calendar.rb

require 'date'

class Cell
  def initialize(content, config, highlight = false)
    @content = content
    @highlight = highlight
    @width = config[:width]
    @color0 = config[:color0]
    @color1 = config[:color1]
  end

  def content
    return @content unless @highlight
    "^fg(#{@color0})^bg(#{@color1})#{@content}^fg()^bg()"
  end

  def formatted(i)
    width = @width / 7 - @content.size
    left_padding(width, i) + content + right_padding(width) + line_return(i)
  end

  def left_padding(width, i)
    if i % 7 == 0
      ' ' * ((@width % 7) / 2)
    else
      ''
    end + (' ' * (width / 2 + width % 2))
  end

  def right_padding(width)
    (' ' * (width / 2))
  end

  def line_return(i)
    ((i % 7) == 6 ? "\n" : '')
  end
end

def get_title(config)
  prev_el = "^ca(1, #{call_calendar(config, true)}) <   ^ca()"
  next_el = "^ca(1, #{call_calendar(config, false)})   > ^ca()"
  "#{prev_el}#{Date.new(config[:year], config[:month], 1).strftime('%B')} #{config[:year]}#{next_el}"
end

def call_calendar(config, previous)
  date = Date.new(config[:year], config[:month], 1).prev_month(previous ? 1 : -1)
  str = <<END
dzen2-calendar \
--bg '#{config[:color0]}' \
--fg '#{config[:color1]}' \
-x #{config[:x]} \
-y #{config[:y]} \
-w #{config[:width]} \
-s #{config[:screen]} \
--month #{date.month} \
--year #{date.year} \
--no-toggle
END
  str.strip
end

def get_header(config)
  %w(Su Mo Tu We Th Fr Sa).map.with_index{ |d, i| Cell.new(d, config).formatted(i) }.join('')
end

def get_body(config)
  width = config[:width]
  dates = (1..days_in_month(config)).map { |d| create_cell(d, config) }.to_a
  cells = (1..Date.new(config[:year], config[:month], 1).wday).map { || Cell.new('', config) } + dates
  format_body(cells, width)
end

def days_in_month(config)
  Date.new(config[:year], config[:month], -1).day
end

def create_cell(day, config)
  date = Date.new(config[:year], config[:month], day)
  Cell.new(day.to_s, config, DateTime.now.to_date == date)
end

def format_body(days, width)
  days.map.with_index { |d, i| d.formatted(i) }.join('')
end