# frozen_string_literal: true

module Runger
  module RBSGenerator
    TYPE_TO_CLASS = {
      string: 'String',
      integer: 'Integer',
      float: 'Float',
      date: 'Date',
      datetime: 'DateTime',
      uri: 'URI',
      boolean: 'bool',
    }.freeze

    # Generate RBS signature from a config class
    def to_rbs
      *namespace, class_name = name.split('::')

      buf = []
      indent = 0
      interface_name = '_Config'

      if namespace.empty?
        interface_name = "_#{class_name}"
      else
        buf << "module #{namespace.join('::')}"
        indent += 1
      end

      # Using interface emulates a module we include to provide getters and setters
      # (thus making `super` possible)
      buf << "#{'  ' * indent}interface #{interface_name}"
      indent += 1

      # Generating setters and getters for config attributes
      config_attributes.each do |param|
        type = coercion_mapping[param] || defaults[param.to_s]

        type =
          case type
          in NilClass
            'untyped'
          in Symbol
            TYPE_TO_CLASS.fetch(type) { defaults[param] ? 'Symbol' : 'untyped' }
          in Array
            'Array[untyped]'
          in array: _, type:, **nil
            "Array[#{TYPE_TO_CLASS.fetch(type, 'untyped')}]"
          in Hash
            'Hash[string,untyped]'
          in TrueClass | FalseClass
            'bool'
          else
            type.class.to_s
          end

        getter_type = type
        getter_type = "#{type}?" unless required_attributes.include?(param)

        buf << "#{'  ' * indent}def #{param}: () -> #{getter_type}"
        buf << "#{'  ' * indent}def #{param}=: (#{type}) -> void"

        if ['bool', 'bool?'].include?(type)
          buf << "#{'  ' * indent}def #{param}?: () -> #{getter_type}"
        end
      end

      indent -= 1
      buf << "#{'  ' * indent}end"

      buf << ''

      buf << "#{'  ' * indent}class #{class_name} < #{superclass.name}"
      indent += 1

      buf << "#{'  ' * indent}include #{interface_name}"

      indent -= 1
      buf << "#{'  ' * indent}end"

      unless namespace.empty?
        buf << 'end'
      end

      buf << ''

      buf.join("\n")
    end
  end

  Config.extend(RBSGenerator)
end