const express = require('express');
const router = express.Router();
const Stripe = require('stripe');
const { supabase } = require('../config/supabase');

const stripe = new Stripe(process.env.STRIPE_SECRET_KEY);

/**
 * POST /api/stripe/create-checkout-session
 * Creates a Stripe Checkout session for purchasing Starter Kit + optional Premium subscription
 */
router.post('/create-checkout-session', async (req, res) => {
  try {
    const {
      userId,
      beneficiaryName,
      beneficiaryAddress,
      beneficiaryPhone,
      beneficiaryNotes,
      shippingAddress,
      includePremium = true
    } = req.body;

    if (!userId) {
      return res.status(400).json({ error: 'userId is required' });
    }

    if (!beneficiaryName || !beneficiaryAddress) {
      return res.status(400).json({ error: 'Beneficiary name and address are required' });
    }

    // Build line items
    const lineItems = [
      {
        price: process.env.STRIPE_PRICE_STARTER_KIT,
        quantity: 1,
      }
    ];

    if (includePremium) {
      lineItems.push({
        price: process.env.STRIPE_PRICE_PREMIUM,
        quantity: 1,
      });
    }

    // Create checkout session
    const sessionConfig = {
      mode: includePremium ? 'subscription' : 'payment',
      payment_method_types: ['card'],
      line_items: lineItems,
      success_url: `${process.env.FRONTEND_URL}/checkout/success?session_id={CHECKOUT_SESSION_ID}`,
      cancel_url: `${process.env.FRONTEND_URL}/checkout/cancel`,
      customer_email: req.body.email,
      metadata: {
        userId,
        beneficiaryName,
        beneficiaryAddress,
        beneficiaryPhone: beneficiaryPhone || '',
        beneficiaryNotes: beneficiaryNotes || '',
        shippingAddress: JSON.stringify(shippingAddress),
        includePremium: includePremium ? 'true' : 'false'
      },
      shipping_address_collection: {
        allowed_countries: ['US', 'CA']
      }
    };

    // Only add shipping options for payment mode (not subscription)
    if (!includePremium) {
      sessionConfig.shipping_options = [
        {
          shipping_rate_data: {
            type: 'fixed_amount',
            fixed_amount: { amount: 0, currency: 'usd' },
            display_name: 'Standard shipping',
            delivery_estimate: {
              minimum: { unit: 'business_day', value: 5 },
              maximum: { unit: 'business_day', value: 7 },
            },
          },
        },
        {
          shipping_rate_data: {
            type: 'fixed_amount',
            fixed_amount: { amount: 1500, currency: 'usd' },
            display_name: 'Express shipping',
            delivery_estimate: {
              minimum: { unit: 'business_day', value: 2 },
              maximum: { unit: 'business_day', value: 3 },
            },
          },
        },
      ];
    }

    const session = await stripe.checkout.sessions.create(sessionConfig);

    res.json({
      sessionId: session.id,
      url: session.url
    });

  } catch (error) {
    console.error('Checkout session error:', error);
    res.status(500).json({ error: error.message });
  }
});

/**
 * POST /api/stripe/create-portal-session
 * Creates a Stripe Customer Portal session for managing subscriptions
 */
router.post('/create-portal-session', async (req, res) => {
  try {
    const { customerId } = req.body;

    if (!customerId) {
      return res.status(400).json({ error: 'customerId is required' });
    }

    const session = await stripe.billingPortal.sessions.create({
      customer: customerId,
      return_url: `${process.env.FRONTEND_URL}/settings`,
    });

    res.json({ url: session.url });

  } catch (error) {
    console.error('Portal session error:', error);
    res.status(500).json({ error: error.message });
  }
});

/**
 * POST /api/stripe/create-payment-sheet
 * Creates PaymentIntent for in-app Payment Sheet (React Native)
 */
router.post('/create-payment-sheet', async (req, res) => {
  try {
    const { email, amount = 24900 } = req.body; // $249.00 default (Starter Kit)

    // Create or retrieve customer
    let customer;
    const existingCustomers = await stripe.customers.list({ email, limit: 1 });

    if (existingCustomers.data.length > 0) {
      customer = existingCustomers.data[0];
    } else {
      customer = await stripe.customers.create({ email });
    }

    // Create ephemeral key for the customer
    const ephemeralKey = await stripe.ephemeralKeys.create(
      { customer: customer.id },
      { apiVersion: '2024-12-18.acacia' }
    );

    // Create PaymentIntent
    const paymentIntent = await stripe.paymentIntents.create({
      amount,
      currency: 'usd',
      customer: customer.id,
      automatic_payment_methods: { enabled: true },
      metadata: req.body.metadata || {},
    });

    res.json({
      paymentIntent: paymentIntent.client_secret,
      ephemeralKey: ephemeralKey.secret,
      customer: customer.id,
      publishableKey: process.env.STRIPE_PUBLISHABLE_KEY,
    });

  } catch (error) {
    console.error('Payment sheet error:', error);
    res.status(500).json({ error: error.message });
  }
});

/**
 * GET /api/stripe/products
 * Returns available products and prices for the frontend
 */
router.get('/products', async (req, res) => {
  try {
    res.json({
      starterKit: {
        name: 'WellNuo Starter Kit',
        description: '2x Motion Sensors + 1x Door Sensor + 1x Hub',
        price: 249.00,
        priceId: process.env.STRIPE_PRICE_STARTER_KIT
      },
      premium: {
        name: 'WellNuo Premium',
        description: 'AI Julia assistant, 90-day history, invite up to 5 family members',
        price: 9.99,
        interval: 'month',
        priceId: process.env.STRIPE_PRICE_PREMIUM
      }
    });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

/**
 * Helper: Get or create Stripe Customer for a beneficiary
 * Customer is tied to BENEFICIARY (not user) so subscription persists when access is transferred
 */
async function getOrCreateStripeCustomer(beneficiaryId) {
  // Get beneficiary from DB (new beneficiaries table)
  const { data: beneficiary, error } = await supabase
    .from('beneficiaries')
    .select('id, name, stripe_customer_id')
    .eq('id', beneficiaryId)
    .single();

  if (error || !beneficiary) {
    throw new Error('Beneficiary not found');
  }

  // If already has Stripe customer, return it
  if (beneficiary.stripe_customer_id) {
    return beneficiary.stripe_customer_id;
  }

  // Create new Stripe customer for this beneficiary
  const customer = await stripe.customers.create({
    name: beneficiary.name || undefined,
    metadata: {
      beneficiary_id: beneficiary.id.toString(),
      type: 'beneficiary'
    }
  });

  // Save stripe_customer_id to DB
  await supabase
    .from('beneficiaries')
    .update({ stripe_customer_id: customer.id })
    .eq('id', beneficiaryId);

  console.log(`✓ Created Stripe customer ${customer.id} for beneficiary ${beneficiaryId}`);
  return customer.id;
}

/**
 * POST /api/stripe/create-subscription
 * Creates a Stripe Subscription for a beneficiary
 * Uses Stripe as the source of truth - no local subscription table needed!
 */
router.post('/create-subscription', async (req, res) => {
  try {
    const { beneficiaryId, paymentMethodId } = req.body;

    if (!beneficiaryId) {
      return res.status(400).json({ error: 'beneficiaryId is required' });
    }

    // Get or create Stripe customer for this beneficiary
    const customerId = await getOrCreateStripeCustomer(beneficiaryId);

    // Attach payment method to customer if provided
    if (paymentMethodId) {
      await stripe.paymentMethods.attach(paymentMethodId, { customer: customerId });
      await stripe.customers.update(customerId, {
        invoice_settings: { default_payment_method: paymentMethodId }
      });
    }

    // Check if customer already has an active subscription
    const existingSubs = await stripe.subscriptions.list({
      customer: customerId,
      status: 'active',
      limit: 1
    });

    if (existingSubs.data.length > 0) {
      const sub = existingSubs.data[0];
      return res.json({
        success: true,
        subscription: {
          id: sub.id,
          status: sub.status,
          plan: 'premium',
          currentPeriodEnd: new Date(sub.current_period_end * 1000).toISOString(),
          cancelAtPeriodEnd: sub.cancel_at_period_end
        },
        message: 'Subscription already active'
      });
    }

    // Create new subscription in Stripe
    const subscription = await stripe.subscriptions.create({
      customer: customerId,
      items: [{ price: process.env.STRIPE_PRICE_PREMIUM }],
      payment_behavior: 'default_incomplete',
      payment_settings: { save_default_payment_method: 'on_subscription' },
      expand: ['latest_invoice.payment_intent'],
      metadata: {
        beneficiary_id: beneficiaryId.toString()
      }
    });

    console.log(`✓ Created Stripe subscription ${subscription.id} for beneficiary ${beneficiaryId}`);

    res.json({
      success: true,
      subscription: {
        id: subscription.id,
        status: subscription.status,
        plan: 'premium',
        currentPeriodEnd: new Date(subscription.current_period_end * 1000).toISOString()
      },
      clientSecret: subscription.latest_invoice?.payment_intent?.client_secret
    });

  } catch (error) {
    console.error('Create subscription error:', error);
    res.status(500).json({ error: error.message });
  }
});

/**
 * Helper: Normalize Stripe subscription status to app statuses
 */
function normalizeStripeStatus(status) {
  switch (status) {
    case 'active':
      return 'active';
    case 'trialing':
      return 'trialing';
    case 'past_due':
    case 'unpaid':
      return 'past_due';
    case 'canceled':
      return 'canceled';
    case 'incomplete':
    case 'incomplete_expired':
      return 'expired';
    default:
      return 'none';
  }
}

/**
 * GET /api/stripe/subscription-status/:beneficiaryId
 * Gets subscription status directly from Stripe (source of truth)
 */
router.get('/subscription-status/:beneficiaryId', async (req, res) => {
  try {
    const { beneficiaryId } = req.params;

    // Get beneficiary's stripe_customer_id
    const { data: beneficiary } = await supabase
      .from('beneficiaries')
      .select('stripe_customer_id')
      .eq('id', beneficiaryId)
      .single();

    if (!beneficiary?.stripe_customer_id) {
      return res.json({
        status: 'none',
        plan: 'free',
        hasSubscription: false
      });
    }

    // Get active subscriptions from Stripe
    const subscriptions = await stripe.subscriptions.list({
      customer: beneficiary.stripe_customer_id,
      status: 'active',
      limit: 1
    });

    if (subscriptions.data.length === 0) {
      // Check for past_due or canceled
      const allSubs = await stripe.subscriptions.list({
        customer: beneficiary.stripe_customer_id,
        limit: 1
      });

      if (allSubs.data.length > 0) {
        const sub = allSubs.data[0];
        const normalizedStatus = normalizeStripeStatus(sub.status);
        return res.json({
          status: normalizedStatus,
          plan: normalizedStatus === 'canceled' || normalizedStatus === 'none' || normalizedStatus === 'expired' ? 'free' : 'premium',
          hasSubscription: normalizedStatus === 'active' || normalizedStatus === 'trialing',
          subscriptionId: sub.id,
          currentPeriodEnd: new Date(sub.current_period_end * 1000).toISOString(),
          cancelAtPeriodEnd: sub.cancel_at_period_end
        });
      }

      return res.json({
        status: 'none',
        plan: 'free',
        hasSubscription: false
      });
    }

    const subscription = subscriptions.data[0];

    res.json({
      status: 'active',
      plan: 'premium',
      hasSubscription: true,
      subscriptionId: subscription.id,
      currentPeriodEnd: new Date(subscription.current_period_end * 1000).toISOString(),
      cancelAtPeriodEnd: subscription.cancel_at_period_end
    });

  } catch (error) {
    console.error('Get subscription status error:', error);
    res.status(500).json({ error: error.message });
  }
});

/**
 * POST /api/stripe/cancel-subscription
 * Cancels subscription at period end
 */
router.post('/cancel-subscription', async (req, res) => {
  try {
    const { beneficiaryId } = req.body;
    console.log('[CANCEL] Request received for beneficiaryId:', beneficiaryId);

    if (!beneficiaryId) {
      return res.status(400).json({ error: 'beneficiaryId is required' });
    }

    // Get beneficiary's stripe_customer_id
    const { data: beneficiary, error: dbError } = await supabase
      .from('beneficiaries')
      .select('stripe_customer_id')
      .eq('id', beneficiaryId)
      .single();

    console.log('[CANCEL] DB result:', { beneficiary, dbError });

    if (!beneficiary?.stripe_customer_id) {
      console.log('[CANCEL] No stripe_customer_id found');
      return res.status(404).json({ error: 'No subscription found' });
    }

    // Get active subscription
    const subscriptions = await stripe.subscriptions.list({
      customer: beneficiary.stripe_customer_id,
      status: 'active',
      limit: 1
    });

    if (subscriptions.data.length === 0) {
      return res.status(404).json({ error: 'No active subscription found' });
    }

    // Cancel at period end (not immediately)
    const subscription = await stripe.subscriptions.update(subscriptions.data[0].id, {
      cancel_at_period_end: true
    });

    console.log(`✓ Subscription ${subscription.id} will cancel at period end:`, subscription.current_period_end);

    const cancelAt = subscription.current_period_end
      ? new Date(subscription.current_period_end * 1000).toISOString()
      : null;

    res.json({
      success: true,
      message: 'Subscription will cancel at the end of the billing period',
      cancelAt
    });

  } catch (error) {
    console.error('Cancel subscription error:', error);
    res.status(500).json({ error: error.message });
  }
});

/**
 * POST /api/stripe/reactivate-subscription
 * Reactivates a subscription that was set to cancel
 */
router.post('/reactivate-subscription', async (req, res) => {
  try {
    const { beneficiaryId } = req.body;

    if (!beneficiaryId) {
      return res.status(400).json({ error: 'beneficiaryId is required' });
    }

    const { data: beneficiary } = await supabase
      .from('beneficiaries')
      .select('stripe_customer_id')
      .eq('id', beneficiaryId)
      .single();

    if (!beneficiary?.stripe_customer_id) {
      return res.status(404).json({ error: 'No subscription found' });
    }

    const subscriptions = await stripe.subscriptions.list({
      customer: beneficiary.stripe_customer_id,
      limit: 1
    });

    if (subscriptions.data.length === 0) {
      return res.status(404).json({ error: 'No subscription found' });
    }

    const subscription = await stripe.subscriptions.update(subscriptions.data[0].id, {
      cancel_at_period_end: false
    });

    console.log(`✓ Subscription ${subscription.id} reactivated`);

    res.json({
      success: true,
      message: 'Subscription reactivated',
      status: subscription.status
    });

  } catch (error) {
    console.error('Reactivate subscription error:', error);
    res.status(500).json({ error: error.message });
  }
});

/**
 * POST /api/stripe/create-subscription-payment-sheet
 * Creates a SetupIntent for collecting payment method in React Native app
 * Then creates subscription with that payment method
 */
router.post('/create-subscription-payment-sheet', async (req, res) => {
  try {
    const { beneficiaryId } = req.body;

    if (!beneficiaryId) {
      return res.status(400).json({ error: 'beneficiaryId is required' });
    }

    // Get or create Stripe customer for this beneficiary
    const customerId = await getOrCreateStripeCustomer(beneficiaryId);

    // Check if already has active subscription
    const existingSubs = await stripe.subscriptions.list({
      customer: customerId,
      status: 'active',
      limit: 1
    });

    if (existingSubs.data.length > 0) {
      return res.json({
        alreadySubscribed: true,
        subscription: {
          id: existingSubs.data[0].id,
          status: 'active',
          currentPeriodEnd: new Date(existingSubs.data[0].current_period_end * 1000).toISOString()
        }
      });
    }

    // Cancel any incomplete subscriptions to avoid duplicates
    const incompleteSubs = await stripe.subscriptions.list({
      customer: customerId,
      status: 'incomplete',
      limit: 10
    });

    for (const sub of incompleteSubs.data) {
      try {
        await stripe.subscriptions.cancel(sub.id);
        console.log(`Canceled incomplete subscription ${sub.id} for customer ${customerId}`);
      } catch (cancelError) {
        console.warn(`Failed to cancel incomplete subscription ${sub.id}:`, cancelError.message);
      }
    }

    // Create ephemeral key
    const ephemeralKey = await stripe.ephemeralKeys.create(
      { customer: customerId },
      { apiVersion: '2024-12-18.acacia' }
    );

    // Create subscription with incomplete status (needs payment)
    const subscription = await stripe.subscriptions.create({
      customer: customerId,
      items: [{ price: process.env.STRIPE_PRICE_PREMIUM }],
      payment_behavior: 'default_incomplete',
      payment_settings: {
        save_default_payment_method: 'on_subscription',
        payment_method_types: ['card']
      },
      expand: ['latest_invoice.payment_intent'],
      metadata: {
        beneficiary_id: beneficiaryId.toString()
      }
    });

    // Try to get payment_intent from expanded invoice
    let clientSecret = subscription.latest_invoice?.payment_intent?.client_secret;

    // Stripe SDK v20+ doesn't expose payment_intent field in Invoice object
    // Need to fetch PaymentIntent via list API as a workaround
    if (!clientSecret && subscription.latest_invoice) {
      const invoiceId = typeof subscription.latest_invoice === 'string'
        ? subscription.latest_invoice
        : subscription.latest_invoice.id;

      if (invoiceId) {
        // List recent PaymentIntents for this customer and find the one for this invoice
        const paymentIntents = await stripe.paymentIntents.list({
          customer: customerId,
          limit: 5
        });

        for (const pi of paymentIntents.data) {
          if (pi.invoice === invoiceId || pi.description?.includes('Subscription')) {
            clientSecret = pi.client_secret;
            break;
          }
        }
      }
    }

    console.log(`[SUBSCRIPTION] Created subscription ${subscription.id}, clientSecret: ${!!clientSecret}`);

    res.json({
      subscriptionId: subscription.id,
      clientSecret: clientSecret,
      ephemeralKey: ephemeralKey.secret,
      customer: customerId,
      publishableKey: process.env.STRIPE_PUBLISHABLE_KEY
    });

  } catch (error) {
    console.error('Create subscription payment sheet error:', error);
    res.status(500).json({ error: error.message });
  }
});

/**
 * POST /api/stripe/confirm-subscription-payment
 * Confirms the latest invoice PaymentIntent for a subscription if needed
 */
router.post('/confirm-subscription-payment', async (req, res) => {
  try {
    const { subscriptionId } = req.body;

    if (!subscriptionId) {
      return res.status(400).json({ error: 'subscriptionId is required' });
    }

    const subscription = await stripe.subscriptions.retrieve(subscriptionId, {
      expand: ['latest_invoice.payment_intent']
    });

    const paymentIntent = subscription.latest_invoice?.payment_intent;
    const paymentIntentId = typeof paymentIntent === 'string' ? paymentIntent : paymentIntent?.id;
    const paymentIntentStatus = typeof paymentIntent === 'string' ? null : paymentIntent?.status;

    if (!paymentIntentId) {
      return res.status(400).json({ error: 'Payment intent not found for subscription' });
    }

    if (paymentIntentStatus === 'requires_confirmation') {
      const confirmed = await stripe.paymentIntents.confirm(paymentIntentId);
      return res.json({ success: true, status: confirmed.status });
    }

    return res.json({ success: true, status: paymentIntentStatus || 'unknown' });
  } catch (error) {
    console.error('Confirm subscription payment error:', error);
    res.status(500).json({ error: error.message });
  }
});

/**
 * GET /api/stripe/transaction-history/:beneficiaryId
 * Gets transaction/invoice history directly from Stripe
 */
router.get('/transaction-history/:beneficiaryId', async (req, res) => {
  try {
    const { beneficiaryId } = req.params;
    const limit = parseInt(req.query.limit) || 10;

    // Get beneficiary's stripe_customer_id
    const { data: beneficiary } = await supabase
      .from('beneficiaries')
      .select('stripe_customer_id')
      .eq('id', beneficiaryId)
      .single();

    if (!beneficiary?.stripe_customer_id) {
      return res.json({
        transactions: [],
        hasMore: false
      });
    }

    // Get invoices from Stripe
    const invoices = await stripe.invoices.list({
      customer: beneficiary.stripe_customer_id,
      limit: limit,
      expand: ['data.subscription']
    });

    // Also get PaymentIntents for one-time purchases (equipment)
    const paymentIntents = await stripe.paymentIntents.list({
      customer: beneficiary.stripe_customer_id,
      limit: limit
    });

    // Format invoices (subscription payments) - only show paid invoices
    const formattedInvoices = invoices.data
      .filter(invoice => invoice.status === 'paid' && invoice.amount_paid > 0)
      .map(invoice => ({
        id: invoice.id,
        type: 'subscription',
        amount: invoice.amount_paid / 100,
        currency: invoice.currency.toUpperCase(),
        status: invoice.status,
        date: new Date(invoice.created * 1000).toISOString(),
        description: invoice.lines.data[0]?.description || 'WellNuo Premium',
        invoicePdf: invoice.invoice_pdf,
        hostedUrl: invoice.hosted_invoice_url
      }));

    // Format payment intents (one-time purchases like equipment)
    // Exclude subscription-related payments (they're already in invoices)
    const formattedPayments = paymentIntents.data
      .filter(pi => {
        if (pi.status !== 'succeeded') return false;
        if (pi.invoice) return false; // Has linked invoice
        // Exclude "Subscription creation" - it's duplicate of invoice
        if (pi.description === 'Subscription creation') return false;
        return true;
      })
      .map(pi => ({
        id: pi.id,
        type: 'one_time',
        amount: pi.amount / 100,
        currency: pi.currency.toUpperCase(),
        status: pi.status,
        date: new Date(pi.created * 1000).toISOString(),
        description: pi.metadata?.orderType === 'starter_kit'
          ? 'WellNuo Starter Kit'
          : (pi.description || 'One-time payment'),
        receiptUrl: pi.charges?.data[0]?.receipt_url
      }));

    // Combine and sort by date (newest first)
    const allTransactions = [...formattedInvoices, ...formattedPayments]
      .sort((a, b) => new Date(b.date).getTime() - new Date(a.date).getTime());

    res.json({
      transactions: allTransactions,
      hasMore: invoices.has_more || paymentIntents.has_more
    });

  } catch (error) {
    console.error('Get transaction history error:', error);
    res.status(500).json({ error: error.message });
  }
});

/**
 * GET /api/stripe/session/:sessionId
 * Get checkout session details (for success page)
 */
router.get('/session/:sessionId', async (req, res) => {
  try {
    const session = await stripe.checkout.sessions.retrieve(req.params.sessionId, {
      expand: ['line_items', 'customer', 'subscription']
    });

    res.json({
      id: session.id,
      status: session.status,
      paymentStatus: session.payment_status,
      customerEmail: session.customer_email,
      amountTotal: session.amount_total / 100,
      metadata: session.metadata
    });

  } catch (error) {
    console.error('Get session error:', error);
    res.status(500).json({ error: error.message });
  }
});

module.exports = router;