import { useState } from "react";
import { useQuery } from "@tanstack/react-query";
import { useAuth } from "@/hooks/useAuth";
import { KPICard } from "@/components/kpi-card";
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select";
import { StatusBadge } from "@/components/status-badge";
import { Users, Calendar, MapPin, AlertTriangle, Clock, CheckCircle, Building2 } from "lucide-react";
import { ShiftWithDetails, GuardWithCertifications, Site } from "@shared/schema";
import { formatDistanceToNow, format } from "date-fns";
import { it } from "date-fns/locale";
import { Skeleton } from "@/components/ui/skeleton";

export default function Dashboard() {
  const { user } = useAuth();
  const [selectedLocation, setSelectedLocation] = useState<string>("all");

  const { data: shifts, isLoading: shiftsLoading } = useQuery<ShiftWithDetails[]>({
    queryKey: ["/api/shifts/active"],
  });

  const { data: guards, isLoading: guardsLoading } = useQuery<GuardWithCertifications[]>({
    queryKey: ["/api/guards"],
  });

  const { data: sites, isLoading: sitesLoading } = useQuery<Site[]>({
    queryKey: ["/api/sites"],
  });

  // Filter data by location
  const filteredGuards = selectedLocation === "all" 
    ? guards 
    : guards?.filter(g => g.location === selectedLocation);
    
  const filteredSites = selectedLocation === "all"
    ? sites
    : sites?.filter(s => s.location === selectedLocation);
    
  const filteredShifts = selectedLocation === "all"
    ? shifts
    : shifts?.filter(s => {
        const site = sites?.find(site => site.id === s.siteId);
        return site?.location === selectedLocation;
      });

  // Calculate KPIs
  const activeShifts = filteredShifts?.filter(s => s.status === "active").length || 0;
  const totalGuards = filteredGuards?.length || 0;
  const activeSites = filteredSites?.filter(s => s.isActive).length || 0;
  
  // Expiring certifications (next 30 days)
  const expiringCerts = filteredGuards?.flatMap(g => 
    g.certifications.filter(c => c.status === "expiring_soon")
  ).length || 0;

  const isLoading = shiftsLoading || guardsLoading || sitesLoading;

  const locationLabels: Record<string, string> = {
    all: "Tutte le Sedi",
    roccapiemonte: "Roccapiemonte",
    milano: "Milano",
    roma: "Roma"
  };

  return (
    <div className="space-y-6">
      <div className="flex items-start justify-between">
        <div>
          <h1 className="text-3xl font-semibold mb-2">Dashboard Operativa</h1>
          <p className="text-muted-foreground">
            Benvenuto, {user?.firstName} {user?.lastName}
          </p>
        </div>
        <div className="flex items-center gap-2">
          <Building2 className="h-5 w-5 text-muted-foreground" />
          <Select value={selectedLocation} onValueChange={setSelectedLocation}>
            <SelectTrigger className="w-[200px]" data-testid="select-location">
              <SelectValue placeholder="Seleziona sede" />
            </SelectTrigger>
            <SelectContent>
              <SelectItem value="all">Tutte le Sedi</SelectItem>
              <SelectItem value="roccapiemonte">Roccapiemonte</SelectItem>
              <SelectItem value="milano">Milano</SelectItem>
              <SelectItem value="roma">Roma</SelectItem>
            </SelectContent>
          </Select>
        </div>
      </div>

      {/* KPI Cards */}
      <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-4">
        {isLoading ? (
          <>
            <Skeleton className="h-32" />
            <Skeleton className="h-32" />
            <Skeleton className="h-32" />
            <Skeleton className="h-32" />
          </>
        ) : (
          <>
            <KPICard
              title="Turni Attivi"
              value={activeShifts}
              icon={Calendar}
              data-testid="kpi-active-shifts"
            />
            <KPICard
              title="Guardie Totali"
              value={totalGuards}
              icon={Users}
              data-testid="kpi-total-guards"
            />
            <KPICard
              title="Siti Attivi"
              value={activeSites}
              icon={MapPin}
              data-testid="kpi-active-sites"
            />
            <KPICard
              title="Certificazioni in Scadenza"
              value={expiringCerts}
              icon={AlertTriangle}
              className={expiringCerts > 0 ? "border-[hsl(25,90%,55%)]" : ""}
              data-testid="kpi-expiring-certs"
            />
          </>
        )}
      </div>

      <div className="grid gap-6 md:grid-cols-2">
        {/* Active Shifts */}
        <Card>
          <CardHeader>
            <CardTitle className="flex items-center gap-2">
              <Clock className="h-5 w-5" />
              Turni in Corso
            </CardTitle>
            <CardDescription>
              Servizi attualmente attivi
            </CardDescription>
          </CardHeader>
          <CardContent>
            {shiftsLoading ? (
              <div className="space-y-3">
                <Skeleton className="h-16" />
                <Skeleton className="h-16" />
              </div>
            ) : filteredShifts && filteredShifts.length > 0 ? (
              <div className="space-y-3">
                {filteredShifts.slice(0, 5).map((shift) => (
                  <div
                    key={shift.id}
                    className="flex items-center justify-between p-3 rounded-md border hover-elevate"
                    data-testid={`shift-${shift.id}`}
                  >
                    <div className="flex-1 min-w-0">
                      <p className="font-medium truncate">{shift.site.name}</p>
                      <p className="text-sm text-muted-foreground">
                        {shift.assignments.length} guardie assegnate
                      </p>
                    </div>
                    <StatusBadge status={shift.status === "active" ? "active" : "pending"}>
                      {shift.status === "active" ? "Attivo" : "Pianificato"}
                    </StatusBadge>
                  </div>
                ))}
              </div>
            ) : (
              <p className="text-sm text-muted-foreground text-center py-8">
                Nessun turno attivo al momento
              </p>
            )}
          </CardContent>
        </Card>

        {/* Alerts & Notifications */}
        <Card>
          <CardHeader>
            <CardTitle className="flex items-center gap-2">
              <AlertTriangle className="h-5 w-5" />
              Alert e Scadenze
            </CardTitle>
            <CardDescription>
              Certificazioni in scadenza prossimi 30 giorni
            </CardDescription>
          </CardHeader>
          <CardContent>
            {guardsLoading ? (
              <div className="space-y-3">
                <Skeleton className="h-16" />
                <Skeleton className="h-16" />
              </div>
            ) : filteredGuards ? (
              <div className="space-y-3">
                {filteredGuards
                  .flatMap(guard => 
                    guard.certifications
                      .filter(c => c.status === "expiring_soon" || c.status === "expired")
                      .map(cert => ({ guard, cert }))
                  )
                  .slice(0, 5)
                  .map(({ guard, cert }) => (
                    <div
                      key={cert.id}
                      className="flex items-center justify-between p-3 rounded-md border border-[hsl(25,90%,55%)]/30 bg-[hsl(25,90%,55%)]/5"
                      data-testid={`alert-${cert.id}`}
                    >
                      <div className="flex-1 min-w-0">
                        <p className="font-medium truncate">
                          {guard.user?.firstName} {guard.user?.lastName}
                        </p>
                        <p className="text-sm text-muted-foreground">
                          {cert.name} - Scade {format(new Date(cert.expiryDate), "dd/MM/yyyy")}
                        </p>
                      </div>
                      <StatusBadge status={cert.status === "expired" ? "emergency" : "late"}>
                        {cert.status === "expired" ? "Scaduto" : "In scadenza"}
                      </StatusBadge>
                    </div>
                  ))}
                {filteredGuards.flatMap(g => g.certifications.filter(c => c.status !== "valid")).length === 0 && (
                  <div className="flex items-center gap-2 text-sm text-muted-foreground justify-center py-8">
                    <CheckCircle className="h-4 w-4 text-[hsl(140,60%,45%)]" />
                    Tutte le certificazioni sono valide
                  </div>
                )}
              </div>
            ) : null}
          </CardContent>
        </Card>
      </div>
    </div>
  );
}