require "gm/notepad/input_handlers/default_handler"
module Gm
  module Notepad
    module InputHandlers
      class QueryTableHandler < DefaultHandler
        QUERY_TABLE_NAMES_PREFIX = '+'.freeze
        def self.handles?(input:)
          # Does not have the table prefix
          return false unless input[0] == QUERY_TABLE_NAMES_PREFIX
          # It is only the table prefix
          return false if input == QUERY_TABLE_NAMES_PREFIX
          # It is querying all tables by way of grep
          return false if input[0..1] == "#{QUERY_TABLE_NAMES_PREFIX}/"
          true
        end

        WITH_GREP_REGEXP = %r{(?<declaration>\/(?<grep>[^\/]+)/)}
        WITH_INDEX_REGEXP = %r{(?<declaration>\[(?<index>[^\]]+)\])}
        WITH_EMPTY_INDEX_REGEX = %r{(?<declaration>\[\])}
        WITH_EMPTY_GREP_REGEX = %r{(?<declaration>\/\/)}
        NON_EXPANDING_CHARATER = '!'.freeze
        def after_initialize!
          self.expand_line = false
          self.to_output = false
          self.to_interactive = true

          line = input[1..-1].to_s
          self.expand_line = false
          if match = WITH_EMPTY_INDEX_REGEX.match(line)
            line = line.sub(match[:declaration], '')
          elsif match = WITH_INDEX_REGEXP.match(line)
            line = line.sub(match[:declaration], '')
            self.index = match[:index]
          elsif match = WITH_EMPTY_GREP_REGEX.match(line)
            line = line.sub(match[:declaration], '')
          elsif match = WITH_GREP_REGEXP.match(line)
            line = line.sub(match[:declaration], '')
            grep = match[:grep]
            self.grep = grep
          end
          if line[-1] == NON_EXPANDING_CHARATER
            line = line[0..-2]
          end
          self.table_name = line.downcase
        end

        attr_accessor :index, :grep, :table_name

        def lines
          begin
            table = table_registry.fetch_table(name: table_name)
          rescue KeyError
            message = "Unknown table #{table_name.inspect}. Did you mean: "
            message += table_registry.table_names.grep(/\A#{table_name}/).map(&:inspect).join(", ")
            return [message]
          end
          if index
            begin
              [table.lookup(index: index)]
            rescue KeyError
              [%(Entry with index "#{index}" not found in "#{table_name}" table)]
            end
          elsif grep
            regexp = %r{#{grep}}i
            table.grep(regexp)
          else
            table.all
          end
        end
      end
    end
  end
end