import { useState } from 'react';
import { supabase } from '@/integrations/supabase/client';
import { toast } from 'sonner';
import {
  AlertDialog,
  AlertDialogAction,
  AlertDialogCancel,
  AlertDialogContent,
  AlertDialogDescription,
  AlertDialogFooter,
  AlertDialogHeader,
  AlertDialogTitle,
} from '@/components/ui/alert-dialog';
import { Input } from '@/components/ui/input';
import { Label } from '@/components/ui/label';
import { Button } from '@/components/ui/button';
import { Alert, AlertDescription } from '@/components/ui/alert';
import { Shield, AlertTriangle } from 'lucide-react';

interface MFARemovalDialogProps {
  open: boolean;
  onOpenChange: (open: boolean) => void;
  factorId: string;
  onSuccess: () => void;
}

export function MFARemovalDialog({ open, onOpenChange, factorId, onSuccess }: MFARemovalDialogProps) {
  const [step, setStep] = useState<'password' | 'totp' | 'confirm'>('password');
  const [password, setPassword] = useState('');
  const [totpCode, setTotpCode] = useState('');
  const [loading, setLoading] = useState(false);

  const handleClose = () => {
    setStep('password');
    setPassword('');
    setTotpCode('');
    setLoading(false);
    onOpenChange(false);
  };

  const handlePasswordVerification = async () => {
    if (!password.trim()) {
      toast.error('Please enter your password');
      return;
    }

    setLoading(true);
    try {
      // Get current user email
      const { data: { user } } = await supabase.auth.getUser();
      if (!user?.email) throw new Error('User email not found');

      // Re-authenticate with password
      const { error } = await supabase.auth.signInWithPassword({
        email: user.email,
        password: password
      });

      if (error) throw error;

      toast.success('Password verified');
      setStep('totp');
    } catch (error: any) {
      console.error('Password verification failed:', error);
      toast.error('Invalid password. Please try again.');
    } finally {
      setLoading(false);
    }
  };

  const handleTOTPVerification = async () => {
    if (!totpCode.trim() || totpCode.length !== 6) {
      toast.error('Please enter a valid 6-digit code');
      return;
    }

    setLoading(true);
    try {
      // Create challenge
      const { data: challengeData, error: challengeError } = await supabase.auth.mfa.challenge({
        factorId
      });

      if (challengeError) throw challengeError;

      // Verify TOTP code
      const { error: verifyError } = await supabase.auth.mfa.verify({
        factorId,
        challengeId: challengeData.id,
        code: totpCode.trim()
      });

      if (verifyError) throw verifyError;

      toast.success('TOTP code verified');
      setStep('confirm');
    } catch (error: any) {
      console.error('TOTP verification failed:', error);
      toast.error('Invalid code. Please try again.');
    } finally {
      setLoading(false);
    }
  };

  const handleMFARemoval = async () => {
    setLoading(true);
    try {
      // Unenroll the factor
      const { error } = await supabase.auth.mfa.unenroll({ factorId });
      if (error) throw error;

      // Log the action
      const { data: { user } } = await supabase.auth.getUser();
      if (user) {
        await supabase.from('admin_audit_log').insert({
          admin_user_id: user.id,
          target_user_id: user.id,
          action: 'mfa_disabled',
          details: {
            factor_id: factorId,
            timestamp: new Date().toISOString(),
            user_agent: navigator.userAgent
          }
        });

        // Trigger email notification
        await supabase.functions.invoke('trigger-notification', {
          body: {
            userId: user.id,
            workflowId: 'security-alert',
            payload: {
              action: 'MFA Disabled',
              message: 'Two-factor authentication has been disabled on your account.',
              timestamp: new Date().toISOString()
            }
          }
        }).catch(err => console.error('Notification error:', err));
      }

      toast.success('Two-factor authentication has been disabled');
      handleClose();
      onSuccess();
    } catch (error: any) {
      console.error('MFA removal failed:', error);
      toast.error('Failed to disable MFA. Please try again.');
    } finally {
      setLoading(false);
    }
  };

  return (
    <AlertDialog open={open} onOpenChange={onOpenChange}>
      <AlertDialogContent>
        <AlertDialogHeader>
          <AlertDialogTitle className="flex items-center gap-2">
            <Shield className="h-5 w-5 text-destructive" />
            Disable Two-Factor Authentication
          </AlertDialogTitle>
          <AlertDialogDescription asChild>
            <div className="space-y-4">
              <Alert variant="destructive">
                <AlertTriangle className="h-4 w-4" />
                <AlertDescription>
                  Disabling MFA will make your account less secure. You'll need to verify your identity first.
                </AlertDescription>
              </Alert>

              {step === 'password' && (
                <div className="space-y-3">
                  <p className="text-sm">Step 1 of 3: Enter your password to continue</p>
                  <div className="space-y-2">
                    <Label htmlFor="password">Password</Label>
                    <Input
                      id="password"
                      type="password"
                      value={password}
                      onChange={(e) => setPassword(e.target.value)}
                      onKeyDown={(e) => e.key === 'Enter' && handlePasswordVerification()}
                      placeholder="Enter your password"
                      disabled={loading}
                    />
                  </div>
                </div>
              )}

              {step === 'totp' && (
                <div className="space-y-3">
                  <p className="text-sm">Step 2 of 3: Enter your current TOTP code</p>
                  <div className="space-y-2">
                    <Label htmlFor="totp">Verification Code</Label>
                    <Input
                      id="totp"
                      type="text"
                      value={totpCode}
                      onChange={(e) => setTotpCode(e.target.value.replace(/\D/g, '').slice(0, 6))}
                      onKeyDown={(e) => e.key === 'Enter' && handleTOTPVerification()}
                      placeholder="000000"
                      maxLength={6}
                      disabled={loading}
                      className="text-center text-2xl tracking-widest"
                    />
                  </div>
                </div>
              )}

              {step === 'confirm' && (
                <div className="space-y-3">
                  <p className="text-sm font-semibold">Step 3 of 3: Final confirmation</p>
                  <p className="text-sm text-muted-foreground">
                    Are you sure you want to disable two-factor authentication? This will:
                  </p>
                  <ul className="text-sm text-muted-foreground list-disc list-inside space-y-1">
                    <li>Remove TOTP protection from your account</li>
                    <li>Send a security notification email</li>
                    <li>Log this action in your security history</li>
                  </ul>
                </div>
              )}
            </div>
          </AlertDialogDescription>
        </AlertDialogHeader>
        <AlertDialogFooter>
          <AlertDialogCancel onClick={handleClose} disabled={loading}>
            Cancel
          </AlertDialogCancel>
          {step === 'password' && (
            <Button onClick={handlePasswordVerification} disabled={loading}>
              {loading ? 'Verifying...' : 'Continue'}
            </Button>
          )}
          {step === 'totp' && (
            <Button onClick={handleTOTPVerification} disabled={loading}>
              {loading ? 'Verifying...' : 'Continue'}
            </Button>
          )}
          {step === 'confirm' && (
            <AlertDialogAction onClick={handleMFARemoval} disabled={loading} className="bg-destructive text-destructive-foreground hover:bg-destructive/90">
              {loading ? 'Disabling...' : 'Disable MFA'}
            </AlertDialogAction>
          )}
        </AlertDialogFooter>
      </AlertDialogContent>
    </AlertDialog>
  );
}
