#!/bin/sh
# the next line starts tcl \
exec tclsh "$0" "$@"

set VERSION 1.0

proc Usage { {msg ""} } {
    
    set msg "$msg\nusage: vnc \[options\] <host>"
    set msg "$msg\n  <host> is the remote host"
    set msg "$msg\n  \[options\] is one of the following:"
    set msg "$msg\n   -v | --vncviewer : path to vncviewer executable"
    set msg "$msg\n   -d | --remote-display <d>: display number on <host>"
    set msg "$msg\n   -h | --help : prints this message and exits"
    set msg "$msg\n   --version : print out the version info and continue"
    puts stderr "$msg\n"
    exit 1
}

#
# simple arg parsing 
#
set PORT ""
set VNCVIEWER c:/cygwin/usr/local/bin/vncviewer.exe
set USER pieper
set REMOTEDISPLAY 0

set strippedargs ""
set argc [llength $argv]
for {set i 0} {$i < $argc} {incr i} {
    set a [lindex $argv $i]
    switch -glob -- $a {
        "--help" - "-h" {
            Usage
            exit 0
        }
        "--vncviewer" - "-vnc" {
            incr i
            if { $i == $argc } {
                Usage "missing argument for $a\n"
            } else {
                set VNCVIEWER [lindex $argv $i]
            }
        }
        "-p" - "--port" {
            incr i
            if { $i == $argc } {
                Usage "missing argument for $a\n"
            } else {
                set PORT [lindex $argv $i]
            }
        }
        "-d" - "--remote-display" {
            incr i
            if { $i == $argc } {
                Usage "missing argument for $a\n"
            } else {
                set REMOTEDISPLAY [lindex $argv $i]
            }
        }
        "-v" - "--version" {
            puts $VERSION
        }
        "-*" {
            Usage "unknown option $a\n"
        }
        default {
            lappend strippedargs $a
        }
    }
}
set argv $strippedargs
set argc [llength $argv]

if {$argc > 1 } {
    Usage
    exit 1
} else {
    set HOST [lindex $argv 0]
    if { [string first @ $HOST] != -1 } {
        scan $HOST {%[^@]@%s} USER HOST
    }
}

proc echo {args} {puts $args}

if { $PORT == "" } {
    # look for an open port
    for {set p 5900} {$p < 6000} {incr p} {
        if { ![ catch "set sp \[socket -server echo $p\]" ] } {
            set PORT $p
            close $sp
            break
        }
    }
}

if { $PORT == "" } {
    puts stderr "couldn't find a free port between 5900 and 6000"
    exit -1
} else {
    puts "found port $PORT"
}

set REMOTEPORT [expr 5900 + $REMOTEDISPLAY]

exec rxvt -e ssh -C -L $PORT:localhost:$REMOTEPORT $USER@$HOST &

for {set tries 0} {$tries < 50} {incr tries} {

    if { ![ catch "set sp \[socket localhost $PORT\]" ] } {

        puts "connected to $PORT"
        close $sp

        set display [expr $PORT - 5900]
        exec /usr/bin/csh -c "$VNCVIEWER localhost:$display" &
        exit
    }
    puts -nonewline "."; flush stdout
    after 100
}

puts "timed out waiting for port $PORT"