#
# PostGIS Adapter
#
# Common Spatial Adapter for ActiveRecord
#
# Code from
# http://georuby.rubyforge.org Spatial Adapter
#

module SpatialAdapter
  #Translation of geometric data types
  def geometry_data_types
    {
      :point => { :name => "POINT" },
      :line_string => { :name => "LINESTRING" },
      :polygon => { :name => "POLYGON" },
      :geometry_collection => { :name => "GEOMETRYCOLLECTION" },
      :multi_point => { :name => "MULTIPOINT" },
      :multi_line_string => { :name => "MULTILINESTRING" },
      :multi_polygon => { :name => "MULTIPOLYGON" },
      :geometry => { :name => "GEOMETRY"}
    }
  end

end


#using a mixin instead of subclassing Column since each adapter can have a specific subclass of Column
module SpatialColumn
  attr_reader  :geometry_type, :srid, :with_z, :with_m

  def initialize(name, default, sql_type = nil, null = true,srid=-1,with_z=false,with_m=false)
    super(name,default,sql_type,null)
    @geometry_type = geometry_simplified_type(@sql_type)
    @srid = srid
    @with_z = with_z
    @with_m = with_m
  end


  #Redefines type_cast to add support for geometries
  def type_cast(value)
    return nil if value.nil?
    case type
    when :geometry then self.class.string_to_geometry(value)
    else super
    end
  end

  #Redefines type_cast_code to add support for geometries.
  #
  #WARNING : Since ActiveRecord keeps only the string values directly returned from the database, it translates from these to the correct types everytime an attribute is read (using the code returned by this method), which is probably ok for simple types, but might be less than efficient for geometries. Also you cannot modify the geometry object returned directly or your change will not be saved.
  def type_cast_code(var_name)
    case type
    when :geometry then "#{self.class.name}.string_to_geometry(#{var_name})"
    else super
    end
  end


  #Redefines klass to add support for geometries
  def klass
    case type
    when :geometry then GeoRuby::SimpleFeatures::Geometry
    else super
    end
  end

  private

  #Redefines the simplified_type method to add behaviour for when a column is of type geometry
  def simplified_type(field_type)
    case field_type
    when /geometry|point|linestring|polygon|multipoint|multilinestring|multipolygon|geometrycollection/i then :geometry
    else super
    end
  end

  #less simlpified geometric type to be use in migrations
  def geometry_simplified_type(field_type)
    case field_type
    when /^point$/i then :point
    when /^linestring$/i then :line_string
    when /^polygon$/i then :polygon
    when /^geometry$/i then :geometry
    when /multipoint/i then :multi_point
    when /multilinestring/i then :multi_line_string
    when /multipolygon/i then :multi_polygon
    when /geometrycollection/i then :geometry_collection
    end
  end


end