module Bumbler
  module Progress
    @item_count   = 0
    @loaded_items = 0
    
    # registry[item_type][item_name] = {:time => 123.45}
    @registry = Hash.new { |h,k| h[k] = {} }
    
    class << self
      def registry
        @registry
      end
      
      def register_item(type, name)
        # Build a blank key for the item
        unless @registry[type][name]
          @item_count  += 1
        end
        
        @registry[type][name] = {}
      end
      
      def item_started(type, name)
        @curr_item = {:type => type, :name => name}
        
        self.render_progress
      end
      
      def item_finished(type, name, time)
        @registry[type][name] = {:time => time}
        
        @loaded_items  += 1
        
        @prev_item = {:type => type, :name => name, :time => time}
        @curr_item = nil if @curr_item && @curr_item[:name] == @prev_item[:name] && @curr_item[:type] == @prev_item[:type]
        
        self.render_progress
      end
      
      def start!
        # No-op for now.
      end
      
      def tty_width
        `tput cols`.to_i || 80
      end
    
      def bar(width)
        inner_size = width - 2
        
        fill_size = ((@loaded_items.to_f / @item_count.to_f) * inner_size).to_i
        fill  = '#' * fill_size
        empty = ' ' * (inner_size - fill_size)
        
        return "[#{fill}#{empty}]"
      end
    
      def render_progress
        unless $stdout.tty?
          puts '(%s/%d) %s' % [@loaded_items.to_s.rjust(@item_count.to_s.size), @item_count, message]
          return
        end
        
        # Do nothing if we don't have any items to load
        return if @item_count == 0
        
        width = self.tty_width
        
        print "\r\e[A\r\e[A" if @outputted_once
        @outputted_once = true
        
        # Output components:
        #   [#######################################]
        #   (##/##) <current>...   <prev> (####.##ms)
        # 
        # Skip the current if there isn't enough room
        count   = '(%s/%d) ' % [@loaded_items.to_s.rjust(@item_count.to_s.size), @item_count]
        current = @curr_item ? "#{@curr_item[:name]}... " : ''
        prev    = @prev_item ? '%s (%sms)' % [@prev_item[:name], ('%.2f' % @prev_item[:time]).rjust(7)] : ''
        
        # Align the bottom row
        space_for_current = width - (count.length + prev.length)
        
        # Render the progress
        puts self.bar(width)
        
        if space_for_current >= current.length
          puts count + current + prev.rjust(width - count.length - current.length)
        else
          puts count + prev.rjust(width - count.length)
        end
      end
    end
  end
end