class BacklogsController < ApplicationController
  skip_before_filter :populate_layout, :only => [:index, :burn_down_chart, :burn_down_chart_thumbnail, :destroy]
  
  # GETs should be safe (see http://www.w3.org/2001/tag/doc/whenToUseGet.html)
  verify :method => :post, :only => [ :destroy, :create, :update ],
  :redirect_to => { :action => :index }
  
  def index
    if Task.find_started.size > 0
      redirect_to :controller => 'tasks', :action => :list_started
      return
    end
    if Backlog.count == 0
      redirect_to :action => :new
      return
    end
    redirect_to :controller => 'periods', :action => :index
  end
  
  def list
    @backlogs = Backlog.find(:all, :order => 'name')
  end
  
  def show
    if params[:id]
      @backlog = Backlog.find(params[:id])
    end
    unless @backlog
      @backlog = Backlog.find(:first)
      unless @backlog
        redirect_to :controller => 'backlogs', :action => :new
        return
      end
    end
    unplanned_tasks = @backlog.tasks.select {|t| t.period.nil? && t.finished_at.nil?}.sort_by {|t| t.position}
    planned_tasks = @backlog.tasks.select {|t| t.period && t.finished_at.nil?}.sort_by {|t| [t.period.end_on, t.position]}
    @tasks = planned_tasks + unplanned_tasks
    @completed_tasks = @backlog.tasks.select {|t| t.finished_at}.sort {|t1, t2| t2.finished_at <=> t1.finished_at}
  end
  
  def new
    @backlog = Backlog.new
  end
  
  def create
    @backlog = Backlog.new(params[:backlog])
    if @backlog.save
      flash[:notice] = 'Backlog was successfully created.'
      redirect_to :action => :show, :id => @backlog
    else
      render :action => 'new'
    end
  end
  
  def edit
    @backlog = Backlog.find(params[:id])
  end
  
  def edit_no_layout
    edit
    render :partial => 'tasks'
  end
  
  def update
    @backlog = Backlog.find(params[:id])
    if @backlog.update_attributes(params[:backlog])
      flash[:notice] = 'Backlog was successfully updated.'
      redirect_to :action => 'show', :id => @backlog
    else
      render :action => 'edit'
    end
  end
  
  def destroy
    Backlog.find(params[:id]).destroy
    flash[:notice] = 'Backlog was successfully deleted.'
    redirect_to :action => 'index'
  end
  
  def burn_down_chart_thumbnail
    send_burn_down_chart 270
  end
  
  def burn_down_chart
    send_burn_down_chart 640
  end
  
  private
  
  def send_burn_down_chart(size)
    backlog = Backlog.find(params[:id])
    g = Gruff::Line.new(size)
    g.theme_37signals
    g.title = "Burn Down Graph" 
    g.font = '/usr/share/fonts/bitstream-vera/Vera.ttf'
    g.hide_dots = true
    g.colors = %w{blue green}
    
    dates = []
    backlog.periods.first.start_on.upto(backlog.periods.last.end_on) {|date| dates << date}
    
    g.data(l(:todo), get_todo_data(dates, backlog))
    g.data(l(:done), get_work_data(dates, backlog))
    g.minimum_value = 0
    
    labels = {0 => dates.first.to_s, dates.length-1 => dates.last.to_s}
    labels.merge({dates.index(Date.today) => Date.today.to_s}) if (dates.index(Date.today).to_f / dates.length) > 0.15
    g.labels = labels
    
    send_data(g.to_blob,
              :disposition => 'inline', 
    :type => 'image/png', 
    :filename => "burn_down_chart.png")
  end
  
  def get_todo_data(dates, backlog)
    dates.map do |date|
      backlog.get_estimate_data(date)
    end
  end
  
  def get_work_data(dates, backlog)
    dates.map do |date|
      backlog.get_work_data(date)
    end
  end
  
end