module Isomorfeus
  module Data
    class ObjectAccelerator
      def self.finalize(acc)
        proc { acc.close_store }
      end

      attr_reader :object_class, :object_class_name
      attr_accessor :store

      def initialize(ruby_class)
        @object_class = ruby_class
        @object_class_name = ruby_class.name
        @class_cache = !Isomorfeus.development?

        @store_path = File.expand_path(File.join(Isomorfeus.data_documents_path, "#{@object_class_name.underscore}"))
        open_store

        ObjectSpace.define_finalizer(self, self.class.finalize(self))
      end

      def serialize(o)
        Oj.dump(o, mode: :strict)
      end

      def unserialize(s)
        Oj.load(s, mode: :strict)
      end

      def destroy_store
        close_store rescue nil
        FileUtils.rm_rf(@store_path)
      end

      def close_store
        @store.close
      end

      def exist?(sid_s:)
        !!get_object_id(sid_s)
      end

      def exist_by_field?(field:, value:)
        top_docs = @store.search("#{field}:\"#{serialize(value)}\"")
        top_docs.total_hits > 0
      end

      def search_each(query, options, &block)
        @store.search_each(query, options, &block)
      rescue => e
        return nil if e.message.include?('frt_sort.c')
        raise e
      end

      def each(&block)
        @store.each { |doc| block.call(doc[:key]) }
      end

      def create(sid_s:, fields:, level: 10)
        id = get_object_id(sid_s)
        return false if id
        data = fields.to_h do |k, v|
          [k, serialize(v)]
        end
        data[:_revision] = serialize(1)
        data[:key] = sid_s
        @store.add_document(data)
        true
      rescue => e
        @store.flush
        raise e if level < 1
        create(sid_s: sid_s, fields: fields, level: level - 1)
      end

      def destroy(sid_s:)
        id = get_object_id(sid_s)
        @store.delete(id) if id
      end

      def load(sid_s: nil, id: nil)
        id = get_object_id(sid_s) if sid_s
        return nil unless id
        data = @store.doc(id)&.to_h
        if data
          data.delete(:key)
          data = data.to_h do |k, v|
            [k, unserialize(v)]
          end
        end
        data
      end

      def field(sid_s:, field:)
        id = get_object_id(sid_s) if sid_s
        return nil unless id
        doc = @store.doc(id)
        v = doc[field]
        unserialize(v) if v
      end

      def load_sid_s(id:)
        doc = @store.doc(id)
        return doc[:key] if doc
      end

      def revision(sid_s:)
        id = get_object_id(sid_s)
        doc = @store.doc(id) if id
        return unserialize(doc[:_revision]) if doc
      end

      def save(sid_s:, fields:, revision:, id: nil, level: 10)
        id = get_object_id(sid_s) unless id
        return false unless id
        data = fields.to_h do |k, v|
          [k, serialize(v)]
        end
        data[:key] = sid_s
        data[:_revision] = serialize(revision)
        @store.update(id, data)
        true
      rescue => e
        @store.flush
        raise e if level < 1
        save(sid_s: sid_s, fields: fields, revision: revision, id: id, level: level - 1)
      end

      def escape(string)
        # special characters must be escaped, characters taken from the ferret query parser documentation
        string.gsub(/([\\\&\:\(\)\[\]\{\}\!\"\~\^\|\<\>\=\*\?\+\-\s])/, '\\\\\1')
      end

      private

      def get_object_id(sid_s)
        top_docs = @store.search("key:\"#{sid_s}\"", limit: 1)
        top_docs.hits[0].doc if top_docs.total_hits == 1
      end

      def open_store
        FileUtils.mkdir_p(Isomorfeus.data_documents_path) unless Dir.exist?(Isomorfeus.data_documents_path)
        field_infos = Isomorfeus::Ferret::Index::FieldInfos.new(store: :yes, index: :no, term_vector: :no)
        @object_class.field_options.each { |field, options| field_infos.add_field(field, options) }
        field_infos.add_field(:key, store: :yes, index: :yes, term_vector: :yes)
        @store = Isomorfeus::Ferret::Index::Index.new(path: @store_path, key: :key, auto_flush: true, lock_retry_time: 5, field_infos: field_infos)
      end
    end
  end
end