module NostrManager
  class VerifyZapRequest < NostrManagerService
    def initialize(amount:, event:, lnurl: nil)
      @amount, @event, @lnurl = amount, event, lnurl
    end

    # https://github.com/nostr-protocol/nips/blob/27fef638e2460139cc9078427a0aec0ce4470517/57.md#appendix-d-lnurl-server-zap-request-validation
    def call
      tags = parse_tags(@event.tags)

      @event.verify_signature &&
      @event.kind == 9734 &&
      tags.present? &&
      valid_p_tag?(tags[:p]) &&
      valid_e_tag?(tags[:e]) &&
      valid_a_tag?(tags[:a]) &&
      valid_amount_tag?(tags[:amount]) &&
      valid_lnurl_tag?(tags[:lnurl])
    end

    def valid_p_tag?(tag)
      return false unless tag.present? && tag.length == 1
      key = Nostr::PublicKey.new(tag.first) rescue nil
      key.present?
    end

    def valid_e_tag?(tag)
      return true unless tag.present?
      # TODO validate format of event ID properly
      tag.length == 1 && tag.first.is_a?(String)
    end

    def valid_a_tag?(tag)
      return true unless tag.present?
      # TODO validate format of event coordinate properly
      tag.length == 1 && tag.first.is_a?(String)
    end

    def valid_amount_tag?(tag)
      return true unless tag.present?
      amount = tag.first
      amount.is_a?(String) && amount.to_i == @amount
    end

    def valid_lnurl_tag?(tag)
      return true unless tag.present?
      # TODO validate lnurl matching recipient's lnurlp
      tag.first.is_a?(String)
    end
  end
end