# frozen_string_literal: true

module RuboCop
  module Cop
    module Rails
      # This cop is used to identify usages of http methods like `get`, `post`,
      # `put`, `patch` without the usage of keyword arguments in your tests and
      # change them to use keyword arguments.
      #
      # @example
      #   # bad
      #   get :new, { user_id: 1}
      #
      #   # good
      #   get :new, params: { user_id: 1 }
      class HttpPositionalArguments < Cop
        MSG = 'Use keyword arguments instead of ' \
              'positional arguments for http call: `%s`.'.freeze
        KEYWORD_ARGS = [
          :headers, :env, :params, :body, :flash, :as, :xhr, :session, :method
        ].freeze
        HTTP_METHODS = [:get, :post, :put, :patch, :delete, :head].freeze

        def_node_matcher :http_request?, <<-END
          (send nil {#{HTTP_METHODS.map(&:inspect).join(' ')}} !nil $_data ...)
        END

        def on_send(node)
          data = http_request?(node)
          # if the data is nil then we don't need to add keyword arguments
          # because there is no data to put in params or headers, so skip
          return if data.nil?
          return unless needs_conversion?(data)

          add_offense(node, node.loc.selector, format(MSG, node.method_name))
        end

        # @return [Boolean] true if the line needs to be converted
        def needs_conversion?(data)
          return true unless data.hash_type?
          children = data.child_nodes

          value = children.find do |d|
            special_keyword_arg?(d.children.first) ||
              (format_arg?(d.children.first) && children.size == 1)
          end

          value.nil?
        end

        def special_keyword_arg?(node)
          KEYWORD_ARGS.include?(node.children.first) if node.type == :sym
        end

        def format_arg?(node)
          node.children.first == :format if node.type == :sym
        end

        def convert_hash_data(data, type)
          # empty hash or no hash return empty string
          return '' if data.nil? || data.children.empty?
          hash_data = if data.hash_type?
                        format('{ %s }', data.pairs.map(&:source).join(', '))
                      else
                        # user supplies an object,
                        # no need to surround with braces
                        data.source
                      end
          format(', %s: %s', type, hash_data)
        end

        # given a pre Rails 5 method: get :new, user_id: @user.id, {}
        #
        # @return lambda of auto correct procedure
        # the result should look like:
        #     get :new, params: { user_id: @user.id }, headers: {}
        # the http_method is the method use to call the controller
        # the controller node can be a symbol, method, object or string
        # that represents the path/action on the Rails controller
        # the data is the http parameters and environment sent in
        # the Rails 5 http call
        def autocorrect(node)
          _receiver, http_method, http_path, *data = *node
          controller_action = http_path.source
          params = convert_hash_data(data.first, 'params')
          headers = convert_hash_data(data.last, 'headers') if data.size > 1
          # the range of the text to replace, which is the whole line
          code_to_replace = node.loc.expression
          # what to replace with
          format = parentheses?(node) ? '%s(%s%s%s)' : '%s %s%s%s'
          new_code = format(format, http_method, controller_action,
                            params, headers)
          ->(corrector) { corrector.replace(code_to_replace, new_code) }
        end
      end
    end
  end
end