module Eco
  module API
    module Common
      module People
        # Helper factory class to generate entries (input entries).
        # @attr_reader schema [Ecoportal::API::V1::PersonSchema] person schema to be used in this entry factory
        class EntryFactory < Eco::API::Common::Session::BaseSession

          attr_reader :schema, :person_parser

          # @param e [Eco::API::Common::Session::Environment] requires a session environment, as any child of `Eco::API::Common::Session::BaseSession`
          # @param schema [Ecoportal::API::V1::PersonSchema] schema of person details that the parser will be based upon.
          # @param person_parser [nil, Eco::API::Common::People::PersonParser] set of attribute, type and format parsers/serializers.
          # @param attr_map [nil, Eco::Data::Mapper] attribute names mapper to translate external names into internal ones and _vice versa_.
          # @param logger [Common::Session::Logger, ::Logger] object to manage logs.
          def initialize(e, schema:, person_parser: nil, attr_map: nil)
            fatal "Constructor needs a PersonSchema. Given: #{schema}" if !schema.is_a?(Ecoportal::API::V1::PersonSchema)
            fatal "Expecting PersonParser. Given: #{person_parser}"    if person_parser && !person_parser.is_a?(Eco::API::Common::People::PersonParser)
            fatal "Expecting Mapper object. Given: #{fields_mapper}"   if attr_map && !attr_map.is_a?(Eco::Data::Mapper)
            super(e)

            @schema = Ecoportal::API::V1::PersonSchema.new(JSON.parse(schema.doc.to_json))

            @source_person_parser = person_parser

            # load default parsers
            @person_parser = Eco::API::Common::People::DefaultParsers.new(schema: @schema)
            # merge the custom parsers
            @person_parser = @person_parser.merge(@source_person_parser)
            @person_parser_patch_version = @source_person_parser.patch_version

            @attr_map = attr_map
          end

          # provides with a Eco::API::Common::People::PersonParser object (collection of attribute parsers)
          # @note if the custom person parser has changed, it updates the copy of this EntryFactory instance
          # @return [Eco::API::Common::People::PersonParser] set of attribute, type and format parsers/serializers.
          def person_parser
            if @person_parser_patch_version < @source_person_parser.patch_version
              @person_parser.merge(@source_person_parser)
              @person_parser_patch_version = @source_person_parser.patch_version
            end
            @person_parser
          end

          # key method to generate objects of `PersonEntry` that share dependencies via this `EntryFactory` environment.
          # @note this method is necessary to make the factory object work as a if it was a class `PersonEntry` you can call `new` on.
          # @param data [Array<Hash>] data to be parsed. The external hashed entry.
          # @return [Eco::API::Common::People::PersonEntry]
          def new(data, dependencies: {})
            PersonEntry.new(
              data,
              person_parser: person_parser,
              attr_map:      @attr_map,
              dependencies:  dependencies,
              logger:        logger
            )
          end

          # Helper that provides a collection of `Entries`, which in turn provides with further helpers to find and exclude entries.
          # It accepts a `file:` and `format:` or `data:` but not both options together.
          # @raise Exception
          #   - if you try to provide `data:` and `file:` at the same time.
          #   - if you provide `file:` but omit `format:`.
          #   - if the `format:` you provide is not a `Symbol`.
          #   - if there is no _parser/serializer_ defined for `format:`.
          # @param data [Array<Hash>] data to be parsed. It cannot be used alongside with `file:`
          # @param file [String] absolute or relative path to the input file. It cannot be used alongside with `data:`.
          # @param format [Symbol] it must be used when you use the option `file:` (i.e. `:xml`, `:csv`), as it specifies the format of the input `file:`.
          # @param encoding [String] optional parameter to read `file:` by expecting certain encoding.
          # @return [Eco::API::Common::People::Entries] collection of `Eco::API::Common::People::PersonEntry`.
          def entries(data: (no_data = true; nil), file: (no_file = true; nil), format: (no_format = true; nil), encoding: nil)
            fatal("You should at least use data: or file:, but not both") if no_data == no_file
            fatal("You must specify a valid format: (symbol) when you use file.") if file && no_format
            fatal("Format should be a Symbol. Given '#{format}'") if format && !format.is_a?(Symbol)
            fatal("There is no parser/serializer for format ':#{format.to_s}'") unless no_format || @person_parser.defined?(format)

            if file
              arr_hash = []
              if Eco::API::Common::Session::FileManager.file_exists?(file)
                encoding   ||= Eco::API::Common::Session::FileManager.encoding(file)
                file_content = File.read(file, encoding: encoding)
                arr_hash     = person_parser.parse(format, file_content)
              else
                logger.warn("File does not exist: #{file}")
              end

              entries(data: arr_hash)
            else
              Entries.new(data, klass: PersonEntry, factory: self)
            end
          end

          # Helper that generates a file out of `data:`.
          # @raise Exception
          #   - if you try to provide `data:` in the wrong format.
          #   - if you `file:` is empty.
          #   - if the `format:` you provide is not a `Symbol`.
          #   - if there is no _parser/serializer_ defined for `format:`.
          # @param data [Eco::API::Organization::People] data to be parsed.
          # @param file [String] absolute or relative path to the ouput file.
          # @param format [Symbol] it specifies the format of the output `file:` (i.e. `:xml`, `:csv`). There must be a parser/serializer defined for it.
          # @param encoding [String] optional parameter to geneate `file:` content by unsing certain encoding.
          # @return [Void].
          def export(data:, file: "export", format: :csv, encoding: "utf-8")
            fatal("data: Expected Eco::API::Organization::People object. Given: #{data.class}") unless data.is_a?(Eco::API::Organization::People)
            fatal("A file should be specified.") unless !file.to_s.strip.empty?
            fatal("Format should be a Symbol. Given '#{format}'") if format && !format.is_a?(Symbol)
            fatal("There is no parser/serializer for format ':#{format.to_s}'") unless @person_parser.defined?(format)

            run = true
            if Eco::API::Common::Session::FileManager.file_exists?(file)
              print "The file '#{file}' already exists. Do you want to overwrite it? (Y/n): "
              res = STDIN.gets.strip
              run = ["y", "Y", ""].include?(res)
            end

            if run
              deps = {"supervisor_id" => {people: data}}

              data_entries = data.map do |person|
                self.new(person, dependencies: deps).to_hash
              end

              File.open(file, "w", enconding: encoding) do |fd|
                fd.write(person_parser.serialize(format, data_entries))
              end
            end

          end

          private

          def fatal(msg)
            logger.fatal(msg)
            raise msg
          end

        end

      end
    end
  end
end