import React, { useEffect, useState } from 'react'
import { Navigate } from 'react-router-dom'
import { useAuth } from '../context/AuthContext'
import api from '../utils/api'
import AdminPageNav from '../components/AdminPageNav'

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

  const [models, setModels] = useState([])
  const [selectedId, setSelectedId] = useState(null)
  const [detail, setDetail] = useState(null)
  const [loading, setLoading] = useState(false)
  const [saving, setSaving] = useState(false)
  const [error, setError] = useState('')
  const [focusAreas, setFocusAreas] = useState([])
  const [styles, setStyles] = useState([])
  const [targetGroups, setTargetGroups] = useState([])
  const [allSkills, setAllSkills] = useState([])

  const [newModel, setNewModel] = useState({
    name: '',
    level_count: 5,
    focus_area_id: '',
    style_direction_id: '',
    target_group_id: '',
    status: 'draft'
  })

  const [meta, setMeta] = useState(null)
  const [levelCount, setLevelCount] = useState(5)
  const [levelsForm, setLevelsForm] = useState([])
  const [cellDraft, setCellDraft] = useState({})
  const [skillToAdd, setSkillToAdd] = useState('')

  useEffect(() => {
    if (!isAdmin) return
    let cancelled = false
    ;(async () => {
      try {
        const [m, fa, sd, tg, sk] = await Promise.all([
          api.listMaturityModels({}),
          api.listFocusAreas({}),
          api.listStyleDirections({}),
          api.listTargetGroups({}),
          api.listSkills({ status: 'active' })
        ])
        if (!cancelled) {
          setModels(m)
          setFocusAreas(fa)
          setStyles(sd)
          setTargetGroups(tg)
          setAllSkills(sk)
        }
      } catch (e) {
        if (!cancelled) setError(e.message)
      }
    })()
    return () => { cancelled = true }
  }, [isAdmin])

  async function refreshModels() {
    const m = await api.listMaturityModels({})
    setModels(m)
  }

  async function selectModel(id) {
    setSelectedId(id)
    setLoading(true)
    setError('')
    try {
      const d = await api.getMaturityModel(id)
      setDetail(d)
      setMeta({
        name: d.name,
        description: d.description || '',
        focus_area_id: d.focus_area_id ?? '',
        style_direction_id: d.style_direction_id ?? '',
        target_group_id: d.target_group_id ?? '',
        status: d.status,
        version: d.version || '1.0'
      })
      const lc = parseInt(String(d.level_count), 10)
      setLevelCount(lc)
      setLevelsForm(
        (d.levels || []).map((l) => ({
          level_number: l.level_number,
          name: l.name,
          description: l.description || '',
          sort_order: l.sort_order
        }))
      )
      const draft = {}
      for (const r of d.skill_levels || []) {
        draft[`${r.skill_id}-${r.level_number}`] = {
          description: r.description || '',
          observable_criteria: r.observable_criteria || ''
        }
      }
      setCellDraft(draft)
    } catch (e) {
      setError(e.message)
      setDetail(null)
      setMeta(null)
    } finally {
      setLoading(false)
    }
  }

  async function handleCreate(e) {
    e.preventDefault()
    setError('')
    setSaving(true)
    try {
      const payload = {
        name: newModel.name.trim(),
        level_count: parseInt(String(newModel.level_count), 10),
        status: newModel.status,
        focus_area_id: newModel.focus_area_id ? parseInt(String(newModel.focus_area_id), 10) : null,
        style_direction_id: newModel.style_direction_id
          ? parseInt(String(newModel.style_direction_id), 10)
          : null,
        target_group_id: newModel.target_group_id
          ? parseInt(String(newModel.target_group_id), 10)
          : null
      }
      const created = await api.createMaturityModel(payload)
      await refreshModels()
      await selectModel(created.id)
      setNewModel({
        name: '',
        level_count: 5,
        focus_area_id: '',
        style_direction_id: '',
        target_group_id: '',
        status: 'draft'
      })
    } catch (e) {
      setError(e.message)
    } finally {
      setSaving(false)
    }
  }

  async function handleSaveMeta() {
    if (!selectedId || !meta) return
    setError('')
    setSaving(true)
    try {
      await api.updateMaturityModel(selectedId, {
        name: meta.name,
        description: meta.description || null,
        focus_area_id: meta.focus_area_id === '' ? null : parseInt(String(meta.focus_area_id), 10),
        style_direction_id:
          meta.style_direction_id === '' ? null : parseInt(String(meta.style_direction_id), 10),
        target_group_id:
          meta.target_group_id === '' ? null : parseInt(String(meta.target_group_id), 10),
        status: meta.status,
        version: meta.version
      })
      await refreshModels()
      await selectModel(selectedId)
    } catch (e) {
      setError(e.message)
    } finally {
      setSaving(false)
    }
  }

  async function handleSaveLevels() {
    if (!selectedId || !meta) return
    setError('')
    setSaving(true)
    try {
      await api.updateMaturityModel(selectedId, {
        level_count: parseInt(String(levelCount), 10),
        levels: levelsForm.map((l) => ({
          level_number: parseInt(String(l.level_number), 10),
          name: l.name,
          description: l.description || null,
          sort_order: parseInt(String(l.sort_order), 10)
        }))
      })
      await refreshModels()
      await selectModel(selectedId)
    } catch (e) {
      setError(e.message)
    } finally {
      setSaving(false)
    }
  }

  async function handleSaveMatrix() {
    if (!selectedId || !detail) return
    if (!detail.model_skills?.length) {
      setError('Matrix: Zuerst Fähigkeiten hinzufügen.')
      return
    }
    setError('')
    setSaving(true)
    try {
      const entries = []
      for (const ms of detail.model_skills) {
        for (const lev of detail.levels || []) {
          const key = `${ms.skill_id}-${lev.level_number}`
          const d = cellDraft[key] || { description: '', observable_criteria: '' }
          entries.push({
            skill_id: ms.skill_id,
            level_number: lev.level_number,
            description: (d.description || '').trim(),
            observable_criteria: (d.observable_criteria || '').trim() || null
          })
        }
      }
      await api.upsertMaturityModelSkillLevels(selectedId, { entries })
      await selectModel(selectedId)
    } catch (e) {
      setError(e.message)
    } finally {
      setSaving(false)
    }
  }

  async function handleAddSkill() {
    if (!selectedId || !skillToAdd) return
    setError('')
    setSaving(true)
    try {
      await api.addMaturityModelSkill(selectedId, { skill_id: parseInt(String(skillToAdd), 10) })
      setSkillToAdd('')
      await selectModel(selectedId)
    } catch (e) {
      setError(e.message)
    } finally {
      setSaving(false)
    }
  }

  async function handleRemoveSkill(skillId) {
    if (!selectedId) return
    if (!confirm('Fähigkeit aus dem Modell entfernen? Zelltexte werden gelöscht.')) return
    setError('')
    setSaving(true)
    try {
      await api.removeMaturityModelSkill(selectedId, skillId)
      await selectModel(selectedId)
    } catch (e) {
      setError(e.message)
    } finally {
      setSaving(false)
    }
  }

  async function handleDeleteModel() {
    if (!selectedId || !isSuperadmin) return
    if (!confirm('Reifegradmodell dauerhaft löschen?')) return
    setError('')
    setSaving(true)
    try {
      await api.deleteMaturityModel(selectedId)
      setSelectedId(null)
      setDetail(null)
      setMeta(null)
      await refreshModels()
    } catch (e) {
      setError(e.message)
    } finally {
      setSaving(false)
    }
  }

  function onLevelCountChange(raw) {
    const next = Math.max(3, Math.min(10, parseInt(String(raw), 10) || 3))
    setLevelCount(next)
    setLevelsForm((prev) => {
      const byNum = Object.fromEntries(prev.map((r) => [r.level_number, { ...r }]))
      const rows = []
      for (let i = 1; i <= next; i++) {
        rows.push(
          byNum[i] || {
            level_number: i,
            name: `Stufe ${i}`,
            description: '',
            sort_order: i
          }
        )
      }
      return rows
    })
  }

  function setCell(skillId, levelNumber, field, value) {
    const key = `${skillId}-${levelNumber}`
    setCellDraft((prev) => ({
      ...prev,
      [key]: {
        description: field === 'description' ? value : (prev[key]?.description ?? ''),
        observable_criteria:
          field === 'observable_criteria' ? value : (prev[key]?.observable_criteria ?? '')
      }
    }))
  }

  if (!isAdmin) {
    return <Navigate to="/" replace />
  }

  return (
    <div style={{ padding: '20px', maxWidth: 1400, margin: '0 auto' }}>
      <AdminPageNav />

      <h1 style={{ marginTop: 0 }}>Admin: Fähigkeitsmatrix</h1>
      <p style={{ color: 'var(--text2)', marginTop: '-8px' }}>
        Reifegradmodelle mit Fokusbereich, Stilrichtung und Zielgruppe. Pro Modell: Stufen definieren,
        Fähigkeiten zuordnen, Zelltexte pflegen.
      </p>

      {error ? (
        <div className="card" style={{ borderColor: 'var(--danger)', marginBottom: 16 }}>
          {error}
        </div>
      ) : null}

      <div
        style={{
          display: 'grid',
          gridTemplateColumns: 'minmax(240px, 320px) 1fr',
          gap: 20,
          alignItems: 'start'
        }}
      >
        <div className="card" style={{ padding: 16 }}>
          <h2 style={{ marginTop: 0, fontSize: '1.1rem' }}>Modelle</h2>
          <ul style={{ listStyle: 'none', padding: 0, margin: 0 }}>
            {models.map((m) => (
              <li key={m.id} style={{ marginBottom: 8 }}>
                <button
                  type="button"
                  className={selectedId === m.id ? 'btn btn-primary' : 'btn btn-secondary'}
                  style={{ width: '100%', textAlign: 'left' }}
                  onClick={() => selectModel(m.id)}
                >
                  <div style={{ fontWeight: 600 }}>{m.name}</div>
                  <div style={{ fontSize: 12, opacity: 0.85 }}>
                    {[m.focus_area_name, m.style_direction_name, m.target_group_name]
                      .filter(Boolean)
                      .join(' · ') || 'Allgemein'}
                  </div>
                  <div style={{ fontSize: 11, opacity: 0.75 }}>{m.status} · {m.level_count} Stufen</div>
                </button>
              </li>
            ))}
          </ul>

          <hr style={{ border: 'none', borderTop: '1px solid var(--border)', margin: '16px 0' }} />

          <h3 style={{ fontSize: '1rem' }}>Neues Modell</h3>
          <form onSubmit={handleCreate} style={{ display: 'flex', flexDirection: 'column', gap: 10 }}>
            <label className="form-label">Name</label>
            <input
              className="form-input"
              value={newModel.name}
              onChange={(e) => setNewModel((s) => ({ ...s, name: e.target.value }))}
              required
            />
            <label className="form-label">Stufenanzahl (3–10)</label>
            <input
              className="form-input"
              type="number"
              min={3}
              max={10}
              value={newModel.level_count}
              onChange={(e) => setNewModel((s) => ({ ...s, level_count: e.target.value }))}
            />
            <label className="form-label">Status</label>
            <select
              className="form-input"
              value={newModel.status}
              onChange={(e) => setNewModel((s) => ({ ...s, status: e.target.value }))}
            >
              <option value="draft">Entwurf</option>
              <option value="active">Aktiv</option>
              <option value="archived">Archiviert</option>
            </select>
            <label className="form-label">Fokusbereich (optional)</label>
            <select
              className="form-input"
              value={newModel.focus_area_id}
              onChange={(e) => setNewModel((s) => ({ ...s, focus_area_id: e.target.value }))}
            >
              <option value="">—</option>
              {focusAreas.map((fa) => (
                <option key={fa.id} value={fa.id}>{fa.name}</option>
              ))}
            </select>
            <label className="form-label">Stilrichtung (optional)</label>
            <select
              className="form-input"
              value={newModel.style_direction_id}
              onChange={(e) => setNewModel((s) => ({ ...s, style_direction_id: e.target.value }))}
            >
              <option value="">—</option>
              {styles.map((s) => (
                <option key={s.id} value={s.id}>{s.name}</option>
              ))}
            </select>
            <label className="form-label">Zielgruppe (optional)</label>
            <select
              className="form-input"
              value={newModel.target_group_id}
              onChange={(e) => setNewModel((s) => ({ ...s, target_group_id: e.target.value }))}
            >
              <option value="">—</option>
              {targetGroups.map((tg) => (
                <option key={tg.id} value={tg.id}>{tg.name}</option>
              ))}
            </select>
            <button type="submit" className="btn btn-primary btn-full" disabled={saving}>
              Anlegen
            </button>
          </form>
        </div>

        <div>
          {loading ? <div className="spinner" /> : null}

          {!loading && !detail && (
            <div className="card" style={{ padding: 24, color: 'var(--text2)' }}>
              Modell links wählen oder neu anlegen.
            </div>
          )}

          {!loading && detail && meta && (
            <>
              <div className="card" style={{ padding: 16, marginBottom: 16 }}>
                <h2 style={{ marginTop: 0, fontSize: '1.1rem' }}>Kontext &amp; Metadaten</h2>
                <div className="form-row" style={{ display: 'grid', gap: 12 }}>
                  <div>
                    <label className="form-label">Name</label>
                    <input
                      className="form-input"
                      value={meta.name}
                      onChange={(e) => setMeta((m) => ({ ...m, name: e.target.value }))}
                    />
                  </div>
                  <div>
                    <label className="form-label">Beschreibung</label>
                    <textarea
                      className="form-input"
                      rows={2}
                      value={meta.description}
                      onChange={(e) => setMeta((m) => ({ ...m, description: e.target.value }))}
                    />
                  </div>
                  <div style={{ display: 'grid', gridTemplateColumns: '1fr 1fr', gap: 12 }}>
                    <div>
                      <label className="form-label">Fokusbereich</label>
                      <select
                        className="form-input"
                        value={meta.focus_area_id === null || meta.focus_area_id === '' ? '' : meta.focus_area_id}
                        onChange={(e) => setMeta((m) => ({ ...m, focus_area_id: e.target.value }))}
                      >
                        <option value="">— (alle)</option>
                        {focusAreas.map((fa) => (
                          <option key={fa.id} value={fa.id}>{fa.name}</option>
                        ))}
                      </select>
                    </div>
                    <div>
                      <label className="form-label">Stilrichtung</label>
                      <select
                        className="form-input"
                        value={
                          meta.style_direction_id === null || meta.style_direction_id === ''
                            ? ''
                            : meta.style_direction_id
                        }
                        onChange={(e) => setMeta((m) => ({ ...m, style_direction_id: e.target.value }))}
                      >
                        <option value="">— (alle)</option>
                        {styles.map((s) => (
                          <option key={s.id} value={s.id}>{s.name}</option>
                        ))}
                      </select>
                    </div>
                  </div>
                  <div>
                    <label className="form-label">Zielgruppe</label>
                    <select
                      className="form-input"
                      value={
                        meta.target_group_id === null || meta.target_group_id === ''
                          ? ''
                          : meta.target_group_id
                      }
                      onChange={(e) => setMeta((m) => ({ ...m, target_group_id: e.target.value }))}
                    >
                      <option value="">— (alle)</option>
                      {targetGroups.map((tg) => (
                        <option key={tg.id} value={tg.id}>{tg.name}</option>
                      ))}
                    </select>
                  </div>
                  <div style={{ display: 'grid', gridTemplateColumns: '1fr 1fr', gap: 12 }}>
                    <div>
                      <label className="form-label">Status</label>
                      <select
                        className="form-input"
                        value={meta.status}
                        onChange={(e) => setMeta((m) => ({ ...m, status: e.target.value }))}
                      >
                        <option value="draft">Entwurf</option>
                        <option value="active">Aktiv</option>
                        <option value="archived">Archiviert</option>
                      </select>
                    </div>
                    <div>
                      <label className="form-label">Version</label>
                      <input
                        className="form-input"
                        value={meta.version}
                        onChange={(e) => setMeta((m) => ({ ...m, version: e.target.value }))}
                      />
                    </div>
                  </div>
                </div>
                <div style={{ display: 'flex', gap: 8, marginTop: 12, flexWrap: 'wrap' }}>
                  <button type="button" className="btn btn-primary" onClick={handleSaveMeta} disabled={saving}>
                    Metadaten speichern
                  </button>
                  {isSuperadmin ? (
                    <button type="button" className="btn btn-secondary" onClick={handleDeleteModel} disabled={saving}>
                      Modell löschen
                    </button>
                  ) : null}
                </div>
              </div>

              <div className="card" style={{ padding: 16, marginBottom: 16 }}>
                <h2 style={{ marginTop: 0, fontSize: '1.1rem' }}>Stufen (Bezeichnungen)</h2>
                <p style={{ fontSize: 14, color: 'var(--text2)', marginTop: 0 }}>
                  Reihenfolge muss lückenlos 1…N sein. Stufenanzahl ändern passt die Tabelle an; danach speichern.
                </p>
                <div style={{ marginBottom: 12, maxWidth: 200 }}>
                  <label className="form-label">Stufenanzahl (3–10)</label>
                  <input
                    className="form-input"
                    type="number"
                    min={3}
                    max={10}
                    value={levelCount}
                    onChange={(e) => onLevelCountChange(e.target.value)}
                  />
                </div>
                <div style={{ overflowX: 'auto' }}>
                  <table style={{ width: '100%', borderCollapse: 'collapse', fontSize: 14 }}>
                    <thead>
                      <tr>
                        <th style={{ textAlign: 'left', padding: 8 }}>Nr.</th>
                        <th style={{ textAlign: 'left', padding: 8 }}>Name</th>
                        <th style={{ textAlign: 'left', padding: 8 }}>Beschreibung</th>
                        <th style={{ textAlign: 'left', padding: 8 }}>Sort</th>
                      </tr>
                    </thead>
                    <tbody>
                      {levelsForm.map((row, idx) => (
                        <tr key={row.level_number} style={{ borderTop: '1px solid var(--border)' }}>
                          <td style={{ padding: 8 }}>{row.level_number}</td>
                          <td style={{ padding: 8 }}>
                            <input
                              className="form-input"
                              value={row.name}
                              onChange={(e) => {
                                const next = [...levelsForm]
                                next[idx] = { ...row, name: e.target.value }
                                setLevelsForm(next)
                              }}
                            />
                          </td>
                          <td style={{ padding: 8 }}>
                            <input
                              className="form-input"
                              value={row.description}
                              onChange={(e) => {
                                const next = [...levelsForm]
                                next[idx] = { ...row, description: e.target.value }
                                setLevelsForm(next)
                              }}
                            />
                          </td>
                          <td style={{ padding: 8, width: 72 }}>
                            <input
                              className="form-input"
                              type="number"
                              value={row.sort_order}
                              onChange={(e) => {
                                const next = [...levelsForm]
                                next[idx] = { ...row, sort_order: e.target.value }
                                setLevelsForm(next)
                              }}
                            />
                          </td>
                        </tr>
                      ))}
                    </tbody>
                  </table>
                </div>
                <button
                  type="button"
                  className="btn btn-secondary"
                  style={{ marginTop: 12 }}
                  onClick={handleSaveLevels}
                  disabled={saving}
                >
                  Stufen speichern
                </button>
              </div>

              <div className="card" style={{ padding: 16, marginBottom: 16 }}>
                <h2 style={{ marginTop: 0, fontSize: '1.1rem' }}>Fähigkeiten im Modell</h2>
                <div style={{ display: 'flex', gap: 8, flexWrap: 'wrap', alignItems: 'flex-end' }}>
                  <div style={{ flex: '1 1 220px' }}>
                    <label className="form-label">Fähigkeit hinzufügen</label>
                    <select
                      className="form-input"
                      value={skillToAdd}
                      onChange={(e) => setSkillToAdd(e.target.value)}
                    >
                      <option value="">— wählen —</option>
                      {allSkills.map((s) => (
                        <option key={s.id} value={s.id}>{s.name}</option>
                      ))}
                    </select>
                  </div>
                  <button type="button" className="btn btn-primary" onClick={handleAddSkill} disabled={saving || !skillToAdd}>
                    Hinzufügen
                  </button>
                </div>
                <ul style={{ marginTop: 12, paddingLeft: 18 }}>
                  {(detail.model_skills || []).map((ms) => (
                    <li key={ms.skill_id} style={{ marginBottom: 6 }}>
                      <strong>{ms.skill_name}</strong>
                      {' '}
                      <button
                        type="button"
                        className="btn btn-secondary"
                        style={{ padding: '2px 8px', fontSize: 12 }}
                        onClick={() => handleRemoveSkill(ms.skill_id)}
                      >
                        entfernen
                      </button>
                    </li>
                  ))}
                </ul>
              </div>

              <div className="card" style={{ padding: 16 }}>
                <h2 style={{ marginTop: 0, fontSize: '1.1rem' }}>Matrix (Zielbild je Stufe)</h2>
                <p style={{ fontSize: 14, color: 'var(--text2)', marginTop: 0 }}>
                  Leere Zellen werden beim Speichern aus der Datenbank entfernt. Beobachtungskriterien optional in
                  zweiter Zeile (nach Speichern mit Beschreibung).
                </p>
                <div style={{ overflow: 'auto', maxHeight: '70vh' }}>
                  <table style={{ borderCollapse: 'collapse', fontSize: 13, minWidth: 600 }}>
                    <thead>
                      <tr>
                        <th style={{ padding: 8, border: '1px solid var(--border)', position: 'sticky', left: 0, background: 'var(--surface)' }}>
                          Fähigkeit
                        </th>
                        {(detail.levels || []).map((l) => (
                          <th
                            key={l.level_number}
                            style={{ padding: 8, border: '1px solid var(--border)', minWidth: 160, background: 'var(--surface2)' }}
                          >
                            {l.level_number}. {l.name}
                          </th>
                        ))}
                      </tr>
                    </thead>
                    <tbody>
                      {(detail.model_skills || []).map((ms) => (
                        <tr key={ms.skill_id}>
                          <td
                            style={{
                              padding: 8,
                              border: '1px solid var(--border)',
                              position: 'sticky',
                              left: 0,
                              background: 'var(--surface)',
                              fontWeight: 600,
                              whiteSpace: 'nowrap'
                            }}
                          >
                            {ms.skill_name}
                          </td>
                          {(detail.levels || []).map((l) => {
                            const key = `${ms.skill_id}-${l.level_number}`
                            const d = cellDraft[key] || { description: '', observable_criteria: '' }
                            return (
                              <td key={l.level_number} style={{ padding: 6, border: '1px solid var(--border)', verticalAlign: 'top' }}>
                                <textarea
                                  className="form-input"
                                  rows={3}
                                  placeholder="Zielbild / Erwartung"
                                  value={d.description}
                                  onChange={(e) => setCell(ms.skill_id, l.level_number, 'description', e.target.value)}
                                  style={{ fontSize: 12, width: '100%', minWidth: 140 }}
                                />
                                <textarea
                                  className="form-input"
                                  rows={2}
                                  placeholder="Beobachtungskriterien (optional)"
                                  value={d.observable_criteria}
                                  onChange={(e) => setCell(ms.skill_id, l.level_number, 'observable_criteria', e.target.value)}
                                  style={{ fontSize: 11, width: '100%', minWidth: 140, marginTop: 4 }}
                                />
                              </td>
                            )
                          })}
                        </tr>
                      ))}
                    </tbody>
                  </table>
                </div>
                <button
                  type="button"
                  className="btn btn-primary"
                  style={{ marginTop: 12 }}
                  onClick={handleSaveMatrix}
                  disabled={saving || !(detail.model_skills || []).length}
                >
                  Matrix speichern
                </button>
              </div>
            </>
          )}
        </div>
      </div>
    </div>
  )
}