const Event = require('../models/Event');
const { success, error } = require('../utils/response');
const { defaultManualEnablementFeeInrFromEnv } = require('../utils/manualTicketingFee');
const { manualQrFieldsSatisfied } = require('../utils/ticketingManualPayment');
const { createManualEnablementCheckoutOrder } = require('../services/ticketingManualEnablement.service');

async function assertEventAccess(eventId, user) {
  const event = await Event.findById(eventId).select('organization').lean();
  if (!event) return { err: (h) => h.response(error('NOT_FOUND', 'Event not found')).code(404) };
  if (
    user.role !== 'super_admin' &&
    String(event.organization) !== String(user.organization?._id || user.organization || '')
  ) {
    return { err: (h) => h.response(error('FORBIDDEN', 'Access denied')).code(403) };
  }
  return { event };
}

function shapeTicketingManualResponse(mp) {
  const raw = mp && typeof mp === 'object' ? mp : {};
  /** Legacy field; buyers are no longer charged a per-order Eventbuzz fee (enablement fee covers the organiser). */
  const fee =
    raw.platformFeeInr != null && Number.isFinite(Number(raw.platformFeeInr)) ? Number(raw.platformFeeInr) : 0;
  const mode = raw.manualQrMode === 'dynamic' ? 'dynamic' : 'upload';
  return {
    enabled: Boolean(raw.enabled),
    manualQrMode: mode,
    upiQrImageUrl: raw.upiQrImageUrl || '',
    upiId: raw.upiId || '',
    payeeName: raw.payeeName || '',
    instructions: raw.instructions || '',
    platformFeeInr: fee,
    platformFeeInrIsDefault: raw.platformFeeInr == null,
    enablementFeeInr: defaultManualEnablementFeeInrFromEnv(),
    enablementPaid: Boolean(raw.enablementFeePaidAt),
    enablementPaidAt: raw.enablementFeePaidAt || null,
  };
}

const patch = async (request, h) => {
  const { eventId } = request.params;
  const user = request.auth.credentials.user;
  const r = await assertEventAccess(eventId, user);
  if (r.err) return r.err(h);

  const p = request.payload;
  const doc = await Event.findById(eventId);
  if (!doc) return h.response(error('NOT_FOUND', 'Event not found')).code(404);

  const prev = doc.ticketingManualPayment && typeof doc.ticketingManualPayment === 'object' ? doc.ticketingManualPayment : {};

  const next = { ...prev };
  if (p.enabled !== undefined) next.enabled = Boolean(p.enabled);
  if (p.manualQrMode !== undefined) {
    next.manualQrMode = p.manualQrMode === 'dynamic' ? 'dynamic' : 'upload';
  }
  if (p.upiQrImageUrl !== undefined) next.upiQrImageUrl = String(p.upiQrImageUrl || '').trim();
  if (p.upiId !== undefined) next.upiId = String(p.upiId || '').trim();
  if (p.payeeName !== undefined) next.payeeName = String(p.payeeName || '').trim();
  if (p.instructions !== undefined) next.instructions = String(p.instructions || '');
  if (p.platformFeeInr !== undefined) {
    if (p.platformFeeInr === null) next.platformFeeInr = null;
    else {
      const n = Number(p.platformFeeInr);
      if (!Number.isFinite(n) || n < 0) {
        return h.response(error('VALIDATION_ERROR', 'platformFeeInr must be a non-negative number or null')).code(400);
      }
      next.platformFeeInr = n;
    }
  }

  const enablementOk = Boolean(next.enablementFeePaidAt || prev.enablementFeePaidAt);
  if (next.enabled && !enablementOk) {
    return h
      .response(
        error(
          'PAYMENT_REQUIRED',
          'Pay the manual UPI enablement fee for this event before enabling manual checkout. The paid transaction appears under Settings → Billing.',
        ),
      )
      .code(402);
  }

  if (next.enabled) {
    const mode = next.manualQrMode === 'dynamic' ? 'dynamic' : 'upload';
    if (mode === 'upload' && !String(next.upiQrImageUrl || '').trim()) {
      return h.response(error('VALIDATION_ERROR', 'Add a UPI QR image or URL before enabling upload mode')).code(400);
    }
    if (mode === 'dynamic' && !String(next.upiId || '').trim()) {
      return h.response(error('VALIDATION_ERROR', 'Enter a UPI ID (VPA) before enabling dynamic QR mode')).code(400);
    }
  }

  if (next.enabled && !manualQrFieldsSatisfied(next)) {
    return h.response(error('VALIDATION_ERROR', 'Complete QR settings before enabling')).code(400);
  }

  doc.ticketingManualPayment = next;
  await doc.save();

  return h.response(
    success({
      ticketingManualPayment: shapeTicketingManualResponse(doc.ticketingManualPayment),
    }),
  );
};

const get = async (request, h) => {
  const { eventId } = request.params;
  const user = request.auth.credentials.user;
  const r = await assertEventAccess(eventId, user);
  if (r.err) return r.err(h);

  const doc = await Event.findById(eventId).select('ticketingManualPayment').lean();
  if (!doc) return h.response(error('NOT_FOUND', 'Event not found')).code(404);

  return h.response(
    success({
      ticketingManualPayment: shapeTicketingManualResponse(doc.ticketingManualPayment || {}),
    }),
  );
};

const checkoutEnablementOrder = async (request, h) => {
  const { eventId } = request.params;
  const user = request.auth.credentials.user;
  const r = await assertEventAccess(eventId, user);
  if (r.err) return r.err(h);

  const orgId = user.organization?._id || user.organization;
  if (!orgId) return h.response(error('VALIDATION_ERROR', 'No organisation')).code(400);

  try {
    const result = await createManualEnablementCheckoutOrder({
      organizationId: orgId,
      userId: user._id,
      eventId,
    });
    return h
      .response(
        success({
          keyId: result.keyId,
          orderId: result.orderId,
          amount: result.amount,
          currency: result.currency,
          transactionId: result.transaction._id.toString(),
          checkoutSource: result.checkoutSource,
          enablementFeeInr: defaultManualEnablementFeeInrFromEnv(),
        }),
      )
      .code(201);
  } catch (e) {
    if (e.code === 'ALREADY_PAID') {
      return h.response(error('VALIDATION_ERROR', e.message)).code(409);
    }
    if (e.code === 'INVALID_CONFIG') {
      return h.response(error('VALIDATION_ERROR', e.message)).code(400);
    }
    if (
      e.code === 'NOT_FOUND' ||
      e.code === 'FORBIDDEN' ||
      e.code === 'NO_GATEWAY' ||
      e.code === 'PLATFORM_RAZORPAY_MISSING' ||
      e.code === 'INVALID_AMOUNT' ||
      e.code === 'RAZORPAY_SDK_MISSING'
    ) {
      return h.response(error('VALIDATION_ERROR', e.message)).code(400);
    }
    throw e;
  }
};

module.exports = { patch, get, checkoutEnablementOrder };