# frozen_string_literal: true

module MasterDataTool
  class MasterData
    attr_reader :csv_path, :model_klass, :columns, :new_records, :updated_records, :no_change_records, :deleted_records
    attr_reader :before_count, :after_count

    def initialize(csv_path, model_klass)
      @csv_path = csv_path
      @model_klass = model_klass

      @loaded = false

      @columns = []
      @new_records = []
      @updated_records = []
      @no_change_records = []
      @deleted_records = []
    end

    def load
      csv = CSV.read(@csv_path, headers: true, skip_blanks: true)
      old_records_by_id = @model_klass.all.index_by(&:id)

      csv_records_by_id = build_records_from_csv(csv, old_records_by_id)
      deleted_ids = old_records_by_id.keys - csv_records_by_id.keys

      @columns = csv.headers

      csv_records_by_id.each do |_, record|
        if record.new_record?
          @new_records << record

          next
        end

        if record.has_changes_to_save?
          @updated_records << record

          next
        end

        @no_change_records << record
      end

      deleted_ids.each do |id|
        @deleted_records << old_records_by_id[id]
      end

      @loaded = true
    end

    def import_records
      new_records + updated_records + no_change_records
    end

    def affected_records
      new_records + updated_records + deleted_records
    end

    def new_records
      raise MasterDataTool::NotLoadedError unless @loaded

      @new_records
    end

    def updated_records
      raise MasterDataTool::NotLoadedError unless @loaded

      @updated_records
    end

    def no_change_records
      raise MasterDataTool::NotLoadedError unless @loaded

      @no_change_records
    end

    def deleted_records
      raise MasterDataTool::NotLoadedError unless @loaded

      @deleted_records
    end

    def loaded?
      @loaded
    end

    def affected?
      return @affected if instance_variable_defined?(:@affected)
      @affected = affected_records.any?
    end

    def before_count
      @before_count ||= updated_records.count + no_change_records.count + deleted_records.count
    end

    def after_count
      @after_count ||= updated_records.count + no_change_records.count + new_records.count
    end

    def table_name
      @model_klass.table_name
    end

    def import!(dry_run: true)
      raise MasterDataTool::NotLoadedError unless @loaded

      MasterDataTool::Report::ImportReport.new(self).tap do |report|
        return report if dry_run
        return report unless affected?

        @model_klass.delete_all

        # マスターデータ間の依存がある場合に投入順制御するのは大変なのでこのタイミングでのバリデーションはしない
        @model_klass.import(import_records, validate: false, on_duplicate_key_update: @columns, timestamps: true)
      end
    end

    def verify!(dry_run: true)
      MasterDataTool::Report::VerifyReport.new(self).tap do |report|
        @model_klass.all.find_each do |record|
          valid = record.valid?
          report.append(MasterDataTool::Report::VerifyReport.build_verify_record_report(self, record, valid))
          next if dry_run

          raise MasterDataTool::VerifyFailed.new("[#{table_name}] id = #{record.id} is invalid") unless valid
        end
      end
    end

    def print_affected_table
      return unless loaded?
      return unless affected?

      MasterDataTool::Report::PrintAffectedTableReport.new(self)
    end

    private

    def build_records_from_csv(csv, old_records_by_id)
      {}.tap do |records|
        csv.each do |row|
          id = row['id'].to_i
          record = old_records_by_id[id] || @model_klass.new(id: id)

          csv.headers.each do |key|
            record[key.to_s] = row[key]
          end

          records[id] = record
        end
      end
    end
  end
end