#!/bin/bash
#
# Copyright (c): Uwe Schmidt, FH Wedel
#
# You may study, modify and distribute this source code
# FOR NON-COMMERCIAL PURPOSES ONLY.
# This copyright message has to remain unchanged.
#
# Note that this document is provided 'as is',
# WITHOUT WARRANTY of any kind either expressed or implied.

#!/bin/bash
# the next line restarts using tclsh \
exec tclsh "$0" "$@"

# $Id: echoserver.tcl,v 1.2 2006/01/08 14:20:20 uwe Exp $

# global state init --------------------

set state(wait)	1
set state(openSock)	{}

source setopt.tcl
source message.tcl

proc evalOptions args {
    global state
    setopt port		4242
    setopt trace	2
    setopt chat		0

    set state(port)	$port
    set state(trace)	$trace
    set state(chat)	$chat

    message 2 "port: $state(port)"
    message 2 "chat: $state(chat)"
}

# the data processing --------------------
#
# here: do nothing, just send the data back

proc echoData {socket req} {
    sendAnswer $socket $req
}

# here: do nothing, just distribute the data to all clients

proc chatData {socket req} {
    global state

    foreach soc $state(openSock) {
	sendAnswer $soc $req
    }
}

# socket communication --------------------

proc sendAnswer {socket ans} {

    if {[catch \
	     {
		 puts $socket $ans
		 flush $socket
	     } err]} {
	message 1 "sendAnswer($socket): error: $err"
	closeServer $socket
	return
    }
    message 3 "sendAnswer($socket): message written:	$ans"
}

proc processRequest {socket} {
    if {[catch \
	     {
		 set cnt [gets $socket req]
	     } err]} {
	message 1 "processRequest($socket):	$err"
	set cnt -1
    }

    if {$cnt == -1} {
	closeServer $socket
	return
    }
    message 3 "processRequest($socket): message read:	$req"

    processData $socket $req

    global state
    set state(wait) 1
}

proc openServer {socket args} {
    global state
    message 2 "openServer: install file event on $socket"

    lappend state(openSock) $socket

    fileevent $socket readable "processRequest $socket"
}

proc closeServer {socket} {
    global state
    message 2 "closeServer: close socket $socket"

    close $socket

    set i [lsearch -exact $state(openSock) $socket]
    set state(openSock) [lreplace $state(openSock) $i $i]

    if {"$state(openSock)" == ""} {
	message 2 "closeServer: server idle, no open connections"
    }
}

proc initServer {} {
    global state

    message 2 "initServer: port is $state(port)"
    if {[catch {socket -server openServer $state(port)} err]} {
	message 1 "initServer failed: $err"
	exit
    }
}

proc eventLoop {} {
    global state

    while {1} {
	vwait state(wait)
	message 3 "eventLoop: do one event"
	update
    }
}

proc init {} {
    global argv state
    eval evalOptions $argv

    if {$state(chat) == 1} {
	rename chatData processData
    } else {
	rename echoData processData
    }

    initServer

    eventLoop
}

init