const pg = require('../pg')
const joinjs = require('join-js').default;
const debug = require('debug')('sos:db:order')
const mappings = require('../mappings')
const dbUtil = require('../util')

const config = require('./config')

const {DateTime} = require('luxon')
const easypost = new (require('@easypost/api'))(process.env.EASYPOST_API_KEY);

const order = module.exports = {}

order.create = async function(cart_uuid, session_uuid){
  const query = {
    text: 'select * from sos.create_order($1, $2)',
    values: [cart_uuid, session_uuid]
  }

  debug(query);

  const {rows} = await pg.query(query)
  return joinjs.map(rows, mappings, 'orderMap', 'order_')[0];
}

order.findForCart = async function(cart_uuid) {
  const query = {
    text: 'select * from sos.find_order_for_cart($1)',
    values: [cart_uuid]
  }

  debug(query)

  const {rows} = await pg.query(query)
  return joinjs.map(rows, mappings, 'orderMap', 'order_')[0];
}

order.findAllForSession = async function(session_uuid) {
  const query = {
    text: 'select * from sos.find_orders_for_session($1)',
    values: [session_uuid]
  }

  debug(query)

  const {rows} = await pg.query(query)
  return joinjs.map(rows, mappings, 'orderMap', 'order_');
}

order.findForTransaction = transaction_uuid =>
  dbUtil.executeFunction({
    name: 'find_order_for_transaction',
    params: [
      transaction_uuid
    ],
    returnType: 'order',
    single: true
  })

order.addAddress = async function (transaction, address){
  // Get parcel size
  const parcel = {
    weight: .2 * transaction.cart.items.length,
    width: 10,
    length: transaction.cart.items.length,
    height: 3
  }

  // Create shipment
  const epShipment = new easypost.Shipment({
    to_address: address.easypost_id,
    from_address: {
      street1: '11381 N. Sampson Drive',
      city: 'Highland',
      state: 'UT',
      zip: '84003',
      country: 'US'
    },
    parcel
  })

  await epShipment.save()

  // Get shipping price (as cents)
  const lowestRate = epShipment.lowestRate(['USPS'])
  const price = parseFloat(lowestRate && lowestRate.retail_rate) * 100
  if(!price)
    throw new Error("Unable to estimate price");

  // Add up tax for all the items
  const tax = epShipment.to_address.state !== 'UT'
    ? null
    : transaction.cart.items
        // For each item type, create an array of length n (number of items of that type in cart)
        // where each index is initialized to the item tax amount
        .map(({item, count}) => new Array(count).fill(item.tax_rate * item.price_cents / 100))
        // Flatten to just be all tax amounts
        .flat()
        // Sum all the numbers
        .reduce((a,c) => (a+c))

  // Update database
  const query = {
    text: 'select * from sos.add_address_to_order($1, $2, $3)',
    values: [transaction.uuid, address.uuid, price]
  }

  debug(query)
  await pg.query(query)

  // Update tax
  return await order.updateTax(transaction.uuid)
}

order.updateTax = async function(transaction_uuid){
  const _order = await order.findForTransaction(transaction_uuid)

  if(!_order.address)
    throw new Error("Order has no address");

  if(_order.address.state !== 'UT'){
    debug("Skipping tax for state: " + _order.address.state);
    return
  }

  const {item_total_price, coupon_effective_discount} = _order.transactions.find(t => t.uuid === transaction_uuid)
  const itemPriceWithDiscount = item_total_price - (coupon_effective_discount || 0)
  const taxRate = await config.getTaxRate()

  const computedTax = Math.round(itemPriceWithDiscount * taxRate / 100)
  return await dbUtil.executeFunction({
    name: 'add_tax_to_transaction',
    params: [
      transaction_uuid,
      computedTax
    ],
    returnType: 'order',
    single: true
  })
}

order.addCoupon = async function(transaction, coupon) {
  // Check coupon validity
  const couponExpireTime = DateTime.fromJSDate(coupon.valid_until)
  if(couponExpireTime.diffNow().as('seconds') < 0)
    throw new Error("Coupon has expired");

  const {item_total_price} = transaction
  let discount = 0;

  if(coupon.flat_discount_cents)
    discount = coupon.flat_discount_cents;

  if(coupon.percent_discount)
    discount = Math.ceil(item_total_price * coupon.percent_discount / 100)

  if(coupon.per_sock_discount_cents)
    discount = transaction.cart.items
      // For each item type, create an array of length n (number of items of that type in cart)
      // where each index is initialized to the item price
      .map(({item, count}) => new Array(count).fill(item.price_cents))
      // Flatten to just be all prices
      .flat()
      // For each price, convert it to the per-item discount (max of item price)
      .map(price => Math.min(price, coupon.per_sock_discount_cents))
      // Sum all the discounts
      .reduce((a,c) => (a+c))

  if(coupon.number_of_socks_free)
    discount = transaction.cart.items
      // For each item type, create an array of length n (number of items of that type in cart)
      // where each index is initialized to the item price
      .map(({item, count}) => new Array(count).fill(item.price_cents))
      // Flatten to just be all prices
      .flat()
      // Order so the most expensive are at the front
      .sort((a,b) => (b-a))
      // Keep only first n items
      .slice(0, coupon.number_of_socks_free)
      // Sum the item costs for total discount
      .reduce((a,c) => (a+c))

  await dbUtil.executeFunction({
    name: 'add_coupon_to_transaction',
    params: [
      transaction.uuid,
      coupon.uuid,
      discount
    ],
    returnType: 'order',
    single: true
  })

  // Update tax
  return await order.updateTax(transaction.uuid)
}

order.addPayment = async function(transaction, paymentIntent){
  const [charge] = paymentIntent.charges.data

  if(!charge.paid) throw new Error("Charge was not paid")

  // TODO: Put these both in a common transaction.  Flag purchase for follow-up
  // and/or send alert and/or refund on Stripe upon failure.

  const order = await dbUtil.executeFunction({
    name: 'add_stripe_payment_to_transaction',
    params: [
      transaction.uuid,
      paymentIntent.amount_received,
      paymentIntent.id,
      paymentIntent.receipt_email
    ],
    returnType: 'order',
    single: true
  })

  await dbUtil.executeFunction({
    name: 'deduct_stock_for_purchase',
    params: [transaction.uuid],
    returnType: 'item',
    single: false
  })

  return order
}