# frozen_string_literal: true

# create PaymentSchedules for various items
class PaymentScheduleService
  ##
  # Compute a payment schedule for a new subscription to the provided plan
  # @param plan {Plan}
  # @param total {Number} Total amount of the current shopping cart (which includes this plan) - without coupon
  # @param coupon {Coupon} apply this coupon, if any
  ##
  def compute(plan, total, coupon: nil, subscription: nil)
    other_items = total - plan.amount
    # base monthly price of the plan
    price = plan.amount
    ps = PaymentSchedule.new(scheduled: plan, total: price + other_items, coupon: coupon)
    deadlines = plan.duration / 1.month
    per_month = (price / deadlines).truncate
    adjustment = if per_month * deadlines + other_items.truncate != ps.total
                   ps.total - (per_month * deadlines + other_items.truncate)
                 else
                   0
                 end
    items = []
    (0..deadlines - 1).each do |i|
      date = DateTime.current + i.months
      details = { recurring: per_month, subscription_id: subscription&.id }
      amount = if i.zero?
                 details[:adjustment] = adjustment.truncate
                 details[:other_items] = other_items.truncate
                 per_month + adjustment.truncate + other_items.truncate
               else
                 per_month
               end
      if coupon
        cs = CouponService.new
        if (coupon.validity_per_user == 'once' && i.zero?) || coupon.validity_per_user == 'forever'
          details[:without_coupon] = amount
          amount = cs.apply(amount, coupon)
        end
      end
      items.push PaymentScheduleItem.new(
        amount: amount,
        due_date: date,
        payment_schedule: ps,
        details: details
      )
    end
    ps.total = items.map(&:amount).reduce(:+)
    { payment_schedule: ps, items: items }
  end

  def create(subscription, total, coupon: nil, operator: nil, payment_method: nil, reservation: nil, user: nil, setup_intent_id: nil)
    subscription = reservation.generate_subscription if !subscription && reservation&.plan_id
    raise InvalidSubscriptionError unless subscription&.persisted?

    schedule = compute(subscription.plan, total, coupon: coupon, subscription: subscription)
    ps = schedule[:payment_schedule]
    items = schedule[:items]

    ps.scheduled = reservation || subscription
    ps.payment_method = payment_method
    ps.stp_setup_intent_id = setup_intent_id
    ps.operator_profile = operator.invoicing_profile
    ps.invoicing_profile = user.invoicing_profile
    ps.statistic_profile = user.statistic_profile
    ps.payment_schedule_items = items
    items.each do |item|
      item.payment_schedule = ps
    end
    ps
  end

  ##
  # Generate the invoice associated with the given PaymentScheduleItem, with the children elements (InvoiceItems).
  # @param stp_invoice is used to determine if the invoice was paid using stripe
  ##
  def generate_invoice(payment_schedule_item, stp_invoice = nil)
    # build the base invoice
    invoice = Invoice.new(
      invoiced: payment_schedule_item.payment_schedule.scheduled,
      invoicing_profile: payment_schedule_item.payment_schedule.invoicing_profile,
      statistic_profile: payment_schedule_item.payment_schedule.statistic_profile,
      operator_profile_id: payment_schedule_item.payment_schedule.operator_profile_id,
      stp_payment_intent_id: stp_invoice&.payment_intent,
      payment_method: stp_invoice ? 'stripe' : nil
    )
    # complete the invoice with some InvoiceItem
    if payment_schedule_item.first?
      complete_first_invoice(payment_schedule_item, invoice)
    else
      complete_next_invoice(payment_schedule_item, invoice)
    end

    # set the total and apply any coupon
    user = payment_schedule_item.payment_schedule.user
    coupon = payment_schedule_item.payment_schedule.coupon
    set_total_and_coupon(payment_schedule_item, invoice, user, coupon)

    # save the results
    invoice.save
    payment_schedule_item.update_attributes(invoice_id: invoice.id)
  end

  ##
  # return a paginated list of PaymentSchedule, optionally filtered, with their associated PaymentScheduleItem
  # @param page {number} page number, used to paginate results
  # @param size {number} number of items per page
  # @param filters {Hash} allowed filters: reference, customer, date.
  ##
  def self.list(page, size, filters = {})
    ps = PaymentSchedule.includes(:invoicing_profile, :payment_schedule_items, :subscription)
                        .joins(:invoicing_profile)
                        .order('payment_schedules.created_at DESC')
                        .page(page)
                        .per(size)


    unless filters[:reference].nil?
      ps = ps.where(
        'payment_schedules.reference LIKE :search',
        search: "#{filters[:reference]}%"
      )
    end
    unless filters[:customer].nil?
      # ILIKE => PostgreSQL case-insensitive LIKE
      ps = ps.where(
        'invoicing_profiles.first_name ILIKE :search OR invoicing_profiles.last_name ILIKE :search',
        search: "%#{filters[:customer]}%"
      )
    end
    unless filters[:date].nil?
      ps = ps.where(
        "date_trunc('day', payment_schedules.created_at) = :search OR date_trunc('day', payment_schedule_items.due_date) = :search",
        search: "%#{DateTime.iso8601(filters[:date]).to_time.to_date}%"
      )
    end

    ps
  end

  def self.cancel(payment_schedule)
    # cancel all item where state != paid
    payment_schedule.ordered_items.each do |item|
      next if item.state == 'paid'

      item.update_attributes(state: 'canceled')
    end
    # cancel subscription
    subscription = Subscription.find(payment_schedule.payment_schedule_items.first.details['subscription_id'])
    subscription.expire(DateTime.current)

    subscription.canceled_at
  end

  private

  ##
  # The first PaymentScheduleItem contains references to the reservation price (if any) and to the adjustement price
  # for the subscription (if any) and the wallet transaction (if any)
  ##
  def complete_first_invoice(payment_schedule_item, invoice)
    # sub-prices for the subscription and the reservation
    details = {
      subscription: payment_schedule_item.details['recurring'] + payment_schedule_item.details['adjustment']
    }

    # the subscription and reservation items
    subscription = Subscription.find(payment_schedule_item.details['subscription_id'])
    if payment_schedule_item.payment_schedule.scheduled_type == Reservation.name
      details[:reservation] = payment_schedule_item.details['other_items']
      reservation = payment_schedule_item.payment_schedule.scheduled
    end

    # the wallet transaction
    invoice[:wallet_amount] = payment_schedule_item.payment_schedule.wallet_amount
    invoice[:wallet_transaction_id] = payment_schedule_item.payment_schedule.wallet_transaction_id

    # build the invoice items
    generate_invoice_items(invoice, details, subscription: subscription, reservation: reservation)
  end

  ##
  # The later PaymentScheduleItems only contain references to the subscription (which is recurring)
  ##
  def complete_next_invoice(payment_schedule_item, invoice)
    # the subscription item
    subscription = Subscription.find(payment_schedule_item.details['subscription_id'])

    # sub-price for the subscription
    details = { subscription: payment_schedule_item.details['recurring'] }

    # build the invoice item
    generate_invoice_items(invoice, details, subscription: subscription)
  end

  ##
  # Generate an array of InvoiceItem according to the provided parameters and saves them in invoice.invoice_items
  ##
  def generate_invoice_items(invoice, payment_details, reservation: nil, subscription: nil)
    generate_reservation_item(invoice, reservation, payment_details) if reservation

    return unless subscription

    generate_subscription_item(invoice, subscription, payment_details)
  end

  ##
  # Generate a single InvoiceItem for the given reservation and save it in invoice.invoice_items.
  # This method must be called only with a valid reservation
  ##
  def generate_reservation_item(invoice, reservation, payment_details)
    raise TypeError unless [Space, Machine, Training].include? reservation.reservable.class

    description = "#{reservation.reservable.name}\n"
    reservation.slots.each do |slot|
      description += " #{I18n.l slot.start_at, format: :long} - #{I18n.l slot.end_at, format: :hour_minute}\n"
    end

    invoice.invoice_items.push InvoiceItem.new(
      amount: payment_details[:reservation],
      description: description
    )
  end

  ##
  # Generate an InvoiceItem for the given subscription and save it in invoice.invoice_items.
  # This method must be called only with a valid subscription
  ##
  def generate_subscription_item(invoice, subscription, payment_details)
    raise TypeError unless subscription

    invoice.invoice_items.push InvoiceItem.new(
      amount: payment_details[:subscription],
      description: subscription.plan.name,
      subscription_id: subscription.id
    )
  end

  ##
  # Set the total price to the invoice, summing all sub-items.
  # Additionally a coupon may be applied to this invoice to make a discount on the total price
  ##
  def set_total_and_coupon(payment_schedule_item, invoice, user, coupon = nil)
    return unless invoice

    total = invoice.invoice_items.map(&:amount).map(&:to_i).reduce(:+)

    unless coupon.nil?
      if (coupon.validity_per_user == 'once' && payment_schedule_item.first?) || coupon.validity_per_user == 'forever'
        total = CouponService.new.apply(total, coupon, user.id)
        invoice.coupon_id = coupon.id
      end
    end

    invoice.total = total
  end
end