cards.rb

# Run this file by placing it in your Rails application's script directory.
# Then you invoke it with:
#
#  rails runner script/cards.rb
#
# Or if you are running Zeus:
#
#  zeus runner script/cards.rb

require "rubygems"
require "prawn"
require "bundler/setup"

class Card
  attr_reader :table_name, :columns, :body
  TYPES = {
    "integer"  => "INT",
    "float"    => "FLT",
    "datetime" => "D/T",
    "boolean"  => "BOOL",
    "string"   => "STR",
    "text"     => "TXT"
  }

  def initialize(table_name, columns)
    @table_name = table_name
    @columns    = columns_as_string columns
    @body       = @columns.join("\n")
  end

  private
  def columns_as_string(columns)
    columns.map do |column|
      type = (TYPES[column.type.to_s] || "??#{column.type}").ljust(5, " ")
      "<font name='Courier'><strong><sup><color rgb='AB66FF'>#{type}</color></sup></strong></font>#{column.name} "
    end
  end
end

class Prawn::Document
  CARD_WIDTH  = 72 * 7 # 7 inches
  CARD_HEIGHT = 72 * 5 # 5 inches
  SPACE_BETWEEN_COLUMN_NAMES = 2

  def self.generate_cards(outfile, cards)
    generate(outfile, :page_layout => :portrait) do
      row = 2

      font "Helvetica"

      cards.each do |card|
        if row == 0
          start_new_page
          row = 2
        end

        draw_card(card, row)

        row -= 1
      end
    end
  end

  def margin_box(margin, &block)
    bounding_box [bounds.left + margin, bounds.top - margin],
      width: bounds.width - (margin * 2), height: bounds.height - (margin * 2),
      &block
  end

  def outline_box
    stroke_rectangle bounds.top_left, bounds.width, bounds.height
  end

  def draw_card(card, row)
    y_offset = CARD_HEIGHT * row + ((bounds.height - (2*CARD_HEIGHT))/2)
    bounding_box [0, y_offset], width: CARD_WIDTH, height: CARD_HEIGHT-10 do # offset the height by a little bit in order to separate the bounding boxes

      outline_box

      margin_box 8 do
        text card.table_name.upcase, :size => 18
        move_down 2
        # stroke_horizontal_rule
        margin_box 12 do
          font "Times-Roman"
          move_down 20
          column_box([0, cursor], columns: 2, width: bounds.width, height: CARD_HEIGHT - 50) do
            text card.body, size: 13, align: :left, leading: SPACE_BETWEEN_COLUMN_NAMES, inline_format: true
          end
        end
      end
    end
  end

end

def generate_pdf(cards)
  file = ARGV[0] || 'tmp/cards.pdf'
  Prawn::Document.generate_cards(file, cards)
  puts "check #{file}"
end

connection = ActiveRecord::Base.connection
cards = []
(connection.tables - ['schema_migrations']).sort.each do |table_name|
  cards << Card.new(table_name, connection.columns(table_name))
end

generate_pdf cards