#!/bin/ksh
# @(#) bell.ksh 1.1 96/02/02
# 93/03/07 john h. dubois iii (john@armory.com)
# 93/03/13 Warn if visual is attempted on a non-console tty.
# 93/04/02 When given visual, make screens switch to other screens on the
#          same adapter.  When given "visual console", map only screens
#          that can be opened and are not running line discipline 2 (ev).
# 93/04/03 Work around need for /dev/stdin
# 94/10/24 If given list of ttys, only try to map those that are readable.
# 94/11/06 Added h option.
# 94/11/17 Added read from /dev/string/cfg

# Sets global Adapters[1..n] to the types of adapters present,
# from the set (mono cga ega vga).
# Returns number of adapters found.
function FindAdapters {
    typeset Name dev=/dev/string/cfg
    typeset -i j=0
    
    if [ -c $dev -a -r $dev ]; then
	# This will work under 3.2v4
	awk '
BEGIN {
    A["mono"] A["cga"] A["ega"] A["vga"]
}
$1 == "%console" {
    sub("^unit=","",$5)
    if ($5 in A)
	print $5
}' /dev/string/cfg | while read Name; do
	    Adapters[j]=$Name
	    let j+=1
	done
    else	
	# This test will fail if proc has no controlling tty,
	# due to a silly test in the /dev/adapter driver.
	for Name in in vga ega cga mono; do
	    if ( < /dev/$Name ) > /dev/null 2>&1; then
		Adapters[j]=$Name
		let j+=1
	    fi
	done
    fi
    [ j -gt 2 ] &&
    print -u2 "$name: found $j video adapters; should not be more than two."
    return $j
}

# Usage: FindConsTTYTypes ttyname ...
# MonoTTYs[1..m] and ColorTTYs[1..c] are set to the tty numbers
# of the mono and color ttys.  
# ttyType[ttynum] is set to $Mono or $Color for each tty number.
# The test used is based on only color adapters having the 8x8 font.
typeset -i ttyType MonoTTYs ColorTTYs
function FindConsTTYTypes {
    typeset -i mi=1 ci=1 l w c=0 ttynum

    for tty; do
	tty=${tty#/dev/}		# Get rid of leading /dev
	ttynum=${tty##*([!0-9])}	# Get rid of non-numeric part
	# tr is defined to always delete null chars from the input
	vidi -d font8x8 < "/dev/$tty" 2>/dev/null | tr | wc -c | read c
	# c (number of non-null chars emitted by vidi) will be
	# 0 if the input was a mono adapter
	if [ c -eq 0 ]; then
	    MonoTTYs[mi]=ttynum
	    ttyType[ttynum]=Mono
	    let mi+=1
	else
	    ColorTTYs[ci]=ttynum
	    ttyType[ttynum]=Color
	    let ci+=1
	fi
	let ttynum+=1
    done
}

# Usage:
# ReplaceBell ttyname sequence [test]
# ttyname is the console tty to change the bell sequence on.
# sequence is the sequence to replace the bell with.
# If sequence is not given, bell mapping is turned off.
# If a third arg is given, no mapping is done.
function ReplaceBell {

    typeset tty=/dev/${1#/dev/} tmpfile
    typeset -i test

    if [ ! -r $tty ]; then
	echo "Cannot read $tty to get current mapping."
	return
    fi

    # Generate tmpfile name if we need one.
    # If the system has /dev/stdin, we don't.
    if [ ! -r /dev/stdin -o LeaveFiles -eq 1 ]; then
	tmpfile=/tmp/bell.$$.${tty#/dev/tty}
	[ verbose -eq 1 ] && echo "mapchan file name: $tmpfile"
    else
	tmpfile=
    fi

    [ $# -ne 3 ]
    test=$?

    mapchan $tty | awk '
    $0 == "output" { 
	InOutput = 1
    }

    # If replacement has not been done yet and we are in the output section
    # and (the old bell mapping or the end of the section) has been found...
    !Done && InOutput && ($1 ~ "^(0x7|dead|compose|control)$") {
	if (replacement != "")
	    map = map "7 " replacement "\n"
	Done = 1
	if ($1 == "0x7")  # Replacing bell sequence, so do not print old one
	    next
    }

    # Channel previously had no mapping
    $0 == "null" {
	if (replacement != "")
	    map = map "input\noutput\n7 " replacement "\n"
	Done = 1
	exit 0
    }

    {
	map = map $0 "\n"
    }

    END {
	if (!Done) {
	    # Old map had only input & output sections & no old map for bell
	    if (InOutput) {
		if (replacement != "")
		    map = map "7 " replacement "\n"
	    }
	    else {
		print "Error interpreting map." | "cat 1>&2"
		exit 1
	    }
	}
#	if (verbose)
#	    print "mapchan input:\n" map
	if (!test) {
	    if (tmpfile == "") {
		procname = "exec mapchan -f /dev/stdin " tty
		print map | procname
	    }
	    else {
		print map > tmpfile
		Cmd =  "mapchan -f " tmpfile " " tty
		if (LeaveFiles == 0)
		    Cmd = Cmd "; exec rm " tmpfile
		system(Cmd)
	    }
	}
    }
    ' replacement="$2" tty="$tty" test=$test tmpfile=$tmpfile \
    verbose=$verbose LeaveFiles=$LeaveFiles
}

# Start of main program

name=${0##*/}

Usage="Usage: $name [-fhvt] [on|off|visual] [console|ttyname ...]"
typeset -i verbose=0 Color=0 Mono=1 LeaveFiles=0

while getopts fhvt opt; do
    case $opt in
    h)
	echo \
"$name: Change the effect of receiving a bell character.
$Usage
$name modifies the bell mapping on the named tty, or on the current tty if
no ttyname is given.  tty names may be given with or without a leading
/dev/.  If console is given, mapping is attempted on all console ttys
(tty01..tty12).  Use /dev/console to specifically map it.  Mapping cannot
be done on a tty that is using the event driver.  Any non-bell mapping
currently in effect on the tty is not changed.
Options:
off	turns off the bell by mapping the bell character (^G) to ^A,
	which does not display anything on most terminals.
on	turns the bell back on by removing any mapping.
visual	replaces the console bell with a visual indication by mapping
	the bell character to a sequence which switches to another
	tty on the same adapter and back.  If -v is given, the switching
	actions that are set up are reported.  visual should only be used
	on console ttys.  
Note: if \"$name visual console\" is going to be done (mapping bell on all
console ttys to visual bell) and all 12 console multiscreens exist (NSCRN =
12), the kernel parameter NEMAP should be increased, since this will result in
12 distinct maps and the default for NEMAP is 10.
Options:
-h: Print this help.
-t: Test.  Do not perform any mapping.
-f: Leave mapchan files in place in /tmp/bell.pid.tty
-v: Set verbose mode.  Show what is being done."
	exit 0
	;;
    f)
	LeaveFiles=1
	;;
    t)
	test=1
	;;
    v)
	verbose=1
	;;
    x)
	debug=true
	;;
    +?)
	print -u2 "$name: options should not be preceded by a '+'."
	exit 1
	;;
    ?) 
	print -u2 "Use -h for help."
	exit 1
	;;
    esac
done
 
# remove args that were options
let OPTIND=OPTIND-1
shift $OPTIND

cmd=$1

case "$2" in
console)
    # Map all console ttys that are readable & are not using the event driver.
    for tty in /dev/tty[01][0-9]; do
	( < $tty ) 2>/dev/null && [[ "`stty < $tty`" != *"line = 2"* ]] &&
	ttys="$ttys $tty"
    done
    ;;
"")	# Map current tty.
    ttys=$(tty)
    ;;
*)	# Map named ttys that are readable
    shift
    for tty; do
	[[ "$tty" != /* ]] && tty="/dev/$tty"
	( < $tty ) 2>/dev/null && ttys="$ttys $tty"
    done
    ;;
esac

case "$cmd" in
on)
    for tty in $ttys; do
	ReplaceBell $tty
    done
    ;;
off)
    for tty in $ttys; do
	ReplaceBell $tty 1
    done
    ;;
visual)
    # Make the always 2 digits to simplify generation of escape sequences.
    typeset -Z2 ToName From
    typeset -i First Last ToNum

    # Only the return value of FindAdapters is currently used.
    FindAdapters	# Find which types of adapters are present
    case $? in
    0)  print -u2 "$name: Warning: no adapters found."
	exit 1
	;;
    1) ;;
    *) 
	# If more than one type of adapter present,
	# need to know which adapter each console tty is on.
	FindConsTTYTypes $ttys
	;;
    esac
    # Set Last[] and First[] to the last & first ttys of each type, so that
    # all but the last can switch to the last tty, and the last can switch to
    # the first.
    Last[Color]=ColorTTYs[${#ColorTTYs[*]}]
    Last[Mono]=MonoTTYs[${#MonoTTYs[*]}]
    First[Color]=ColorTTYs[1]
    First[Mono]=MonoTTYs[1]
    for tty in $ttys; do
	tty=${tty#/dev/}
	ttynum=${tty##*([!0-9])}
	if [[ "$ttynum" != [01][0-9] ]]; then
	    echo "$tty: Not a console tty."
	    continue
	fi
	if [ ttynum -eq Last[ttyType[ttynum]] ]; then
	    ToNum=First[ttyType[ttynum]]
	else
	    ToNum=Last[ttyType[ttynum]]
	fi
	ToName=$ToNum
	[ verbose -eq 1 ] && echo "$tty switches to tty$ToName and back."
	From=$((ttynum-1))
	ToName=$((ToName-1))
	Sequence=\
"033 '[' '${ToName%?}' '${ToName#?}' 'z' 033 '[' '${From%?}' '${From#?}' 'z'"
	[ verbose -eq 1 ] && echo "Bell map: $Sequence"
	ReplaceBell $tty "$Sequence" $test
    done
    ;;
*)
    print -u2 "$Usage\nUse -h for help."
    ;;
esac