"use client";

import { useEffect, useState } from "react";
import { 
  getDatabaseIntegrity, 
  repairDatabaseSchema, 
  optimizeDatabaseIndices 
} from "@/lib/actions/admin";
import { Button } from "@/components/ui/button";
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
import { Badge } from "@/components/ui/badge";
import { Loader2, RefreshCw, Wrench, Database, AlertTriangle, CheckCircle2, XCircle, Terminal, ArrowLeft } from "lucide-react";
import Link from "next/link";
import { createClient } from "@/lib/supabase/client";
import { useRouter } from "next/navigation";

interface TableStatus {
  exists: boolean;
  count: number;
}

interface IntegrityData {
  tables: Record<string, TableStatus>;
  errors: {
    foreign_keys: number;
  };
}

export default function AdminToolsPage() {
  const [integrity, setIntegrity] = useState<IntegrityData | null>(null);
  const [isLoading, setIsLoading] = useState(false);
  const [logs, setLogs] = useState<string[]>([]);
  const [activeAction, setActiveAction] = useState<string | null>(null);
  const [loading, setLoading] = useState(true);
  const router = useRouter();

  const addLog = (message: string) => {
    const timestamp = new Date().toLocaleTimeString();
    setLogs((prev) => [...prev, `[${timestamp}] ${message}`]);
  };

  const loadStatus = async (quiet = false) => {
    if (!quiet) setIsLoading(true);
    addLog("Starte Integritätsscan der Datenbank...");
    const res = await getDatabaseIntegrity();
    if (res.success && res.data) {
      setIntegrity(res.data as IntegrityData);
      addLog("Integritätsscan erfolgreich abgeschlossen.");
    } else {
      addLog(`FEHLER beim Scannen: ${res.error}`);
    }
    if (!quiet) setIsLoading(false);
  };

  const handleRepair = async () => {
    setIsLoading(true);
    setActiveAction("repair");
    addLog("Starte automatische Schemareparatur...");
    const res = await repairDatabaseSchema();
    if (res.success && res.data) {
      const repaired = (res.data as any).repaired || [];
      if (repaired.length > 0) {
        addLog(`Erfolgreich reparierte Tabellen: ${repaired.join(", ")}`);
      } else {
        addLog("Keine fehlenden Tabellen gefunden. Schema intakt.");
      }
      await loadStatus(true);
    } else {
      addLog(`FEHLER bei Schemareparatur: ${res.error}`);
    }
    setIsLoading(false);
    setActiveAction(null);
  };

  const handleOptimize = async () => {
    setIsLoading(true);
    setActiveAction("optimize");
    addLog("Starte Reindexierung des Schemas public...");
    const res = await optimizeDatabaseIndices();
    if (res.success) {
      addLog("Reindexierung erfolgreich abgeschlossen. Suchindizes neu aufgebaut.");
    } else {
      addLog(`FEHLER bei Reindexierung: ${res.error}`);
    }
    setIsLoading(false);
    setActiveAction(null);
  };

  useEffect(() => {
    async function checkAccess() {
      const supabase = createClient();
      const { data: { user } } = await supabase.auth.getUser();
      if (!user) {
        router.push('/auth/login');
        return;
      }
      const { data: userData } = await supabase
        .from('users')
        .select('role')
        .eq('id', user.id)
        .single();
      if (!userData || userData.role === 'verwaltung') {
        router.push('/admin');
        return;
      }
      setLoading(false);
      loadStatus();
    }
    checkAccess();
  }, [router]);

  if (loading) {
    return <div className="min-h-screen bg-[#020617] text-white flex justify-center items-center"><Loader2 className="w-8 h-8 animate-spin text-primary" /></div>;
  }

  return (
    <div className="min-h-screen bg-[#020617] text-white px-4 py-12 relative overflow-hidden">
      {/* Background decoration */}
      <div className="absolute top-0 left-1/2 -translate-x-1/2 w-[1000px] h-[600px] bg-blue-600/10 blur-[120px] rounded-full -z-10 opacity-30" />
      
      {/* Loading Overlay */}
      {isLoading && (
        <div className="fixed inset-0 bg-black/60 backdrop-blur-sm z-50 flex flex-col items-center justify-center gap-4">
          <Loader2 className="w-12 h-12 text-primary animate-spin" />
          <p className="text-slate-200 text-lg font-medium">
            {activeAction === "repair" 
              ? "Schema wird repariert..." 
              : activeAction === "optimize" 
              ? "Datenbank wird indexiert..." 
              : "Verbindung zur Datenbank wird aufgebaut..."}
          </p>
        </div>
      )}

      <div className="max-w-5xl mx-auto space-y-8">
        {/* Header */}
        <div className="flex items-center gap-4">
          <Link href="/">
            <Button variant="ghost" size="sm" className="text-slate-400 hover:text-white">
              <ArrowLeft className="w-4 h-4 mr-2" /> Startseite
            </Button>
          </Link>
          <div>
            <h1 className="text-3xl font-extrabold tracking-tight flex items-center gap-3">
              <Database className="w-8 h-8 text-primary" />
              Admin Datenbank-Cockpit
            </h1>
            <p className="text-slate-400 text-sm mt-1">
              Verwalten und reparieren Sie Systemtabellen, Sicherheitsrichtlinien (RLS) und Datenbank-Indizes.
            </p>
          </div>
        </div>

        {/* Action Controls */}
        <div className="grid md:grid-cols-3 gap-6">
          <Card className="glass-dark border-white/10 flex flex-col justify-between">
            <CardHeader>
              <CardTitle className="text-white text-lg flex items-center gap-2">
                <RefreshCw className="w-5 h-5 text-blue-400" />
                Integritätsscan
              </CardTitle>
              <CardDescription className="text-slate-400">
                Prüft die physische Existenz der Tabellen und zählt deren Zeilenanzahl.
              </CardDescription>
            </CardHeader>
            <CardContent className="pt-0">
              <Button 
                onClick={() => loadStatus()} 
                disabled={isLoading}
                className="w-full bg-blue-600 hover:bg-blue-700 text-white"
              >
                Status aktualisieren
              </Button>
            </CardContent>
          </Card>

          <Card className="glass-dark border-white/10 flex flex-col justify-between">
            <CardHeader>
              <CardTitle className="text-white text-lg flex items-center gap-2">
                <Wrench className="w-5 h-5 text-emerald-400" />
                Schema reparieren
              </CardTitle>
              <CardDescription className="text-slate-400">
                Erstellt fehlende Kerntabellen automatisch neu und konfiguriert die RLS-Rechte.
              </CardDescription>
            </CardHeader>
            <CardContent className="pt-0">
              <Button 
                onClick={handleRepair} 
                disabled={isLoading}
                className="w-full bg-emerald-600 hover:bg-emerald-700 text-white"
              >
                Schema reparieren
              </Button>
            </CardContent>
          </Card>

          <Card className="glass-dark border-white/10 flex flex-col justify-between">
            <CardHeader>
              <CardTitle className="text-white text-lg flex items-center gap-2">
                <Database className="w-5 h-5 text-amber-400" />
                Index optimieren
              </CardTitle>
              <CardDescription className="text-slate-400">
                Baut korrupte Suchindizes im Schema public mittels REINDEX neu auf.
              </CardDescription>
            </CardHeader>
            <CardContent className="pt-0">
              <Button 
                onClick={handleOptimize} 
                disabled={isLoading}
                className="w-full bg-amber-600 hover:bg-amber-700 text-white"
              >
                Index optimieren
              </Button>
            </CardContent>
          </Card>
        </div>

        {/* Tabellenstatus */}
        <Card className="glass-dark border-white/10">
          <CardHeader>
            <CardTitle className="text-white text-xl">Tabellen-Status & Diagnose</CardTitle>
          </CardHeader>
          <CardContent className="space-y-6">
            <div className="grid sm:grid-cols-2 md:grid-cols-4 gap-4">
              {integrity?.tables ? (
                Object.entries(integrity.tables).map(([name, status]) => (
                  <div 
                    key={name} 
                    className="p-4 rounded-xl border bg-white/5 border-white/10 flex flex-col justify-between gap-2"
                  >
                    <span className="font-semibold text-slate-300 text-sm capitalize">
                      {name.replace("_", " ")}
                    </span>
                    <div className="flex items-center justify-between">
                      <span className="text-xs text-slate-500">Zeilen: {status.count}</span>
                      {status.exists ? (
                        <Badge className="bg-emerald-500/10 text-emerald-400 border-emerald-500/20 gap-1">
                          <CheckCircle2 className="w-3.5 h-3.5" /> OK
                        </Badge>
                      ) : (
                        <Badge className="bg-red-500/10 text-red-400 border-red-500/20 gap-1">
                          <XCircle className="w-3.5 h-3.5" /> Fehlt
                        </Badge>
                      )}
                    </div>
                  </div>
                ))
              ) : (
                <div className="col-span-4 py-8 text-center text-slate-500 text-sm">
                  Lade Diagnosedaten...
                </div>
              )}
            </div>

            {/* Foreign Key Errors */}
            {integrity && integrity.errors.foreign_keys > 0 && (
              <div className="p-4 rounded-xl bg-red-500/10 border border-red-500/20 flex gap-3 items-center">
                <AlertTriangle className="w-6 h-6 text-red-400 shrink-0" />
                <div>
                  <p className="font-bold text-red-200">Fremdschlüssel-Fehler gefunden!</p>
                  <p className="text-red-300/80 text-sm">
                    Es wurden {integrity.errors.foreign_keys} verwaiste Lizenzen ohne zugeordneten Endkunden in der Tabelle `licenses` detektiert.
                  </p>
                </div>
              </div>
            )}
          </CardContent>
        </Card>

        {/* Console / Output logs */}
        <Card className="glass-dark border-white/10">
          <CardHeader className="flex flex-row items-center justify-between">
            <CardTitle className="text-white text-lg flex items-center gap-2">
              <Terminal className="w-5 h-5 text-primary" />
              Diagnose-Konsole
            </CardTitle>
            <Button 
              variant="ghost" 
              size="sm" 
              onClick={() => setLogs([])}
              className="text-slate-400 hover:text-white text-xs"
            >
              Konsole leeren
            </Button>
          </CardHeader>
          <CardContent className="pt-0">
            <div className="font-mono text-xs bg-black/50 p-4 rounded-xl border border-white/5 h-64 overflow-y-auto space-y-1.5 scrollbar-thin">
              {logs.length === 0 ? (
                <span className="text-slate-600 italic">Konsole bereit. Führen Sie einen Scan aus.</span>
              ) : (
                logs.map((log, index) => (
                  <div key={index} className={log.includes("FEHLER") ? "text-red-400" : log.includes("Erfolgreich") ? "text-emerald-400" : "text-slate-300"}>
                    {log}
                  </div>
                ))
              )}
            </div>
          </CardContent>
        </Card>
      </div>
    </div>
  );
}