const { getDb } = require('../config/db');
const { AppError } = require('../middleware/error-handler');
const { formatMoney, parseMoney } = require('../utils/money');
const { fetchProviderServices } = require('./provider.service');

function parseMarkupPercent(value = process.env.DEFAULT_MARKUP_PERCENT || '0') {
  const raw = String(value).trim();

  if (!/^\d+(?:\.\d{1,4})?$/.test(raw)) {
    throw new AppError('Invalid markup percent', 400, 'INVALID_MARKUP_PERCENT');
  }

  return raw;
}

function calculateSellPrice(providerPrice, markupPercent = process.env.DEFAULT_MARKUP_PERCENT || '0') {
  const price = parseMoney(String(providerPrice));
  const markup = BigInt(Math.round(Number(markupPercent) * 10000));
  const sellPrice = (price * (1000000n + markup) + 500000n) / 1000000n;

  return formatMoney(sellPrice);
}

function normalizeProviderService(service, markupPercent) {
  const providerServiceId = String(service.service ?? service.provider_service_id ?? '').trim();
  const name = String(service.name ?? '').trim();
  const category = String(service.category ?? 'Uncategorized').trim() || 'Uncategorized';
  const providerPrice = String(service.rate ?? service.price ?? service.provider_price ?? '').trim();
  const min = Number(service.min);
  const max = Number(service.max);

  if (!providerServiceId || !name || !providerPrice || !Number.isInteger(min) || !Number.isInteger(max)) {
    throw new AppError('Provider service item is invalid', 502, 'INVALID_PROVIDER_SERVICE');
  }

  return {
    provider_service_id: providerServiceId,
    name,
    category,
    provider_price: formatMoney(parseMoney(providerPrice)),
    markup_percent: markupPercent,
    sell_price: calculateSellPrice(providerPrice, markupPercent),
    min,
    max,
    is_active: true
  };
}

async function syncServicesFromProvider(markupPercentInput) {
  const markupPercent = parseMarkupPercent(markupPercentInput);
  const providerServices = await fetchProviderServices();
  const services = providerServices.map((service) => normalizeProviderService(service, markupPercent));
  const db = getDb();

  await db.transaction(async (trx) => {
    for (const service of services) {
      const existing = await trx('services')
        .select('id')
        .where({ provider_service_id: service.provider_service_id })
        .first();

      if (existing) {
        await trx('services').where({ id: existing.id }).update(service);
      } else {
        await trx('services').insert(service);
      }
    }
  });

  return {
    synced: services.length
  };
}

async function listActiveServices() {
  return getDb()('services')
    .select('id', 'provider_service_id', 'name', 'category', 'sell_price', 'min', 'max', 'is_active', 'updated_at')
    .where({ is_active: true })
    .orderBy('category', 'asc')
    .orderBy('name', 'asc');
}

async function listAdminServices() {
  return getDb()('services')
    .select('id', 'provider_service_id', 'name', 'category', 'provider_price', 'markup_percent', 'sell_price', 'min', 'max', 'is_active', 'updated_at')
    .orderBy('category', 'asc')
    .orderBy('name', 'asc');
}

async function updateService(serviceId, input) {
  const db = getDb();
  const service = await db('services').where({ id: serviceId }).first();

  if (!service) {
    throw new AppError('Service not found', 404, 'SERVICE_NOT_FOUND');
  }

  const update = {};

  if (input.name !== undefined) update.name = input.name;
  if (input.category !== undefined) update.category = input.category;
  if (input.min !== undefined) update.min = input.min;
  if (input.max !== undefined) update.max = input.max;
  if (input.is_active !== undefined) update.is_active = input.is_active;
  if (input.sell_price !== undefined) update.sell_price = formatMoney(parseMoney(input.sell_price));

  if (input.markup_percent !== undefined) {
    update.markup_percent = parseMarkupPercent(input.markup_percent);
    update.sell_price = calculateSellPrice(service.provider_price, update.markup_percent);
  }

  if (Object.keys(update).length === 0) {
    throw new AppError('No service changes provided', 400, 'NO_SERVICE_CHANGES');
  }

  await db('services').where({ id: serviceId }).update(update);

  return db('services')
    .select('id', 'provider_service_id', 'name', 'category', 'provider_price', 'markup_percent', 'sell_price', 'min', 'max', 'is_active', 'updated_at')
    .where({ id: serviceId })
    .first();
}

module.exports = {
  calculateSellPrice,
  listActiveServices,
  listAdminServices,
  syncServicesFromProvider,
  updateService
};