graph.rb

class AsciiGraph
  attr_reader :title

  def initialize(x, y, title, data)
    @x = x
    @y = y
    @title = title
    @data = data
  end

  def plot
    draw_axes
    draw_title
    draw_data

    self
  end

  def canvas
    @canvas ||= (@y).times.to_a.map { Array.new @x, " " }
  end

  def draw_axes
    @x_axis = @y - 2
    @y_axis = 4

    (1..@y-3).each { |i| canvas[i][@y_axis] = "|" }
    (2..@x-2).each { |i| canvas[@x_axis][i] = "-" }

    canvas[@x_axis][@y_axis - 1] = "-"
    canvas[@x_axis][@y_axis] = "+"
    canvas[@x_axis + 1][@y_axis] = "|"
  end

  def draw_title
    canvas[@y] = @title.center(@x).split("")
  end

  def draw_data
    min = @data.min
    max = @data.max

    graph_width = @x - @x_axis - 3
    width = @data.size

    if width > graph_width
      columns = (0..graph_width).to_a
    else
      r = width.to_f / graph_width
      columns = Array.new(graph_width) { |i| (i * r).to_i }
    end

    graph_y = @y - 3
    graph_height = @y - 5
    height = max + 1 - min
    r = graph_height.to_f / height

    columns.each do |c|
      y = graph_y - (@data[c] - min) * r
      x = c + @y_axis + 2

      @canvas[y][x] = "."
    end
  end

  def to_s
    canvas.map { |r| r.join << "\n" }.join
  end
end

filename = ARGV.shift

contents = File.readlines filename
metrics = contents.shift.chomp.split ", "

rows = contents.map { |x| x.chomp.split.map { |n| n.to_i } }

data = { }

metrics.each_with_index do |m, i|
  data[m] = rows.map { |r| r[i] }
end

width = Rubinius::TERMINAL_WIDTH
height = 12

graphs = data.map do |t, d|
  AsciiGraph.new width, height, t, d
end

graphs.sort! { |a, b| a.title <=> b.title }

graphs.each { |g| puts g.plot.to_s }