gistfile1.rb

#!/usr/bin/env ruby

require 'fileutils'
require 'rubygems'
require 'sqlite3'

class WeightTracker
  def initialize
    @db_file = File.expand_path("~/.wt.db")
  end

  def setup
    db.execute <<-SQL
      create table if not exists weights (
        time datetime,
        weight float
      )
    SQL
  end

  def teardown
    FileUtils.cp(@db_file, @db_file + ".bkp.#{Date.today}")
    FileUtils.rm(@db_file)
  end

  def insert(time, weight)
    db.execute("insert into weights values(?, ?)", [time.to_s, weight])
  end

  def averages
    db.execute("select date(time), avg(weight) from weights group by date(time) order by date(time)")
  end

  private
  def db
    @db ||= SQLite3::Database.new(@db_file)
  end
end

class ConsoleAverageWeightRenderer
  def initialize(data)
    @data = data
  end

  def render
    puts "-" * 30

    older_weight = 0
    @data.each do |date, weight|
      pretty_weight = "% 4.1f" % weight

      if weight > older_weight
        pretty_weight = red(pretty_weight)
      else
        pretty_weight = green(pretty_weight)
      end

      older_weight = weight

      puts "| %s %s | %s |" % [date, " " * 6, pretty_weight]
    end
    puts "-" * 30
  end

  private
  def green(str) "\e[32m#{str}\e[0m" end
  def red(str) "\e[31m#{str}\e[0m" end
end

tracker = WeightTracker.new

case ARGV[0]
when 'setup'
  tracker.setup
  puts "Setup ran correctly."
when 'teardown'
  tracker.teardown
  puts "Teardown ran correctly."
when 'insert'
  value = Float(ARGV[1].to_s)
  tracker.insert(DateTime.now, value)
  puts "Weight #{value} inserted for time #{DateTime.now}! Keep up the good work!"
when 'averages'
  ConsoleAverageWeightRenderer.new(tracker.averages).render
else
  puts "No idea what you mean by that dude"
end