class Order < ApplicationRecord
  attr_accessor :ignore_warnings, :transport_distribution

  # Associations
  has_many :order_articles, dependent: :destroy
  has_many :articles, through: :order_articles
  has_many :group_orders, dependent: :destroy
  has_many :ordergroups, through: :group_orders
  has_many :users_ordered, through: :ordergroups, source: :users
  has_many :comments, -> { order('created_at') }, class_name: 'OrderComment'
  has_many :stock_changes
  belongs_to :invoice, optional: true
  belongs_to :supplier, optional: true
  belongs_to :updated_by, class_name: 'User', foreign_key: 'updated_by_user_id'
  belongs_to :created_by, class_name: 'User', foreign_key: 'created_by_user_id'

  enum end_action: { no_end_action: 0, auto_close: 1, auto_close_and_send: 2, auto_close_and_send_min_quantity: 3 }
  enum transport_distribution: { skip: 0, ordergroup: 1, price: 2, articles: 3 }

  # Validations
  validates :starts, presence: true
  validate :starts_before_ends, :include_articles
  validate :keep_ordered_articles

  before_validation :distribute_transport
  # Callbacks
  after_save :save_order_articles, :update_price_of_group_orders!

  # Finders
  scope :started, -> { where('starts <= ?', Time.now) }
  scope :closed, -> { where(state: 'closed').order(ends: :desc) }
  scope :stockit, -> { where(supplier_id: nil).order(ends: :desc) }
  scope :recent, -> { order(starts: :desc).limit(10) }
  scope :stock_group_order, -> { group_orders.where(ordergroup_id: nil).first }
  scope :with_invoice, -> { where.not(invoice: nil) }

  # State related finders
  # Diagram for `Order.state` looks like this:
  # * -> open -> finished (-> received) -> closed
  # So orders can
  # 1. ...only transition in one direction (e.g. an order that has been `finished` currently cannot be reopened)
  # 2. ...be set to `closed` when having the `finished` state. (`received` is optional)
  scope :open, -> { where(state: 'open').order(ends: :desc) }
  scope :finished, -> { where(state: %w[finished received closed]).order(ends: :desc) }
  scope :finished_not_closed, -> { where(state: %w[finished received]).order(ends: :desc) }

  # Allow separate inputs for date and time
  #   with workaround for https://github.com/einzige/date_time_attribute/issues/14
  include DateTimeAttributeValidate
  date_time_attribute :starts, :boxfill, :ends

  def self.ransackable_attributes(_auth_object = nil)
    %w[id state supplier_id starts boxfill ends pickup]
  end

  def self.ransackable_associations(_auth_object = nil)
    %w[supplier articles order_articles]
  end

  def stockit?
    supplier_id.nil?
  end

  def name
    stockit? ? I18n.t('orders.model.stock') : supplier.name
  end

  def articles_for_ordering
    if stockit?
      # make sure to include those articles which are no longer available
      # but which have already been ordered in this stock order
      StockArticle.available.includes(:article_category)
                  .order('article_categories.name', 'articles.name').reject do |a|
        a.quantity_available <= 0 && !a.ordered_in_order?(self)
      end.group_by { |a| a.article_category.name }
    else
      supplier.articles.available.group_by { |a| a.article_category.name }
    end
  end

  def supplier_articles
    if stockit?
      StockArticle.undeleted.reorder('articles.name')
    else
      supplier.articles.undeleted.reorder('articles.name')
    end
  end

  # Save ids, and create/delete order_articles after successfully saved the order
  attr_writer :article_ids

  def article_ids
    @article_ids ||= order_articles.map { |a| a.article_id.to_s }
  end

  # Returns an array of article ids that lead to a validation error.
  def erroneous_article_ids
    @erroneous_article_ids ||= []
  end

  def open?
    state == 'open'
  end

  def finished?
    state == 'finished' || state == 'received'
  end

  def received?
    state == 'received'
  end

  def closed?
    state == 'closed'
  end

  def boxfill?
    !!FoodsoftConfig[:use_boxfill] && open? && boxfill.present? && boxfill < Time.now
  end

  def is_boxfill_useful?
    !!FoodsoftConfig[:use_boxfill] && !!supplier.try(:has_tolerance?)
  end

  def expired?
    ends.present? && ends < Time.now
  end

  # sets up first guess of dates when initializing a new object
  # I guess `def initialize` would work, but it's tricky http://stackoverflow.com/questions/1186400
  def init_dates
    self.starts ||= Time.now
    if FoodsoftConfig[:order_schedule]
      # try to be smart when picking a reference day
      last = begin
        DateTime.parse(FoodsoftConfig[:order_schedule][:initial])
      rescue StandardError
        nil
      end
      last ||= Order.finished.reorder(:starts).first.try(:starts)
      last ||= self.starts
      # adjust boxfill and end date
      if is_boxfill_useful?
        self.boxfill ||= FoodsoftDateUtil.next_occurrence last, self.starts,
                                                          FoodsoftConfig[:order_schedule][:boxfill]
      end
      self.ends ||= FoodsoftDateUtil.next_occurrence last, self.starts, FoodsoftConfig[:order_schedule][:ends]
    end
    self
  end

  # fetch current Order scope's records and map the current user's GroupOrders in (if any)
  # (performance enhancement as opposed to fetching each GroupOrder separately from the view)
  def self.ordergroup_group_orders_map(ordergroup)
    orders = includes(:supplier)
    group_orders = GroupOrder.where(ordergroup_id: ordergroup.id, order_id: orders.map(&:id))
    group_orders_hash = group_orders.index_by { |go| go.order_id }
    orders.map do |order|
      {
        order: order,
        group_order: group_orders_hash[order.id]
      }
    end
  end

  # search GroupOrder of given Ordergroup
  def group_order(ordergroup)
    group_orders.where(ordergroup_id: ordergroup.id).first
  end

  def stock_group_order
    group_orders.where(ordergroup_id: nil).first
  end

  # Returns OrderArticles in a nested Array, grouped by category and ordered by article name.
  # The array has the following form:
  # e.g: [["drugs",[teethpaste, toiletpaper]], ["fruits" => [apple, banana, lemon]]]
  def articles_grouped_by_category
    @articles_grouped_by_category ||= order_articles
                                      .includes([:article_price, :group_order_articles, { article: :article_category }])
                                      .order('articles.name')
                                      .group_by { |a| a.article.article_category.name }
                                      .sort { |a, b| a[0] <=> b[0] }
  end

  def articles_sort_by_category
    order_articles.includes(:article).order('articles.name').sort do |a, b|
      a.article.article_category.name <=> b.article.article_category.name
    end
  end

  # Returns the defecit/benefit for the foodcoop
  # Requires a valid invoice, belonging to this order
  # FIXME: Consider order.foodcoop_result
  def profit(options = {})
    markup = options[:without_markup] || false
    return unless invoice

    groups_sum = markup ? sum(:groups_without_markup) : sum(:groups)
    groups_sum - invoice.net_amount
  end

  # Returns the all round price of a finished order
  # :groups returns the sum of all GroupOrders
  # :clear returns the price without tax, deposit and markup
  # :gross includes tax and deposit. this amount should be equal to suppliers bill
  # :fc, guess what...
  def sum(type = :gross)
    total = 0
    if %i[net gross net_deposit gross_without_deposit fc_deposit deposit fc].include?(type)
      for oa in order_articles.ordered.includes(:article, :article_price)
        quantity = oa.units * oa.price.unit_quantity
        case type
        when :net
          total += quantity * oa.price.price
        when :gross
          total += quantity * oa.price.gross_price
        when :gross_without_deposit
          total += quantity * oa.price.gross_price_without_deposit
        when :fc
          total += quantity * oa.price.fc_price
        when :net_deposit
          total += quantity * oa.price.net_deposit_price
        when :fc_deposit
          total += quantity * oa.price.fc_deposit_price
        when :deposit
          total += quantity * oa.price.deposit
        end
      end
    elsif %i[groups groups_without_markup].include?(type)
      for go in group_orders.includes(group_order_articles: { order_article: %i[article article_price] })
        for goa in go.group_order_articles
          case type
          when :groups
            total += goa.result * goa.order_article.price.fc_price
          when :groups_without_markup
            total += goa.result * goa.order_article.price.gross_price
          end
        end
      end
    end
    total
  end

  # Finishes this order. This will set the order state to "finish" and the end property to the current time.
  # Ignored if the order is already finished.
  def finish!(user)
    return if finished?

    Order.transaction do
      # set new order state (needed by notify_order_finished)
      update!(state: 'finished', ends: Time.now, updated_by: user)

      # Update order_articles. Save the current article_price to keep price consistency
      # Also save results for each group_order_result
      # Clean up
      order_articles.includes(:article).find_each do |oa|
        oa.update_attribute(:article_price, oa.article.article_prices.first)
        oa.group_order_articles.each do |goa|
          goa.save_results!
          # Delete no longer required order-history (group_order_article_quantities) and
          # TODO: Do we need articles, which aren't ordered? (units_to_order == 0 ?)
          #    A: Yes, we do - for redistributing articles when the number of articles
          #       delivered changes, and for statistics on popular articles. Records
          #       with both tolerance and quantity zero can be deleted.
          # goa.group_order_article_quantities.clear
        end
      end

      # Update GroupOrder prices
      group_orders.each(&:update_price!)

      # Stats
      ordergroups.each(&:update_stats!)

      # Notifications
      NotifyFinishedOrderJob.perform_later(self)
    end
  end

  # Sets order.status to 'close' and updates all Ordergroup.account_balances
  def close!(user, transaction_type = nil)
    raise I18n.t('orders.model.error_closed') if closed?

    update_price_of_group_orders!

    transaction do                                        # Start updating account balances
      charge_group_orders!(user, transaction_type)

      if stockit?                                         # Decreases the quantity of stock_articles
        for oa in order_articles.includes(:article)
          oa.update_results!                              # Update units_to_order of order_article
          stock_changes.create! stock_article: oa.article, quantity: oa.units_to_order * -1
        end
      end

      update!(state: 'closed', updated_by: user, foodcoop_result: profit)
    end
  end

  # Close the order directly, without automaticly updating ordergroups account balances
  def close_direct!(user)
    raise I18n.t('orders.model.error_closed') if closed?

    unless FoodsoftConfig[:charge_members_manually]
      comments.create(user: user,
                      text: I18n.t('orders.model.close_direct_message'))
    end
    update!(state: 'closed', updated_by: user)
  end

  def send_to_supplier!(user)
    Mailer.deliver_now_with_default_locale do
      Mailer.order_result_supplier(user, self)
    end
    update!(last_sent_mail: Time.now)
  end

  def do_end_action!
    if auto_close?
      finish!(created_by)
    elsif auto_close_and_send?
      finish!(created_by)
      send_to_supplier!(created_by)
    elsif auto_close_and_send_min_quantity?
      finish!(created_by)
      send_to_supplier!(created_by) if sum >= supplier.min_order_quantity.to_r
    end
  end

  def self.finish_ended!
    orders = Order.where.not(end_action: Order.end_actions[:no_end_action]).where(state: 'open').where('ends <= ?',
                                                                                                       DateTime.now)
    orders.each do |order|
      order.do_end_action!
    rescue StandardError => e
      ExceptionNotifier.notify_exception(e, data: { foodcoop: FoodsoftConfig.scope, order_id: order.id })
    end
  end

  protected

  def starts_before_ends
    delta = Rails.env.test? ? 1 : 0 # since Rails 4.2 tests appear to have time differences, with this validation failing
    errors.add(:ends, I18n.t('orders.model.error_starts_before_ends')) if ends && starts && ends <= (starts - delta)
    errors.add(:ends, I18n.t('orders.model.error_boxfill_before_ends')) if ends && boxfill && ends <= (boxfill - delta)
    return unless boxfill && starts && boxfill <= (starts - delta)

    errors.add(:boxfill,
               I18n.t('orders.model.error_starts_before_boxfill'))
  end

  def include_articles
    errors.add(:articles, I18n.t('orders.model.error_nosel')) if article_ids.empty?
  end

  def keep_ordered_articles
    chosen_order_articles = order_articles.where(article_id: article_ids)
    to_be_removed = order_articles - chosen_order_articles
    to_be_removed_but_ordered = to_be_removed.select { |a| a.quantity > 0 || a.tolerance > 0 }
    return if to_be_removed_but_ordered.empty? || ignore_warnings

    errors.add(:articles, I18n.t(stockit? ? 'orders.model.warning_ordered_stock' : 'orders.model.warning_ordered'))
    @erroneous_article_ids = to_be_removed_but_ordered.map { |a| a.article_id }
  end

  def save_order_articles
    # fetch selected articles
    articles_list = Article.find(article_ids)
    # create new order_articles
    (articles_list - articles).each { |article| order_articles.create(article: article) }
    # delete old order_articles
    articles.reject { |article| articles_list.include?(article) }.each do |article|
      order_articles.detect { |order_article| order_article.article_id == article.id }.destroy
    end
  end

  private

  def distribute_transport
    return unless group_orders.any?

    case transport_distribution.try(&:to_i)
    when Order.transport_distributions[:ordergroup]
      amount = transport / group_orders.size
      group_orders.each do |go|
        go.transport = amount.ceil(2)
      end
    when Order.transport_distributions[:price]
      amount = transport / group_orders.sum(:price)
      group_orders.each do |go|
        go.transport = (amount * go.price).ceil(2)
      end
    when Order.transport_distributions[:articles]
      amount = transport / group_orders.includes(:group_order_articles).sum(:result)
      group_orders.each do |go|
        go.transport = (amount * go.group_order_articles.sum(:result)).ceil(2)
      end
    end
  end

  # Updates the "price" attribute of GroupOrders or GroupOrderResults
  # This will be either the maximum value of a current order or the actual order value of a finished order.
  def update_price_of_group_orders!
    group_orders.each(&:update_price!)
  end

  def charge_group_orders!(user, transaction_type = nil)
    note = transaction_note
    group_orders.includes(:ordergroup).find_each do |group_order|
      if group_order.ordergroup
        price = group_order.total * -1 # decrease! account balance
        group_order.ordergroup.add_financial_transaction!(price, note, user, transaction_type, nil, group_order)
      end
    end
  end

  def transaction_note
    I18n.t('orders.model.notice_close', name: name, ends: ends.strftime(I18n.t('date.formats.default')))
  end
end