# frozen_string_literal: true

require 'spree/order/checkout'
require 'open_food_network/enterprise_fee_calculator'
require 'open_food_network/feature_toggle'
require 'open_food_network/tag_rule_applicator'
require 'concerns/order_shipment'

module Spree
  class Order < ActiveRecord::Base
    prepend OrderShipment
    include Checkout

    checkout_flow do
      go_to_state :address
      go_to_state :delivery
      go_to_state :payment, if: ->(order) {
        order.update_totals
        order.payment_required?
      }
      go_to_state :complete
    end

    state_machine.after_transition to: :payment, do: :charge_shipping_and_payment_fees!

    state_machine.event :restart_checkout do
      transition to: :cart, unless: :completed?
    end

    token_resource

    belongs_to :user, class_name: Spree.user_class.to_s
    belongs_to :created_by, class_name: Spree.user_class.to_s

    belongs_to :bill_address, foreign_key: :bill_address_id, class_name: 'Spree::Address'
    alias_attribute :billing_address, :bill_address

    belongs_to :ship_address, foreign_key: :ship_address_id, class_name: 'Spree::Address'
    alias_attribute :shipping_address, :ship_address

    has_many :state_changes, as: :stateful
    has_many :line_items, -> { order('created_at ASC') }, dependent: :destroy
    has_many :payments, dependent: :destroy
    has_many :return_authorizations, dependent: :destroy, inverse_of: :order
    has_many :adjustments, -> { order "#{Spree::Adjustment.table_name}.created_at ASC" },
             as: :adjustable,
             dependent: :destroy

    has_many :line_item_adjustments, through: :line_items, source: :adjustments
    has_many :all_adjustments, class_name: 'Spree::Adjustment', dependent: :destroy

    has_many :shipments, dependent: :destroy do
      def states
        pluck(:state).uniq
      end
    end

    belongs_to :order_cycle
    belongs_to :distributor, class_name: 'Enterprise'
    belongs_to :customer
    has_one :proxy_order
    has_one :subscription, through: :proxy_order

    accepts_nested_attributes_for :line_items
    accepts_nested_attributes_for :bill_address
    accepts_nested_attributes_for :ship_address
    accepts_nested_attributes_for :payments
    accepts_nested_attributes_for :shipments

    delegate :admin_and_handling_total, :payment_fee, :ship_total, to: :adjustments_fetcher

    # Needs to happen before save_permalink is called
    before_validation :set_currency
    before_validation :generate_order_number, on: :create
    before_validation :clone_billing_address, if: :use_billing?
    before_validation :associate_customer, unless: :customer_id?
    before_validation :ensure_customer, unless: :customer_is_valid?

    validates :customer, presence: true, if: :require_customer?
    validate :products_available_from_new_distribution, if: lambda {
      distributor_id_changed? || order_cycle_id_changed?
    }
    validate :disallow_guest_order

    attr_accessor :use_billing

    before_create :link_by_email
    after_create :create_tax_charge!

    validate :has_available_shipment
    validates :email, presence: true,
                      format: /\A([\w\.%\+\-']+)@([\w\-]+\.)+([\w]{2,})\z/i,
                      if: :require_email

    make_permalink field: :number

    before_save :update_shipping_fees!, if: :complete?
    before_save :update_payment_fees!, if: :complete?

    # -- Scopes
    scope :managed_by, lambda { |user|
      if user.has_spree_role?('admin')
        where(nil)
      else
        # Find orders that are distributed by the user or have products supplied by the user
        # WARNING: This only filters orders,
        #   you'll need to filter line items separately using LineItem.managed_by
        with_line_items_variants_and_products_outer.
          where('spree_orders.distributor_id IN (?) OR spree_products.supplier_id IN (?)',
                user.enterprises.select(&:id),
                user.enterprises.select(&:id)).
          select('DISTINCT spree_orders.*')
      end
    }

    scope :distributed_by_user, lambda { |user|
      if user.has_spree_role?('admin')
        where(nil)
      else
        where('spree_orders.distributor_id IN (?)', user.enterprises.select(&:id))
      end
    }

    scope :with_line_items_variants_and_products_outer, lambda {
      joins('LEFT OUTER JOIN spree_line_items ON (spree_line_items.order_id = spree_orders.id)').
        joins('LEFT OUTER JOIN spree_variants ON (spree_variants.id = spree_line_items.variant_id)').
        joins('LEFT OUTER JOIN spree_products ON (spree_products.id = spree_variants.product_id)')
    }

    scope :not_state, lambda { |state|
      where("state != ?", state)
    }

    # All the states an order can be in after completing the checkout
    FINALIZED_STATES = %w(complete canceled resumed awaiting_return returned).freeze

    scope :finalized, -> { where(state: FINALIZED_STATES) }

    def self.by_number(number)
      where(number: number)
    end

    def self.between(start_date, end_date)
      where(created_at: start_date..end_date)
    end

    def self.by_customer(customer)
      joins(:user).where("#{Spree.user_class.table_name}.email" => customer)
    end

    def self.by_state(state)
      where(state: state)
    end

    def self.complete
      where('completed_at IS NOT NULL')
    end

    def self.incomplete
      where(completed_at: nil)
    end

    # For compatiblity with Calculator::PriceSack
    def amount
      line_items.inject(0.0) { |sum, li| sum + li.amount }
    end

    def currency
      self[:currency] || Spree::Config[:currency]
    end

    def display_outstanding_balance
      Spree::Money.new(outstanding_balance, currency: currency)
    end

    def display_item_total
      Spree::Money.new(item_total, currency: currency)
    end

    def display_adjustment_total
      Spree::Money.new(adjustment_total, currency: currency)
    end

    def display_tax_total
      Spree::Money.new(tax_total, currency: currency)
    end

    def display_ship_total
      Spree::Money.new(ship_total, currency: currency)
    end

    def display_total
      Spree::Money.new(total, currency: currency)
    end

    def to_param
      number.to_s.to_url.upcase
    end

    def completed?
      completed_at.present?
    end

    # Indicates whether or not the user is allowed to proceed to checkout.
    # Currently this is implemented as a check for whether or not there is at
    # least one LineItem in the Order.  Feel free to override this logic in your
    # own application if you require additional steps before allowing a checkout.
    def checkout_allowed?
      line_items.count > 0
    end

    def changes_allowed?
      complete? && distributor.andand.allow_order_changes? && order_cycle.andand.open?
    end

    # Is this a free order in which case the payment step should be skipped
    # This allows unpaid subscription orders to be completed.
    #   Subscriptions place orders at the beginning of an order cycle. They need to
    #   be completed to draw from stock levels and trigger emails.
    def payment_required?
      total.to_f > 0.0 && !skip_payment_for_subscription?
    end

    # Indicates the number of items in the order
    def item_count
      line_items.inject(0) { |sum, li| sum + li.quantity }
    end

    def backordered?
      shipments.any?(&:backordered?)
    end

    # Returns the relevant zone (if any) to be used for taxation purposes.
    # Uses default tax zone unless there is a specific match
    def tax_zone
      Zone.match(tax_address) || Zone.default_tax
    end

    # Indicates whether tax should be backed out of the price calcualtions in
    # cases where prices include tax but the customer is not required to pay
    # taxes in that case.
    def exclude_tax?
      return false unless Spree::Config[:prices_inc_tax]

      tax_zone != Zone.default_tax
    end

    # Returns the address for taxation based on configuration
    def tax_address
      Spree::Config[:tax_using_ship_address] ? ship_address : bill_address
    end

    # Array of totals grouped by Adjustment#label. Useful for displaying line item
    # adjustments on an invoice. For example, you can display tax breakout for
    # cases where tax is included in price.
    def line_item_adjustment_totals
      Hash[line_item_adjustments.eligible.group_by(&:label).map do |label, adjustments|
        total = adjustments.sum(&:amount)
        [label, Spree::Money.new(total, currency: currency)]
      end]
    end

    def updater
      @updater ||= OrderManagement::Order::Updater.new(self)
    end

    def update!
      updater.update
    end

    delegate :update_totals, to: :updater

    def clone_billing_address
      if bill_address && ship_address.nil?
        self.ship_address = bill_address.clone
      else
        ship_address.attributes = bill_address.attributes.except('id', 'updated_at', 'created_at')
      end
      true
    end

    def allow_cancel?
      return false unless completed? && (state != 'canceled')

      shipment_state.nil? || %w{ready backorder pending}.include?(shipment_state)
    end

    def allow_resume?
      # we shouldn't allow resume for legacy orders b/c we lack the information
      # necessary to restore to a previous state
      return false if state_changes.empty? || state_changes.last.previous_state.nil?

      true
    end

    def awaiting_returns?
      return_authorizations.any?(&:authorized?)
    end

    # This is currently used when adding a variant to an order in the BackOffice.
    # Spree::OrderContents#add is equivalent but slightly different from add_variant below.
    def contents
      @contents ||= Spree::OrderContents.new(self)
    end

    # This is currently used when adding a variant to an order in the FrontOffice.
    # This add_variant is equivalent but slightly different from Spree::OrderContents#add above.
    # Spree::OrderContents#add is the more modern version in Spree history
    #   but this add_variant has been customized for OFN FrontOffice.
    def add_variant(variant, quantity = 1, max_quantity = nil, currency = nil)
      line_items(:reload)
      current_item = find_line_item_by_variant(variant)

      # Notify bugsnag if we get line items with a quantity of zero
      if quantity == 0
        Bugsnag.notify(RuntimeError.new("Zero Quantity Line Item"),
                       current_item: current_item.as_json,
                       line_items: line_items.map(&:id),
                       variant: variant.as_json)
      end

      if current_item
        current_item.quantity = quantity
        current_item.max_quantity = max_quantity

        current_item.currency = currency unless currency.nil?
        current_item.save
      else
        current_item = Spree::LineItem.new(quantity: quantity, max_quantity: max_quantity)
        current_item.variant = variant
        if currency
          current_item.currency = currency unless currency.nil?
          current_item.price    = variant.price_in(currency).amount
        else
          current_item.price    = variant.price
        end
        line_items << current_item
      end

      reload
      current_item
    end

    def set_variant_attributes(variant, attributes)
      line_item = find_line_item_by_variant(variant)

      return unless line_item

      if attributes.key?(:max_quantity) && attributes[:max_quantity].to_i < line_item.quantity
        attributes[:max_quantity] = line_item.quantity
      end

      line_item.assign_attributes(attributes)
      line_item.save!
    end

    # Associates the specified user with the order.
    def associate_user!(user)
      self.user = user
      self.email = user.email
      self.created_by = user if created_by.blank?

      return unless persisted?

      # Persist the changes we just made,
      #   but don't use save since we might have an invalid address associated
      self.class.unscoped.where(id: id).update_all(email: user.email,
                                                   user_id: user.id,
                                                   created_by_id: created_by_id)
    end

    # FIXME refactor this method and implement validation using validates_* utilities
    def generate_order_number
      record = true
      while record
        random = "R#{Array.new(9){ rand(9) }.join}"
        record = self.class.find_by(number: random)
      end
      self.number = random if number.blank?
      number
    end

    def shipped_shipments
      shipments.shipped
    end

    def contains?(variant)
      find_line_item_by_variant(variant).present?
    end

    def find_line_item_by_variant(variant)
      line_items.detect { |line_item| line_item.variant_id == variant.id }
    end

    def ship_total
      adjustments.shipping.sum(:amount)
    end

    def tax_total
      adjustments.tax.sum(:amount)
    end

    # Creates new tax charges if there are any applicable rates. If prices already
    # include taxes then price adjustments are created instead.
    def create_tax_charge!
      Spree::TaxRate.adjust(self)
    end

    def outstanding_balance
      total - payment_total
    end

    def outstanding_balance?
      outstanding_balance != 0
    end

    def name
      address = bill_address || ship_address
      return unless address

      "#{address.firstname} #{address.lastname}"
    end

    def can_ship?
      complete? || resumed? || awaiting_return? || returned?
    end

    def credit_cards
      credit_card_ids = payments.from_credit_card.pluck(:source_id).uniq
      CreditCard.where(id: credit_card_ids)
    end

    # Finalizes an in progress order after checkout is complete.
    # Called after transition to complete state when payments will have been processed
    def finalize!
      touch :completed_at

      adjustments.update_all state: 'closed'

      # update payment and shipment(s) states, and save
      updater.update_payment_state
      shipments.each do |shipment|
        shipment.update!(self)
        shipment.finalize!
      end

      updater.update_shipment_state
      updater.before_save_hook
      save

      deliver_order_confirmation_email

      state_changes.create(
        previous_state: 'cart',
        next_state: 'complete',
        name: 'order',
        user_id: user_id
      )
    end

    def deliver_order_confirmation_email
      return if subscription.present?

      ConfirmOrderJob.perform_later(id)
    end

    # Helper methods for checkout steps
    def paid?
      payment_state == 'paid' || payment_state == 'credit_owed'
    end

    def available_payment_methods
      @available_payment_methods ||= PaymentMethod.available(:front_end)
    end

    # "Checkout" is the initial state and, for card payments, "pending" is the state after auth
    # These are both valid states to process the payment
    def pending_payments
      (payments.select(&:pending?) +
        payments.select(&:processing?) +
        payments.select(&:checkout?)).uniq
    end

    # processes any pending payments and must return a boolean as it's
    # return value is used by the checkout state_machine to determine
    # success or failure of the 'complete' event for the order
    #
    # Returns:
    # - true if all pending_payments processed successfully
    # - true if a payment failed, ie. raised a GatewayError
    #   which gets rescued and converted to TRUE when
    #   :allow_checkout_gateway_error is set to true
    # - false if a payment failed, ie. raised a GatewayError
    #   which gets rescued and converted to FALSE when
    #   :allow_checkout_on_gateway_error is set to false
    #
    def process_payments!
      process_each_payment(&:process!)
    rescue Core::GatewayError => e
      result = !!Spree::Config[:allow_checkout_on_gateway_error]
      errors.add(:base, e.message) && (return result)
    end

    def process_payments_offline!
      process_each_payment(&:process_offline!)
    rescue Core::GatewayError => e
      errors.add(:base, e.message)
      false
    end

    def billing_firstname
      bill_address.try(:firstname)
    end

    def billing_lastname
      bill_address.try(:lastname)
    end

    def products
      line_items.map(&:product)
    end

    def variants
      line_items.map(&:variant)
    end

    def insufficient_stock_lines
      line_items.select(&:insufficient_stock?)
    end

    def empty!
      line_items.destroy_all
      adjustments.destroy_all
      payments.clear
      shipments.destroy_all
    end

    def state_changed(name)
      state = "#{name}_state"
      return unless persisted?

      old_state = __send__("#{state}_was")
      state_changes.create(
        previous_state: old_state,
        next_state: __send__(state),
        name: name,
        user_id: user_id
      )
    end

    def shipped?
      %w(partial shipped).include?(shipment_state)
    end

    # Does this order have shipments that can be shipped?
    def ready_to_ship?
      shipments.any?(&:can_ship?)
    end

    # Ship all pending orders
    def ship
      shipments.each do |s|
        s.ship if s.can_ship?
      end
    end

    def line_item_variants
      if line_items.loaded?
        line_items.map(&:variant)
      else
        line_items.includes(:variant).map(&:variant)
      end
    end

    # Show already bought line items of this order cycle
    def finalised_line_items
      return [] unless order_cycle && user && distributor

      order_cycle.items_bought_by_user(user, distributor)
    end

    def create_proposed_shipments
      adjustments.shipping.delete_all
      shipments.destroy_all

      packages = OrderManagement::Stock::Coordinator.new(self).packages
      packages.each do |package|
        shipments << package.to_shipment
      end

      shipments
    end

    # Clean shipments and make order back to address state
    #
    # At some point the might need to force the order to transition from address
    # to delivery again so that proper updated shipments are created.
    # e.g. customer goes back from payment step and changes order items
    def ensure_updated_shipments
      return unless shipments.any?

      shipments.destroy_all
      update_columns(
        state: "address",
        updated_at: Time.zone.now
      )
    end

    def refresh_shipment_rates
      shipments.map(&:refresh_rates)
    end

    # Check that line_items in the current order are available from a newly selected distribution
    def products_available_from_new_distribution
      return if OrderCycleDistributedVariants.new(order_cycle, distributor)
        .distributes_order_variants?(self)

      errors.add(:base, I18n.t(:spree_order_availability_error))
    end

    def disallow_guest_order
      return unless using_guest_checkout? && registered_email?

      errors.add(:base, I18n.t('devise.failure.already_registered'))
    end

    # After changing line items of a completed order
    def update_shipping_fees!
      shipments.each do |shipment|
        next if shipment.shipped?

        update_adjustment! shipment.adjustment if shipment.adjustment
        save_or_rescue_shipment(shipment)
      end
    end

    def save_or_rescue_shipment(shipment)
      shipment.save # updates included tax
    rescue ActiveRecord::RecordNotUnique => e
      # This error was seen in production on `shipment.save` above.
      # It caused lost payments and duplicate payments due to database rollbacks.
      # While we don't understand the cause of this error yet, we rescue here
      # because an outdated shipping fee is not as bad as a lost payment.
      # And the shipping fee is already up-to-date when this error occurs.
      # https://github.com/openfoodfoundation/openfoodnetwork/issues/3924
      Bugsnag.notify(e) do |report|
        report.add_tab(:order, attributes)
        report.add_tab(:shipment, shipment.attributes)
        report.add_tab(:shipment_in_db, Spree::Shipment.find_by(id: shipment.id).attributes)
      end
    end

    # After changing line items of a completed order
    def update_payment_fees!
      payments.each do |payment|
        next if payment.completed?

        update_adjustment! payment.adjustment if payment.adjustment
        payment.save
      end
    end

    def update_distribution_charge!
      # `with_lock` acquires an exclusive row lock on order so no other
      # requests can update it until the transaction is commited.
      # See https://github.com/rails/rails/blob/3-2-stable/activerecord/lib/active_record/locking/pessimistic.rb#L69
      # and https://www.postgresql.org/docs/current/static/sql-select.html#SQL-FOR-UPDATE-SHARE
      with_lock do
        EnterpriseFee.clear_all_adjustments_on_order self

        loaded_line_items =
          line_items.includes(variant: :product, order: [:distributor, :order_cycle]).all

        loaded_line_items.each do |line_item|
          if provided_by_order_cycle? line_item
            OpenFoodNetwork::EnterpriseFeeCalculator.new.create_line_item_adjustments_for line_item
          end
        end

        if order_cycle
          OpenFoodNetwork::EnterpriseFeeCalculator.new.create_order_adjustments_for self
        end
      end
    end

    def set_order_cycle!(order_cycle)
      return if self.order_cycle == order_cycle

      self.order_cycle = order_cycle
      self.distributor = nil unless order_cycle.nil? || order_cycle.has_distributor?(distributor)
      empty!
      save!
    end

    def remove_variant(variant)
      line_items(:reload)
      current_item = find_line_item_by_variant(variant)
      current_item.andand.destroy
    end

    def cap_quantity_at_stock!
      line_items.includes(variant: :stock_items).find_each(&:cap_quantity_at_stock!)
    end

    def set_distributor!(distributor)
      self.distributor = distributor
      self.order_cycle = nil unless order_cycle.andand.has_distributor? distributor
      save!
    end

    def set_distribution!(distributor, order_cycle)
      self.distributor = distributor
      self.order_cycle = order_cycle
      save!
    end

    def distribution_set?
      distributor && order_cycle
    end

    def shipping_tax
      adjustments(:reload).shipping.sum(:included_tax)
    end

    def enterprise_fee_tax
      adjustments(:reload).enterprise_fee.sum(:included_tax)
    end

    def total_tax
      (adjustments.to_a + line_item_adjustments.to_a).sum(&:included_tax)
    end

    def price_adjustment_totals
      Hash[tax_adjustment_totals.map do |tax_rate, tax_amount|
        [tax_rate.name,
         Spree::Money.new(tax_amount, currency: currency)]
      end]
    end

    def has_taxes_included
      !line_items.with_tax.empty?
    end

    def address_from_distributor
      address = distributor.address.clone
      if bill_address
        address.firstname = bill_address.firstname
        address.lastname = bill_address.lastname
        address.phone = bill_address.phone
      end
      address
    end

    private

    def process_each_payment
      raise Core::GatewayError, Spree.t(:no_pending_payments) if pending_payments.empty?

      pending_payments.each do |payment|
        break if payment_total >= total

        yield payment

        if payment.completed?
          self.payment_total += payment.amount
        end
      end
    end

    def link_by_email
      self.email = user.email if user
    end

    # Determine if email is required (we don't want validation errors before we hit the checkout)
    def require_email
      return true unless new_record? || (state == 'cart')
    end

    def ensure_line_items_present
      return if line_items.present?

      errors.add(:base, Spree.t(:there_are_no_items_for_this_order)) && (return false)
    end

    def has_available_shipment
      return unless address?
      return unless ship_address&.valid?
      # errors.add(:base, :no_shipping_methods_available) if available_shipping_methods.empty?
    end

    def ensure_available_shipping_rates
      return unless shipments.empty? || shipments.any? { |shipment| shipment.shipping_rates.blank? }

      errors.add(:base, Spree.t(:items_cannot_be_shipped)) && (return false)
    end

    def after_cancel
      shipments.each(&:cancel!)

      OrderMailer.cancel_email(id).deliver_later
      self.payment_state = 'credit_owed' unless shipped?
    end

    def after_resume
      shipments.each(&:resume!)
    end

    def use_billing?
      @use_billing == true || @use_billing == 'true' || @use_billing == '1'
    end

    def set_currency
      self.currency = Spree::Config[:currency] if self[:currency].nil?
    end

    def using_guest_checkout?
      require_email && !user.andand.id
    end

    def registered_email?
      Spree.user_class.exists?(email: email)
    end

    def adjustments_fetcher
      @adjustments_fetcher ||= OrderAdjustmentsFetcher.new(self)
    end

    def skip_payment_for_subscription?
      subscription.present? && order_cycle.orders_close_at.andand > Time.zone.now
    end

    def provided_by_order_cycle?(line_item)
      order_cycle_variants = order_cycle.andand.variants || []
      order_cycle_variants.include? line_item.variant
    end

    def require_customer?
      return true unless new_record? || state == 'cart'
    end

    def customer_is_valid?
      return true unless require_customer?

      customer.present? && customer.enterprise_id == distributor_id && customer.email == email_for_customer
    end

    def email_for_customer
      (user.andand.email || email).andand.downcase
    end

    def associate_customer
      return customer if customer.present?

      self.customer = Customer.of(distributor).find_by(email: email_for_customer)
    end

    def ensure_customer
      return if associate_customer

      customer_name = bill_address.andand.full_name
      self.customer = Customer.create(enterprise: distributor, email: email_for_customer,
                                      user: user, name: customer_name,
                                      bill_address: bill_address.andand.clone,
                                      ship_address: ship_address.andand.clone)
    end

    def update_adjustment!(adjustment)
      return if adjustment.finalized?

      state = adjustment.state
      adjustment.state = 'open'
      adjustment.update!
      update!
      adjustment.state = state
    end

    # object_params sets the payment amount to the order total, but it does this
    # before the shipping method is set. This results in the customer not being
    # charged for their order's shipping. To fix this, we refresh the payment
    # amount here.
    def charge_shipping_and_payment_fees!
      update_totals
      return unless pending_payments.any?

      pending_payments.first.update_attribute :amount, total
    end
  end
end