module Ecoportal
  module API
    class V2
      class S3
        class Upload
          class MissingFile < ArgumentError; end

          DEFAULT_MIME_TYPE = 'application/octet-stream'.freeze
          EXPECTED_CODE     = "204".freeze # No Content
          MAX_RETRIES       = 5

          attr_reader :filename

          def initialize(credentials, file:)
            msg = "Expecting #{credentials_class}. Given: #{credentials.class}"
            raise ArgumentError, msg unless credentials.is_a?(credentials_class)

            @credentials = credentials
            @filename    = file
          end

          def upload!
            require_deps!

            @response = Net::HTTP.start(
              uri.hostname,
              uri.port,
              use_ssl: true
            ) do |https|
              https.max_retries = self.class::MAX_RETRIES
              https.request(request)
            end

            return unless success?

            yield(s3_file_reference) if block_given?
            s3_file_reference
          end

          def failed?
            return false unless response

            response.code != EXPECTED_CODE
          end

          def success?
            return false unless response

            response.code == EXPECTED_CODE
          end

          def s3_file_reference
            return unless success?

            @s3_file_reference ||= {
              'filename' => file_basename,
              'filetype' => mime_type,
              'filesize' => file_size,
              'path'     => s3_file_path
            }
          end

          private

          attr_reader :credentials
          attr_reader :response

          def request
            Net::HTTP::Post.new(uri).tap do |req|
              req.set_form form_data, 'multipart/form-data'
            end
          end

          def uri
            @uri ||= URI(credentials[:s3_endpoint])
          end

          def form_data
            [
              ['key', s3_file_path],
              *aws_params,
              *file_params
            ]
          end

          def s3_file_path
            "#{user_tmpdir}/#{file_basename}"
          end

          def user_tmpdir
            credentials[:user_tmpdir]
          end

          def aws_params
            params = %i[AWSAccessKeyId policy signature x-amz-server-side-encryption]
            params.map do |key|
              [key.to_s, credentials[key]]
            end
          end

          def file_params
            [
              ['content-type', mime_type],
              ['file',         io_stream]
            ]
          end

          def mime_type
            @mime_type ||= lib_mime_type || DEFAULT_MIME_TYPE
          end

          def lib_mime_type
            MIME::Types.type_for(file_extension).first&.content_type
          end

          def io_stream
            require_file!
            File.open(file_fullname)
          end

          def credentials_class
            Ecoportal::API::V2::S3::Data
          end

          def file_size
            @file_size ||= File.size(file_fullname)
          end

          def file_extension
            @file_extension ||= File.extname(filename)[1..]
          end

          def file_basename
            @file_basename ||= File.basename(filename)
          end

          def file_fullname
            @file_fullname ||= File.expand_path(filename)
          end

          def require_file!
            msg = "File '#{file_basename}' doesn't exist"
            raise MissingFile, msg unless File.exist?(file_fullname)
          end

          def require_deps!
            require 'net/http'
            require 'mime/types'
          end
        end
      end
    end
  end
end