require 'date'
require 'time'
require 'SVG/Graph/Plot'

module SVG
  module Graph
    class RoomSchedule < Graph
      # In addition to the defaults set by Graph::initialize and
      # Plot::set_defaults, sets:
      # [x_label_format] '%Y-%m-%d %H:%M:%S'
      # [popup_format]  '%Y-%m-%d %H:%M:%S'
      def set_defaults
        init_with(
          :x_label_format     => '%Y-%m-%d %H:%M:%S',
          :popup_format       => '%Y-%m-%d %H:%M:%S',
          :scale_x_divisions  => false,
          :scale_x_integers   => false,
          :bar_gap            => true
        )
      end

      # The format string use do format the X axis labels.
      # See Time::strformat
      attr_accessor :x_label_format
      # Use this to set the spacing between dates on the axis.  The value
      # must be of the form
      # "\d+ ?(days|weeks|months|years|hours|minutes|seconds)?"
      #
      # EG:
      #
      #   graph.timescale_divisions = "2 weeks"
      #
      # will cause the chart to try to divide the X axis up into segments of
      # two week periods.
      attr_accessor :timescale_divisions
      # The formatting used for the popups.  See x_label_format
      attr_accessor :popup_format
      attr_accessor :scale_x_divisions
      attr_accessor :scale_x_integers
      attr_accessor :bar_gap

      protected

      def format x, y
        Time.at( x ).strftime( popup_format )
      end

      def get_x_labels
        rv = get_x_values.collect { |v| v.strftime( x_label_format ) }
      end

      def y_label_offset( height )
        height / -2.0
      end

      def get_y_labels
        @data.map {|room| room[:title] }
      end

      def draw_data
        bargap = bar_gap ? (field_height < 10 ? field_height / 2 : 10) : 0
        subbar_height = field_height - bargap

        field_count = 1
        y_mod = (subbar_height / 2) + (font_size / 2)
        min,max,div = x_range
        scale = (@graph_width) / (max - min).to_f
        @data.each do |room|
          room[:data].each do |entry|
            x_start = (entry.start_time - min).to_f
            x_end = (entry.end_time - min).to_f
            y = @graph_height - (field_height * field_count)
            bar_width = (x_end - x_start) * scale
            bar_start = x_start * scale

            event = @graph.add_element( "rect", {
              "x" => bar_start.to_s,
              "y" => y.to_s,
              "width" => bar_width.to_s,
              "height" => subbar_height.to_s,
              "class" => "fill#{field_count+1}"
            })
            switch = @graph.add_element("switch")
            fo = switch.add_element("foreignObject", {
              "x" => (bar_start + @font_size / 2).to_s,
              "y" => y.to_s,
              "width" => bar_width.to_s,
              "height" => subbar_height.to_s,
              "requiredExtensions" => "http://www.w3.org/1999/xhtml",
            })
            body = fo.add_element("body", {
              "xmlns" => "http://www.w3.org/1999/xhtml",
            })
            p = body.add_element("p", {
              "class" => "event-title",
            })
            if entry.link
              p = p.add_element("a", { "href" => entry.link })
            end
            p.add_text(entry.title)
            t = switch.add_element("text", {
              "x" => (bar_start + @font_size / 2).to_s,
              "y" => (y + 2 * @font_size).to_s,
            })
            t.add_text(entry.title)
          end
          field_count += 1
        end
      end

      def get_css
        return <<EOL
/* default fill styles for multiple datasets (probably only use a single dataset on this graph though) */
.key1,.fill1{
	fill: #ff0000;
	fill-opacity: 0.5;
	stroke: none;
	stroke-width: 0.5px;
}
.key2,.fill2{
	fill: #0000ff;
	fill-opacity: 0.5;
	stroke: none;
	stroke-width: 1px;
}
.key3,.fill3{
	fill: #00ff00;
	fill-opacity: 0.5;
	stroke: none;
	stroke-width: 1px;
}
.key4,.fill4{
	fill: #ffcc00;
	fill-opacity: 0.5;
	stroke: none;
	stroke-width: 1px;
}
.key5,.fill5{
	fill: #00ccff;
	fill-opacity: 0.5;
	stroke: none;
	stroke-width: 1px;
}
.key6,.fill6{
	fill: #ff00ff;
	fill-opacity: 0.5;
	stroke: none;
	stroke-width: 1px;
}
.key7,.fill7{
	fill: #00ffff;
	fill-opacity: 0.5;
	stroke: none;
	stroke-width: 1px;
}
.key8,.fill8{
	fill: #ffff00;
	fill-opacity: 0.5;
	stroke: none;
	stroke-width: 1px;
}
.key9,.fill9{
	fill: #cc6666;
	fill-opacity: 0.5;
	stroke: none;
	stroke-width: 1px;
}
.key10,.fill10{
	fill: #663399;
	fill-opacity: 0.5;
	stroke: none;
	stroke-width: 1px;
}
.key11,.fill11{
	fill: #339900;
	fill-opacity: 0.5;
	stroke: none;
	stroke-width: 1px;
}
.key12,.fill12{
	fill: #9966FF;
	fill-opacity: 0.5;
	stroke: none;
	stroke-width: 1px;
}
.event-title {
  font-size: 80%;
}
EOL
      end

      private

      def timescale_unit
        if timescale_divisions
          timescale_divisions =~ /(\d+) ?(days|weeks|hours|minutes|seconds)?/
          division_units = $2 ? $2 : "days"
          amount = $1.to_i
          unit =  nil
          case division_units
            when "weeks"
              unit = 7
            when "days"
              unit = 1
            when "hours"
              unit = (1.0 / 24)
            when "minutes"
              unit = (1.0 / 1440)
            when "seconds"
              unit = (1.0 / 86400)
          end
        end
        [ amount, unit ]
      end

      def x_range
        max_value = @data.map {|room| room[:data].map {|e| e.end_time}.max}.max
        min_value = @data.map {|room| room[:data].map {|e| e.start_time}.min}.min

        amount, unit = timescale_unit
        max_value += unit * (amount - (max_value.min % amount))
        range = max_value - min_value
        right_pad = 0 #range == 0 ? 10 : range / 20.0
        scale_range = (max_value + right_pad) - min_value

        scale_division = scale_x_divisions || (scale_range / 10.0)

        if scale_x_integers
          scale_division = scale_division < 1 ? 1 : scale_division.round
        end

        [min_value, max_value, scale_division]
      end

      def get_x_values
        rv = []
        min, max, scale_division = x_range
        if timescale_divisions
          amount, unit = timescale_unit
          min.step( max, amount * unit) {|v| rv << v} if amount
          return rv
        end
        min.step(max, scale_division) {|v| rv << v}
        return rv
      end
    end
  end
end