#!/usr/bin/env tclsh8.4

cd ~/src/backups

proc find.latest.mtime dir {
 set peak 0

 foreach f [glob -nocomplain [file join $dir *]] {
  if {[file mtime $f] > $peak} {
   set peak [file mtime $f]
  }

  if {[file isdirectory $f]} {
   set mtime [find.latest.mtime $f]

   if {$mtime > $peak} {
    set peak $mtime
   }
  }
 }

 return $peak
}

proc main {} {

 set lastpeak 0
 # 5 minutes
 set delay [expr {1000 * 60 * 5}]

 while 1 {
  set curpeak [find.latest.mtime /work]
  if {$curpeak == $lastpeak} {
   puts NOSAVE
   after $delay
   continue
  }

  catch {exec tar -zcvf [clock format [clock seconds] -format "%a_%b-%d_%H-%M"].tar.gz /work} err
  puts $err
  after $delay
  set lastpeak $curpeak
 } 
}
main