#MODULE IS AT THE BOTTOM

class ShapeFile

  include GeoRuby::Shp4r
  include PortableFiles

  attr_accessor :files, :columns
  attr_reader :shape_file, :table_name

  def initialize(options ={})
    @files = {}
    @files[:shp_file] = options[:shp_file]
    @files[:shx_file] = options[:shx_file]
    @files[:dbf_file]= options[:dbf_file]
  end

  def read_columns
    @columns = Array.new
    each_column do |field|
      @columns << { :name => field.name.downcase, :type => field_type_to_rails(field.type) }
    end
  end

  def import_data(fields = [])
    cl = classify
    ShpFile.open(self) do |shp|
      shp.each do |shape|
        record = cl.new
        shp.fields.each do |field|
          record[field.name.downcase] = shape.data[field.name] if fields.include? field.name.downcase or fields.blank?
        end
        record.the_geom = shape.geometry
        record.save
      end
    end
  end


  def each_column
    ShpFile.open(self) do |shp|
      shp.fields.each do |field|
        yield(field)
      end
    end
  end

  private

  def field_type_to_rails(type)
    case type
      when 'N' then :integer
      when 'F' then :float
      when 'D' then :date
    else
      :string
    end
  end

end




module PortableFiles

 attr_accessor :file_paths

  #adds table prefix 'layer_' to each layer
  def table_name=(name)
    @table_name = "layer_table_#{name}"
  end

  # adds the layer to the layers table
  def add_layer
    Layer.create(:name => @table_name, :table_name => @table_name.to_s, :geometric_column_name => "the_geom")
  end

  def table_has_unique_name?
    ActiveRecord::Base.connection.execute("SELECT * FROM information_schema.tables WHERE \"table_name\" = '#{@table_name}';").to_a.size == 0
  end

  def generate_table_name
    until table_has_unique_name? and @table_name
      self.table_name = ((rand*10000000000000).to_i).to_s
    end
  end

  def create_table
    #empty block : the columns will be added afterwards
    unless @table_name.blank?
      ActiveRecord::Schema.create_table(@table_name){}
      @table_created = true
    end
  end

  def create_table_structure
    if @table_created
      @columns.each do |column|
        begin
          ActiveRecord::Schema.add_column(@table_name, column[:name], column[:type])
        rescue
          puts "Couldnt add field #{column[:name].downcase}"
        end
      end
      ActiveRecord::Schema.add_column(table_name,"the_geom", :geometry,:null => false)
      ActiveRecord::Schema.add_index(table_name,"the_geom",:spatial => true)
    end
  end

  def classify
    temp_table_name = self.table_name
    Class.new(ActiveRecord::Base) do
      set_table_name temp_table_name
    end
  end

  # takes the contents of the files hash and copies them from temp files
  # and stores them in /temp_uploads. On upload, filename should get a random seed prefixed
  # to the filename, but i've added an extra 4 digit random seed to each filename just for
  # extra protextion. returns a hash with paths pointing to files as values. this is a workaround
  # because you cant store files in the session variable.
  def copy_files
    require 'ftools'
    @files.inject({}) do |result, file|
      seed = (rand * 1000).to_i
      File.syscopy(file[1].path, "temp_uploads/#{seed}" + file[1].path.split('/').last)
      result[file[0].to_sym] = "#{seed}#{file[1].path}"
      result
    end
  end

  def clear_files
    @files = nil
  end

  def prepare_for_session
    @file_paths = copy_files
    clear_files
  end

  def load_from_session
    @files = {}
    @file_paths.each do |file|
      @files[file[0]] = File.new("temp_uploads/#{file[1]}")
    end
  end

end