/* eslint-disable react-hooks/exhaustive-deps, react-hooks/set-state-in-effect, react-hooks/immutability */
import React, { useState, useEffect } from 'react';
import { useAuth } from './AuthContext';
import { useNavigate } from 'react-router-dom';
import {
  Shield,
  Zap,
  Check,
  Target,
  ArrowRight,
  Briefcase
} from 'lucide-react';

const RAZORPAY_SCRIPT = 'https://checkout.razorpay.com/v1/checkout.js';

const FALLBACK_TIERS = [
  { id: 'quick', name: 'Quick Scan', monthly_price: 499, monthly_price_inr: 49900 },
  { id: 'advanced', name: 'Advanced Scan', monthly_price: 4499, monthly_price_inr: 399900 },
  { id: 'deep', name: 'Deep Scan', monthly_price: 9999, monthly_price_inr: 899900 },
  { id: 'enterprise', name: 'Custom Solutions', monthly_price: 0, monthly_price_inr: 0 }
];

let razorpayScriptPromise = null;

const loadRazorpayScript = () => {
  if (typeof window === 'undefined') return Promise.reject(new Error('Browser only'));
  if (window.Razorpay) return Promise.resolve(true);
  if (razorpayScriptPromise) return razorpayScriptPromise;

  razorpayScriptPromise = new Promise((resolve, reject) => {
    const script = document.createElement('script');
    script.src = RAZORPAY_SCRIPT;
    script.async = true;
    script.onload = () => resolve(true);
    script.onerror = () => {
      razorpayScriptPromise = null;
      reject(new Error('Unable to load the Razorpay checkout. Check your network or ad-blocker.'));
    };
    document.body.appendChild(script);
  });

  return razorpayScriptPromise;
};

const detectCurrency = () => {
  try {
    const timeZone = Intl.DateTimeFormat().resolvedOptions().timeZone || '';
    const locale = new Intl.Locale(navigator.language || 'en-US');
    if (timeZone === 'Asia/Kolkata' || locale.region === 'IN') return 'INR';
  } catch {
    // Intl.Locale unsupported - fall through to USD
  }
  return 'USD';
};

const formatMoney = (minor, currency) => {
  const value = Number(minor || 0) / 100;
  if (currency === 'INR') {
    return `₹${value.toLocaleString('en-IN', {
      minimumFractionDigits: value % 1 === 0 ? 0 : 2,
      maximumFractionDigits: 2
    })}`;
  }
  return `$${value.toFixed(2)}`;
};

export default function PricingSection({ embedded = false, hideCurrentPlan = false }) {
  const { user, token, refreshAccessToken } = useAuth();
  const navigate = useNavigate();
  const [loadingPlan, setLoadingPlan] = useState(null);
  const [paymentSuccess, setPaymentSuccess] = useState(false);
  const [paymentError, setPaymentError] = useState(null);
  const [dynamicPrices, setDynamicPrices] = useState({});
  const [currency, setCurrency] = useState(detectCurrency);
  const [quote, setQuote] = useState(null);
  const [orderLoading, setOrderLoading] = useState(false);
  const [feeConfig, setFeeConfig] = useState({ platform_fee_percent: 2, gst_percent: 18 });

  useEffect(() => {
    fetch('/api/billing/tiers')
      .then(res => res.json())
      .then(data => {
        const prices = {};
        data.forEach(t => {
          prices[t.id] = {
            monthly_price: t.monthly_price,
            monthly_price_inr: t.monthly_price_inr
          };
        });
        setDynamicPrices(prices);
      })
      .catch(err => console.error('Failed to load dynamic prices', err));

    fetch('/api/billing/config')
      .then(res => (res.ok ? res.json() : null))
      .then(data => {
        if (data && data.platform_fee_percent !== undefined) {
          setFeeConfig({
            platform_fee_percent: data.platform_fee_percent,
            gst_percent: data.gst_percent || 0
          });
        }
      })
      .catch(() => {});
  }, []);

  const authFetch = async (url, options = {}) => {
    let res = await fetch(url, options);
    if (res.status === 401 && refreshAccessToken) {
      const newToken = await refreshAccessToken();
      if (newToken) {
        res = await fetch(url, {
          ...options,
          headers: {
            ...(options.headers || {}),
            'Authorization': `Bearer ${newToken}`
          }
        });
      }
    }
    return res;
  };

  const priceFor = (planId) => {
    if (planId === 'enterprise') return 'Custom';
    const tier = dynamicPrices[planId] || FALLBACK_TIERS.find(t => t.id === planId);
    if (!tier) return '—';
    const minor = currency === 'INR' ? tier.monthly_price_inr : tier.monthly_price;
    return formatMoney(minor, currency);
  };

  const handleSubscribe = async (planId) => {
    if (planId === 'enterprise') {
      window.location.href = '#booking';
      return;
    }

    if (!user) {
      navigate('/login');
      return;
    }

    setLoadingPlan(planId);
    try {
      const res = await authFetch('/api/billing/quote', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ tier_id: planId, currency })
      });
      const data = await res.json();
      if (!res.ok) {
        setPaymentError(data.message || 'Could not calculate the order total.');
        setLoadingPlan(null);
        return;
      }
      setQuote(data);
    } catch (err) {
      console.error(err);
      setPaymentError('Could not reach the payment service. Please try again.');
    }
    setLoadingPlan(null);
  };

  const verifyRazorpayPayment = async (response) => {
    try {
      const res = await authFetch('/api/billing/verify-payment', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'Authorization': `Bearer ${token}`
        },
        body: JSON.stringify({
          razorpay_order_id: response.razorpay_order_id,
          razorpay_payment_id: response.razorpay_payment_id,
          razorpay_signature: response.razorpay_signature
        })
      });

      const data = await res.json().catch(() => ({}));
      if (res.ok && data.status === 'success') {
        setPaymentSuccess(true);
        setQuote(null);
        setLoadingPlan(null);
        setTimeout(() => {
          window.location.reload();
        }, 3500);
        return;
      }

      setPaymentError(data.message || 'We could not verify the payment. If money was deducted, contact support with your payment id.');
    } catch (err) {
      console.error(err);
      setPaymentError('Payment verification failed due to a network error. Please contact support before retrying.');
    }
    setLoadingPlan(null);
  };

  const confirmPayment = async () => {
    if (!quote) return;
    setOrderLoading(true);
    try {
      const res = await authFetch('/api/billing/create-order', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'Authorization': `Bearer ${token}`
        },
        body: JSON.stringify({ tier_id: quote.tier_id, currency: quote.currency })
      });

      const order = await res.json().catch(() => ({}));
      if (!res.ok || !order.order_id) {
        setPaymentError(order.message || 'Could not start the payment. Please try again.');
        setOrderLoading(false);
        return;
      }

      await loadRazorpayScript();

      const options = {
        key: order.key_id,
        amount: order.amount,
        currency: order.currency,
        name: 'LarShield',
        description: order.description,
        order_id: order.order_id,
        prefill: order.prefill,
        notes: { tier_id: order.tier.id },
        theme: { color: '#2563eb' },
        modal: {
          ondismiss: () => {
            setLoadingPlan(null);
            setOrderLoading(false);
          }
        },
        handler: (response) => {
          verifyRazorpayPayment(response);
        }
      };

      const checkout = new window.Razorpay(options);
      checkout.on('payment.failed', (resp) => {
        const description = resp?.error?.description || 'Payment failed. Please try a different method.';
        setPaymentError(description);
        setLoadingPlan(null);
      });

      setQuote(null);
      setOrderLoading(false);
      checkout.open();
    } catch (err) {
      console.error(err);
      setPaymentError(err.message || 'Could not open the Razorpay checkout.');
      setOrderLoading(false);
      setLoadingPlan(null);
    }
  };

  const plans = [
    {
      id: 'quick',
      name: 'Quick Scan',
      icon: <Zap className="w-8 h-8 text-primary" />,
      description: 'Essential reconnaissance & basic security health checks.',
      scanners: '13 Security Modules',
      features: [
        '3 Scans for 1 Target Website',
        'Fast Recon (Headers, Nmap Quick, WHOIS, WAF)',
        'DNS Security & SSL/TLS Audit',
        'Cookies, CSP & Clickjacking Checks',
        'Git Repository Exposure Detection',
        'Instant PDF Report Export'
      ],
      popular: false
    },
    {
      id: 'advanced',
      name: 'Advanced Scan',
      icon: <Shield className="w-8 h-8 text-primary" />,
      description: 'Core vulnerability auditing & deep path analysis.',
      scanners: '36 Security Modules',
      popular: false,
      features: [
        '3 Scans for 1 Target Website',
        'Everything in Quick Scan',
        'Subdomain Discovery (Subfinder, Amass, crt.sh)',
        'XSS, SQL Injection & Path Traversal Fuzzing',
        'REST API, Cloud Bucket & Secrets Leak Scan',
        'CVE Database & Nikto Web Server Engine',
        'AI Remediation & Strategy Generator'
      ]
    },
    {
      id: 'deep',
      name: 'Deep Scan',
      icon: <Target className="w-8 h-8 text-primary" />,
      description: 'Exhaustive threat inspection & active DAST attack simulation.',
      scanners: '89 Security Modules',
      popular: true,
      features: [
        '3 Scans for 1 Target Website',
        'Everything in Advanced Scan',
        'Full 65535-Port Nmap with NSE Vulnerability Scripts',
        'Nuclei Scanner Engine (Critical/High/Med/Low)',
        'OWASP ZAP DAST Engine (Active Attack Mode)',
        'XXE, SSTI, IDOR, GraphQL & Business Logic Flaws',
        'HTTP/2 Desync, JS Supply Chain & SAML/OAuth Bypasses'
      ]
    },
    {
      id: 'enterprise',
      name: 'Custom Solutions',
      icon: <Briefcase className="w-8 h-8 text-primary" />,
      price: 'Custom',
      description: 'Tailored VAPT services and dedicated security infrastructure.',
      scanners: 'Expert Manual VAPT',
      popular: false,
      features: [
        'Everything in Deep Scan',
        'Quarterly Manual VAPT',
        'Dedicated Security Architect',
        'Custom Compliance Reporting',
        'On-Premise Deployment Options',
        '1-Hour SLA'
      ]
    }
  ];

  const gstApplies = currency === 'INR';
  const feeNote = gstApplies
    ? `+ ${feeConfig.platform_fee_percent}% platform fee + ${feeConfig.gst_percent}% GST on the fee`
    : `+ ${feeConfig.platform_fee_percent}% platform fee at checkout`;

  return (
    <div className={`${embedded ? 'py-8' : 'py-12'} bg-surface-container-lowest text-on-surface px-4 sm:px-6 relative overflow-hidden border-b border-outline-variant/30`}>

      {paymentError && (
        <div className="fixed bottom-10 left-1/2 -translate-x-1/2 z-[100] flex items-center bg-error text-on-error px-md py-sm rounded-lg shadow-xl animate-fade-in gap-sm border border-on-error/20 max-w-[90vw]">
          <span className="material-symbols-outlined">error</span>
          <span className="font-bold text-[14px]">{paymentError}</span>
          <button onClick={() => setPaymentError(null)} className="ml-md text-on-error/80 hover:text-on-error bg-transparent border-0 cursor-pointer p-0 flex items-center">
            <span className="material-symbols-outlined text-[18px]">close</span>
          </button>
        </div>
      )}

      {paymentSuccess && (
        <div className="fixed inset-0 z-[100] flex items-center justify-center bg-surface-container-lowest/80 backdrop-blur-sm animate-fade-in">
          <div className="bg-surface-container border border-outline-variant rounded-2xl p-xl shadow-2xl max-w-sm w-full text-center flex flex-col items-center transform animate-scale-up">
            <div className="w-20 h-20 bg-emerald-500/20 text-emerald-500 rounded-full flex items-center justify-center mb-md shadow-sm border border-emerald-500/30">
              <span className="material-symbols-outlined text-[48px] animate-pulse">check_circle</span>
            </div>
            <h2 className="font-headline-md font-bold text-on-surface mb-sm">Payment Successful</h2>
            <p className="font-body-md text-on-surface-variant mb-lg">Your Razorpay payment is verified. We are unlocking your scan package...</p>
            <div className="w-full bg-surface-container-highest rounded-full h-1.5 overflow-hidden">
              <div className="bg-emerald-500 h-full animate-[progress_3.5s_ease-in-out_forwards]"></div>
            </div>
          </div>
        </div>
      )}

      {quote && (
        <div className="fixed inset-0 z-[100] flex items-center justify-center bg-surface-container-lowest/80 backdrop-blur-sm px-4">
          <div className="bg-surface-container border border-outline-variant rounded-2xl p-lg shadow-2xl max-w-md w-full">
            <div className="flex items-start justify-between mb-md">
              <div>
                <h2 className="font-headline-md font-bold text-on-surface">Order Summary</h2>
                <p className="font-body-sm text-on-surface-variant text-[12.5px] mt-1">{quote.tier_name}</p>
              </div>
              <button
                onClick={() => setQuote(null)}
                className="bg-transparent border-0 cursor-pointer text-on-surface-variant hover:text-on-surface p-1"
                aria-label="Close"
              >
                <span className="material-symbols-outlined text-[20px]">close</span>
              </button>
            </div>

            <div className="bg-surface-container-lowest border border-outline-variant/60 rounded-xl p-sm text-[13px]">
              <div className="flex justify-between py-1.5 border-b border-outline-variant/30">
                <span className="text-on-surface-variant font-medium">Service price</span>
                <span className="font-bold text-on-surface">
                  {formatMoney(quote.base_amount, quote.currency)}
                </span>
              </div>
              <div className="flex justify-between py-1.5 border-b border-outline-variant/30">
                <span className="text-on-surface-variant font-medium">
                  Platform fee ({quote.fee_percent}%)
                </span>
                <span className="font-bold text-on-surface">
                  {formatMoney(quote.platform_fee, quote.currency)}
                </span>
              </div>
              {quote.tax_amount > 0 && (
                <div className="flex justify-between py-1.5 border-b border-outline-variant/30">
                  <span className="text-on-surface-variant font-medium">
                    GST on platform fee ({quote.gst_percent}%)
                  </span>
                  <span className="font-bold text-on-surface">
                    {formatMoney(quote.tax_amount, quote.currency)}
                  </span>
                </div>
              )}
              <div className="flex justify-between pt-2 mt-1 border-t-2 border-outline-variant/60">
                <span className="font-extrabold text-on-surface">Total payable</span>
                <span className="font-extrabold text-primary text-[16px]">
                  {formatMoney(quote.total_amount, quote.currency)}
                </span>
              </div>
            </div>

            <div className="flex items-center gap-xs mt-md bg-primary/10 border border-primary/20 rounded-lg px-3 py-2">
              <span className="material-symbols-outlined text-primary text-[18px]">verified</span>
              <span className="text-[12px] font-semibold text-on-surface">
                Includes {quote.scans_included} scans for 1 target website
              </span>
            </div>

            <p className="text-[11.5px] text-on-surface-variant mt-sm leading-relaxed">
              Secure checkout by Razorpay. UPI, credit/debit cards, netbanking, wallets and international cards accepted.
            </p>

            <div className="flex gap-sm mt-md">
              <button
                onClick={() => setQuote(null)}
                disabled={orderLoading}
                className="flex-1 py-2.5 rounded-lg font-bold text-sm border border-outline-variant bg-surface-container-lowest text-on-surface cursor-pointer disabled:opacity-60"
              >
                Cancel
              </button>
              <button
                onClick={confirmPayment}
                disabled={orderLoading}
                className="flex-1 py-2.5 rounded-lg font-bold text-sm border-0 bg-primary text-on-primary shadow-md cursor-pointer hover:opacity-90 disabled:opacity-60 flex items-center justify-center gap-xs"
              >
                {orderLoading ? (
                  <>
                    <span className="material-symbols-outlined animate-spin text-[18px]">sync</span>
                    Opening...
                  </>
                ) : (
                  <>Pay {formatMoney(quote.total_amount, quote.currency)}</>
                )}
              </button>
            </div>
          </div>
        </div>
      )}

      {/* Background Soft Gradients (Adapted to Light Theme) */}
      <div className="absolute top-0 left-1/4 w-[500px] h-[500px] bg-primary/5 rounded-full blur-[100px] -z-10 pointer-events-none"></div>
      <div className="absolute bottom-0 right-1/4 w-[600px] h-[600px] bg-secondary/5 rounded-full blur-[100px] -z-10 pointer-events-none"></div>

      <div className="max-w-[1400px] mx-auto">
        <div className="text-center mb-10 relative">
          <div className="inline-flex items-center space-x-2 bg-surface-container-low border border-outline-variant/60 rounded-full px-4 py-1 mb-4 shadow-sm">
            <Shield className="w-3.5 h-3.5 text-primary" />
            <span className="font-label-sm text-on-surface font-bold tracking-wider uppercase text-[10px]">LarShield Target Scan Packages</span>
          </div>
          <h1 className="font-display-lg text-3xl md:text-4xl font-extrabold text-on-surface mb-4 tracking-tight">
            Single Domain Scan Packages
          </h1>
          <p className="font-body-md text-base text-on-surface-variant max-w-2xl mx-auto mb-4 leading-relaxed">
            Purchase a plan once and perform up to <strong className="text-on-surface font-extrabold">3 complete scans</strong> on the same target website.
          </p>

          <div className="inline-flex items-center gap-xs bg-primary/10 text-primary border border-primary/20 rounded-full px-4 py-1.5 text-xs font-bold shadow-sm mb-4">
            <span className="material-symbols-outlined text-[16px]">verified</span>
            1 Plan Purchase = 3 Scans Allowed for 1 Target Website
          </div>

          <div className="flex items-center justify-center gap-sm">
            <div className="inline-flex items-center bg-surface-container-low border border-outline-variant rounded-full p-1">
              {['INR', 'USD'].map((code) => (
                <button
                  key={code}
                  onClick={() => { setCurrency(code); setQuote(null); }}
                  className={`px-3 py-1 rounded-full text-[12px] font-bold border-0 cursor-pointer transition-all ${currency === code
                    ? 'bg-primary text-on-primary shadow-sm'
                    : 'bg-transparent text-on-surface-variant hover:text-on-surface'
                    }`}
                >
                  {code === 'INR' ? '₹ INR' : '$ USD'}
                </button>
              ))}
            </div>
            <span className="text-[11.5px] text-on-surface-variant font-medium">
              {currency === 'INR' ? 'India (UPI, cards, netbanking)' : 'International cards'}
            </span>
          </div>
        </div>

        {/* Pricing Cards */}
        <div className="grid md:grid-cols-2 lg:grid-cols-4 gap-6 w-full mx-auto z-10 relative">
          {plans.map((plan) => {
            const isCurrentPlan = hideCurrentPlan ? false : user?.subscription_tier === plan.id;

            return (
              <div
                key={plan.id}
                className={`relative bg-surface-container-lowest rounded-2xl p-6 transition-all duration-300 flex flex-col group border-2 ${plan.popular ? 'border-primary shadow-xl scale-[1.02]' : 'border-outline-variant/50 shadow-sm hover:border-primary/50 hover:-translate-y-1 hover:shadow-lg'}`}
              >
                {plan.popular && (
                  <div className="absolute -top-3.5 left-1/2 -translate-x-1/2 bg-primary text-on-primary px-4 py-1 rounded-full font-label-sm text-[10px] font-extrabold uppercase tracking-wider shadow-sm whitespace-nowrap">
                    Recommended
                  </div>
                )}

                <div className="mb-4 flex flex-col gap-xs">
                  <div className="w-10 h-10 rounded-xl flex items-center justify-center mb-1 transition-transform duration-300 bg-primary/10">
                    {React.cloneElement(plan.icon, { className: 'w-5 h-5 text-primary' })}
                  </div>
                  <h3 className="font-headline-md text-lg font-extrabold text-on-surface">{plan.name}</h3>
                  <p className="font-body-sm text-on-surface-variant text-[12.5px] leading-snug min-h-[36px]">{plan.description}</p>
                </div>

                <div className="mb-2 flex items-baseline">
                  <span className="font-display-lg text-3xl lg:text-4xl font-extrabold text-on-surface tracking-tight">
                    {priceFor(plan.id)}
                  </span>
                </div>
                {plan.id !== 'enterprise' && (
                  <p className="text-[10.5px] text-on-surface-variant font-semibold mb-3">{feeNote}</p>
                )}

                <div className="mb-4 border-t border-outline-variant/40 pt-3">
                  <div className="inline-block bg-surface-container-low rounded-md px-2.5 py-0.5 font-label-sm text-[10px] font-bold text-primary uppercase tracking-wider border border-primary/10">
                    {plan.scanners}
                  </div>
                </div>

                <ul className="space-y-2 mb-6 flex-1">
                  {plan.features.map((feature, idx) => (
                    <li key={idx} className="flex items-start">
                      <Check className="w-4 h-4 mr-2.5 shrink-0 mt-0.5 text-primary" strokeWidth={3} />
                      <span className="font-body-sm text-on-surface text-[12.5px] leading-snug font-medium">{feature}</span>
                    </li>
                  ))}
                </ul>

                <button
                  onClick={() => handleSubscribe(plan.id)}
                  disabled={loadingPlan === plan.id || isCurrentPlan}
                  className={`w-full py-2.5 rounded-lg font-label-md text-sm transition-all duration-300 flex items-center justify-center font-bold border-0 cursor-pointer ${isCurrentPlan
                    ? 'bg-surface-container-highest text-on-surface-variant cursor-not-allowed opacity-80'
                    : 'bg-primary text-on-primary shadow-md hover:opacity-90 hover:shadow-lg active:scale-[0.98]'
                    }`}
                >
                  {loadingPlan === plan.id ? (
                    <span className="flex items-center gap-xs"><span className="material-symbols-outlined animate-spin text-[18px]">sync</span> Processing...</span>
                  ) : isCurrentPlan ? 'Current Plan' : plan.id === 'enterprise' ? 'Contact Sales' : 'Get Started'}
                  {!isCurrentPlan && loadingPlan !== plan.id && <ArrowRight className="w-4 h-4 ml-2 opacity-70" />}
                </button>
              </div>
            );
          })}
        </div>

        <p className="text-center text-[11.5px] text-on-surface-variant mt-6 font-medium">
          All payments are processed securely by Razorpay. Platform fee and applicable GST are shown before payment.
        </p>
      </div>
    </div>
  );
}