'use client'

import { useState, useEffect, useCallback } from 'react'
import {
  CATEGORY_VENDORS, countNonEWRVendors, isEWR, isOutsideEWR,
} from '@/components/sdk/cookie-banner-vendors'

/**
 * Cookie Banner Live-Vorschau — simulates a real website with the banner.
 *
 * Purpose: Test the full consent flow end-to-end:
 * 1. Visitor lands on simulated website → banner appears
 * 2. Visitor makes consent choice (accept/reject/custom + EWR toggle)
 * 3. Consent is recorded via Banner API (POST /banner/consent)
 * 4. Admin can verify in /sdk/consent-management and /sdk/einwilligungen
 *
 * This page runs OUTSIDE the SDK layout to simulate a real website experience.
 */

const API_BASE = typeof window !== 'undefined'
  ? (process.env.NEXT_PUBLIC_SDK_URL || `${window.location.protocol}//${window.location.hostname}:8093`)
  : ''
const SITE_ID = 'preview-test-site'
const TENANT_ID = '9282a473-5c95-4b3a-bf78-0ecc0ec71d3e'

interface ConsentRecord {
  id: string
  categories: string[]
  ewrOnly: boolean
  blockedVendors: string[]
  timestamp: string
  device_fingerprint: string
}

function generateFingerprint(): string {
  const nav = typeof navigator !== 'undefined' ? navigator : null
  const seed = [
    nav?.userAgent || '',
    nav?.language || '',
    screen?.width || 0,
    screen?.height || 0,
    new Date().getTimezoneOffset(),
  ].join('|')
  let hash = 0
  for (let i = 0; i < seed.length; i++) {
    hash = ((hash << 5) - hash + seed.charCodeAt(i)) | 0
  }
  return `fp-${Math.abs(hash).toString(36)}-${Date.now().toString(36)}`
}

export default function CookieBannerPreviewPage() {
  const [consent, setConsent] = useState<ConsentRecord | null>(null)
  const [showBanner, setShowBanner] = useState(true)
  const [ewrOnly, setEwrOnly] = useState(false)
  const [categories, setCategories] = useState({ necessary: true, statistics: false, marketing: false, functional: false })
  const [saving, setSaving] = useState(false)
  const [apiResult, setApiResult] = useState<any>(null)
  const [fingerprint] = useState(() => generateFingerprint())

  // Check for existing consent on this simulated site
  useEffect(() => {
    async function check() {
      try {
        const res = await fetch(
          `${API_BASE}/banner/consent?site_id=${SITE_ID}&device_fingerprint=${fingerprint}`,
          { headers: { 'X-Tenant-ID': TENANT_ID } },
        )
        if (res.ok) {
          const data = await res.json()
          if (data.has_consent) {
            setConsent(data.consent)
            setShowBanner(false)
          }
        }
      } catch { /* first visit */ }
    }
    check()
  }, [fingerprint])

  const saveConsent = useCallback(async (cats: typeof categories) => {
    setSaving(true)
    const blocked: string[] = []
    if (ewrOnly) {
      for (const [key, cat] of Object.entries(CATEGORY_VENDORS)) {
        if (!cats[key as keyof typeof cats]) continue
        for (const v of cat.vendors) {
          if (isOutsideEWR(v.country)) blocked.push(v.name)
        }
      }
    }
    try {
      const res = await fetch(`${API_BASE}/banner/consent`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json', 'X-Tenant-ID': TENANT_ID },
        body: JSON.stringify({
          site_id: SITE_ID,
          device_fingerprint: fingerprint,
          categories: Object.entries(cats).filter(([, v]) => v).map(([k]) => k),
          vendors: [],
          consent_string: JSON.stringify({ ewrOnly, blockedVendors: blocked }),
          user_agent: navigator.userAgent,
        }),
      })
      const data = await res.json()
      setApiResult(data)
      setConsent({ ...data, ewrOnly, blockedVendors: blocked, timestamp: new Date().toISOString() })
      setShowBanner(false)
    } catch (err: any) {
      setApiResult({ error: err.message })
    }
    setSaving(false)
  }, [ewrOnly, fingerprint])

  const nonEWRCount = countNonEWRVendors()

  return (
    <div className="min-h-screen bg-white">
      {/* Simulated Website Header */}
      <header className="bg-slate-800 text-white px-8 py-4">
        <div className="max-w-6xl mx-auto flex items-center justify-between">
          <div className="flex items-center gap-3">
            <div className="w-8 h-8 bg-blue-500 rounded-lg" />
            <span className="font-semibold text-lg">MusterShop GmbH</span>
          </div>
          <nav className="flex items-center gap-6 text-sm text-slate-300">
            <span className="hover:text-white cursor-pointer">Produkte</span>
            <span className="hover:text-white cursor-pointer">Ueber uns</span>
            <span className="hover:text-white cursor-pointer">Kontakt</span>
            <span className="px-3 py-1.5 bg-blue-600 text-white rounded-lg text-sm">Warenkorb (2)</span>
          </nav>
        </div>
      </header>

      {/* Simulated Website Content */}
      <main className="max-w-6xl mx-auto px-8 py-12">
        <div className="grid grid-cols-3 gap-8">
          <div className="col-span-2 space-y-6">
            <h1 className="text-3xl font-bold text-gray-900">Willkommen bei MusterShop</h1>
            <p className="text-gray-600 leading-relaxed">
              Dies ist eine simulierte Website um den Cookie-Banner zu testen.
              Die Consent-Daten werden ueber die echte Banner-API gespeichert und
              erscheinen in Ihrem CMP unter Consent-Records und Consent-Verwaltung.
            </p>
            <div className="grid grid-cols-2 gap-4">
              {['Premium Paket', 'Standard Paket', 'Starter Paket', 'Enterprise'].map(p => (
                <div key={p} className="bg-gray-50 border border-gray-200 rounded-xl p-6">
                  <div className="w-full h-24 bg-gray-200 rounded-lg mb-3" />
                  <h3 className="font-semibold text-gray-900">{p}</h3>
                  <p className="text-sm text-gray-500 mt-1">Lorem ipsum dolor sit amet</p>
                </div>
              ))}
            </div>
          </div>

          {/* API Debug Panel */}
          <div className="space-y-4">
            <div className="bg-slate-50 border border-slate-200 rounded-xl p-4">
              <h3 className="font-semibold text-slate-800 text-sm flex items-center gap-2">
                <svg className="w-4 h-4 text-purple-600" fill="none" stroke="currentColor" viewBox="0 0 24 24">
                  <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M10 20l4-16m4 4l4 4-4 4M6 16l-4-4 4-4" />
                </svg>
                API Debug
              </h3>
              <div className="mt-3 space-y-2 text-xs">
                <div className="flex justify-between">
                  <span className="text-slate-500">Site ID</span>
                  <code className="text-slate-700">{SITE_ID}</code>
                </div>
                <div className="flex justify-between">
                  <span className="text-slate-500">Fingerprint</span>
                  <code className="text-slate-700 truncate ml-2">{fingerprint}</code>
                </div>
                <div className="flex justify-between">
                  <span className="text-slate-500">Consent</span>
                  <span className={consent ? 'text-green-600 font-medium' : 'text-amber-600'}>
                    {consent ? 'Gespeichert' : 'Ausstehend'}
                  </span>
                </div>
                {consent && (
                  <>
                    <div className="flex justify-between">
                      <span className="text-slate-500">Kategorien</span>
                      <span className="text-slate-700">{consent.categories?.join(', ')}</span>
                    </div>
                    <div className="flex justify-between">
                      <span className="text-slate-500">EWR-Only</span>
                      <span className={consent.ewrOnly ? 'text-blue-600' : 'text-slate-400'}>
                        {consent.ewrOnly ? 'Ja' : 'Nein'}
                      </span>
                    </div>
                    {consent.blockedVendors?.length > 0 && (
                      <div>
                        <span className="text-slate-500">Blockiert:</span>
                        <div className="mt-1 flex flex-wrap gap-1">
                          {consent.blockedVendors.map(v => (
                            <span key={v} className="px-1.5 py-0.5 bg-red-100 text-red-700 rounded text-[10px]">{v}</span>
                          ))}
                        </div>
                      </div>
                    )}
                  </>
                )}
              </div>
              {consent && (
                <button
                  onClick={() => { setConsent(null); setShowBanner(true); setApiResult(null) }}
                  className="mt-3 w-full text-xs text-purple-600 hover:text-purple-700 underline"
                >
                  Consent zuruecksetzen (Banner erneut anzeigen)
                </button>
              )}
            </div>

            {apiResult && (
              <div className="bg-slate-900 text-green-400 rounded-xl p-4 text-xs font-mono overflow-auto max-h-48">
                <div className="text-slate-500 mb-1">POST /banner/consent Response:</div>
                {JSON.stringify(apiResult, null, 2)}
              </div>
            )}

            <div className="bg-purple-50 border border-purple-200 rounded-xl p-4 text-xs text-purple-800">
              <div className="font-semibold mb-1">Pruefen Sie das Ergebnis in:</div>
              <ul className="space-y-1 mt-2">
                <li><a href="/sdk/consent-management" className="underline hover:text-purple-600">Consent-Verwaltung</a></li>
                <li><a href="/sdk/einwilligungen" className="underline hover:text-purple-600">Consent-Records</a></li>
                <li><a href="/sdk/dsr" className="underline hover:text-purple-600">DSR Portal</a></li>
              </ul>
            </div>
          </div>
        </div>
      </main>

      {/* Simulated Website Footer */}
      <footer className="bg-slate-100 border-t border-slate-200 px-8 py-6 mt-12">
        <div className="max-w-6xl mx-auto flex items-center justify-between text-sm text-slate-500">
          <span>MusterShop GmbH — Simulierte Test-Website</span>
          <div className="flex items-center gap-4">
            <button onClick={() => setShowBanner(true)} className="underline hover:text-purple-600">
              Cookie-Einstellungen
            </button>
            <span>Datenschutz</span>
            <span>Impressum</span>
          </div>
        </div>
      </footer>

      {/* === REAL COOKIE BANNER === */}
      {showBanner && (
        <>
          <div className="fixed inset-0 bg-black/40 z-[9998]" />
          <div className="fixed bottom-0 left-0 right-0 z-[9999]">
            <div className="max-w-3xl mx-auto m-4 bg-white rounded-2xl shadow-2xl border border-gray-200 overflow-hidden">
              {/* Header */}
              <div className="px-6 pt-5 pb-3">
                <div className="flex items-start justify-between gap-4">
                  <div className="flex-1">
                    <h2 className="text-lg font-semibold text-gray-900">Cookie-Einstellungen</h2>
                    <p className="text-sm text-gray-600 mt-1">
                      Waehlen Sie, welche Cookie-Kategorien Sie zulassen moechten.
                    </p>
                  </div>
                  {/* EWR Toggle */}
                  <div className="flex flex-col items-end gap-1 shrink-0">
                    <div className="flex items-center gap-2">
                      <span className={`text-xs font-medium ${ewrOnly ? 'text-blue-700' : 'text-gray-500'}`}>
                        Nur EU/EWR
                      </span>
                      <button
                        onClick={() => setEwrOnly(!ewrOnly)}
                        className={`relative inline-flex h-6 w-11 items-center rounded-full transition-colors cursor-pointer ${
                          ewrOnly ? 'bg-blue-600' : 'bg-gray-200'
                        }`}
                      >
                        <span className={`inline-block h-4 w-4 transform rounded-full bg-white shadow-sm transition-transform ${
                          ewrOnly ? 'translate-x-6' : 'translate-x-1'
                        }`} />
                      </button>
                    </div>
                  </div>
                </div>
              </div>

              {/* Categories */}
              <div className="px-6 pb-3 space-y-1.5 max-h-[40vh] overflow-y-auto border-t border-gray-100 pt-3">
                {Object.entries(CATEGORY_VENDORS).map(([key, cat]) => {
                  const checked = key === 'necessary' ? true : categories[key as keyof typeof categories]
                  const nonEU = cat.vendors.filter(v => isOutsideEWR(v.country))
                  const blocked = ewrOnly && checked ? nonEU.length : 0
                  return (
                    <div key={key} className="flex items-center justify-between gap-3 px-4 py-2.5 border border-gray-100 rounded-lg bg-gray-50/50">
                      <div>
                        <div className="text-sm font-medium text-gray-900">
                          {cat.label}
                          <span className="ml-2 text-xs font-normal text-gray-400">
                            {blocked > 0 ? `${cat.vendors.length - blocked} aktiv, ${blocked} blockiert` : `${cat.vendors.length} Verarbeiter`}
                          </span>
                        </div>
                        <div className="text-xs text-gray-500">{cat.description}</div>
                      </div>
                      <button
                        onClick={() => key !== 'necessary' && setCategories(prev => ({ ...prev, [key]: !prev[key as keyof typeof prev] }))}
                        disabled={key === 'necessary'}
                        className={`relative inline-flex h-6 w-11 items-center rounded-full transition-colors shrink-0 ${
                          checked ? (key === 'necessary' ? 'bg-gray-400' : 'bg-purple-600') : 'bg-gray-200'
                        } ${key === 'necessary' ? 'cursor-not-allowed opacity-60' : 'cursor-pointer'}`}
                      >
                        <span className={`inline-block h-4 w-4 transform rounded-full bg-white shadow-sm transition-transform ${
                          checked ? 'translate-x-6' : 'translate-x-1'
                        }`} />
                      </button>
                    </div>
                  )
                })}
              </div>

              {/* Buttons */}
              <div className="px-6 py-4 bg-gray-50 border-t border-gray-100">
                <div className="flex items-center gap-3">
                  <button
                    onClick={() => saveConsent({ necessary: true, statistics: true, marketing: true, functional: true })}
                    disabled={saving}
                    className="flex-1 px-4 py-2.5 bg-purple-600 text-white rounded-lg font-medium hover:bg-purple-700 transition-colors text-sm disabled:opacity-50"
                  >
                    {saving ? 'Speichern...' : 'Alle akzeptieren'}
                  </button>
                  <button
                    onClick={() => saveConsent(categories)}
                    disabled={saving}
                    className="flex-1 px-4 py-2.5 bg-gray-200 text-gray-700 rounded-lg font-medium hover:bg-gray-300 transition-colors text-sm disabled:opacity-50"
                  >
                    Auswahl speichern
                  </button>
                </div>
                <div className="flex items-center justify-between mt-3">
                  <button
                    onClick={() => saveConsent({ necessary: true, statistics: false, marketing: false, functional: false })}
                    className="text-xs text-gray-500 hover:text-gray-700 underline"
                  >
                    Nur notwendige Cookies
                  </button>
                  <div className="flex items-center gap-3 text-xs text-gray-400">
                    <span>Datenschutzerklaerung</span>
                    <span>Impressum</span>
                  </div>
                </div>
              </div>
            </div>
          </div>
        </>
      )}
    </div>
  )
}
