Class: Dscf::Credit::CreditScoringEngine

Inherits:
Object
  • Object
show all
Defined in:
app/services/dscf/credit/credit_scoring_engine.rb

Instance Method Summary collapse

Constructor Details

#initialize(loan_application) ⇒ CreditScoringEngine

Returns a new instance of CreditScoringEngine.



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# File 'app/services/dscf/credit/credit_scoring_engine.rb', line 3

def initialize(loan_application)
  @loan_application = loan_application
  @credit_product = loan_application.credit_product
  @scoring_table = @credit_product&.scoring_table
  @data_by_source_id = load_data_by_source
end

Instance Method Details

#calculate_score ⇒ Object 



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# File 'app/services/dscf/credit/credit_scoring_engine.rb', line 10

def calculate_score
  return failure("No credit product assigned to loan application") unless @credit_product
  return failure("No scoring table configured for credit product '#{@credit_product.name}'") unless @scoring_table

  parameters = @scoring_table.scoring_table_parameters
                              .includes(:scoring_parameter, :scoring_table_normalizers, :information_source)
                              .order(:order)

  return failure("Scoring table '#{@scoring_table.name}' has no parameters configured") if parameters.empty?

  total_weight       = 0.0
  weighted_score     = 0.0
  parameters_list    = []
  parameters_skipped = 0
  missing_required   = []

  parameters.each do |table_param|
    param     = table_param.scoring_parameter
    source_id = table_param.information_source_id

    datum     = @data_by_source_id[source_id]
    raw_value = datum&.data&.[](param.id.to_s)

    if raw_value.nil?
      if table_param.required
        missing_required << "Missing required parameter: #{param.name}"
      else
        parameters_skipped += 1
      end
      next
    end

    normalized = normalize(table_param, raw_value)
    if normalized.nil?
      parameters_skipped += 1
      next
    end

    weight       = table_param.weight.to_f
    weighted     = normalized * weight
    weighted_score += weighted
    total_weight   += weight

    parameters_list << {
      "parameter_id"           => param.id,
      "code"                   => param.code,
      "name"                   => param.name,
      "data_type"              => param.data_type,
      "information_source"     => table_param.information_source&.name,
      "raw_value"              => raw_value,
      "normalized_value"       => normalized.round(4),
      "weight"                 => weight,
      "weighted_contribution"  => weighted.round(4)
    }
  end

  return failure(missing_required.first) if missing_required.any?

  return failure("No scoreable data found for loan application") if total_weight.zero?

  final_score      = (weighted_score / total_weight) * 100.0
  passing_score    = @scoring_table.passing_score.to_f
  pending_threshold = @scoring_table.pending_threshold.to_f

  status = if final_score >= passing_score
             "approved"
  elsif final_score >= pending_threshold
             "pending"
  else
             "rejected"
  end

  breakdown = {
    "parameters"           => parameters_list,
    "total_weighted_sum"   => weighted_score.round(6),
    "total_weight"         => total_weight.round(6),
    "parameters_processed" => parameters_list.size,
    "parameters_skipped"   => parameters_skipped,
    "scoring_table_code"   => @scoring_table.code,
    "passing_score"        => passing_score,
    "pending_threshold"    => pending_threshold,
    "final_score"          => final_score.round(2),
    "status"               => status
  }

  {
    success:   true,
    score:     final_score.round(2),
    status:    status,
    breakdown: breakdown,
    errors:    []
  }
end