import { useEffect, useState } from 'react';
import { invokeWithTracking } from '@/lib/edgeFunctionTracking';
import { useNavigate } from 'react-router-dom';
import { supabase } from '@/integrations/supabase/client';
import { useToast } from '@/hooks/use-toast';
import { Loader2, CheckCircle2 } from 'lucide-react';
import { Header } from '@/components/layout/Header';
import { handlePostAuthFlow, verifyMfaUpgrade } from '@/lib/authService';
import type { AuthMethod } from '@/types/auth';
import { Card, CardHeader, CardTitle, CardDescription, CardContent } from '@/components/ui/card';
import { Label } from '@/components/ui/label';
import { Input } from '@/components/ui/input';
import { Button } from '@/components/ui/button';
import { getErrorMessage } from '@/lib/errorHandler';
import { MFAStepUpModal } from '@/components/auth/MFAStepUpModal';
import { useDocumentTitle } from '@/hooks/useDocumentTitle';

export default function AuthCallback() {
  useDocumentTitle('Sign In - Processing');
  const navigate = useNavigate();
  const { toast } = useToast();
  const [status, setStatus] = useState<'processing' | 'success' | 'error' | 'mfa_required'>('processing');
  const [mfaFactorId, setMfaFactorId] = useState<string | null>(null);
  const [isRecoveryMode, setIsRecoveryMode] = useState(false);
  const [newPassword, setNewPassword] = useState('');
  const [confirmPassword, setConfirmPassword] = useState('');
  const [settingPassword, setSettingPassword] = useState(false);

  useEffect(() => {
    const processOAuthCallback = async () => {
      try {
        // Check if this is a password recovery flow first
        const hash = window.location.hash;
        if (hash.includes('type=recovery')) {
          setIsRecoveryMode(true);
          setStatus('success'); // Stop the loading spinner
          return; // Don't process further
        }

        // Get the current session
        const { data: { session }, error: sessionError } = await supabase.auth.getSession();
        
        if (sessionError) {
          throw sessionError;
        }

        if (!session) {
          navigate('/auth');
          return;
        }

        const user = session.user;

        // Check if this is a new OAuth user (created within last minute)
        const createdAt = new Date(user.created_at);
        const now = new Date();
        const isNewUser = (now.getTime() - createdAt.getTime()) < 60000; // 1 minute

        // Check if user has an OAuth provider
        const provider = user.app_metadata?.provider;
        const isOAuthUser = provider === 'google' || provider === 'discord';

        // If new OAuth user, process profile
        if (isNewUser && isOAuthUser) {
          setStatus('processing');
          
          try {
            const { data, error, requestId } = await invokeWithTracking(
              'process-oauth-profile',
              {},
              user.id
            );

            if (error) {
              // Don't throw - allow sign-in to continue even if profile processing fails
            }
          } catch (error) {
            // Continue anyway - don't block sign-in
          }
        }

        // Determine authentication method
        let authMethod: AuthMethod = 'magiclink';
        if (isOAuthUser) {
          authMethod = 'oauth';
        }

        // Unified post-authentication flow for ALL methods (OAuth, magic link, etc.)
        const result = await handlePostAuthFlow(session, authMethod);
        
        if (result.success && result.data?.shouldRedirect) {
          // Get factor ID and show modal instead of redirecting
          const { data: factors } = await supabase.auth.mfa.listFactors();
          const totpFactor = factors?.totp?.find(f => f.status === 'verified');
          
          if (totpFactor) {
            setMfaFactorId(totpFactor.id);
            setStatus('mfa_required');
            return;
          }
        }

        setStatus('success');
        
        // Show success message
        toast({
          title: 'Welcome to ThrillWiki!',
          description: isNewUser 
            ? 'Your account has been created successfully.' 
            : 'You have been signed in successfully.',
        });

        // Redirect to home after a short delay
        setTimeout(() => {
          navigate('/');
        }, 500);

      } catch (error) {
        const errorMsg = getErrorMessage(error);
        setStatus('error');
        
        toast({
          variant: 'destructive',
          title: 'Sign in error',
          description: errorMsg,
        });

        // Redirect to auth page after error
        setTimeout(() => {
          navigate('/auth');
        }, 2000);
      }
    };

    processOAuthCallback();
  }, [navigate, toast]);

  const handleMfaSuccess = async () => {
    const { data: { session } } = await supabase.auth.getSession();
    const verification = await verifyMfaUpgrade(session);
    
    if (!verification.success) {
      toast({
        variant: "destructive",
        title: "MFA Verification Failed",
        description: verification.error || "Failed to upgrade session."
      });
      await supabase.auth.signOut();
      navigate('/auth');
      return;
    }
    
    setMfaFactorId(null);
    setStatus('success');
    
    toast({
      title: 'Welcome to ThrillWiki!',
      description: 'You have been signed in successfully.',
    });
    
    setTimeout(() => navigate('/'), 500);
  };

  const handlePasswordReset = async (e: React.FormEvent) => {
    e.preventDefault();
    
    if (newPassword !== confirmPassword) {
      toast({
        variant: 'destructive',
        title: 'Passwords do not match',
        description: 'Please make sure both passwords are identical.',
      });
      return;
    }
    
    if (newPassword.length < 8) {
      toast({
        variant: 'destructive',
        title: 'Password too short',
        description: 'Password must be at least 8 characters long.',
      });
      return;
    }
    
    setSettingPassword(true);
    
    try {
      const { error } = await supabase.auth.updateUser({
        password: newPassword
      });
      
      if (error) throw error;
      
      toast({
        title: 'Password Set Successfully!',
        description: 'You can now sign in with your email and password.',
      });
      
      setTimeout(() => {
        navigate('/auth');
      }, 1500);
      
    } catch (error) {
      const errorMsg = getErrorMessage(error);
      toast({
        variant: 'destructive',
        title: 'Failed to set password',
        description: errorMsg,
      });
      setSettingPassword(false);
    }
  };

  return (
    <div className="min-h-screen bg-background">
      <Header />
      
      <main className="container mx-auto px-4 py-16">
        <div className="max-w-md mx-auto text-center">
          {isRecoveryMode ? (
            <Card className="w-full">
              <CardHeader>
                <CardTitle>Set Your New Password</CardTitle>
                <CardDescription>
                  Enter a new password for your account
                </CardDescription>
              </CardHeader>
              <CardContent>
                <form onSubmit={handlePasswordReset} className="space-y-4">
                  <div className="text-left">
                    <Label htmlFor="new-password">New Password</Label>
                    <Input
                      id="new-password"
                      type="password"
                      value={newPassword}
                      onChange={(e) => setNewPassword(e.target.value)}
                      placeholder="At least 8 characters"
                      required
                      minLength={8}
                    />
                  </div>
                  <div className="text-left">
                    <Label htmlFor="confirm-password">Confirm Password</Label>
                    <Input
                      id="confirm-password"
                      type="password"
                      value={confirmPassword}
                      onChange={(e) => setConfirmPassword(e.target.value)}
                      placeholder="Re-enter password"
                      required
                    />
                  </div>
                  <Button type="submit" className="w-full" disabled={settingPassword}>
                    {settingPassword ? (
                      <>
                        <Loader2 className="w-4 h-4 mr-2 animate-spin" />
                        Setting Password...
                      </>
                    ) : (
                      'Set Password'
                    )}
                  </Button>
                </form>
              </CardContent>
            </Card>
          ) : (
            <div className="flex flex-col items-center gap-4">
              {status === 'processing' && (
              <>
                <Loader2 className="h-8 w-8 animate-spin text-primary" />
                <h2 className="text-2xl font-bold">Setting up your profile...</h2>
                <p className="text-muted-foreground">
                  We're preparing your ThrillWiki experience
                </p>
              </>
            )}
            
            {status === 'success' && (
              <>
                <div className="h-8 w-8 rounded-full bg-green-500 flex items-center justify-center">
                  <span className="text-white text-xl">✓</span>
                </div>
                <h2 className="text-2xl font-bold">Welcome!</h2>
                <p className="text-muted-foreground">
                  Redirecting you to ThrillWiki...
                </p>
              </>
            )}
            
            {status === 'error' && (
              <>
                <div className="h-8 w-8 rounded-full bg-destructive flex items-center justify-center">
                  <span className="text-destructive-foreground text-xl">✕</span>
                </div>
                <h2 className="text-2xl font-bold">Something went wrong</h2>
                <p className="text-muted-foreground">
                  Redirecting you to sign in...
                </p>
              </>
            )}
            </div>
          )}
        </div>
      </main>
      
      {status === 'mfa_required' && mfaFactorId && (
        <MFAStepUpModal
          open={true}
          factorId={mfaFactorId}
          onSuccess={handleMfaSuccess}
          onCancel={() => {
            setMfaFactorId(null);
            navigate('/auth');
          }}
        />
      )}
    </div>
  );
}
