module RuboCop::Cop::Betterment::Utils::Parser

def self.explicit_returns(node)
  node.descendants.select(&:return_type?).filter_map do |x|
    x&.children&.first
  end
end

def self.get_extracted_parameters(node, param_aliases: []) # rubocop:disable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity
  return [] unless node.send_type?
  parameter_names = []
  param_aliases << :params
  if node.method?(:[]) && param_aliases.include?(get_root_token(node))
    return node.arguments.select { |x|
      x.sym_type? || x.str_type?
    }.map(&:value)
  end
  children = node.descendants.select do |child|
    child.send_type? && param_aliases.include?(child.method_name)
  end
  children.each do |child|
    ancestors = child.ancestors.select do |ancestor|
      ancestor.send_type? && ancestor.method?(:permit)
    end
    ancestors.each do |ancestor|
      parameter_names += params_from_arguments(ancestor.arguments)
    end
  end
  parameter_names.map(&:to_sym)
end

def self.get_return_values(node)
  return [] unless node
  return explicit_returns(node) + get_return_values(node.body) if node.def_type?
  return [node] if node.literal? || node.variable?
  case node.type
  when :begin
    get_return_values(node.children.last)
  when :block
    get_return_values(node.body)
  when :if
    if_rets = get_return_values(node.if_branch)
    else_rets = get_return_values(node.else_branch)
    if_rets + else_rets
  when :case
    cases = []
    node.each_when do |block|
      cases += get_return_values(block.body)
    end
    cases + get_return_values(node.else_branch)
  when :send
    [node]
  else
    []
  end
end

def self.get_root_token(node) # rubocop:disable Metrics/PerceivedComplexity
  return nil unless node
  return get_root_token(node.receiver) if node.receiver
  # rubocop:disable InternalAffairs/NodeDestructuring
  if node.send_type?
    name = node.method_name
  elsif node.variable?
    name, = *node
  elsif node.literal?
    _, name = *node
  elsif node.const_type?
    name = node.const_name.to_sym
  elsif node.sym_type?
    name = node.value
  elsif node.self_type?
    name = :self
  elsif node.block_pass_type?
    name, = *node.children
  else
    name = nil
  end
  # rubocop:enable InternalAffairs/NodeDestructuring
  name
end

def self.params_from_arguments(arguments) # rubocop:disable Metrics/PerceivedComplexity
  parameter_names = []
  arguments.each do |arg|
    if arg.hash_type?
      arg.children.each do |pair|
        value = pair.value
        parameter_names << value.value if value.sym_type? || value.str_type?
      end
    elsif arg.sym_type? || arg.str_type?
      parameter_names << arg.value
    end
  end
  parameter_names
end