ledermann/keepr

# frozen_string_literal: true

class Keepr::Account < ActiveRecord::Base
  self.table_name = 'keepr_accounts'

  has_ancestry orphan_strategy: :restrict

  enum kind: %i[asset liability revenue expense forward debtor creditor]

  validates_presence_of :number, :name
  validates_uniqueness_of :number
  validate :group_validation
  validate :tax_validation

  has_many :keepr_postings, class_name: 'Keepr::Posting', foreign_key: 'keepr_account_id', dependent: :restrict_with_error
  has_many :keepr_taxes, class_name: 'Keepr::Tax', foreign_key: 'keepr_account_id', dependent: :restrict_with_error

  belongs_to :keepr_tax, class_name: 'Keepr::Tax'
  belongs_to :keepr_group, class_name: 'Keepr::Group'
  belongs_to :accountable, polymorphic: true

  default_scope { order(:number) }

  def self.with_sums(options = {})
    raise ArgumentError unless options.is_a?(Hash)

    subquery = Keepr::Posting
               .select('SUM(keepr_postings.amount)')
               .joins(:keepr_journal)
               .where('keepr_postings.keepr_account_id = keepr_accounts.id')

    date           = options[:date]
    permanent_only = options[:permanent_only]

    case date
    when nil
    when Date
      subquery = subquery.where('keepr_journals.date <= ?', date)
    when Range
      subquery = subquery.where(keepr_journals: { date: date.first..date.last })
    else
      raise ArgumentError
    end

    subquery = subquery.where(keepr_journals: { permanent: true }) if permanent_only

    select "keepr_accounts.*, (#{subquery.to_sql}) AS sum_amount"
  end

  def self.merged_with_sums(options = {})
    accounts = with_sums(options).to_a

    # Sum up child accounts to parent
    position = 0
    while (account = accounts[position])
      if account.parent_id && account.sum_amount
        parent_account = accounts.find { |a| a.id == account.parent_id }
        raise RuntimeError unless parent_account

        parent_account.sum_amount ||= 0
        parent_account.sum_amount += account.sum_amount
        accounts.delete_at(position)
      else
        position += 1
      end
    end

    accounts
  end

  def profit_and_loss?
    revenue? || expense?
  end

  def keepr_postings
    Keepr::Posting
      .joins(:keepr_account)
      .merge(subtree)
  end

  def balance(date = nil)
    scope = case date
            when nil
              keepr_postings
            when Date
              keepr_postings
            .joins(:keepr_journal)
            .where('keepr_journals.date <= ?', date)
            when Range
              keepr_postings
            .joins(:keepr_journal)
            .where(keepr_journals: { date: date.first..date.last })
            else
              raise ArgumentError
            end

    scope.sum(:amount)
  end

  def number_as_string
    if number < 1000
      format('%04d', number)
    else
      number.to_s
    end
  end

  def to_s
    "#{number_as_string} (#{name})"
  end

  private

  def group_validation
    return unless keepr_group.present?

    if asset?
      errors.add(:kind, :group_mismatch) unless keepr_group.asset?
    elsif liability?
      errors.add(:kind, :group_mismatch) unless keepr_group.liability?
    elsif profit_and_loss?
      errors.add(:kind, :group_mismatch) unless keepr_group.profit_and_loss?
    else
      errors.add(:kind, :group_conflict)
    end

    errors.add(:keepr_group_id, :no_group_allowed_for_result) if keepr_group.is_result
  end

  def tax_validation
    errors.add(:keepr_tax_id, :circular_reference) if keepr_tax && keepr_tax.keepr_account == self
  end
end