module Sidetree
  module Model
    # https://identity.foundation/sidetree/spec/#provisional-proof-file
    class ProvisionalProofFile < CASFileBase
      attr_reader :update_proofs

      # Initialize
      # @param [Array[JSON::JWS]] update_proofs Array of update proof.
      def initialize(update_proofs)
        @update_proofs = update_proofs
      end

      # Parse provisional proof file from compressed data.
      # @param [String] proof_file compressed provisional proof file.
      # @param [Boolean] compressed Whether the proof_file is compressed or not, default: true.
      # @return [Sidetree::Model::ProvisionalProofFile]
      # @raise [Sidetree::Error]
      def self.parse(proof_file, compressed: true)
        decompressed =
          (
            if compressed
              decompress(proof_file, Sidetree::Params::MAX_PROOF_FILE_SIZE)
            else
              proof_file
            end
          )
        begin
          json = JSON.parse(decompressed, symbolize_names: true)
          json.keys.each do |k|
            unless k == :operations
              raise Sidetree::Error,
                    "Unexpected property #{k.to_s} in provisional proof file"
            end
          end
          unless json[:operations]
            raise Sidetree::Error,
                  "Provisional proof file does not have any operation proofs"
          end
          json[:operations].keys.each do |k|
            unless k == :update
              raise Sidetree::Error,
                    "Unexpected property #{k.to_s} in provisional proof file"
            end
          end
          unless json[:operations][:update].is_a?(Array)
            raise Sidetree::Error,
                  "Provisional proof file update property not array"
          end
          update_proofs =
            json[:operations][:update].each.map do |update|
              update.keys.each do |k|
                unless k == :signedData
                  raise Sidetree::Error,
                        "Unexpected property #{k.to_s} in provisional proof file"
                end
              end
              Sidetree::Util::JWS.parse(update[:signedData])
            end
          if update_proofs.empty?
            raise Sidetree::Error, "Provisional proof file has no proof"
          end
          ProvisionalProofFile.new(update_proofs)
        rescue JSON::ParserError
          raise Sidetree::Error, "Provisional proof file is not json"
        end
      end

      # Build json string to be stored in CAS.
      # @return [String] json string.
      def to_json
        params = {
          operations: {
            update: update_proofs.map { |u| { signedData: u.to_s } }
          }
        }
        params.to_json
      end
    end
  end
end