'use client';

import React, { useState, useEffect } from 'react';
import { useRouter } from 'next/navigation';
import { Card } from '@/components/ui/Card';
import { Button } from '@/components/ui/Button';
import { Badge } from '@/components/ui/Badge';
import { Mail, Users, Send, CheckCircle, AlertCircle, Loader2, Lock, LogOut } from 'lucide-react';

interface Subscriber {
  email: string;
  createdAt: string;
}

interface BroadcastInfo {
  total: number;
  recent: Subscriber[];
}

export default function NewsletterPage() {
  const router = useRouter();
  const [isAuthenticated, setIsAuthenticated] = useState(false);
  const [isAuthenticating, setIsAuthenticating] = useState(true);
  const [loginError, setLoginError] = useState('');
  const [email, setEmail] = useState('');
  const [password, setPassword] = useState('');

  const [info, setInfo] = useState<BroadcastInfo | null>(null);
  const [loading, setLoading] = useState(true);
  const [broadcasting, setBroadcasting] = useState(false);
  const [result, setResult] = useState<{
    success: boolean;
    message: string;
    sent?: number;
    failed?: number;
  } | null>(null);

  useEffect(() => {
    checkAuth();
  }, []);

  const checkAuth = async () => {
    try {
      const response = await fetch('/api/newsletter/broadcast');
      if (response.ok) {
        setIsAuthenticated(true);
        const data = await response.json();
        setInfo(data);
        setLoading(false);
      } else {
        setIsAuthenticated(false);
      }
    } catch (error) {
      setIsAuthenticated(false);
    } finally {
      setIsAuthenticating(false);
    }
  };

  const handleLogin = async (e: React.FormEvent) => {
    e.preventDefault();
    setLoginError('');
    setIsAuthenticating(true);

    try {
      const response = await fetch('/api/newsletter/admin-login', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({ email, password }),
      });

      if (response.ok) {
        setIsAuthenticated(true);
        await checkAuth();
      } else {
        const data = await response.json();
        setLoginError(data.error || 'Invalid credentials');
      }
    } catch (error) {
      setLoginError('Login failed. Please try again.');
    } finally {
      setIsAuthenticating(false);
    }
  };

  const handleLogout = async () => {
    await fetch('/api/auth/logout', { method: 'POST' });
    router.push('/');
  };

  const fetchSubscriberInfo = async () => {
    try {
      const response = await fetch('/api/newsletter/broadcast');
      if (response.ok) {
        const data = await response.json();
        setInfo(data);
      }
    } catch (error) {
      console.error('Failed to fetch subscriber info:', error);
    }
  };

  const handleBroadcast = async () => {
    if (!confirm(`Are you sure you want to send the AI feature launch email to ${info?.total} subscribers?`)) {
      return;
    }

    setBroadcasting(true);
    setResult(null);

    try {
      const response = await fetch('/api/newsletter/broadcast', {
        method: 'POST',
      });

      const data = await response.json();

      setResult({
        success: response.ok,
        message: data.message || data.error,
        sent: data.sent,
        failed: data.failed,
      });

      if (response.ok) {
        await fetchSubscriberInfo();
      }
    } catch (error) {
      setResult({
        success: false,
        message: 'Failed to send broadcast. Please try again.',
      });
    } finally {
      setBroadcasting(false);
    }
  };

  // Login Screen
  if (!isAuthenticated) {
    return (
      <div className="min-h-screen flex items-center justify-center bg-gradient-to-br from-purple-50 to-pink-50 dark:from-purple-950/20 dark:to-pink-950/20 px-4">
        <Card className="w-full max-w-md p-8">
          <div className="text-center mb-6">
            <div className="w-16 h-16 bg-gradient-to-br from-purple-100 to-pink-100 dark:from-purple-900/30 dark:to-pink-900/30 rounded-full flex items-center justify-center mx-auto mb-4">
              <Lock className="w-8 h-8 text-purple-600 dark:text-purple-400" />
            </div>
            <h1 className="text-2xl font-bold mb-2">Newsletter Admin</h1>
            <p className="text-muted-foreground text-sm">
              Sign in to manage subscribers
            </p>
          </div>

          <form onSubmit={handleLogin} className="space-y-4">
            <div>
              <label className="block text-sm font-medium mb-2">Email</label>
              <input
                type="email"
                value={email}
                onChange={(e) => setEmail(e.target.value)}
                placeholder="Email"
                required
                className="w-full px-4 py-3 rounded-xl bg-background border border-border focus:border-purple-500 focus:ring-2 focus:ring-purple-500/20 outline-none transition-all"
              />
            </div>

            <div>
              <label className="block text-sm font-medium mb-2">Password</label>
              <input
                type="password"
                value={password}
                onChange={(e) => setPassword(e.target.value)}
                placeholder="Password"
                required
                className="w-full px-4 py-3 rounded-xl bg-background border border-border focus:border-purple-500 focus:ring-2 focus:ring-purple-500/20 outline-none transition-all"
              />
            </div>

            {loginError && (
              <p className="text-sm text-red-600 dark:text-red-400">{loginError}</p>
            )}

            <Button
              type="submit"
              disabled={isAuthenticating}
              className="w-full bg-gradient-to-r from-purple-600 to-pink-600 hover:from-purple-700 hover:to-pink-700 text-white"
            >
              {isAuthenticating ? (
                <>
                  <Loader2 className="w-4 h-4 mr-2 animate-spin" />
                  Signing in...
                </>
              ) : (
                'Sign In'
              )}
            </Button>
          </form>

          <div className="mt-6 pt-6 border-t text-center">
            <p className="text-xs text-muted-foreground">
              Admin credentials required
            </p>
          </div>
        </Card>
      </div>
    );
  }

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

  // Admin Dashboard
  return (
    <div className="min-h-screen bg-gradient-to-br from-purple-50/30 to-pink-50/30 dark:from-purple-950/10 dark:to-pink-950/10">
      <div className="container mx-auto px-4 py-8 max-w-4xl">
        <div className="flex items-center justify-between mb-8">
          <div>
            <h1 className="text-3xl font-bold mb-2">Newsletter Management</h1>
            <p className="text-muted-foreground">
              Manage AI feature launch notifications
            </p>
          </div>
          <Button
            onClick={handleLogout}
            variant="outline"
            className="flex items-center gap-2"
          >
            <LogOut className="w-4 h-4" />
            Logout
          </Button>
        </div>

        {/* Stats Card */}
        <Card className="p-6 mb-6">
          <div className="flex items-center justify-between mb-6">
            <div className="flex items-center gap-3">
              <div className="w-12 h-12 bg-purple-100 dark:bg-purple-900/20 rounded-lg flex items-center justify-center">
                <Users className="w-6 h-6 text-purple-600 dark:text-purple-400" />
              </div>
              <div>
                <h2 className="text-2xl font-bold">{info?.total || 0}</h2>
                <p className="text-sm text-muted-foreground">Total Subscribers</p>
              </div>
            </div>
            <Badge className="bg-green-100 text-green-700 dark:bg-green-900/30 dark:text-green-300">
              Active
            </Badge>
          </div>

          {/* Broadcast Button */}
          <div className="border-t pt-6">
            <div className="mb-4">
              <h3 className="font-semibold mb-2 flex items-center gap-2">
                <Send className="w-4 h-4" />
                Broadcast AI Feature Launch
              </h3>
              <p className="text-sm text-muted-foreground mb-4">
                Send the AI feature launch announcement to all {info?.total} subscribers.
                This will inform them that the features are now available.
              </p>
            </div>

            <Button
              onClick={handleBroadcast}
              disabled={broadcasting || !info?.total}
              className="w-full sm:w-auto bg-gradient-to-r from-purple-600 to-pink-600 hover:from-purple-700 hover:to-pink-700 text-white"
            >
              {broadcasting ? (
                <>
                  <Loader2 className="w-4 h-4 mr-2 animate-spin" />
                  Sending Emails...
                </>
              ) : (
                <>
                  <Mail className="w-4 h-4 mr-2" />
                  Send Launch Notification to All
                </>
              )}
            </Button>
          </div>
        </Card>

        {/* Result Message */}
        {result && (
          <Card
            className={`p-4 mb-6 ${
              result.success
                ? 'bg-green-50 dark:bg-green-950/20 border-green-200 dark:border-green-900'
                : 'bg-red-50 dark:bg-red-950/20 border-red-200 dark:border-red-900'
            }`}
          >
            <div className="flex items-start gap-3">
              {result.success ? (
                <CheckCircle className="w-5 h-5 text-green-600 dark:text-green-400 flex-shrink-0 mt-0.5" />
              ) : (
                <AlertCircle className="w-5 h-5 text-red-600 dark:text-red-400 flex-shrink-0 mt-0.5" />
              )}
              <div className="flex-1">
                <p
                  className={`font-medium ${
                    result.success
                      ? 'text-green-900 dark:text-green-100'
                      : 'text-red-900 dark:text-red-100'
                  }`}
                >
                  {result.message}
                </p>
                {result.sent !== undefined && (
                  <p className="text-sm text-muted-foreground mt-1">
                    Sent: {result.sent} | Failed: {result.failed}
                  </p>
                )}
              </div>
            </div>
          </Card>
        )}

        {/* Recent Subscribers */}
        <Card className="p-6">
          <h3 className="font-semibold mb-4">Recent Subscribers</h3>
          {info?.recent && info.recent.length > 0 ? (
            <div className="space-y-3">
              {info.recent.map((subscriber, index) => (
                <div
                  key={index}
                  className="flex items-center justify-between py-2 border-b border-border last:border-0"
                >
                  <div className="flex items-center gap-2">
                    <Mail className="w-4 h-4 text-muted-foreground" />
                    <span className="text-sm">{subscriber.email}</span>
                  </div>
                  <span className="text-xs text-muted-foreground">
                    {new Date(subscriber.createdAt).toLocaleDateString()}
                  </span>
                </div>
              ))}
            </div>
          ) : (
            <p className="text-sm text-muted-foreground">No subscribers yet</p>
          )}

          <div className="mt-4 pt-4 border-t">
            <p className="text-xs text-muted-foreground">
              💡 Tip: View all subscribers in{' '}
              <a
                href="http://localhost:5555"
                target="_blank"
                rel="noopener noreferrer"
                className="text-primary hover:underline"
              >
                Prisma Studio
              </a>
              {' '}(NewsletterSubscription table)
            </p>
          </div>
        </Card>
      </div>
    </div>
  );
}