = 'slate' }) {
  const tones = {
    slate: 'border-white/10 bg-white/5 text-white/70',
    amber: 'border-amber-300/20 bg-amber-400/10 text-amber-100',
    rose: 'border-rose-300/20 bg-rose-400/10 text-rose-100',
    emerald: 'border-emerald-300/20 bg-emerald-400/10 text-emerald-100',
  }

  return (
    <span className={`inline-flex items-center rounded-full border px-2 py-0.5 text-[10px] font-semibold uppercase tracking-wide ${tones[tone] || tones.slate}`}>
      {children}
    </span>
  )
}

export default function AdminUploadQueue() {
  const [items, setItems] = useState([])
  const [loading, setLoading] = useState(false)
  const [error, setError] = useState('')
  const [notes, setNotes] = useState({})
  const [selected, setSelected] = useState(null)
  const [busyId, setBusyId] = useState(null)

  const loadPending = async () => {
    setLoading(true)
    setError('')

    try {
      const [legacyResponse, artworkResponse] = await Promise.all([
        window.axios.get('/api/admin/uploads/pending'),
        window.axios.get('/api/admin/artwork-review/pending'),
      ])
      const legacyItems = Array.isArray(legacyResponse?.data?.data)
        ? legacyResponse.data.data.map((item) => ({ ...item, queue: 'upload' }))
        : []
      const artworkItems = Array.isArray(artworkResponse?.data?.data)
        ? artworkResponse.data.data.map((item) => ({ ...item, queue: 'artwork' }))
        : []
      setItems([...artworkItems, ...legacyItems])
    } catch (loadError) {
      setError(loadError?.response?.data?.message || 'Failed to load moderation queue.')
    } finally {
      setLoading(false)
    }
  }

  useEffect(() => {
    loadPending()
  }, [])

  useEffect(() => {
    if (!selected) {
      return undefined
    }

    const onKeyDown = (event) => {
      if (event.key === 'Escape') {
        setSelected(null)
      }
    }

    window.addEventListener('keydown', onKeyDown)
    return () => window.removeEventListener('keydown', onKeyDown)
  }, [selected])

  const moderate = async (item, action) => {
    const id = item?.id
    if (!id || busyId) {
      return
    }

    setBusyId(id)
    try {
      const payload = { note: String(notes[id] || '') }
      const base = item.queue === 'artwork' ? '/api/admin/artwork-review' : '/api/admin/uploads'
      await window.axios.post(`${base}/${id}/${action}`, payload)
      setItems((prev) => prev.filter((candidate) => !(candidate.id === id && candidate.queue === item.queue)))
      setSelected((current) => (current?.id === id && current?.queue === item.queue ? null : current))
    } catch (moderateError) {
      setError(moderateError?.response?.data?.message || `Failed to ${action} upload.`)
    } finally {
      setBusyId(null)
    }
  }

  const renderMeta = (item, { compact = false } = {}) => {
    const tags = tagList(item)
    const categories = categoryList(item)
    const createdAt = formatDate(item.created_at)

    return (
      <div className="min-w-0">
        <div className="flex flex-wrap items-center gap-2">
          <div className="text-sm font-medium text-white">{item.title || '(untitled upload)'}</div>
          <Badge tone={item.queue === 'artwork' ? 'emerald' : 'slate'}>
            {item.queue === 'artwork' ? 'Artwork' : 'Draft upload'}
          </Badge>
          {isMature(item) ? <Badge tone="rose">NSFW</Badge> : null}
        </div>
        <div className="mt-1 text-xs text-white/65">
          {creatorName(item)} · {item.type} · {item.id}
        </div>
        {createdAt ? <div className="mt-1 text-[11px] text-white/40">{createdAt}</div> : null}
        {item.description ? (
          <p className={`mt-2 text-xs leading-5 text-white/70 ${compact ? 'line-clamp-3' : 'whitespace-pre-wrap'}`}>
            {item.description}
          </p>
        ) : (
          <p className="mt-2 text-xs text-white/40">No description</p>
        )}
        {categories.length > 0 ? (
          <div className="mt-2 text-[11px] text-amber-200/80">{categories.join(' · ')}</div>
        ) : null}
        {tags.length > 0 ? (
          <div className="mt-2 flex flex-wrap gap-1">
            {(compact ? tags.slice(0, 10) : tags).map((tag) => (
              <span key={tag} className="rounded-full border border-white/10 bg-white/5 px-2 py-0.5 text-[10px] text-white/70">
                {tag}
              </span>
            ))}
          </div>
        ) : (
          <div className="mt-2 text-[11px] text-white/40">No tags</div>
        )}
        {item.moderation_note ? (
          <div className="mt-2 text-[11px] text-sky-200/80">Review reasons: {item.moderation_note}</div>
        ) : null}
      </div>
    )
  }

  const renderActions = (item) => (
    <div className="w-full max-w-sm space-y-2">
      <input
        type="text"
        aria-label={`Moderation note for ${item.id}`}
        value={notes[item.id] || ''}
        onChange={(event) => setNotes((prev) => ({ ...prev, [item.id]: event.target.value }))}
        placeholder="Moderation note"
        className="w-full rounded-lg border border-white/15 bg-white/10 px-3 py-2 text-xs text-white"
      />
      <div className="flex flex-wrap gap-2">
        <button
          type="button"
          aria-label={`Open details for ${item.id}`}
          onClick={() => setSelected(item)}
          className="rounded-lg border border-white/20 px-3 py-2 text-xs font-semibold text-white"
        >
          Details
        </button>
        <button
          type="button"
          aria-label={`Approve upload ${item.id}`}
          disabled={busyId === item.id}
          onClick={() => moderate(item, 'approve')}
          className="rounded-lg bg-emerald-500 px-3 py-2 text-xs font-semibold text-black disabled:opacity-60"
        >
          {busyId === item.id ? 'Saving…' : 'Approve'}
        </button>
        <button
          type="button"
          aria-label={`Reject upload ${item.id}`}
          disabled={busyId === item.id}
          onClick={() => moderate(item, 'reject')}
          className="rounded-lg bg-rose-500 px-3 py-2 text-xs font-semibold text-white disabled:opacity-60"
        >
          Reject
        </button>
      </div>
    </div>
  )

  return (
    <section aria-label="Moderation queue" className="mx-auto w-full max-w-6xl rounded-2xl border border-white/10 bg-slate-900/60 p-4 md:p-6">
      <div className="mb-4 flex items-center justify-between">
        <h2 className="text-lg font-semibold text-white">Pending Upload Moderation</h2>
        <button type="button" onClick={loadPending} className="rounded-lg border border-white/20 px-3 py-1 text-xs text-white">
          Refresh
        </button>
      </div>

      {loading ? <p role="status" className="text-sm text-white/70">Loading…</p> : null}
      {error ? <p role="alert" className="mb-3 text-sm text-rose-200">{error}</p> : null}
      {!loading && items.length === 0 ? <p role="status" className="text-sm text-white/60">No pending uploads.</p> : null}

      <ul className="space-y-3">
        {items.map((item) => {
          const previewSrc = item.preview_url || item.preview_lg_url || null

          return (
            <li key={`${item.queue}-${item.id}`} aria-label={`Pending upload ${item.id}`} className="rounded-xl border border-white/10 bg-white/5 p-3">
              <div className="flex flex-col gap-3 lg:flex-row lg:items-start lg:justify-between">
                <button
                  type="button"
                  aria-label={`Open details for ${item.title || item.id}`}
                  onClick={() => setSelected(item)}
                  className="flex min-w-0 flex-1 items-start gap-4 text-left"
                >
                  <PreviewImage
                    src={previewSrc}
                    alt={item.title || 'Artwork preview'}
                    className="h-40 w-40 shrink-0 rounded-lg object-cover"
                  />
                  {renderMeta(item, { compact: true })}
                </button>

                {renderActions(item)}
              </div>
            </li>
          )
        })}
      </ul>

      {selected ? (
        <div
          role="dialog"
          aria-modal="true"
          aria-label={`Details for ${selected.title || selected.id}`}
          className="fixed inset-0 z-50 flex items-center justify-center bg-black/70 p-4"
          onClick={() => setSelected(null)}
        >
          <div
            className="max-h-[92vh] w-full max-w-5xl overflow-y-auto rounded-2xl border border-white/10 bg-slate-950 p-5 shadow-2xl"
            onClick={(event) => event.stopPropagation()}
          >
            <div className="mb-4 flex items-start justify-between gap-3">
              <div>
                <div className="text-lg font-semibold text-white">{selected.title || '(untitled upload)'}</div>
                <div className="mt-1 text-xs text-white/60">
                  {creatorName(selected)} · {selected.type} · {selected.id}
                </div>
              </div>
              <button
                type="button"
                aria-label="Close details"
                onClick={() => setSelected(null)}
                className="rounded-lg border border-white/20 px-3 py-1 text-xs text-white"
              >
                Close
              </button>
            </div>

            <PreviewImage
              src={selected.preview_lg_url || selected.preview_url}
              alt={selected.title || 'Artwork preview'}
              className="mb-4 max-h-[62vh] w-full rounded-xl bg-black/40 object-contain"
            />

            <div className="grid gap-6 lg:grid-cols-[minmax(0,1fr)_18rem]">
              <div className="space-y-3 text-sm text-white/80">
                <div>
                  <div className="text-[11px] font-semibold uppercase tracking-widest text-white/40">Description</div>
                  <p className="mt-1 whitespace-pre-wrap leading-6">{selected.description || 'No description'}</p>
                </div>
                <div>
                  <div className="text-[11px] font-semibold uppercase tracking-widest text-white/40">Categories</div>
                  <p className="mt-1">{categoryList(selected).join(', ') || 'None'}</p>
                </div>
                <div>
                  <div className="text-[11px] font-semibold uppercase tracking-widest text-white/40">Tags</div>
                  <div className="mt-2 flex flex-wrap gap-1">
                    {tagList(selected).length > 0 ? tagList(selected).map((tag) => (
                      <span key={tag} className="rounded-full border border-white/10 bg-white/5 px-2 py-0.5 text-[11px] text-white/70">
                        {tag}
                      </span>
                    )) : <span className="text-white/40">None</span>}
                  </div>
                </div>
                <div className="grid gap-3 text-xs text-white/70 sm:grid-cols-2">
                  <div>
                    <div className="text-[11px] font-semibold uppercase tracking-widest text-white/40">Visibility</div>
                    <p className="mt-1">{selected.visibility || 'n/a'}</p>
                  </div>
                  <div>
                    <div className="text-[11px] font-semibold uppercase tracking-widest text-white/40">Maturity</div>
                    <p className="mt-1">{isMature(selected) ? 'NSFW / mature' : (selected.maturity_status || 'safe')}</p>
                  </div>
                  <div>
                    <div className="text-[11px] font-semibold uppercase tracking-widest text-white/40">License</div>
                    <p className="mt-1">{selected.license || 'n/a'}</p>
                  </div>
                  <div>
                    <div className="text-[11px] font-semibold uppercase tracking-widest text-white/40">Submitted</div>
                    <p className="mt-1">{formatDate(selected.created_at) || 'n/a'}</p>
                  </div>
                </div>
                {selected.moderation_note ? (
                  <div>
                    <div className="text-[11px] font-semibold uppercase tracking-widest text-white/40">Review reasons</div>
                    <p className="mt-1">{selected.moderation_note}</p>
                  </div>
                ) : null}
              </div>

              {renderActions(selected)}
            </div>
          </div>
        </div>
      ) : null}
    </section>
  )
}