#!/usr/bin/tclsh

set ::test 0
set ::debug 1

set ::ontime 30
set ::lockfile /var/lock/doormonitor

set ::owfs /mnt/1wire
if {$test} {
    set ::sensor 12.0C4A02000000
    set ::sensoract $::sensor/latch.B
    set ::sensorinit [list \
			  [list $::sensor/set_alarm 211] \
			  [list $::sensor/PIO.ALL 0,0] \
			  [list $::sensor/latch.ALL 0,0] \
		     ]
} else {
    set ::sensor 12.8C4229000000
    set ::sensoract $::sensor/latch.A
    set ::sensorinit [list \
			  [list $::sensor/set_alarm 111] \
			  [list $::sensor/PIO.ALL 0,0] \
			  [list $::sensor/latch.ALL 1,1] \
		     ]
}
set ::driver 12.90D21C000000
set ::driverpio $::driver/PIO.A
set ::driverinit [list \
		      [list $::driver/set_alarm 011] \
		      [list $::driver/PIO.A 0] \
		      [list $::driver/latch.ALL 1,1] \
		 ]


proc logger {msg {priority err}} {
    syslog -facility daemon -ident doormonitor $priority $msg
}

proc owget {name} {
    if {[catch {open $::owfs/$name} f]} {
	logger "ERROR: $f"
	return ""
    }
    set res [read -nonewline $f]
    close $f
    return $res
}
                                                                                                             
proc owput {name {val ""}} {
    if {[catch {open $::owfs/$name WRONLY} f]} {
	logger "ERROR(owput): $f"
	return 0
    }
    puts $f $val
    close $f
    return 1
}

proc IsActivity {} {
    return [owget $::uncached$::sensoract]
}

proc ClearActivity {} {
    if {$::debug} {
	logger ClearActivity info
    }
    owput $::sensoract 1
}

proc DoInit {{dev ""}} {
    if {($dev=="") || ($dev==$::sensor)} {
	if {$::debug} {logger "sensor init" info}
	foreach l $::sensorinit {owput [lindex $l 0] [lindex $l 1]}
	ClearActivity
    }
    if {($dev=="") || ($dev==$::driver)} {
	if {$::debug} {logger "driver init" info}
	foreach l $::driverinit {owput [lindex $l 0] [lindex $l 1]}
    }
}

proc TurnOn {} {
    if {$::debug} {
	logger "driver ON" info
    }
    owput $::driverpio 1
}

proc TurnOff {} {
    if {$::debug} {
	logger "driver OFF" info
    }
    owput $::driverpio 0
    file delete -force $::lockfile
}

proc ReadLockFile {} {
    if {[catch {open $::lockfile} lck]} {
	logger "ERROR: $lck"
	return ""
    }
    set str [string trim [gets $lck]]
    close $lck
    if {[regexp {^(\d+)\s+(\d+)$} $str foo pid tim]} {
	return [list $pid $tim]
    } else {
	logger "ERROR: Bad data in $::lockfile"
	return ""
    }
}

proc UpdateLockfile {pid tim} {
    if {[catch {open $::lockfile w} lck]} {
	logger "ERROR: $lck"
	return 0
    }
    puts $lck "$pid $tim"
    close $lck
    return 1
}

proc CheckProcess {pid} {
    # return:
    # 0 - error
    # 1 - process not found
    # 2 - process exists
    global errorCode
    if {[catch {kill 0 $pid} msg]} {
	if {[lindex $errorCode 1] == "ESRCH"} {
	    if {$::debug} {logger "process not found" info}
	    return 1
	} else {
	    logger "ERROR: Cannot send signal to process($pid): $msg"
	    return 0
	}
    } else {
	    if {$::debug} {logger "process exists" info}
	return 2
    }
}

proc TurnOnAndWait {} {
    if {[UpdateLockfile [pid] [clock seconds]] == 0} {
	exit 1
    }
    TurnOn
    set difftime $::ontime
    while {1} {
	after [expr $difftime * 1000]
	set currtime [clock seconds]
	if {[set old [ReadLockFile]] == ""} {
	    TurnOff
	    exit 1
	}
	set stoptime [expr [lindex $old 1] + $difftime]
	if {$stoptime <= $currtime} {
	    TurnOff
	    exit 0
	} else {
	    set difftime [expr $stoptime - $currtime]
	}
    }
}

if {($argc < 1) || (([set mode [lindex $argv 0]] != "init") && ($mode != "start"))} {
    puts stderr "Usage: $argv0 init [device]|start"
    exit 1
}
package require Syslog
package require Tclx
if {[file exists $::owfs/uncached]} {set ::uncached uncached/} {set ::uncached ""}
if {$mode == "init"} {
    DoInit [lindex $argv 1]
    TurnOff
    exit 0
}
if {$mode == "start"} {
    if {![IsActivity]} {
#	exit 0
    }
    ClearActivity
    if {[file exists $::lockfile]} {
	if {[set old [ReadLockfile]] == ""} {exit 1}
	switch [CheckProcess [lindex $old 0]] {
	    0 {exit 1}
	    1 TurnOnAndWait
	    2 {
		if {[UpdateLockfile [lindex $old 0] [clock seconds]]} {
		    exit 0
		} else {
		    exit 1
		}
	    }
	}
    } else {
	TurnOnAndWait
    }
    exit 0
}