'use client'

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

interface DocItem {
  id: string | null
  doc_type: string
  doc_type_label: string
  title: string
  content_md: string | null
  version: number
  requirements_coverage: Record<string, unknown>
  status: string
  signed_by: string | null
  signed_at: string | null
  generated_at: string | null
  superseded_at: string | null
}

interface DocListResponse {
  project_id: string
  total: number
  items: DocItem[]
}

const STATUS_STYLE: Record<string, string> = {
  draft: 'bg-yellow-100 text-yellow-800',
  reviewed: 'bg-blue-100 text-blue-800',
  approved: 'bg-green-100 text-green-800',
  superseded: 'bg-gray-200 text-gray-600',
  not_generated: 'bg-gray-100 text-gray-400',
}

const STATUS_LABEL: Record<string, string> = {
  draft: 'Entwurf',
  reviewed: 'Geprueft',
  approved: 'Freigegeben',
  superseded: 'Veraltet',
  not_generated: 'Nicht erzeugt',
}

export default function DocumentsPage({
  params,
}: {
  params: Promise<{ projectId: string }>
}) {
  const { projectId } = use(params)
  const [data, setData] = useState<DocListResponse | null>(null)
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState('')
  const [generating, setGenerating] = useState<string | null>(null)
  const [expanded, setExpanded] = useState<string | null>(null)
  const [docContent, setDocContent] = useState<Record<string, string>>({})

  // Generation params per doc type
  const [manufacturer, setManufacturer] = useState('')
  const [notifiedBody, setNotifiedBody] = useState('')
  const [securityContact, setSecurityContact] = useState('')

  // Approval form
  const [approving, setApproving] = useState<string | null>(null)
  const [signedBy, setSignedBy] = useState('')

  const tenant = '00000000-0000-0000-0000-000000000001'

  const load = useCallback(async () => {
    try {
      const res = await fetch(`/api/sdk/v1/cra/projects/${projectId}/documents`, {
        headers: { 'X-Tenant-ID': tenant },
      })
      if (!res.ok) throw new Error(await res.text())
      setData(await res.json())
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Fehler beim Laden')
    } finally {
      setLoading(false)
    }
  }, [projectId])

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

  const generate = async (docType: string) => {
    setGenerating(docType)
    setError('')
    try {
      const body: Record<string, string> = { doc_type: docType }
      if (docType === 'doc_eu_conformity') {
        if (manufacturer) body.manufacturer = manufacturer
        if (notifiedBody) body.notified_body = notifiedBody
      }
      if (docType === 'doc_cvd_policy' && securityContact) {
        body.security_contact = securityContact
      }
      const res = await fetch(`/api/sdk/v1/cra/projects/${projectId}/documents/generate`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json', 'X-Tenant-ID': tenant },
        body: JSON.stringify(body),
      })
      if (!res.ok) throw new Error(await res.text())
      const doc = await res.json()
      setDocContent(prev => ({ ...prev, [doc.id]: doc.content_md }))
      await load()
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Generierung fehlgeschlagen')
    } finally {
      setGenerating(null)
    }
  }

  const loadContent = async (docId: string) => {
    if (docContent[docId]) {
      setExpanded(expanded === docId ? null : docId)
      return
    }
    try {
      const res = await fetch(`/api/sdk/v1/cra/documents/${docId}`, {
        headers: { 'X-Tenant-ID': tenant },
      })
      if (!res.ok) throw new Error(await res.text())
      const doc = await res.json()
      setDocContent(prev => ({ ...prev, [docId]: doc.content_md }))
      setExpanded(docId)
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Laden fehlgeschlagen')
    }
  }

  const approve = async (docId: string, status: string) => {
    if (!signedBy.trim()) {
      setError('Bitte Namen zur Freigabe eintragen.')
      return
    }
    setApproving(docId)
    setError('')
    try {
      const res = await fetch(`/api/sdk/v1/cra/documents/${docId}/approve`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json', 'X-Tenant-ID': tenant },
        body: JSON.stringify({ signed_by: signedBy, status }),
      })
      if (!res.ok) throw new Error(await res.text())
      await load()
    } catch (e) {
      setError(e instanceof Error ? e.message : 'Freigabe fehlgeschlagen')
    } finally {
      setApproving(null)
    }
  }

  const download = (doc: DocItem) => {
    const content = docContent[doc.id || ''] || doc.content_md || ''
    if (!content) return
    const blob = new Blob([content], { type: 'text/markdown;charset=utf-8' })
    const url = URL.createObjectURL(blob)
    const a = document.createElement('a')
    a.href = url
    a.download = `${doc.doc_type}_v${doc.version}_${doc.id?.slice(0, 8)}.md`
    a.click()
    URL.revokeObjectURL(url)
  }

  if (loading) return <div className="min-h-screen bg-gray-50 p-8"><p className="text-gray-500">Laedt...</p></div>

  return (
    <div className="min-h-screen bg-gray-50 py-8">
      <div className="max-w-5xl mx-auto px-4">
        <div className="mb-6">
          <a href={`/sdk/cra/${projectId}`} className="text-sm text-blue-600 hover:underline">
            &larr; Zurueck zum Projekt
          </a>
          <h1 className="text-2xl font-bold text-gray-900 mt-2">CRA-Dokumente</h1>
          <p className="text-sm text-gray-600 mt-1">
            DoC (Annex VII), Technische Doku (Annex V), CVD-Policy, Update-Policy, SBOM-Bericht — generiert aus aktuellem Projektstand.
          </p>
        </div>

        {error && (
          <div className="mb-4 bg-red-50 border border-red-200 rounded-lg p-3 text-sm text-red-700">
            <pre className="whitespace-pre-wrap">{error}</pre>
            <button onClick={() => setError('')} className="text-xs underline mt-1">Schliessen</button>
          </div>
        )}

        {/* Generation params */}
        <details className="bg-white rounded-xl border border-gray-200 p-4 mb-4">
          <summary className="cursor-pointer text-sm font-medium text-gray-700">
            Optionale Parameter fuer Generierung (Hersteller, NoBo, Security-Contact)
          </summary>
          <div className="mt-3 space-y-3">
            <div>
              <label className="block text-xs text-gray-600 mb-1">Hersteller (fuer DoC)</label>
              <input value={manufacturer} onChange={e => setManufacturer(e.target.value)} placeholder="Acme GmbH, Musterstr. 1, 80331 Muenchen" className="w-full px-3 py-2 border rounded text-sm" />
            </div>
            <div>
              <label className="block text-xs text-gray-600 mb-1">Notified Body (falls Modul C)</label>
              <input value={notifiedBody} onChange={e => setNotifiedBody(e.target.value)} placeholder="TUEV Nord (NB-0044)" className="w-full px-3 py-2 border rounded text-sm" />
            </div>
            <div>
              <label className="block text-xs text-gray-600 mb-1">Security-Contact (fuer CVD-Policy)</label>
              <input type="email" value={securityContact} onChange={e => setSecurityContact(e.target.value)} placeholder="security@example.com" className="w-full px-3 py-2 border rounded text-sm" />
            </div>
          </div>
        </details>

        <div className="space-y-3">
          {data?.items.map(doc => (
            <div key={doc.doc_type} className="bg-white rounded-xl shadow-sm border border-gray-200 p-5">
              <div className="flex items-start justify-between gap-4 mb-3">
                <div className="flex-1 min-w-0">
                  <div className="flex items-center gap-2 flex-wrap">
                    <h3 className="font-semibold text-gray-900">{doc.doc_type_label}</h3>
                    {doc.version > 0 && (
                      <span className="text-xs text-gray-500">v{doc.version}</span>
                    )}
                    <span className={`px-2 py-0.5 text-xs rounded ${STATUS_STYLE[doc.status]}`}>
                      {STATUS_LABEL[doc.status]}
                    </span>
                  </div>
                  {doc.generated_at && (
                    <p className="text-xs text-gray-500 mt-1">
                      Generiert: {new Date(doc.generated_at).toLocaleString('de-DE')}
                      {doc.signed_by && doc.signed_at && (
                        <> · Freigegeben von <span className="font-medium">{doc.signed_by}</span> am {new Date(doc.signed_at).toLocaleString('de-DE')}</>
                      )}
                    </p>
                  )}
                  {doc.requirements_coverage && Object.keys(doc.requirements_coverage).length > 0 && (
                    <p className="text-xs text-gray-500 mt-1">
                      Coverage: {String(doc.requirements_coverage.fields_filled || 0)} / {String(doc.requirements_coverage.fields_required || 0)} Pflichtfelder · {String(doc.requirements_coverage.annex_anchor || '')}
                    </p>
                  )}
                </div>
                <div className="flex gap-2 flex-shrink-0">
                  <button
                    onClick={() => generate(doc.doc_type)}
                    disabled={generating === doc.doc_type}
                    className="px-3 py-1.5 bg-red-600 text-white text-sm rounded hover:bg-red-700 disabled:bg-gray-300"
                  >
                    {generating === doc.doc_type ? 'Generiere...' : (doc.version === 0 ? 'Generieren' : 'Neu generieren')}
                  </button>
                  {doc.id && (
                    <button
                      onClick={() => loadContent(doc.id!)}
                      className="px-3 py-1.5 bg-gray-100 text-gray-700 text-sm rounded hover:bg-gray-200"
                    >
                      {expanded === doc.id ? 'Einklappen' : 'Inhalt'}
                    </button>
                  )}
                </div>
              </div>

              {expanded === doc.id && doc.id && docContent[doc.id] && (
                <div className="mt-3 border-t border-gray-200 pt-3">
                  <div className="flex items-center justify-between mb-2">
                    <p className="text-xs text-gray-500 font-mono">Markdown-Vorschau</p>
                    <button
                      onClick={() => download(doc)}
                      className="text-xs px-2 py-1 bg-blue-100 text-blue-700 rounded hover:bg-blue-200"
                    >
                      ⬇ Download (.md)
                    </button>
                  </div>
                  <pre className="bg-gray-50 rounded p-3 text-xs overflow-x-auto max-h-96 whitespace-pre-wrap font-mono">
                    {docContent[doc.id]}
                  </pre>

                  {doc.status === 'draft' && (
                    <div className="mt-3 p-3 bg-yellow-50 border border-yellow-200 rounded">
                      <p className="text-xs text-yellow-800 mb-2">
                        Vor Freigabe pruefen ob alle <code>[zu ergaenzen]</code>-Stellen gefuellt sind.
                      </p>
                      <div className="flex items-center gap-2">
                        <input
                          type="text"
                          value={signedBy}
                          onChange={e => setSignedBy(e.target.value)}
                          placeholder="Name + Rolle des Freigebenden"
                          className="flex-1 px-2 py-1 border rounded text-sm"
                        />
                        <button
                          onClick={() => approve(doc.id!, 'reviewed')}
                          disabled={approving === doc.id || !signedBy.trim()}
                          className="px-3 py-1 bg-blue-600 text-white text-xs rounded hover:bg-blue-700 disabled:bg-gray-300"
                        >
                          Als geprueft markieren
                        </button>
                        <button
                          onClick={() => approve(doc.id!, 'approved')}
                          disabled={approving === doc.id || !signedBy.trim()}
                          className="px-3 py-1 bg-green-600 text-white text-xs rounded hover:bg-green-700 disabled:bg-gray-300"
                        >
                          Freigeben
                        </button>
                      </div>
                    </div>
                  )}
                </div>
              )}
            </div>
          ))}
        </div>

        <div className="mt-6 bg-blue-50 border border-blue-200 rounded-xl p-4 text-sm text-blue-900">
          <strong>Hinweis:</strong> Diese Dokumente sind <em>Skelette</em> aus dem aktuellen Projektstand. Markdown-Format, manuelles Editieren + Unterzeichnung erforderlich vor Inverkehrbringen. PDF-Export folgt in Phase 5.5.
        </div>
      </div>
    </div>
  )
}