require 'open-uri'

module SpatialFeatures
  module Importers
    class File < SimpleDelegator
      INVALID_ARCHIVE = "Archive did not contain a .kml, .shp, .json, or .geojson file.".freeze
      SUPPORTED_FORMATS = "Supported formats are KMZ, KML, zipped ArcGIS shapefiles, ESRI JSON, and GeoJSON.".freeze

      FILE_PATTERNS = [/\.kml$/, /\.shp$/, /\.json$/, /\.geojson$/]
      def self.create_all(data, **options)
        Download.open_each(data, unzip: FILE_PATTERNS, downcase: true, tmpdir: options[:tmpdir]).map do |file|
          new(data, **options, current_file: file)
        end
      rescue Unzip::PathNotFound
        raise ImportError, INVALID_ARCHIVE + " " + SUPPORTED_FORMATS
      end

      # The File importer may be initialized multiple times by `::create_all` if it
      # receives ZIP data containing multiple KML or SHP files. We use `current_file`
      # to distinguish which file in the archive is currently being
      # processed.
      #
      # If no `current_file` is passed then we just take the first valid file that we find.
      def initialize(data, current_file: nil, **options)
        begin
          @current_file = current_file || Download.open_each(data, unzip: FILE_PATTERNS, downcase: true, tmpdir: options[:tmpdir]).first
        rescue Unzip::PathNotFound
          raise ImportError, INVALID_ARCHIVE
        end

        case ::File.extname(data).downcase
        when '.kmz' # KMZ always has a single kml in it, so no need to show mention it
          options[:source_identifier] = ::File.basename(data)
        else
          options[:source_identifier] = [::File.basename(data), ::File.basename(@current_file.path)].uniq.join('/')
        end

        case ::File.extname(filename)
        when '.kml'
          __setobj__(KMLFile.new(@current_file, **options))
        when '.shp'
          __setobj__(Shapefile.new(@current_file, **options))
        when '.json', '.geojson'
          __setobj__(ESRIGeoJSON.new(@current_file.path, **options))
        else
          import_error
        end
      end

      private

      def import_error!
        raise ImportError, "Could not import #{filename}. " + SUPPORTED_FORMATS
      end

      def filename
        @filename ||= @current_file.path.downcase
      end
    end
  end
end