sure/app/models/trade_import.rb

class TradeImport < Import
  def import!
    transaction do
      mappings.each(&:create_mappable!)

      trades = rows.map do |row|
        mapped_account = if account
          account
        else
          mappings.accounts.mappable_for(row.account)
        end

        # Try to find or create security with ticker only
        security = find_or_create_security(
          ticker: row.ticker,
          exchange_operating_mic: row.exchange_operating_mic
        )

        Trade.new(
          security: security,
          qty: row.qty,
          currency: row.currency.presence || mapped_account.currency,
          price: row.price,
          category: investment_category_for(row.qty, mapped_account.family),
          entry: Entry.new(
            account: mapped_account,
            date: row.date_iso,
            amount: row.signed_amount,
            name: row.name,
            currency: row.currency.presence || mapped_account.currency,
            import: self
          ),
        )
      end

      Trade.import!(trades, recursive: true)
    end
  end

  def mapping_steps
    base = []
    base << Import::AccountMapping if account.nil?
    base
  end

  def required_column_keys
    %i[date ticker qty price]
  end

  def column_keys
    base = %i[date ticker exchange_operating_mic currency qty price name]
    base.unshift(:account) if account.nil?
    base
  end

  def dry_run
    mappings = { transactions: rows_count }

    mappings.merge(
      accounts: Import::AccountMapping.for_import(self).creational.count
    ) if account.nil?

    mappings
  end

  def csv_template
    template = <<-CSV
      date*,ticker*,exchange_operating_mic,currency,qty*,price*,account,name
      05/15/2024,AAPL,XNAS,USD,10,150.00,Trading Account,Apple Inc. Purchase
      05/16/2024,GOOGL,XNAS,USD,-5,2500.00,Investment Account,Alphabet Inc. Sale
      05/17/2024,TSLA,XNAS,USD,2,700.50,Retirement Account,Tesla Inc. Purchase
    CSV

    csv = CSV.parse(template, headers: true)
    csv.delete("account") if account.present?
    csv
  end

  private
    def investment_category_for(qty, family)
      # Buy trades (positive qty) are categorized as "Savings & Investments"
      # Sell trades are left uncategorized - users will be prompted to categorize
      return nil unless qty.to_d.positive?

      family.categories.find_by(name: "Savings & Investments")
    end

    def find_or_create_security(ticker: nil, exchange_operating_mic: nil)
      return nil unless ticker.present?

      # Avoids resolving the same security over and over again (resolver potentially makes network calls)
      @security_cache ||= {}

      cache_key = [ ticker, exchange_operating_mic ].compact.join(":")

      security = @security_cache[cache_key]

      return security if security.present?

      security = Security::Resolver.new(
        ticker,
        exchange_operating_mic: exchange_operating_mic.presence
      ).resolve

      @security_cache[cache_key] = security

      security
    end
end