0m

#! /usr/bin/env tclsh

###############################################################################
# 0m: desktop utility for positioning monitors

source $::env(HOME)/bin/lib.tcl

need rg \
     xrandr

###############################################################################

proc help {} {
  global ME
  puts "Usage: $ME <option>"
  puts {  x     off}
  puts {  s  =  same}
  puts {  d  b  bot  bottom  down}
  puts {  u  t  up}
  puts {  l     left}
  puts {  r     right}
  exit
}

proc detect {which} {
  catch {exec xrandr --query | rg -A1 primary} grep_prm
  set prm [lindex $grep_prm 0]
  switch -regexp -- $which {
    ^prm.* {
      if {{prm} eq $which} {
        return $prm
      }
      return [lindex [exec echo $grep_prm | tail -1] 0]
    }
    ^ext.* {
      catch {exec xrandr --query | rg -v $prm | rg -A1 " connected"} grep_ext
      if {{ext} eq $which} {
        return [lindex $grep_ext 0]
      }
      # matches the last line, so presumes a single external
      return [lindex [exec echo $grep_ext | tail -1] 0]
    }
    ^first$ {
      catch {exec xrandr --query | rg {\+0\+0 \(}} grep_first
      return [lindex $grep_first 0]
    }
  }
  return {}
}

proc connected {} {
  global ext
  if {[string length $::env(DISPLAY)] \
      && ![catch {exec xrandr -q | rg "^$ext connected "}]} {
      return true
  } else {
    return false
  }
}

proc opt {rel dir ref} {
  global prm prm_res ext ext_res
  if {[string equal $rel {prm}]} {
    set dir "primary --orientation normal --rotate normal --$dir"
  }
  return "--auto --output [subst $${rel}]\
          --mode [subst $${rel}_res]\
          --$dir [subst $${ref}]"
}

###############################################################################

set arg [lindex $::argv 0]
set prm [detect prm]
set ext [detect ext]
set prm_res [detect prm_res]
set ext_res [detect ext_res]
set cmd1 {xrandr}
set cmd2 {}

switch -- $arg {
  {} - x - off - \
  = - s - same - \
  b - d - bot - bottom - down - \
  t - u - top - up - \
  l - left - \
  r - right {
    if {![connected]} { fail "no external monitor connected" }
  }
  default { help }
}

switch -- $arg {
  {} - x - off {
    append cmd1 " --output $ext --off"
  }
  = - s - same {
    append cmd1 " [opt prm same-as ext]"
  }
  b - d - bot - bottom - down {
    set cmd2 "$cmd1 [opt prm above ext]"
    append cmd1 " [opt ext {rotate normal --below} prm]"
  }
  t - u - top - up {
    set cmd2 "$cmd1 [opt prm below ext]"
    append cmd1 " [opt ext {rotate normal --above} prm]"
  }
  l - left {
    set cmd2 "$cmd1 [opt prm right-of ext]"
    append cmd1 " [opt ext {rotate normal --left-of} prm]"
  }
  r - right {
    set cmd2 "$cmd1 [opt prm left-of ext]"
    append cmd1 " [opt ext {rotate normal --right-of} prm]"
  }
  default { help }
}

# workaround: polybar seems to mess monitor borders
catch {exec pkill polybar}

exec {*}$cmd1
if {{} ne $cmd2} { exec {*}$cmd2 }

# workaround: restart polybar on "northwest-most" monitor
set ::env(MONITOR) [detect first]
exec >>&$LOGX nohup polybar 0bar &