require 'erb'
require 'yaml'

module Columbus3
  # renderer controls the transformation of a V900 tracks into a displayable format,
  # whatever this means
  module LeafletRenderer
    # apply the ERB in html/show.html.erb (which includes all the tracks to display)
    # and save it in the current directory, under _show.html
    def self.show filename, files
      template = File.join(File.dirname(__FILE__), "/../../html/show.html.erb")
      renderer = ERB.new(File.read(template))
      
      # context: location of css and js + list of files to show
      bower_dir = File.join(File.dirname(__FILE__), "/../../../bower_components")
      @leaflet_providers = File.join(bower_dir, 'leaflet-providers/leaflet-providers.js')
      @leaflet_js = File.join(bower_dir, 'leaflet/dist/leaflet.js')
      @leaflet_css = File.join(bower_dir, 'leaflet/dist/leaflet.css')
      @files = files

      # generate the output
      html = renderer.result(binding)

      # save it to file
      File.open(filename, "w") do |file|
        file << html
      end
    end

    # make a v900 track into a leaflet layer cached to disk
    def self.to_leaflet filename, force = false

      target = to_leaflet_filename filename

      if force or not File.exists? target
        track = V900Track.new filename
        File.open(target, "w") do |file|
          id = sanitize filename

          file.printf <<EOS
latlong_#{id} = #{track.range.each.map { |i| track[i].lat_lon }};\n
start_#{id} = L.marker(#{track.first.lat_lon}).bindPopup('Start');\n
end_#{id} = L.marker(#{track.last.lat_lon}).bindPopup('End');\n
poly_#{id} = L.polyline(latlong_#{id}, {color: 'red'});\n

max_speed_#{id} = L.marker(#{track[track.max_speed_idx].lat_lon}).bindPopup('Max speed #{track.max_speed}')\n;
max_height_#{id} = L.marker(#{track[track.max_height_idx].lat_lon}).bindPopup('Max height #{track.max_height}')\n;
min_height_#{id} = L.marker(#{track[track.min_height_idx].lat_lon}).bindPopup('Min height #{track.min_height}')\n;

#{to_leaflet_layername filename} = L.layerGroup([start_#{id}, end_#{id}, poly_#{id}, max_speed_#{id}, max_height_#{id}, min_height_#{id}]);\n
#{to_leaflet_layername filename}.addTo(map);\n
EOS
        end
      end

    end

    def self.to_leaflet_filename filename
      filename + ".js"
    end

    def self.to_leaflet_layername filename
      "layer_" + sanitize(filename)
    end

    private
    
    def self.sanitize filename
      filename.gsub(/[^0-9A-Za-z\-]/, "_")
    end

  end
end