require "active_record"

namespace :compass_ae do
  namespace :backup do
  	
  	PG_BACKUP_DIR = '/backup/postgres'
  	SU_POSTGRES = true # set this to false on OS X and true on debian
  	TIMESTAMP_FORMAT = "%Y-%m-%d_%Hh%Mm%Ss" # keep a single underscore or the purge_old task will break
  	@purge_dumps_older_than = 2.weeks.ago
  	
  	desc 'backup all postgres databases'
    task :postgres => :environment do
      create_directory(PG_BACKUP_DIR)

      databases = ActiveRecord::Base.connection.select_values('SELECT datname FROM pg_database;')

      puts red("Backing up ALL postgres databases via pg_dump")
      databases.each do |db|
        unless db == "template0"
          puts "Dumping #{db} to #{PG_BACKUP_DIR}"
          cmd = "pg_dump #{db} > #{PG_BACKUP_DIR}/#{db}_#{Time.now.strftime(TIMESTAMP_FORMAT)}.pgsql"
          cmd = "sudo su postgres -c \"#{cmd}\"" if SU_POSTGRES
          execute_command(cmd)
        else
          puts "Skipping template0 database ..."
        end
      end
      
      puts "\nBackup Complete."
    end

    namespace :postgres do
      # age should be in days
      task :purge_old, [:age] => :environment do |t,args|
        age = (args.age.blank? ? @purge_dumps_older_than : args.age.to_i.days.ago)
        puts "Purging postgres dumps older than #{age}"
        puts green("Default is 2 weeks. You can pass in number of days if you want something different.") if args.age.blank?
        puts green("Example: rake compass_ae:backup:postgres:purge_old[7]") if args.age.blank?

        chdir(PG_BACKUP_DIR)
        
        # get list of files and loop thru them
        files = Dir.glob("*.pgsql")

        files.each do |f|
          puts "Examining dump #{f}"
          # split filename
          filename_split = f.split('_')
          
          # get timestamp
          timestamp = filename_split[-2] + ' ' + filename_split[-1]
          timestamp = timestamp.gsub('.pgsql', '')
          timestamp = timestamp.gsub('h', ':')
          timestamp = timestamp.gsub('m', ':')
          timestamp = timestamp.gsub('s', '')
          
          # convert timestamp to Time object
          timeobject = Time.parse(timestamp)

          # compare time object with purge_dumps_older_than and delete if too old
          if timeobject < age
            puts red("Purging dump #{f}: Older than #{age}")
            cmd = "rm -f #{f}"
            execute_command(cmd)
          end        
        end
        
      end
    end
    
    def create_directory(foldername)
      FileUtils.mkdir_p(foldername) unless File.directory?(foldername)
    end

    def green(text); 
      colorize(text, "\033[32m")
    end

    def red(text)
      colorize(text, "\033[31m")
    end

    def colorize(text, color_code)
      "#{color_code}#{text}\033[0m"
    end

    def execute_command(cmd)
      puts green(cmd)
      system cmd
    end    
  end
end