Class: RailsMcpInsight::Formatters::MermaidFormatter

Inherits:
Object
  • Object
show all
Defined in:
lib/rails_mcp_insight/formatters/mermaid_formatter.rb

Overview

Generates Mermaid diagram syntax for Entity Relationship Diagrams.

Instance Method Summary collapse

Constructor Details

#initialize(model_analyzer) ⇒ MermaidFormatter

Returns a new instance of MermaidFormatter.



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# File 'lib/rails_mcp_insight/formatters/mermaid_formatter.rb', line 7

def initialize(model_analyzer)
  @model_analyzer = model_analyzer
end

Instance Method Details

#generate_erd(model_names: nil) ⇒ Object

Generate an ERD for the given models (or all models if nil)



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# File 'lib/rails_mcp_insight/formatters/mermaid_formatter.rb', line 12

def generate_erd(model_names: nil)
  models = if model_names
             model_names.filter_map { |name| @model_analyzer.analyze(name) }
           else
             @model_analyzer.list_all.filter_map { |m| @model_analyzer.analyze(m[:name]) }
           end

  return "erDiagram\n  %% No models found" if models.empty?

  lines = ["erDiagram"]

  # Add entity definitions with columns
  models.each do |model|
    lines << "  #{model[:name]} {"
    (model[:columns] || []).each do |col|
      lines << "    #{col[:type]} #{col[:name]}"
    end
    lines << "  }"
  end

  # Add relationships
  model_names_set = models.to_set { |m| m[:name] }
  models.each do |model|
    (model[:associations] || []).each do |assoc|
      target = classify(assoc[:name])
      next unless model_names_set.include?(target)

      case assoc[:type]
      when "has_many"
        lines << "  #{model[:name]} ||--o{ #{target} : \"has many\""
      when "has_one"
        lines << "  #{model[:name]} ||--|| #{target} : \"has one\""
      when "belongs_to"
        lines << "  #{model[:name]} }o--|| #{target} : \"belongs to\""
      when "has_and_belongs_to_many"
        lines << "  #{model[:name]} }o--o{ #{target} : \"HABTM\""
      end
    end
  end

  lines.join("\n")
end