import { useEffect, useState, useCallback } from 'react'
import { Link } from 'react-router-dom'
import {
  LayoutGrid,
  List,
  MoreVertical,
  X,
} from 'lucide-react'
import { useAuth } from '../context/AuthContext'
import api from '../utils/api'
import AdminPageNav from '../components/AdminPageNav'
import { resolveMediaAssetFileUrl } from '../utils/exerciseMediaUrl'

const LC_OPTIONS = [
  { value: 'active', label: 'Aktiv' },
  { value: 'trash_soft', label: 'Papierkorb (1)' },
  { value: 'trash_hidden', label: 'Ausgeblendet (2)' },
  { value: 'all', label: 'Alle' },
]

const VIS_OPTIONS = [
  { value: 'private', label: 'Privat' },
  { value: 'club', label: 'Verein' },
  { value: 'official', label: 'Offiziell' },
]

function lcLabel(code) {
  const o = LC_OPTIONS.find((x) => x.value === code)
  return o ? o.label : code
}

function uploaderLabel(it, viewer) {
  if (!viewer?.show_uploader_meta) return null
  const n = (it.uploader_name || '').trim()
  const e = (it.uploader_email || '').trim()
  if (n) return n
  if (e) return e
  return it.uploaded_by_profile_id != null ? `Profil #${it.uploaded_by_profile_id}` : '—'
}

function MediaThumb({ mediaId, mimeType }) {
  const url = resolveMediaAssetFileUrl(mediaId)
  const mime = (mimeType || '').toLowerCase()
  if (mime.startsWith('video/')) {
    return (
      <video
        className="media-library__thumb-video"
        src={url}
        muted
        playsInline
        preload="metadata"
        onLoadedMetadata={(e) => {
          const el = e.target
          try {
            const d = el.duration
            el.currentTime = Number.isFinite(d) && d > 0 ? Math.min(0.05, d * 0.01) : 0.05
          } catch {
            /* ignore */
          }
        }}
      />
    )
  }
  if (mime.startsWith('image/')) {
    return (
      <img
        className="media-library__thumb-img"
        src={url}
        alt=""
        loading="lazy"
        onError={(e) => {
          e.target.style.display = 'none'
        }}
      />
    )
  }
  if (mime.includes('pdf')) {
    return <div className="media-library__thumb-ph">PDF</div>
  }
  return <div className="media-library__thumb-ph">◆</div>
}

export default function MediaLibraryPage() {
  const { user } = useAuth()
  const isPlatformAdmin = user?.role === 'admin' || user?.role === 'superadmin'
  const isSuperadmin = user?.role === 'superadmin'

  const [lifecycle, setLifecycle] = useState('active')
  const [q, setQ] = useState('')
  const [items, setItems] = useState([])
  const [viewer, setViewer] = useState(null)
  const [clubs, setClubs] = useState([])
  const [viewMode, setViewMode] = useState('grid')
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState('')
  const [selected, setSelected] = useState(() => new Set())
  const [modal, setModal] = useState(null)
  const [modalDraft, setModalDraft] = useState(null)
  const [bulkOpen, setBulkOpen] = useState(false)
  const [bulkCopyright, setBulkCopyright] = useState('')
  const [bulkVis, setBulkVis] = useState('private')
  const [bulkClubId, setBulkClubId] = useState('')
  const [bulkApplyVis, setBulkApplyVis] = useState(false)
  const [busy, setBusy] = useState(false)

  const loadClubs = useCallback(async () => {
    try {
      const c = await api.listClubs()
      setClubs(Array.isArray(c) ? c : [])
    } catch {
      setClubs([])
    }
  }, [])

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

  const loadItems = useCallback(async () => {
    setLoading(true)
    setError('')
    try {
      const res = await api.listMediaAssets({
        lifecycle,
        q: q.trim(),
        limit: 100,
        offset: 0,
      })
      setItems(res.items || [])
      setViewer(res.viewer || null)
      setSelected(new Set())
    } catch (e) {
      setError(e.message || String(e))
    } finally {
      setLoading(false)
    }
  }, [lifecycle, q])

  useEffect(() => {
    const t = setTimeout(() => {
      loadItems()
    }, 320)
    return () => clearTimeout(t)
  }, [lifecycle, q, loadItems])

  const toggleSel = (id) => {
    setSelected((prev) => {
      const n = new Set(prev)
      if (n.has(id)) n.delete(id)
      else n.add(id)
      return n
    })
  }

  const selectAll = () => {
    if (selected.size === items.length) setSelected(new Set())
    else setSelected(new Set(items.map((x) => x.id)))
  }

  const openEdit = (it) => {
    const p = it.permissions || {}
    setModal(it)
    setModalDraft({
      display_name: it.original_filename != null ? String(it.original_filename) : '',
      copyright_notice: it.copyright_notice != null ? String(it.copyright_notice) : '',
      visibility: (it.visibility || 'private').toLowerCase(),
      club_id: it.club_id != null ? String(it.club_id) : '',
      superTarget: 'active',
    })
  }

  const closeModal = () => {
    setModal(null)
    setModalDraft(null)
  }

  const saveModal = async () => {
    if (!modal || !modalDraft) return
    const p = modal.permissions || {}
    setBusy(true)
    try {
      const body = {}
      if (p.edit_metadata) {
        body.original_filename = modalDraft.display_name
        body.copyright_notice = modalDraft.copyright_notice
      }
      if (p.change_visibility) {
        body.visibility = modalDraft.visibility
        if (modalDraft.visibility === 'club') {
          const cid = Number(modalDraft.club_id)
          if (!cid) {
            alert('Bitte einen Verein wählen.')
            setBusy(false)
            return
          }
          body.club_id = cid
        }
      }
      if (Object.keys(body).length) {
        await api.patchMediaAsset(modal.id, body)
      }
      closeModal()
      await loadItems()
    } catch (e) {
      alert(e.message || String(e))
    } finally {
      setBusy(false)
    }
  }

  const runLc = async (id, action, confirmMsg, extra = {}) => {
    if (confirmMsg && !window.confirm(confirmMsg)) return
    setBusy(true)
    try {
      await api.postMediaAssetLifecycle(id, action, extra)
      await loadItems()
      closeModal()
    } catch (e) {
      alert(e.message || String(e))
    } finally {
      setBusy(false)
    }
  }

  const runBulkPatch = async () => {
    const ids = [...selected]
    if (!ids.length) return
    const body = { media_asset_ids: ids }
    let has = false
    if (bulkCopyright.trim()) {
      body.copyright_notice = bulkCopyright.trim()
      has = true
    }
    if (bulkApplyVis) {
      body.visibility = bulkVis
      if (bulkVis === 'club') {
        const cid = Number(bulkClubId)
        if (!cid) {
          alert('Bitte einen Verein wählen.')
          return
        }
        body.club_id = cid
      }
      has = true
    }
    if (!has) {
      alert('Mindestens Copyright ausfüllen oder „Sichtbarkeit ändern“ aktivieren.')
      return
    }
    setBusy(true)
    try {
      const res = await api.bulkPatchMediaAssets(body)
      if (res.failed_count) {
        alert(
          `${res.updated_count} aktualisiert, ${res.failed_count} fehlgeschlagen. Erste Meldung: ${res.failed[0]?.detail || ''}`,
        )
      }
      setBulkOpen(false)
      await loadItems()
    } catch (e) {
      alert(e.message || String(e))
    } finally {
      setBusy(false)
    }
  }

  const runBulkLifecycle = async (action) => {
    const ids = [...selected]
    if (!ids.length) return
    setBusy(true)
    try {
      const res = await api.bulkMediaLifecycle({ media_asset_ids: ids, action })
      if (res.failed_count) {
        alert(
          `${res.updated_count} OK, ${res.failed_count} fehlgeschlagen: ${res.failed[0]?.detail || ''}`,
        )
      }
      await loadItems()
    } catch (e) {
      alert(e.message || String(e))
    } finally {
      setBusy(false)
    }
  }

  const selCount = selected.size

  return (
    <div className="app-page media-library">
      {isPlatformAdmin ? <AdminPageNav /> : null}

      <div className="media-library__container">
        <header className="media-library__hero">
          <div className="media-library__hero-row">
            <h1 className="media-library__title">Medienbibliothek</h1>
            <div className="media-library__hero-links">
              <Link to="/exercises">Übungen</Link>
              {isPlatformAdmin ? <Link to="/admin/hierarchy">Admin</Link> : null}
            </div>
          </div>
          <p className="media-library__intro">
            Veröffentlichte Medien (Verein/Plattform) und eigene Uploads. Bearbeiten und Papierkorb über das
            Menü pro Medium — Bulk unten in der Leiste.
          </p>
        </header>

        <div className="media-library__toolbar">
          <div className="media-library__toolbar-row">
            <input
              type="search"
              className="form-input media-library__search"
              placeholder="Suche Dateiname …"
              value={q}
              onChange={(e) => setQ(e.target.value)}
              aria-label="Suche"
            />
            <select
              className="form-input media-library__select"
              value={lifecycle}
              onChange={(e) => setLifecycle(e.target.value)}
              aria-label="Lebenszyklus"
            >
              {LC_OPTIONS.map((o) => (
                <option key={o.value} value={o.value}>
                  {o.label}
                </option>
              ))}
            </select>
            <div className="media-library__view-toggle" role="group" aria-label="Darstellung">
              <button
                type="button"
                className={`media-library__icon-btn${viewMode === 'grid' ? ' media-library__icon-btn--on' : ''}`}
                onClick={() => setViewMode('grid')}
                title="Kacheln"
              >
                <LayoutGrid size={20} />
              </button>
              <button
                type="button"
                className={`media-library__icon-btn${viewMode === 'list' ? ' media-library__icon-btn--on' : ''}`}
                onClick={() => setViewMode('list')}
                title="Liste"
              >
                <List size={20} />
              </button>
            </div>
            <button
              type="button"
              className="btn btn-secondary media-library__refresh"
              onClick={loadItems}
              disabled={loading}
            >
              Aktualisieren
            </button>
          </div>
          <div className="media-library__toolbar-meta">
            <label className="media-library__check-all">
              <input type="checkbox" checked={items.length > 0 && selCount === items.length} onChange={selectAll} />
              <span>alle sichtbaren</span>
            </label>
            {selCount > 0 ? (
              <button type="button" className="btn btn-secondary" onClick={() => setBulkOpen(true)}>
                Bulk ({selCount})
              </button>
            ) : null}
          </div>
        </div>

        {error ? (
          <p className="media-library__err" role="alert">
            {error}
          </p>
        ) : null}

        {loading && !items.length ? <div className="spinner media-library__spinner" /> : null}

        {!loading && !items.length && !error ? (
          <p className="media-library__empty">Keine Medien für diese Filter.</p>
        ) : null}

        {viewMode === 'grid' && items.length > 0 ? (
          <div className="media-library__grid">
            {items.map((it) => {
              const lc = (it.lifecycle_state || '').toLowerCase()
              const chk = selected.has(it.id)
              return (
                <div key={it.id} className="media-library__card">
                  <label className="media-library__card-check">
                    <input type="checkbox" checked={chk} onChange={() => toggleSel(it.id)} />
                  </label>
                  <button
                    type="button"
                    className="media-library__card-menu"
                    onClick={() => openEdit(it)}
                    title="Bearbeiten"
                    aria-label="Bearbeiten"
                  >
                    <MoreVertical size={20} />
                  </button>
                  <div className="media-library__card-thumb-wrap">
                    <MediaThumb mediaId={it.id} mimeType={it.mime_type} />
                  </div>
                  <div className="media-library__card-footer">
                    <div className="media-library__card-name" title={it.original_filename || `#${it.id}`}>
                      {it.original_filename || `Medium #${it.id}`}
                    </div>
                    <div className="media-library__card-tags">
                      <span>{it.visibility}</span>
                      <span>{lcLabel(lc)}</span>
                    </div>
                  </div>
                </div>
              )
            })}
          </div>
        ) : null}

        {viewMode === 'list' && items.length > 0 ? (
          <div className="media-library__table-wrap">
            <table className="media-library__table">
              <thead>
                <tr>
                  <th className="media-library__th-check" />
                  <th>Vorschau</th>
                  <th>Bezeichnung</th>
                  <th>Sichtbarkeit</th>
                  <th>Status</th>
                  {viewer?.show_club_meta ? <th>Verein</th> : null}
                  {viewer?.show_uploader_meta ? <th>Uploader</th> : null}
                  <th className="media-library__th-act" />
                </tr>
              </thead>
              <tbody>
                {items.map((it) => {
                  const lc = (it.lifecycle_state || '').toLowerCase()
                  return (
                    <tr key={it.id}>
                      <td>
                        <input type="checkbox" checked={selected.has(it.id)} onChange={() => toggleSel(it.id)} />
                      </td>
                      <td className="media-library__td-thumb">
                        <div className="media-library__table-thumb">
                          <MediaThumb mediaId={it.id} mimeType={it.mime_type} />
                        </div>
                      </td>
                      <td className="media-library__td-name">{it.original_filename || `#${it.id}`}</td>
                      <td>{it.visibility}</td>
                      <td>{lcLabel(lc)}</td>
                      {viewer?.show_club_meta ? (
                        <td className="media-library__td-sub">{it.club_name || it.club_id || '—'}</td>
                      ) : null}
                      {viewer?.show_uploader_meta ? (
                        <td className="media-library__td-sub">{uploaderLabel(it, viewer) || '—'}</td>
                      ) : null}
                      <td>
                        <button
                          type="button"
                          className="media-library__icon-btn"
                          onClick={() => openEdit(it)}
                          aria-label="Bearbeiten"
                        >
                          <MoreVertical size={18} />
                        </button>
                      </td>
                    </tr>
                  )
                })}
              </tbody>
            </table>
          </div>
        ) : null}
      </div>

      {bulkOpen ? (
        <div className="media-library__overlay" role="dialog" aria-modal="true" aria-labelledby="bulk-title">
          <div className="media-library__modal media-library__modal--wide">
            <div className="media-library__modal-head">
              <h2 id="bulk-title">Bulk für {selCount} Medien</h2>
              <button type="button" className="media-library__icon-btn" onClick={() => setBulkOpen(false)} aria-label="Schließen">
                <X size={22} />
              </button>
            </div>
            <div className="media-library__modal-body">
              <p className="media-library__hint">Nur ausgefüllte Felder werden gesetzt. Fehlende Rechte pro Medium werden im Ergebnis gemeldet.</p>
              <label className="form-label">Copyright (optional)</label>
              <textarea
                className="form-input"
                rows={2}
                value={bulkCopyright}
                onChange={(e) => setBulkCopyright(e.target.value)}
              />
              <label className="media-library__check">
                <input
                  type="checkbox"
                  checked={bulkApplyVis}
                  onChange={(e) => setBulkApplyVis(e.target.checked)}
                />
                <span>Sichtbarkeit ändern</span>
              </label>
              {bulkApplyVis ? (
                <>
                  <select className="form-input" value={bulkVis} onChange={(e) => setBulkVis(e.target.value)}>
                    {VIS_OPTIONS.map((o) => (
                      <option key={o.value} value={o.value}>
                        {o.label}
                      </option>
                    ))}
                  </select>
                  {bulkVis === 'club' ? (
                    <select className="form-input" value={bulkClubId} onChange={(e) => setBulkClubId(e.target.value)}>
                      <option value="">— Verein —</option>
                      {clubs.map((c) => (
                        <option key={c.id} value={String(c.id)}>
                          {c.name || c.id}
                        </option>
                      ))}
                    </select>
                  ) : null}
                </>
              ) : null}
              <div className="media-library__modal-actions">
                <button type="button" className="btn btn-secondary" disabled={busy} onClick={runBulkPatch}>
                  Metadaten anwenden
                </button>
                <button
                  type="button"
                  className="btn btn-secondary"
                  disabled={busy}
                  onClick={() => {
                    if (!window.confirm('Ausgewählte aktiven Medien in Papierkorb (1)?')) return
                    runBulkLifecycle('trash_soft')
                  }}
                >
                  Papierkorb (1)
                </button>
                {isSuperadmin ? (
                  <button
                    type="button"
                    className="btn btn-secondary"
                    disabled={busy}
                    onClick={() => {
                      if (!window.confirm('Superadmin: Ausgewählte endgültig löschen?')) return
                      runBulkLifecycle('superadmin_hard_delete')
                    }}
                  >
                    Hard-Delete
                  </button>
                ) : null}
              </div>
            </div>
          </div>
        </div>
      ) : null}

      {modal && modalDraft ? (
        <div className="media-library__overlay" role="dialog" aria-modal="true" aria-labelledby="edit-media-title">
          <div className="media-library__modal">
            <div className="media-library__modal-head">
              <h2 id="edit-media-title">Medium #{modal.id}</h2>
              <button type="button" className="media-library__icon-btn" onClick={closeModal} aria-label="Schließen">
                <X size={22} />
              </button>
            </div>
            <div className="media-library__modal-body">
              {(viewer?.show_club_meta || viewer?.show_uploader_meta) && (
                <div className="media-library__meta-block">
                  {viewer?.show_club_meta ? (
                    <div>
                      <span className="media-library__meta-k">Verein</span>
                      <span className="media-library__meta-v">{modal.club_name || modal.club_id || '—'}</span>
                    </div>
                  ) : null}
                  {viewer?.show_uploader_meta ? (
                    <div>
                      <span className="media-library__meta-k">Uploader</span>
                      <span className="media-library__meta-v">{uploaderLabel(modal, viewer) || '—'}</span>
                    </div>
                  ) : null}
                  <div>
                    <span className="media-library__meta-k">Technisch</span>
                    <span className="media-library__meta-v mono">
                      {modal.mime_type || '—'} · ID {modal.id}
                      {isSuperadmin && modal.storage_key ? ` · ${modal.storage_key}` : ''}
                    </span>
                  </div>
                </div>
              )}

              {modal.permissions?.edit_metadata ? (
                <>
                  <label className="form-label">Bezeichnung (Dateiname / Anzeige)</label>
                  <input
                    className="form-input"
                    value={modalDraft.display_name}
                    onChange={(e) => setModalDraft((d) => ({ ...d, display_name: e.target.value }))}
                  />
                  <label className="form-label">Copyright</label>
                  <textarea
                    className="form-input"
                    rows={3}
                    value={modalDraft.copyright_notice}
                    onChange={(e) => setModalDraft((d) => ({ ...d, copyright_notice: e.target.value }))}
                  />
                </>
              ) : (
                <p className="media-library__hint">Keine Berechtigung für Metadaten — nur Verwaltende dieser Stufe.</p>
              )}

              {modal.permissions?.change_visibility ? (
                <>
                  <label className="form-label">Sichtbarkeit</label>
                  <select
                    className="form-input"
                    value={modalDraft.visibility}
                    onChange={(e) => setModalDraft((d) => ({ ...d, visibility: e.target.value }))}
                  >
                    {VIS_OPTIONS.map((o) => (
                      <option key={o.value} value={o.value}>
                        {o.label}
                      </option>
                    ))}
                  </select>
                  {modalDraft.visibility === 'club' ? (
                    <>
                      <label className="form-label">Verein</label>
                      <select
                        className="form-input"
                        value={modalDraft.club_id}
                        onChange={(e) => setModalDraft((d) => ({ ...d, club_id: e.target.value }))}
                      >
                        <option value="">— wählen —</option>
                        {clubs.map((c) => (
                          <option key={c.id} value={String(c.id)}>
                            {c.name || c.id}
                          </option>
                        ))}
                      </select>
                    </>
                  ) : null}
                </>
              ) : null}

              <div className="media-library__modal-actions">
                <button type="button" className="btn btn-secondary" disabled={busy} onClick={saveModal}>
                  Speichern
                </button>
              </div>

              <div className="media-library__lc-block">
                <div className="media-library__lc-title">Lebenszyklus</div>
                <div className="media-library__lc-btns">
                  {modal.permissions?.trash_soft ? (
                    <button
                      type="button"
                      className="btn btn-secondary"
                      disabled={busy}
                      onClick={() =>
                        runLc(modal.id, 'trash_soft', 'In Papierkorb (Stufe 1) legen?')
                      }
                    >
                      Papierkorb
                    </button>
                  ) : null}
                  {modal.permissions?.trash_hidden ? (
                    <button
                      type="button"
                      className="btn btn-secondary"
                      disabled={busy}
                      onClick={() =>
                        runLc(
                          modal.id,
                          'trash_hidden',
                          'Ausblenden (Stufe 2)? Öffentliche Ansicht verliert das Medium.',
                        )
                      }
                    >
                      Ausblenden
                    </button>
                  ) : null}
                  {modal.permissions?.recover ? (
                    <button type="button" className="btn btn-secondary" disabled={busy} onClick={() => runLc(modal.id, 'recover', null)}>
                      ↩ Stufe 1
                    </button>
                  ) : null}
                  {modal.permissions?.reactivate ? (
                    <button
                      type="button"
                      className="btn btn-secondary"
                      disabled={busy}
                      onClick={() => runLc(modal.id, 'reactivate', null)}
                    >
                      Wieder aktiv
                    </button>
                  ) : null}
                  {modal.permissions?.purge ? (
                    <button
                      type="button"
                      className="btn btn-secondary"
                      disabled={busy}
                      onClick={() =>
                        runLc(
                          modal.id,
                          'purge',
                          'Endgültig löschen (nur Superadmin, Stufe 2)? Datei und DB-Eintrag.',
                        )
                      }
                    >
                      Endgültig löschen
                    </button>
                  ) : null}
                </div>
              </div>

              {modal.permissions?.superadmin_lifecycle ? (
                <div className="media-library__lc-block media-library__lc-block--danger">
                  <div className="media-library__lc-title">Superadmin</div>
                  <div className="media-library__row">
                    <select
                      className="form-input"
                      value={modalDraft.superTarget}
                      onChange={(e) => setModalDraft((d) => ({ ...d, superTarget: e.target.value }))}
                    >
                      <option value="active">aktiv</option>
                      <option value="trash_soft">Papierkorb 1</option>
                      <option value="trash_hidden">ausgeblendet 2</option>
                    </select>
                    <button
                      type="button"
                      className="btn btn-secondary"
                      disabled={busy}
                      onClick={() =>
                        runLc(
                          modal.id,
                          'superadmin_force_lifecycle',
                          `Zustand erzwingen: ${modalDraft.superTarget}?`,
                          { target_lifecycle: modalDraft.superTarget },
                        )
                      }
                    >
                      Zustand setzen
                    </button>
                  </div>
                  {modal.permissions?.superadmin_hard_delete ? (
                    <button
                      type="button"
                      className="btn btn-secondary"
                      disabled={busy}
                      onClick={() =>
                        runLc(
                          modal.id,
                          'superadmin_hard_delete',
                          'Medium komplett entfernen (DB + Datei)?',
                        )
                      }
                    >
                      Komplett löschen
                    </button>
                  ) : null}
                </div>
              ) : null}
            </div>
          </div>
        </div>
      ) : null}
    </div>
  )
}