class AsciiChart

# File lib/asciichart.rb, line 6
def initialize(rows=20)
        @rows = rows
        @series = []
        @maxx = 0
        @miny = 0
        @maxy = 0
        @@colours = %w{red green blue}.map(&:to_sym)
end

# File lib/asciichart.rb, line 15
def add_series(series, name=nil)
        @series << {
                values: series, 
                colour: pick_colour(@series.length), 
                name: name ? name.capitalize : "Series #{@series.length}"
        }
        @miny = [series.min, @miny].min
        @maxy = [series.max, @maxy].max
        @maxx = [series.length, @maxx].max
end

# File lib/asciichart.rb, line 64
def get_ascii_char(series, time, value_range)
        # returns an ascii character to represent the value-range for the given series at the given time
        # if the series does not have a high enough value at that time, we return ' '
        value = series[:values][time]
        if value and value >= value_range.max.to_f
                c = '#'
        elsif value and value > value_range.min.to_f
                c = '.'
        else
                c = ' '
        end
        c.send(series[:colour])
end

# File lib/asciichart.rb, line 26
def num_series
        @series.length
end

# File lib/asciichart.rb, line 78
def pick_colour(index)
        @@colours[index % @@colours.length]
end

# File lib/asciichart.rb, line 30
def render
        # we need one column for each series up the maximum
        # length of any one series, plus one for padding
        width = ((num_series + 2) * @maxx) + 2
        step = (@maxy - @miny) / @rows.to_f
        y_top = @maxy.to_f
        
        bitmap = '-' * (width + 2)
        bitmap += "\r\n|" + (' ' * width) + '|'

        @rows.times do
                bitmap += "\r\n|  "
                
                # loop on each distinct time/x value
                @maxx.times do |x|
                        @series.each do |s|
                                bitmap += get_ascii_char(s, x, (y_top - step)..y_top)
                        end
                        bitmap += '  '
                end
                bitmap += '|'
                y_top = (y_top - step).round(2)
        end
        bitmap += "\r\n" + ('-' * (width + 2))

        # the legend
        bitmap += "\r\n"
        @series.each do |s|
                bitmap += "\r\n" + s[:name].send(s[:colour])
        end

        puts bitmap
end