# frozen_string_literal: true

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

    # @param [MasterDataTool::MasterDataFile] master_data_file
    def initialize(master_data_file, model_klass)
      @master_data_file = master_data_file
      @model_klass = model_klass

      @loaded = false

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

    class << self
      def build(master_data_file, load: false)
        model_klass = Object.const_get(master_data_file.table_name.classify)
        new(master_data_file, model_klass).tap do |record|
          record.load if load
        end
      end
    end

    def basename
      @master_data_file.basename
    end

    def load
      csv = CSV.read(@master_data_file.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, delete_all_ignore_foreign_key: false)
      raise MasterDataTool::NotLoadedError unless @loaded

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

        disable_foreign_key_checks if delete_all_ignore_foreign_key
        @model_klass.delete_all
        enable_foreign_key_checks if delete_all_ignore_foreign_key

        # 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!(ignore_fail: false)
      MasterDataTool::Report::VerifyReport.new(self).tap do |report|
        scoped = @model_klass.all
        scoped = scoped.preload(preload_associations) if preload_associations
        scoped = scoped.eager_load(eager_load_associations) if eager_load_associations

        scoped.find_each do |record|
          valid = record.valid?
          report.append(MasterDataTool::Report::VerifyReport.build_verify_record_report(self, record, valid))
          next if valid
          next if ignore_fail

          e = MasterDataTool::VerifyFailed.new("[#{table_name}] id = #{record.id} is invalid")
          e.errors = record.errors

          raise e
        end
      end
    end

    def print_affected_table
      return unless loaded?
      return unless affected?

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

    private

    def preload_associations
      @preload_associations ||= MasterDataTool.config.preload_associations.dig(@model_klass.to_s.to_sym)
    end

    def eager_load_associations
      @eager_load_associations ||= MasterDataTool.config.eager_load_associations.dig(@model_klass.to_s.to_sym)
    end

    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

    def enable_foreign_key_checks
      ApplicationRecord.connection.execute('SET FOREIGN_KEY_CHECKS = 1')
    end

    def disable_foreign_key_checks
      ApplicationRecord.connection.execute('SET FOREIGN_KEY_CHECKS = 0')
    end
  end
end