class MatryoshkaView

# File lib/matryoshka_view.rb, line 17
def logger
  ActiveRecord::Base.logger
end

# File lib/matryoshka_view.rb, line 40
def initialize(base:, geom_source: nil, the_geom_geojson: nil, name: nil)
  @base = base
  @the_geom_geojson = the_geom_geojson
  @geom_source = geom_source
  @name = name
end

# File lib/matryoshka_view.rb, line 12
def setup
  Record.create_table
end

# File lib/matryoshka_view.rb, line 21
    def view_exists?(*expected_names)
      result = ActiveRecord::Base.connection_pool.with_connection do |conn|
        conn.select_values <<-SQL
          SELECT 1
          FROM   pg_catalog.pg_class mv
          WHERE
            mv.oid::regclass::text IN (#{expected_names.map { |name| conn.quote(name) }.join(',')})
            AND mv.relkind = 'r'
        SQL
      end
      result.length == expected_names.length
    end

# File lib/matryoshka_view.rb, line 118
def eql?(other)
  # puts "#{uniq_attrs} <-> #{other.uniq_attrs}"
  other.is_a?(MatryoshkaView) and uniq_attrs == other.uniq_attrs
end

# File lib/matryoshka_view.rb, line 110
def from_sql
  name
end

# File lib/matryoshka_view.rb, line 47
def lookup(geom_source: nil, the_geom_geojson: nil)
  # FIXME move to Record class method
  hit = with_connection do |c|
    if geom_source
      if geom_source.changed?
        Record.where("(base = #{c.quote base}) AND (the_geom && #{c.quote geom_source.the_geom}) AND ST_Contains(ST_Buffer(the_geom, 0.00001), #{c.quote geom_source.the_geom})").order("ST_Area(the_geom, false) ASC").first
      else
        Record.where("(base = #{c.quote base}) AND (the_geom && (SELECT the_geom FROM #{geom_source.class.quoted_table_name} WHERE id = #{c.quote(geom_source.id)})) AND ST_Contains(ST_Buffer(the_geom, 0.00001), (SELECT the_geom FROM #{geom_source.class.quoted_table_name} WHERE id = #{c.quote(geom_source.id)}))").order("ST_Area(the_geom, false) ASC").first
      end
    elsif the_geom_geojson
      Record.where("(base = #{c.quote base}) AND (the_geom && ST_SetSRID(ST_GeomFromGeoJSON(#{c.quote the_geom_geojson}), 4326)) AND ST_Contains(ST_Buffer(the_geom, 0.00001), ST_SetSRID(ST_GeomFromGeoJSON(#{c.quote the_geom_geojson}), 4326))").order("ST_Area(the_geom, false) ASC").first
    else
      raise "expecting geom_source or the_geom_geojson"
    end
  end
  hit.try(:view) || self
end

# File lib/matryoshka_view.rb, line 102
def name
  @name ||= if inner?
    "#{SCHEMA_NAME}.t#{HashDigest.digest3(uniq_attrs)}"
  else
    base
  end
end

# File lib/matryoshka_view.rb, line 114
def name_without_schema
  @name_without_schema ||= name.split('.', 2).last
end

# File lib/matryoshka_view.rb, line 96
def quoted_base
  @quoted_base ||= with_connection do |c|
    base.split('.', 2).map { |part| c.quote_column_name(part) }.join('.')
  end
end

# File lib/matryoshka_view.rb, line 65
def spawn(attrs)
  child = MatryoshkaView.new attrs.reverse_merge(base: base)
  child.spawn!
  child
end

# File lib/matryoshka_view.rb, line 71
  def spawn!
    with_connection do |c|
      c.execute "CREATE SCHEMA IF NOT EXISTS #{SCHEMA_NAME}"
      c.execute <<-SQL
        CREATE TABLE #{name} (LIKE #{quoted_base} INCLUDING ALL)
      SQL
      c.execute <<-SQL
        INSERT INTO #{name}
          SELECT *
          FROM #{quoted_base}
          WHERE ST_Contains(ST_SetSRID(ST_GeomFromGeoJSON(#{c.quote(the_geom_geojson)}), 4326), #{quoted_base}.the_geom)
      SQL
      record = Record.new
      record.name = name
      record.base = base
      record.save!
      record.the_geom_geojson = the_geom_geojson
      record.save!
    end
  end

# File lib/matryoshka_view.rb, line 92
def the_geom_geojson
  @the_geom_geojson ||= geom_source.try :the_geom_geojson
end

# File lib/matryoshka_view.rb, line 124
def uniq_attrs
  {
    base_table_name: base,
    the_geom_geojson: the_geom_geojson,
  }
end

# File lib/matryoshka_view.rb, line 133
def inner?
  !the_geom_geojson.nil?
end

# File lib/matryoshka_view.rb, line 158
def with_connection
  ActiveRecord::Base.connection_pool.with_connection do |conn|
    yield conn
  end
end