require 'yaml'

module Statsample
  # This module aids to code open questions
  # * Select one or more vectors of a dataset, to create a yaml files, on which each vector is a hash, which keys and values are the vector's factors . If data have Statsample::SPLIT_TOKEN on a value, each value will be separated on two or more hash keys.
  # * Edit the yaml and replace the values of hashes with your codes. If you need to create two or mores codes for an answer, use the separator (default Statsample::SPLIT_TOKEN)
  # * Recode the vectors, loading the yaml file:
  #   * recode_dataset_simple!() : The new vectors have the same name of the original plus "_recoded"
  #   * recode_dataset_split!() : Create equal number of vectors as values. See Vector.add_vectors_by_split() for arguments
  #
  # Usage:
  #   recode_file="recodification.yaml"
  #   phase=:first # flag
  #   if phase==:first
  #     File.open(recode_file,"w") {|fp|
  #       Statsample::Codification.create_yaml(ds,%w{vector1 vector2}, ",",fp)
  #     }
  #   # Edit the file recodification.yaml and verify changes
  #   elsif phase==:second
  #     File.open(recode_file,"r") {|fp|
  #       Statsample::Codification.verify(fp,['vector1'])
  #     }
  #   # Add new vectors to the dataset
  #   elsif phase==:third
  #     File.open(recode_file,"r") {|fp|
  #       Statsample::Codification.recode_dataset_split!(ds,fp,"*")
  #     }
  #   end
  #
  module Codification
    class << self
      # Create a hash, based on vectors, to create the dictionary.
      # The keys will be vectors name on dataset and the values
      # will be hashes, with keys = values, for recodification
      def create_hash(dataset, vectors, sep=Statsample::SPLIT_TOKEN)
        raise ArgumentError,"Array should't be empty" if vectors.size==0
        pro_hash=vectors.inject({}){|h,v_name|
          raise Exception, "Vector #{v_name} doesn't exists on Dataset" if !dataset.fields.include? v_name
          v=dataset[v_name]
          split_data=v.splitted(sep).flatten.collect {|c| c.to_s}.find_all {|c| !c.nil?}

          factors=split_data.uniq.compact.sort.inject({}) {|ac,val| ac[val]=val;ac }
          h[v_name]=factors
          h
        }
        pro_hash
      end
      # Create a yaml to create a dictionary, based on vectors
      # The keys will be vectors name on dataset and the values
      # will be hashes, with keys = values, for recodification
      #
      #   v1=%w{a,b b,c d}.to_vector
      #   ds={"v1"=>v1}.to_dataset
      #   Statsample::Codification.create_yaml(ds,['v1'])
      #   => "--- \nv1: \n  a: a\n  b: b\n  c: c\n  d: d\n"
      def create_yaml(dataset, vectors, io=nil, sep=Statsample::SPLIT_TOKEN)
        pro_hash=create_hash(dataset, vectors, sep)
        YAML.dump(pro_hash,io)
      end
      # Create a excel to create a dictionary, based on vectors.
      # Raises an error if filename exists
      # The rows will be:
      # * field: name of vector
      # * original: original name
      # * recoded: new code

      def create_excel(dataset, vectors, filename, sep=Statsample::SPLIT_TOKEN)
        require 'spreadsheet'
        if File.exist?(filename)
          raise "Exists a file named #{filename}. Delete ir before overwrite."
        end
        book = Spreadsheet::Workbook.new
        sheet = book.create_worksheet
        sheet.row(0).concat(%w{field original recoded})
        i=1
        create_hash(dataset, vectors, sep).sort.each do |field, inner_hash|
          inner_hash.sort.each do |k,v|
            sheet.row(i).concat([field.dup,k.dup,v.dup])
            i+=1
          end
        end
        book.write(filename)
      end
      # From a excel generates a dictionary hash
      # to use on recode_dataset_simple!() or recode_dataset_split!().
      #
      def excel_to_recoded_hash(filename)
        require 'spreadsheet'
        h={}
        book = Spreadsheet.open filename
        sheet= book.worksheet 0
        row_i=0
        sheet.each do |row|
          row_i+=1
          next if row_i==1 or row[0].nil? or row[1].nil? or row[2].nil?
          h[row[0]]={} if h[row[0]].nil?
          h[row[0]][row[1]]=row[2]
        end
        h
      end

      def inverse_hash(h, sep=Statsample::SPLIT_TOKEN)
        h.inject({}) do |a,v|
          v[1].split(sep).each do |val|
            a[val]||=[]
            a[val].push(v[0])
          end
          a
        end
      end

      def dictionary(h, sep=Statsample::SPLIT_TOKEN)
        h.inject({}) {|a,v| a[v[0]]=v[1].split(sep); a }
      end

      def recode_vector(v,h,sep=Statsample::SPLIT_TOKEN)
        dict=dictionary(h,sep)
        new_data=v.splitted(sep)
        new_data.collect do |c|
          if c.nil?
            nil
          else
            c.collect{|value| dict[value] }.flatten.uniq
          end
        end
      end
      def recode_dataset_simple!(dataset, dictionary_hash ,sep=Statsample::SPLIT_TOKEN)
        _recode_dataset(dataset,dictionary_hash ,sep,false)
      end
      def recode_dataset_split!(dataset, dictionary_hash, sep=Statsample::SPLIT_TOKEN)
        _recode_dataset(dataset, dictionary_hash, sep,true)
      end

      def _recode_dataset(dataset, h , sep=Statsample::SPLIT_TOKEN, split=false)
        v_names||=h.keys
        v_names.each do |v_name|
          raise Exception, "Vector #{v_name} doesn't exists on Dataset" if !dataset.fields.include? v_name
          recoded=recode_vector(dataset[v_name], h[v_name],sep).collect { |c|
            if c.nil?
              nil
            else
              c.join(sep)
            end
          }.to_vector
          if(split)
            recoded.split_by_separator(sep).each {|k,v|
              dataset[v_name+"_"+k]=v
            }
          else
            dataset[v_name+"_recoded"]=recoded
          end
        end
      end


      def verify(h, v_names=nil,sep=Statsample::SPLIT_TOKEN,io=$>)
        require 'pp'
        v_names||=h.keys
        v_names.each{|v_name|
          inverse=inverse_hash(h[v_name],sep)
          io.puts "- Field: #{v_name}"
          inverse.sort{|a,b| -(a[1].count<=>b[1].count)}.each {|k,v|
            io.puts "  - \"#{k}\" (#{v.count}) :\n    -'"+v.join("\n    -'")+"'"
          }
        }
      end
    end
  end
end