'use client'

import React, { useState, useCallback, useEffect } from 'react'
import { useRouter } from 'next/navigation'
import { useSDK } from '@/lib/sdk'
import { StepHeader, STEP_EXPLANATIONS } from '@/components/sdk/StepHeader'
import { DocumentUploadSection, type UploadedDocument } from '@/components/sdk'

// =============================================================================
// TYPES
// =============================================================================

interface DSFA {
  id: string
  title: string
  description: string
  status: 'draft' | 'in-review' | 'approved' | 'needs-update'
  createdAt: string
  updatedAt: string
  approvedBy: string | null
  riskLevel: 'low' | 'medium' | 'high' | 'critical'
  processingActivity: string
  dataCategories: string[]
  recipients: string[]
  measures: string[]
}

// =============================================================================
// COMPONENTS
// =============================================================================

function DSFACard({
  dsfa,
  onStatusChange,
  onDelete,
}: {
  dsfa: DSFA
  onStatusChange: (id: string, status: string) => void
  onDelete: (id: string) => void
}) {
  const statusColors = {
    draft: 'bg-gray-100 text-gray-600 border-gray-200',
    'in-review': 'bg-yellow-100 text-yellow-700 border-yellow-200',
    approved: 'bg-green-100 text-green-700 border-green-200',
    'needs-update': 'bg-orange-100 text-orange-700 border-orange-200',
  }

  const statusLabels = {
    draft: 'Entwurf',
    'in-review': 'In Pruefung',
    approved: 'Genehmigt',
    'needs-update': 'Aktualisierung erforderlich',
  }

  const riskColors = {
    low: 'bg-green-100 text-green-700',
    medium: 'bg-yellow-100 text-yellow-700',
    high: 'bg-orange-100 text-orange-700',
    critical: 'bg-red-100 text-red-700',
  }

  const createdDate = dsfa.createdAt
    ? new Date(dsfa.createdAt).toLocaleDateString('de-DE')
    : '—'

  return (
    <div className={`bg-white rounded-xl border-2 p-6 ${
      dsfa.status === 'needs-update' ? 'border-orange-200' :
      dsfa.status === 'approved' ? 'border-green-200' : 'border-gray-200'
    }`}>
      <div className="flex items-start justify-between">
        <div className="flex-1">
          <div className="flex items-center gap-2 mb-2">
            <span className={`px-2 py-1 text-xs rounded-full ${statusColors[dsfa.status]}`}>
              {statusLabels[dsfa.status]}
            </span>
            <span className={`px-2 py-1 text-xs rounded-full ${riskColors[dsfa.riskLevel]}`}>
              Risiko: {dsfa.riskLevel === 'low' ? 'Niedrig' :
                       dsfa.riskLevel === 'medium' ? 'Mittel' :
                       dsfa.riskLevel === 'high' ? 'Hoch' : 'Kritisch'}
            </span>
          </div>
          <h3 className="text-lg font-semibold text-gray-900">{dsfa.title}</h3>
          <p className="text-sm text-gray-500 mt-1">{dsfa.description}</p>
        </div>
      </div>

      <div className="mt-4 text-sm text-gray-600">
        <p><span className="text-gray-500">Verarbeitungstaetigkeit:</span> {dsfa.processingActivity}</p>
      </div>

      <div className="mt-3 flex flex-wrap gap-1">
        {dsfa.dataCategories.map(cat => (
          <span key={cat} className="px-2 py-0.5 text-xs bg-blue-50 text-blue-600 rounded">
            {cat}
          </span>
        ))}
      </div>

      {dsfa.measures.length > 0 && (
        <div className="mt-3">
          <span className="text-sm text-gray-500">Massnahmen:</span>
          <div className="flex flex-wrap gap-1 mt-1">
            {dsfa.measures.map(m => (
              <span key={m} className="px-2 py-0.5 text-xs bg-green-50 text-green-600 rounded">
                {m}
              </span>
            ))}
          </div>
        </div>
      )}

      <div className="mt-4 pt-4 border-t border-gray-100 flex items-center justify-between text-sm">
        <div className="text-gray-500">
          <span>Erstellt: {createdDate}</span>
          {dsfa.approvedBy && (
            <span className="ml-4">Genehmigt von: {dsfa.approvedBy}</span>
          )}
        </div>
        <div className="flex items-center gap-2">
          {dsfa.status === 'draft' && (
            <button
              onClick={() => onStatusChange(dsfa.id, 'in-review')}
              className="px-3 py-1 text-yellow-600 hover:bg-yellow-50 rounded-lg transition-colors text-xs"
            >
              Zur Pruefung
            </button>
          )}
          {dsfa.status === 'in-review' && (
            <button
              onClick={() => onStatusChange(dsfa.id, 'approved')}
              className="px-3 py-1 text-green-600 hover:bg-green-50 rounded-lg transition-colors text-xs"
            >
              Genehmigen
            </button>
          )}
          <button
            onClick={() => onDelete(dsfa.id)}
            className="px-3 py-1 text-red-500 hover:bg-red-50 rounded-lg transition-colors text-xs"
          >
            Loeschen
          </button>
        </div>
      </div>
    </div>
  )
}

function GeneratorWizard({ onClose, onSubmit }: { onClose: () => void; onSubmit: (data: Partial<DSFA>) => Promise<void> }) {
  const [step, setStep] = useState(1)
  const [saving, setSaving] = useState(false)
  const [title, setTitle] = useState('')
  const [description, setDescription] = useState('')
  const [processingActivity, setProcessingActivity] = useState('')
  const [selectedCategories, setSelectedCategories] = useState<string[]>([])
  const [riskLevel, setRiskLevel] = useState<'low' | 'medium' | 'high' | 'critical'>('low')
  const [selectedMeasures, setSelectedMeasures] = useState<string[]>([])

  const riskMap: Record<string, 'low' | 'medium' | 'high' | 'critical'> = {
    Niedrig: 'low', Mittel: 'medium', Hoch: 'high', Kritisch: 'critical',
  }

  const handleSubmit = async () => {
    setSaving(true)
    try {
      await onSubmit({
        title,
        description,
        processingActivity,
        dataCategories: selectedCategories,
        riskLevel,
        measures: selectedMeasures,
        status: 'draft',
      })
      onClose()
    } finally {
      setSaving(false)
    }
  }

  return (
    <div className="bg-white rounded-xl border border-gray-200 p-6">
      <div className="flex items-center justify-between mb-6">
        <h3 className="text-lg font-semibold text-gray-900">Neue DSFA erstellen</h3>
        <button onClick={onClose} className="text-gray-400 hover:text-gray-600">
          <svg className="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M6 18L18 6M6 6l12 12" />
          </svg>
        </button>
      </div>

      {/* Progress Steps */}
      <div className="flex items-center gap-2 mb-6">
        {[1, 2, 3, 4].map(s => (
          <React.Fragment key={s}>
            <div className={`w-8 h-8 rounded-full flex items-center justify-center text-sm font-medium ${
              s < step ? 'bg-green-500 text-white' :
              s === step ? 'bg-purple-600 text-white' : 'bg-gray-200 text-gray-500'
            }`}>
              {s < step ? (
                <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                  <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M5 13l4 4L19 7" />
                </svg>
              ) : s}
            </div>
            {s < 4 && <div className={`flex-1 h-1 ${s < step ? 'bg-green-500' : 'bg-gray-200'}`} />}
          </React.Fragment>
        ))}
      </div>

      {/* Step Content */}
      <div className="min-h-48">
        {step === 1 && (
          <div className="space-y-4">
            <div>
              <label className="block text-sm font-medium text-gray-700 mb-1">Titel der DSFA</label>
              <input
                type="text"
                value={title}
                onChange={e => setTitle(e.target.value)}
                placeholder="z.B. DSFA - Mitarbeiter-Monitoring"
                className="w-full px-4 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-purple-500"
              />
            </div>
            <div>
              <label className="block text-sm font-medium text-gray-700 mb-1">Beschreibung der Verarbeitung</label>
              <textarea
                rows={3}
                value={description}
                onChange={e => setDescription(e.target.value)}
                placeholder="Beschreiben Sie die geplante Datenverarbeitung..."
                className="w-full px-4 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-purple-500"
              />
            </div>
            <div>
              <label className="block text-sm font-medium text-gray-700 mb-1">Verarbeitungstaetigkeit</label>
              <input
                type="text"
                value={processingActivity}
                onChange={e => setProcessingActivity(e.target.value)}
                placeholder="z.B. Automatisierte Auswertung von Kundendaten"
                className="w-full px-4 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-purple-500"
              />
            </div>
          </div>
        )}
        {step === 2 && (
          <div className="space-y-4">
            <div>
              <label className="block text-sm font-medium text-gray-700 mb-2">Datenkategorien</label>
              <div className="grid grid-cols-2 gap-2">
                {['Kontaktdaten', 'Identifikationsdaten', 'Finanzdaten', 'Gesundheitsdaten', 'Standortdaten', 'Nutzungsdaten'].map(cat => (
                  <label key={cat} className="flex items-center gap-2 p-2 border rounded-lg hover:bg-gray-50">
                    <input
                      type="checkbox"
                      className="w-4 h-4 text-purple-600"
                      checked={selectedCategories.includes(cat)}
                      onChange={e => setSelectedCategories(prev =>
                        e.target.checked ? [...prev, cat] : prev.filter(c => c !== cat)
                      )}
                    />
                    <span className="text-sm">{cat}</span>
                  </label>
                ))}
              </div>
            </div>
          </div>
        )}
        {step === 3 && (
          <div className="space-y-4">
            <div>
              <label className="block text-sm font-medium text-gray-700 mb-2">Risikobewertung</label>
              <p className="text-sm text-gray-500 mb-4">Bewerten Sie die Risiken fuer die Rechte und Freiheiten der Betroffenen.</p>
              <div className="space-y-2">
                {(['Niedrig', 'Mittel', 'Hoch', 'Kritisch'] as const).map(level => (
                  <label key={level} className="flex items-center gap-3 p-3 border rounded-lg hover:bg-gray-50 cursor-pointer">
                    <input
                      type="radio"
                      name="risk"
                      className="w-4 h-4 text-purple-600"
                      checked={riskLevel === riskMap[level]}
                      onChange={() => setRiskLevel(riskMap[level])}
                    />
                    <span className="text-sm font-medium">{level}</span>
                  </label>
                ))}
              </div>
            </div>
          </div>
        )}
        {step === 4 && (
          <div className="space-y-4">
            <div>
              <label className="block text-sm font-medium text-gray-700 mb-2">Schutzmassnahmen</label>
              <div className="grid grid-cols-2 gap-2">
                {['Verschluesselung', 'Pseudonymisierung', 'Zugriffskontrolle', 'Loeschkonzept', 'Schulungen', 'Menschliche Pruefung'].map(m => (
                  <label key={m} className="flex items-center gap-2 p-2 border rounded-lg hover:bg-gray-50">
                    <input
                      type="checkbox"
                      className="w-4 h-4 text-purple-600"
                      checked={selectedMeasures.includes(m)}
                      onChange={e => setSelectedMeasures(prev =>
                        e.target.checked ? [...prev, m] : prev.filter(x => x !== m)
                      )}
                    />
                    <span className="text-sm">{m}</span>
                  </label>
                ))}
              </div>
            </div>
          </div>
        )}
      </div>

      {/* Navigation */}
      <div className="flex items-center justify-between mt-6 pt-4 border-t border-gray-200">
        <button
          onClick={() => step > 1 ? setStep(step - 1) : onClose()}
          className="px-4 py-2 text-gray-600 hover:bg-gray-100 rounded-lg transition-colors"
          disabled={saving}
        >
          {step === 1 ? 'Abbrechen' : 'Zurueck'}
        </button>
        <button
          onClick={() => step < 4 ? setStep(step + 1) : handleSubmit()}
          disabled={saving || (step === 1 && !title.trim())}
          className="px-6 py-2 bg-purple-600 text-white rounded-lg hover:bg-purple-700 transition-colors disabled:opacity-50"
        >
          {step === 4 ? (saving ? 'Wird erstellt...' : 'DSFA erstellen') : 'Weiter'}
        </button>
      </div>
    </div>
  )
}

// =============================================================================
// MAIN PAGE
// =============================================================================

export default function DSFAPage() {
  const router = useRouter()
  const { state } = useSDK()
  const [dsfas, setDsfas] = useState<DSFA[]>([])
  const [isLoading, setIsLoading] = useState(true)
  const [error, setError] = useState<string | null>(null)
  const [showGenerator, setShowGenerator] = useState(false)
  const [filter, setFilter] = useState<string>('all')

  const loadDSFAs = useCallback(async () => {
    setIsLoading(true)
    setError(null)
    try {
      const res = await fetch('/api/sdk/v1/dsfa?tenant_id=default')
      if (!res.ok) throw new Error(`Fehler: ${res.status}`)
      const data = await res.json()
      const mapped: DSFA[] = (Array.isArray(data) ? data : []).map((d: Record<string, unknown>) => ({
        id: d.id as string,
        title: d.title as string,
        description: (d.description as string) || '',
        status: (d.status as DSFA['status']) || 'draft',
        createdAt: d.created_at as string,
        updatedAt: d.updated_at as string,
        approvedBy: (d.approved_by as string) || null,
        riskLevel: (d.risk_level as DSFA['riskLevel']) || 'low',
        processingActivity: (d.processing_activity as string) || '',
        dataCategories: (d.data_categories as string[]) || [],
        recipients: (d.recipients as string[]) || [],
        measures: (d.measures as string[]) || [],
      }))
      setDsfas(mapped)
    } catch (err) {
      setError(err instanceof Error ? err.message : 'Unbekannter Fehler')
    } finally {
      setIsLoading(false)
    }
  }, [])

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

  const handleCreateDSFA = useCallback(async (data: Partial<DSFA>) => {
    const res = await fetch('/api/sdk/v1/dsfa?tenant_id=default', {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({
        title: data.title,
        description: data.description || '',
        processing_activity: data.processingActivity || '',
        data_categories: data.dataCategories || [],
        recipients: data.recipients || [],
        measures: data.measures || [],
        risk_level: data.riskLevel || 'low',
        status: data.status || 'draft',
      }),
    })
    if (!res.ok) throw new Error(`Fehler beim Erstellen: ${res.status}`)
    await loadDSFAs()
  }, [loadDSFAs])

  const handleStatusChange = useCallback(async (id: string, status: string) => {
    const res = await fetch(`/api/sdk/v1/dsfa/${id}/status?tenant_id=default`, {
      method: 'PATCH',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ status }),
    })
    if (!res.ok) throw new Error(`Statuswechsel fehlgeschlagen: ${res.status}`)
    await loadDSFAs()
  }, [loadDSFAs])

  const handleDeleteDSFA = useCallback(async (id: string) => {
    if (!confirm('DSFA wirklich loeschen?')) return
    const res = await fetch(`/api/sdk/v1/dsfa/${id}?tenant_id=default`, { method: 'DELETE' })
    if (!res.ok) throw new Error(`Loeschen fehlgeschlagen: ${res.status}`)
    await loadDSFAs()
  }, [loadDSFAs])

  // Handle uploaded document
  const handleDocumentProcessed = useCallback((doc: UploadedDocument) => {
    console.log('[DSFA Page] Document processed:', doc)
  }, [])

  // Open document in workflow editor
  const handleOpenInEditor = useCallback((doc: UploadedDocument) => {
    router.push(`/sdk/workflow?documentType=dsfa&documentId=${doc.id}&mode=change`)
  }, [router])

  const filteredDSFAs = filter === 'all'
    ? dsfas
    : dsfas.filter(d => d.status === filter)

  const draftCount = dsfas.filter(d => d.status === 'draft').length
  const inReviewCount = dsfas.filter(d => d.status === 'in-review').length
  const approvedCount = dsfas.filter(d => d.status === 'approved').length

  const stepInfo = STEP_EXPLANATIONS['dsfa']

  return (
    <div className="space-y-6">
      {/* Step Header */}
      <StepHeader
        stepId="dsfa"
        title={stepInfo.title}
        description={stepInfo.description}
        explanation={stepInfo.explanation}
        tips={stepInfo.tips}
      >
        {!showGenerator && (
          <button
            onClick={() => setShowGenerator(true)}
            className="flex items-center gap-2 px-4 py-2 bg-purple-600 text-white rounded-lg hover:bg-purple-700 transition-colors"
          >
            <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 6v6m0 0v6m0-6h6m-6 0H6" />
            </svg>
            Neue DSFA
          </button>
        )}
      </StepHeader>

      {/* Generator */}
      {showGenerator && (
        <GeneratorWizard
          onClose={() => setShowGenerator(false)}
          onSubmit={handleCreateDSFA}
        />
      )}

      {/* Document Upload Section */}
      <DocumentUploadSection
        documentType="dsfa"
        onDocumentProcessed={handleDocumentProcessed}
        onOpenInEditor={handleOpenInEditor}
      />

      {/* Stats */}
      <div className="grid grid-cols-1 md:grid-cols-4 gap-4">
        <div className="bg-white rounded-xl border border-gray-200 p-6">
          <div className="text-sm text-gray-500">Gesamt</div>
          <div className="text-3xl font-bold text-gray-900">{dsfas.length}</div>
        </div>
        <div className="bg-white rounded-xl border border-gray-200 p-6">
          <div className="text-sm text-gray-500">Entwuerfe</div>
          <div className="text-3xl font-bold text-gray-500">{draftCount}</div>
        </div>
        <div className="bg-white rounded-xl border border-yellow-200 p-6">
          <div className="text-sm text-yellow-600">In Pruefung</div>
          <div className="text-3xl font-bold text-yellow-600">{inReviewCount}</div>
        </div>
        <div className="bg-white rounded-xl border border-green-200 p-6">
          <div className="text-sm text-green-600">Genehmigt</div>
          <div className="text-3xl font-bold text-green-600">{approvedCount}</div>
        </div>
      </div>

      {/* Error */}
      {error && (
        <div className="bg-red-50 border border-red-200 rounded-xl p-4 text-red-700 text-sm">
          Fehler beim Laden: {error}
          <button onClick={loadDSFAs} className="ml-4 underline">Erneut versuchen</button>
        </div>
      )}

      {/* Filter */}
      <div className="flex items-center gap-2">
        <span className="text-sm text-gray-500">Filter:</span>
        {['all', 'draft', 'in-review', 'approved', 'needs-update'].map(f => (
          <button
            key={f}
            onClick={() => setFilter(f)}
            className={`px-3 py-1 text-sm rounded-full transition-colors ${
              filter === f
                ? 'bg-purple-600 text-white'
                : 'bg-gray-100 text-gray-600 hover:bg-gray-200'
            }`}
          >
            {f === 'all' ? 'Alle' :
             f === 'draft' ? 'Entwuerfe' :
             f === 'in-review' ? 'In Pruefung' :
             f === 'approved' ? 'Genehmigt' : 'Update erforderlich'}
          </button>
        ))}
      </div>

      {/* Loading */}
      {isLoading && (
        <div className="text-center py-12 text-gray-500">Lade DSFAs...</div>
      )}

      {/* DSFA List */}
      {!isLoading && (
        <div className="space-y-4">
          {filteredDSFAs.map(dsfa => (
            <DSFACard
              key={dsfa.id}
              dsfa={dsfa}
              onStatusChange={handleStatusChange}
              onDelete={handleDeleteDSFA}
            />
          ))}
        </div>
      )}

      {!isLoading && filteredDSFAs.length === 0 && !showGenerator && (
        <div className="bg-white rounded-xl border border-gray-200 p-12 text-center">
          <div className="w-16 h-16 mx-auto bg-purple-100 rounded-full flex items-center justify-center mb-4">
            <svg className="w-8 h-8 text-purple-600" fill="none" stroke="currentColor" viewBox="0 0 24 24">
              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9 12h6m-6 4h6m2 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" />
            </svg>
          </div>
          <h3 className="text-lg font-semibold text-gray-900">Keine DSFAs gefunden</h3>
          <p className="mt-2 text-gray-500">Erstellen Sie eine neue Datenschutz-Folgenabschaetzung.</p>
          <button
            onClick={() => setShowGenerator(true)}
            className="mt-4 px-6 py-2 bg-purple-600 text-white rounded-lg hover:bg-purple-700 transition-colors"
          >
            Erste DSFA erstellen
          </button>
        </div>
      )}
    </div>
  )
}