require 'roo'

class ReportParser
  FORM_DEFINITIONS = {
    '1.1' => {
      parser: ReportParsers::Form11Parser,
      sheet_name: 'Бухгалтерский баланс'
    },
    '1.2' => {
      parser: ReportParsers::Form12Parser,
      sheet_name: 'Отчет о финансовых результатах'
    },
    '1.3' => {
      parser: nil,
      sheet_name: 'Отчет об изменениях капитала'
    },
    '1.4' => {
      parser: ReportParsers::Form14Parser,
      sheet_name: 'Отчет о движении денежных средств'
    }
  }.freeze

  DEFAULT_MISSING_VALUE = '-'

  def initialize(yearly_file)
    @yearly_file = yearly_file
  end

  def call
    ActiveRecord::Base.transaction do
      ReportParsers::OrganizationInfoParser.new(@yearly_file, spreadsheet: spreadsheet).call

      parsed_forms = parse_forms
      save_aggregated_statements(parsed_forms)
    end
  end

  private

  def spreadsheet
    @spreadsheet ||= begin
      tempfile = Tempfile.new(['report', '.xlsx'])
      tempfile.binmode
      @yearly_file.file.download { |chunk| tempfile.write(chunk) }
      tempfile.rewind
      Roo::Excelx.new(tempfile.path)
    end
  end

  def parse_forms
    FORM_DEFINITIONS.each_with_object({}) do |(form_code, config), hash|
      parser_class = config.fetch(:parser)
      hash[form_code] = parser_class ? parser_class.new(@yearly_file, spreadsheet: spreadsheet).call : {}
    end
  end

  def save_aggregated_statements(parsed_forms)
    codes = report_codes
    return if codes.blank?

    target_years = extract_target_years(parsed_forms)
    return if target_years.blank?

    target_years.each do |year|
      statement = find_or_build_statement(year)
      if should_update_statement?(statement)
        statement.assign_attributes(
          yearly_file: @yearly_file,
          sheet_number: year,
          data: build_payload_for_year(year, parsed_forms, codes)
        )
        statement.save!
      end

      cleanup_duplicate_statements(year, statement.id)
    end
  end

  def extract_target_years(parsed_forms)
    years = parsed_forms.values.flat_map(&:keys).map(&:to_i).select(&:positive?).uniq
    years = [@yearly_file.year.to_i] if years.blank? && @yearly_file.year.to_i.positive?
    years.sort.reverse
  end

  def build_payload_for_year(year, parsed_forms, codes)
    forms_payload = FORM_DEFINITIONS.each_with_object({}) do |(form_code, config), hash|
      form_data = parsed_forms.fetch(form_code, {})[year] || {}
      source_rows = form_data[:rows] || form_data['rows'] || []
      rows_by_code = index_rows_by_code(source_rows)

      hash[form_code] = {
        form_code: form_code,
        sheet_name: form_data[:sheet_name] || form_data['sheet_name'] || config.fetch(:sheet_name),
        rows: codes.map do |report_code|
          source_row = rows_by_code[report_code.code]
          source_value = source_row && (source_row[:value] || source_row['value'])

          {
            line_name: report_code.name,
            line_code: report_code.code,
            value: source_value.presence || DEFAULT_MISSING_VALUE
          }
        end
      }
    end

    {
      data_year: year,
      forms: forms_payload
    }
  end

  def index_rows_by_code(rows)
    rows.each_with_object({}) do |row, hash|
      normalized_code = normalize_code(row[:line_code] || row['line_code'])
      next if normalized_code.blank?

      # Keep first non-blank value for duplicated codes inside one form/year.
      existing = hash[normalized_code]
      next if existing.present? && (existing[:value] || existing['value']).present?

      hash[normalized_code] = row
    end
  end

  def find_or_build_statement(year)
    existing = FinancialStatement
               .joins(:yearly_file)
               .where(sheet_number: year)
               .where(yearly_files: { organization_id: @yearly_file.organization_id })
               .order('yearly_files.year DESC NULLS LAST, financial_statements.updated_at DESC')
               .first

    return existing if existing

    @yearly_file.financial_statements.new(sheet_number: year)
  end

  def should_update_statement?(statement)
    return true if statement.new_record?

    existing_source_year = statement.yearly_file&.year.to_i
    current_source_year = @yearly_file.year.to_i

    existing_source_year <= current_source_year
  end

  def normalize_code(value)
    value.to_s.scan(/\d+/).join.presence
  end

  def report_codes
    @report_codes ||= ReportCode.order(:code).select(:code, :name).to_a
  end

  def cleanup_duplicate_statements(year, keeper_id)
    FinancialStatement
      .joins(:yearly_file)
      .where(sheet_number: year)
      .where(yearly_files: { organization_id: @yearly_file.organization_id })
      .where.not(id: keeper_id)
      .delete_all
  end

end