import { useState } from 'react';
import { Card, CardHeader, CardTitle, CardContent } from './ui/card';
import { Button } from './ui/button';
import { Input, Label } from './ui';
import { Alert, AlertDescription } from './ui/alert';
import { Wifi, Loader2, Edit2, Check, X, Trash2, Plus, RotateCw, CheckCircle, AlertCircle } from 'lucide-react';
import { Badge } from './ui/badge';
import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
import { useDhcp } from '../hooks/useDhcp';
import { useDnsmasq } from '../hooks/useDnsmasq';
import { dhcpConfigApi, type DHCPConfig } from '../services/api/settings';
import type { DhcpStaticLease } from '../services/api/networking';

export function DhcpComponent() {
  const queryClient = useQueryClient();
  const { data: dhcpConfig } = useQuery({ queryKey: ['dhcp', 'config'], queryFn: () => dhcpConfigApi.get() });
  const dhcpMutation = useMutation({
    mutationFn: (data: Partial<DHCPConfig>) => dhcpConfigApi.update(data),
    onSuccess: () => queryClient.invalidateQueries({ queryKey: ['dhcp', 'config'] }),
  });
  const isUpdating = dhcpMutation.isPending;
  const { leases, isLoadingLeases, refetchLeases, addStatic, isAddingStatic, deleteStatic } = useDhcp();
  const { generateConfig: generateDnsConfig } = useDnsmasq();

  const [editingDhcpConfig, setEditingDhcpConfig] = useState(false);
  const [dhcpConfigForm, setDhcpConfigForm] = useState({ enabled: false, rangeStart: '', rangeEnd: '', leaseTime: '24h', gateway: '' });
  const [showAddLease, setShowAddLease] = useState(false);
  const [newLease, setNewLease] = useState<DhcpStaticLease>({ mac: '', ip: '', hostname: '' });
  const [successMessage, setSuccessMessage] = useState<string | null>(null);
  const [errorMessage, setErrorMessage] = useState<string | null>(null);

  const showSuccess = (msg: string) => {
    setSuccessMessage(msg);
    setErrorMessage(null);
    setTimeout(() => setSuccessMessage(null), 5000);
  };

  const showError = (msg: string) => {
    setErrorMessage(msg);
    setSuccessMessage(null);
    setTimeout(() => setErrorMessage(null), 8000);
  };

  const handleDhcpConfigEdit = () => {
    setDhcpConfigForm({
      enabled: dhcpConfig?.enabled ?? false,
      rangeStart: dhcpConfig?.rangeStart ?? '',
      rangeEnd: dhcpConfig?.rangeEnd ?? '',
      leaseTime: dhcpConfig?.leaseTime ?? '24h',
      gateway: dhcpConfig?.gateway ?? '',
    });
    setEditingDhcpConfig(true);
  };

  const handleDhcpConfigSave = async () => {
    try {
      await dhcpMutation.mutateAsync({
        enabled: dhcpConfigForm.enabled,
        rangeStart: dhcpConfigForm.rangeStart,
        rangeEnd: dhcpConfigForm.rangeEnd,
        leaseTime: dhcpConfigForm.leaseTime,
        gateway: dhcpConfigForm.gateway || undefined,
      });
      setEditingDhcpConfig(false);
      if (dhcpConfigForm.enabled) {
        generateDnsConfig(true);
      }
      showSuccess(dhcpConfigForm.enabled ? 'DHCP configuration saved and applied' : 'DHCP disabled');
    } catch (e) {
      showError(`Failed to save DHCP config: ${e instanceof Error ? e.message : String(e)}`);
    }
  };

  return (
    <div className="space-y-6">
      <div className="flex items-center gap-4">
        <div className="p-2 bg-primary/10 rounded-lg">
          <Wifi className="h-6 w-6 text-primary" />
        </div>
        <div>
          <h2 className="text-2xl font-semibold">DHCP</h2>
          <p className="text-muted-foreground">Assigns IP addresses to devices on your local network</p>
        </div>
      </div>

      {successMessage && (
        <Alert className="border-green-200 bg-green-50 dark:border-green-800 dark:bg-green-950/20">
          <CheckCircle className="h-4 w-4 text-green-600" />
          <AlertDescription className="text-green-700 dark:text-green-300">{successMessage}</AlertDescription>
        </Alert>
      )}
      {errorMessage && (
        <Alert variant="error">
          <AlertCircle className="h-4 w-4" />
          <AlertDescription>{errorMessage}</AlertDescription>
        </Alert>
      )}

      <Card>
        <CardHeader>
          <div className="flex items-center justify-between">
            <CardTitle>Configuration</CardTitle>
            <div className="flex items-center gap-2">
              <Badge variant={dhcpConfig?.enabled ? 'success' : 'secondary'} className="gap-1">
                {dhcpConfig?.enabled && <CheckCircle className="h-3 w-3" />}
                {dhcpConfig?.enabled ? 'Enabled' : 'Disabled'}
              </Badge>
              {!editingDhcpConfig && (
                <Button variant="outline" size="sm" onClick={handleDhcpConfigEdit} className="gap-1 h-7 text-xs">
                  <Edit2 className="h-3 w-3" />
                  Configure
                </Button>
              )}
            </div>
          </div>
        </CardHeader>
        <CardContent className="space-y-3">
          {editingDhcpConfig ? (
            <div className="space-y-3">
              <div className="flex items-center gap-2">
                <input
                  type="checkbox"
                  id="dhcp-enabled"
                  checked={dhcpConfigForm.enabled}
                  onChange={e => setDhcpConfigForm(prev => ({ ...prev, enabled: e.target.checked }))}
                />
                <Label htmlFor="dhcp-enabled">Enable DHCP server</Label>
              </div>
              {dhcpConfigForm.enabled && (
                <>
                  <div className="grid grid-cols-2 gap-3">
                    <div>
                      <Label htmlFor="dhcp-range-start">Range Start</Label>
                      <Input
                        id="dhcp-range-start"
                        value={dhcpConfigForm.rangeStart}
                        onChange={e => setDhcpConfigForm(prev => ({ ...prev, rangeStart: e.target.value }))}
                        placeholder="192.168.8.100"
                        className="mt-1 font-mono text-sm"
                      />
                    </div>
                    <div>
                      <Label htmlFor="dhcp-range-end">Range End</Label>
                      <Input
                        id="dhcp-range-end"
                        value={dhcpConfigForm.rangeEnd}
                        onChange={e => setDhcpConfigForm(prev => ({ ...prev, rangeEnd: e.target.value }))}
                        placeholder="192.168.8.200"
                        className="mt-1 font-mono text-sm"
                      />
                    </div>
                  </div>
                  <div className="grid grid-cols-2 gap-3">
                    <div>
                      <Label htmlFor="dhcp-lease-time">Lease Time</Label>
                      <Input
                        id="dhcp-lease-time"
                        value={dhcpConfigForm.leaseTime}
                        onChange={e => setDhcpConfigForm(prev => ({ ...prev, leaseTime: e.target.value }))}
                        placeholder="24h"
                        className="mt-1 font-mono text-sm"
                      />
                    </div>
                    <div>
                      <Label htmlFor="dhcp-gateway">Gateway (optional)</Label>
                      <Input
                        id="dhcp-gateway"
                        value={dhcpConfigForm.gateway}
                        onChange={e => setDhcpConfigForm(prev => ({ ...prev, gateway: e.target.value }))}
                        placeholder="192.168.8.1"
                        className="mt-1 font-mono text-sm"
                      />
                    </div>
                  </div>
                </>
              )}
              <div className="flex gap-2">
                <Button size="sm" onClick={handleDhcpConfigSave} disabled={isUpdating}>
                  {isUpdating ? <Loader2 className="h-3 w-3 animate-spin mr-1" /> : null}
                  Save
                </Button>
                <Button variant="outline" size="sm" onClick={() => setEditingDhcpConfig(false)}>
                  Cancel
                </Button>
              </div>
            </div>
          ) : (
            <div className="space-y-2 text-sm">
              {dhcpConfig?.enabled ? (
                <>
                  <div className="flex items-center gap-4">
                    <div>
                      <span className="text-muted-foreground">Range: </span>
                      <span className="font-mono">
                        {dhcpConfig!.rangeStart} – {dhcpConfig!.rangeEnd}
                      </span>
                    </div>
                    <div>
                      <span className="text-muted-foreground">Lease: </span>
                      <span className="font-mono">{dhcpConfig!.leaseTime || '24h'}</span>
                    </div>
                  </div>
                  {dhcpConfig!.gateway && (
                    <div>
                      <span className="text-muted-foreground">Gateway: </span>
                      <span className="font-mono">{dhcpConfig!.gateway}</span>
                    </div>
                  )}
                </>
              ) : (
                <p className="text-muted-foreground text-xs">DHCP is disabled. Enable it to assign IPs to LAN devices.</p>
              )}
            </div>
          )}
        </CardContent>
      </Card>

      <Card>
        <CardHeader>
          <div className="flex items-center justify-between">
            <CardTitle>Leases</CardTitle>
            <div className="flex gap-2">
              <Button variant="outline" size="sm" onClick={() => refetchLeases()} className="gap-1">
                <RotateCw className="h-3 w-3" />
                Refresh
              </Button>
              <Button size="sm" onClick={() => setShowAddLease(!showAddLease)} className="gap-1">
                <Plus className="h-3 w-3" />
                Static
              </Button>
            </div>
          </div>
        </CardHeader>
        <CardContent className="space-y-3">
          {showAddLease && (
            <Card className="p-3 border-dashed">
              <div className="grid grid-cols-3 gap-2 mb-2">
                <div>
                  <Label htmlFor="lease-mac" className="text-xs">MAC Address</Label>
                  <Input
                    id="lease-mac"
                    value={newLease.mac}
                    onChange={(e) => setNewLease(l => ({ ...l, mac: e.target.value }))}
                    placeholder="aa:bb:cc:dd:ee:ff"
                    className="mt-1 font-mono text-xs"
                  />
                </div>
                <div>
                  <Label htmlFor="lease-ip" className="text-xs">IP Address</Label>
                  <Input
                    id="lease-ip"
                    value={newLease.ip}
                    onChange={(e) => setNewLease(l => ({ ...l, ip: e.target.value }))}
                    placeholder="192.168.8.10"
                    className="mt-1 font-mono text-xs"
                  />
                </div>
                <div>
                  <Label htmlFor="lease-hostname" className="text-xs">Hostname (optional)</Label>
                  <Input
                    id="lease-hostname"
                    value={newLease.hostname ?? ''}
                    onChange={(e) => setNewLease(l => ({ ...l, hostname: e.target.value }))}
                    placeholder="node1"
                    className="mt-1 text-xs"
                  />
                </div>
              </div>
              <div className="flex justify-end gap-2">
                <Button variant="outline" size="sm" onClick={() => setShowAddLease(false)}>
                  <X className="h-3 w-3 mr-1" />Cancel
                </Button>
                <Button
                  size="sm"
                  disabled={!newLease.mac || !newLease.ip || isAddingStatic}
                  onClick={() => {
                    addStatic(newLease, {
                      onSuccess: () => {
                        showSuccess(`Static lease added for ${newLease.ip}`);
                        setShowAddLease(false);
                        setNewLease({ mac: '', ip: '', hostname: '' });
                      },
                      onError: (e: Error) => {
                        showError(`Failed to add lease: ${e.message}`);
                      },
                    });
                  }}
                >
                  {isAddingStatic ? <Loader2 className="h-3 w-3 mr-1 animate-spin" /> : <Check className="h-3 w-3 mr-1" />}
                  Add
                </Button>
              </div>
            </Card>
          )}
          {isLoadingLeases ? (
            <div className="flex items-center justify-center py-4">
              <Loader2 className="h-5 w-5 animate-spin text-muted-foreground" />
            </div>
          ) : leases.length === 0 ? (
            <p className="text-sm text-muted-foreground text-center py-4">
              No active leases. DHCP must be enabled in config.
            </p>
          ) : (
            <div className="overflow-x-auto">
              <table className="w-full text-xs">
                <thead>
                  <tr className="text-muted-foreground border-b">
                    <th className="text-left pb-1">MAC</th>
                    <th className="text-left pb-1">IP</th>
                    <th className="text-left pb-1">Hostname</th>
                    <th className="text-left pb-1">Expires</th>
                    <th className="pb-1" />
                  </tr>
                </thead>
                <tbody>
                  {leases.map((lease) => (
                    <tr key={lease.mac} className="border-b last:border-0">
                      <td className="py-1 font-mono">{lease.mac}</td>
                      <td className="py-1 font-mono">{lease.ip}</td>
                      <td className="py-1">{lease.hostname || '—'}</td>
                      <td className="py-1 text-muted-foreground">
                        {lease.expiry ? new Date(lease.expiry).toLocaleString() : '—'}
                      </td>
                      <td className="py-1">
                        <Button
                          variant="ghost"
                          size="sm"
                          className="h-6 w-6 p-0 text-muted-foreground hover:text-red-500"
                          onClick={() => deleteStatic(lease.mac, {
                            onSuccess: () => showSuccess(`Lease for ${lease.mac} deleted`),
                            onError: (e: Error) => showError(`Failed to delete lease: ${e.message}`),
                          })}
                        >
                          <Trash2 className="h-3 w-3" />
                        </Button>
                      </td>
                    </tr>
                  ))}
                </tbody>
              </table>
            </div>
          )}
        </CardContent>
      </Card>
    </div>
  );
}