#!/usr/bin/env ruby

#

# ruby program to generate a performance report in PDF/png over git revisions, based on work

# originally done for gegl by pippin@gimp.org, the original program is in the public domain.

require 'cairo'

def cairo_surface(w,h)

    surface = Cairo::PDFSurface.new("report.pdf", w,h)

    cr = Cairo::Context.new(surface)

    yield(cr)

end 

class Database

    def initialize()

        @vals = Hash.new

        @runs = Array.new

        @colors = [

          [0,1,0, 0.8],

          [0,1,1, 0.8],

          [1,0,0, 0.8],

          [1,0,1, 0.8],

          [1,1,0, 0.8],

          #[0.5,0.5,0.5,0.8],

          # gray doesnt have sufficient contrast against background

          [0.5,0.5,1, 0.8],

          [0.5,1,0.5, 0.8],

          [0.5,1,1, 0.8],

          [1,0.5,0.5, 0.8],

          [1,0.5,1, 0.8],

          [1,1,0.5, 0.8],

          [1,1,1, 0.8],

        ]

        @width  = 1800

        @height = 500

        @marginlx = 10

        @marginrx = 180

        @rgap = 40

        @marginy = 10

    end

    def val_max(key)

       max=0

       @runs.each { |run|

         val = @vals[key][run]

         if val and val > max

           max = val

         end

       }

       max

    end

    def val_min(key)

       min=9999990

       @runs.each { |run|

         val = @vals[key][run]

         min = val  if val and val < min

       }

       #min

       0   # this shows the relative noise in measurements better

    end

    def add_run(run)

        @runs = @runs + [run]

    end

    def add_entry(run, name, val)

        if !@vals[name]

            @vals[name]=Hash.new

        end

        # check if there is an existing value,

        # and perhaps have different behaviors

        # associated with 

        @vals[name][run] = val.to_f

    end

    def drawbg cr

      cr.set_source_rgba(0.2, 0.2, 0.2, 1)

      cr.paint 

      i=0

        @runs.each { |run|

         if i % 2 == 1

           cr.move_to 1.0 * i / @runs.length * (@width - @marginlx-@marginrx) + @marginlx, 0 * (@height - @marginy*2) + @marginy

           cr.line_to 1.0 * i / @runs.length * (@width - @marginlx-@marginrx) + @marginlx, 1.0 * (@height - @marginy*2) + @marginy

           cr.rel_line_to(1.0 / @runs.length * (@width - @marginlx-@marginrx), 0)

           cr.rel_line_to(0, -(@height - @marginy*2))

           cr.set_source_rgba([0.25,0.25,0.25,1])

           cr.fill

         end

         i+=1

        }

    end

    def drawtext cr

      i = 0

      @runs.each { |run|

        y = i * 10 + 20

        while y > @height - @marginy

          y = y - @height + @marginy + 10

        end

        cr.move_to 1.0 * i / @runs.length * (@width - @marginlx-@marginrx) + @marginlx, y

        cr.set_source_rgba(0.6,0.6,0.6,1)

        cr.show_text(run[0..6])

        i+=1

      }

    end

    def draw_limits cr, key

      cr.move_to @width - @marginrx + @rgap, 20

      cr.set_source_rgba(1.0, 1.0, 1.0, 1.0)

      cr.show_text(" #{val_max(key)} ")

      cr.move_to @width - @marginrx + @rgap, @height - @marginy

      cr.show_text(" #{val_min(key)} ")

    end

    def draw_val cr, key, valno

      min = val_min(key)

      max = val_max(key)

      cr.set_source_rgba(@colors[valno])

      cr.move_to(@width - @marginrx + @rgap, valno * 14 + @marginy + 20)

      cr.show_text(key)

      cr.line_width = 2

      cr.new_path

      i = 0

      @runs.each { |run|

        val = @vals[key][run]

        if val 

          cr.line_to 1.0 * (i+0.5) / @runs.length * (@width - @marginlx-@marginrx) + @marginlx,

                     (1.0 - ((val-min) * 1.0 / (max - min))) * (@height - @marginy*2) + @marginy

        end

        i = i + 1

      }

      cr.stroke

    end

    def create_report

      cairo_surface(@width, @height) { |cr|

        drawbg cr

        valno = 0

        @vals.each { |key, value|

           draw_val cr, key, valno

           valno += 1

        }

        drawtext cr

        cr.target.write_to_png("report.png")

        valno = 0

        @vals.each { |key, value|

           cr.show_page

           drawbg cr

           draw_val cr, key, valno

           drawtext cr

           draw_limits cr, key

           valno += 1

        }

      }

    end

end

generator = Database.new

items = File.open('jobs').each { |rev|

  rev.strip!

  generator.add_run(rev)

  filename = "reports/" + rev;

  if File.exist?(filename)

      File.open(filename).each { |line| 

         if line =~ /^@ (.*):(.*)/

            generator.add_entry(rev, $1, $2)

         end

      }

  end

}

generator.create_report