# encoding: utf-8
require 'rails_best_practices/reviews/review'

module RailsBestPractices
  module Reviews
    # Check ruby 1.8 style hash and suggest to change hash syntax to 1.9.
    #
    # Review process:
    #   check hash nodes in all files,
    #   if the sexp type of hash key nodes is not :@lable,
    #   then the hash is ruby 1.8 style.
    class HashSyntaxReview < Review
      interesting_nodes :hash, :bare_assoc_hash
      interesting_files ALL_FILES

      VALID_SYMBOL_KEY = /\A[@$_A-Za-z]([_\w]*[!_=?\w])?\z/

      def initialize(options = {})
        super()
        @only_symbol = options[:only_symbol]
        @only_string = options[:only_string]
      end

      # check hash node to see if it is ruby 1.8 style.
      def start_hash(node)
        if !empty_hash?(node) &&
           hash_is_18?(node) &&
           valid_keys?(node) &&
           !haml_class_node?(node)
          add_error "change Hash Syntax to 1.9"
        end
      end

      alias_method :start_bare_assoc_hash, :start_hash

      protected
        # check if hash node is empty.
        def empty_hash?(node)
          s(:hash, nil) == node || s(:bare_assoc_hash, nil) == node
        end

        # check if hash key/value pairs are ruby 1.8 style.
        def hash_is_18?(node)
          pair_nodes = :hash == node.sexp_type ? node[1][1] : node[1]
          return false if pair_nodes.blank?

          pair_nodes.size.times do |i|
            if @only_symbol
              return true if :symbol_literal == pair_nodes[i][1].sexp_type
            elsif @only_string
              return true if :string_literal == pair_nodes[i][1].sexp_type
            elsif :symbol_literal == pair_nodes[i][1].sexp_type ||
                  :string_literal == pair_nodes[i][1].sexp_type
              return true
            end
          end

          false
        end

        # check if the hash keys are valid to be converted to ruby 1.9
        # syntax.
        def valid_keys?(node)
          node.hash_keys.all? { |key| key =~ VALID_SYMBOL_KEY }
        end

        # check if hash is generated by haml class or id nodes.
        def haml_class_node?(node)
          node.hash_size == 1 && (node.hash_keys.first == "class" || node.hash_keys.first == "id")
        end
    end
  end
end