#!/usr/bin/tclsh8.4
# -*- tcl -*-

proc debug {m} { puts "DEBUG $m" }

proc log {m} { puts "LOG $m" }

proc experror {m} {
    error $m {} EXPECTED
}

proc find-devices {} {
    global errorCode errorInfo devices
    set base /sys/class/tty
    foreach candidate [glob -nocomplain -directory $base -tails ttyACM*] {
	debug "candidate $candidate"
	if {[catch { file link $base/$candidate/device } ltarget]} {
	    debug " readlink failed [lrange $errorCode 0 1]"
	    switch -glob $errorCode {
		{POSIX EINVAL *} continue
		{POSIX ENOENT *} continue
		default { error "$ltarget \[$errorCode] $errorInfo $errorCode" }
	    }
	}
	if {![regexp {^(.*)\.(\d+)$} $ltarget dummy dbase interf]} {
	    debug " readlink bad target $ltarget"
	    continue
	}
	debug " approved $dbase $interf $candidate"
	lappend devs($dbase) [list $interf $candidate]
    }
    set howmany [array size devs]
    if {!$howmany} {
	experror "no appropriate device(s) found"
    }
    if {$howmany > 1} {
	experror "several appropriate device(s) found [array names $devs]"
    }
    set devices {}
    foreach dev [lsort -index 0 -integer $devs([lindex [array names devs] 0])] {
	lappend devices [lindex $dev 1]
    }
}

proc reopen-our-device {} {
    global devices dchan
    find-devices
    set dchan [open /dev/[lindex $devices 1] r+]
    fconfigure $dchan -blocking no -buffering line -translation {crlf cr}
    read $dchan; # flush input
    puts $dchan ATE0
    flush $dchan
    after 250
    set result [read $dchan]
    if {![regexp -line {^OK$} $result]} { experror "got [logquote $result]" }
    fileevent $dchan readable dchan-readable
}

proc devfailure {emsg} {
    global errorCode errorInfo dchan
    switch -glob $errorCode {
	{POSIX *} - EXPECTED {
	    log "device failure: $emsg"
	}
	default {
	    log "unexpected device failure: $emsg"
	    foreach l [split $errorInfo "\n"] {
		log "  $l"
	    }
	}
    }
    if {[info exists dchan]} {
	catch { close $dchan }
	catch { unset dchan }
    }
}

proc try-open-our-device {} {
    global devices
    if {[catch {
	reopen-our-device
    } emsg]} {
	devfailure $emsg
	return
    }
    sendout-async *TTYATMUX "*TTYATMUXDEVS [join $devices ,]"
    sendout-async *TTYATMUX "*TTYATMUXOPEN"
}

proc dchan-readable {args} {
    global dchan
    while 1 {
	if {[catch {
	    gets $dchan l
	} r]} {
	    devfailure $r
	    return
	}
	if {$r<0} {
	    if {![eof $dchan]} return
	    set errorCode EXPECTED
	    devfailure "eof"
	    return
	}
	dchan-line $l
    }
}

proc async-notif-or-resp-varies {async_values asid l} {
    set ll [llength [split $l ,]]
    if {$ll == $async_values} {
	async-notif $asid $l
    } elseif {$ll == $async_values+1} {
	sync-reply $l
    } else {
	bad-data $l "async-notif-or-resp-varies $ll"
    }
}

proc async-notif-or-resp-fixed {asid l} {
    global current_command_asid
    if {![string compare $asid $current_command_asid]} {
	sync-reply $l
    } else {
	async-notif $asid $l
    }
}

proc async-notif-creg {asid l} {
    set ll [llength [split $l ,]]
    switch -exact $ll {
	4 { sync-reply $l }
	3 { 
	    async-notif {+CREG} 2 2 $l
	    async-notif {+CREG} 1 1 [lindex [split $l ,] 0]
	}
	2 { sync-reply $l }
	1 { 
	    async-notif {+CREG} 1 2 $l
	}
	default {
	    bad-data $l "async-notif-creg $ll"
	}
    }
}

proc async-control-max0 {c l allows} {
    async-control-core $c $l $allows {
	set wanted 0
    } {
	set tw 0
	manyset $ca($c) tw
	if {$tw} { set wanted 1 }
    } {
	set send $wanted
	foreach allow $allows { lappend $send [lindex $allow 0] }
	sync-subcommand $c "$cmd=[join $send ,]" async-updated-ok $c
    }
}

proc async-control-cmer {c l allows} {
    async-control-core $c $l $allows {
	set send 0,0,0,0
    } {
	set mode 0; set ind 0
	manyset $ca($c) mode keyp disp ind bfr
	if {$mode==3 && $ind} { set send 3,0,0,1 }
    } {
	sync-subcommand $c "$cmd=$send" async-updated-ok $c
    }
}

proc async-updated-ok

proc async-control-core {c l allows ubody_init ubody_perclient ubody_finish} {
    global clients
    uplevel 1 cmd cmd
    if {[regexp {^(AT[^=?])\?$} dummy cmd]} {
	sync-subcommand $c $cmd async-massage-result-subs $c $cmd
    } elseif {[regexp {^(AT[^=?])=\?$} dummy cmd]} {
	sync-subcommand $c $cmd async-massage-result-support $c $cmd $allows
    } elseif {[regexp {^(AT[^=?])=([0-9,]+)$} dummy cmd values]} {
	set values [split $values ,]
	if {[llength $values] > [llength $allows]} {
	    bad-command "too many values"
	    return
	}
	while {[llength $values] < [llength $allows]} {
	    lappend values 0
	}
	foreach val $values allow $allows {
	    if {[lsearch -exact $allow $val]<0} {
		bad-command "$val not in allowed $allow ($allows)"
		return
	    }
	}
	uplevel 1 [list upvar #0 client_async/$cmd ca]
	upvar #0 client_async/$cmd ca
	set ca($c) $values
	uplevel 1 $ubody_init
	upvar 1 c uc
	foreach uc [array names clients] {
	    uplevel 1 $ubody_perclient
	}
	uplevel 1 $ubody_finish
    } else {
	bad-command "unknown async control syntax"
    }
}

proc set-client-echo {c yn} {
    global client_echo
    set client_echo($c) 0
    client-command-complete $c OK
}

proc process-client-command {c nl} {
    switch -regexp $l {
	{^AT\+CREG\b} { async-control-max0 $c $l {{0 1 2}} }
	{^AT\+CGREG\b} { async-control-max0 $c $l {{0 1 2}} }
	{^AT\*ERINFO\b} { async-control-max0 $c $l {{0 1}} }
	{^AT\+CGEREP\b} { async-control-max0 $c $l {{0 1 2} 0} }
	{^AT\+CMER\b} { async-control-cmer $c $l {{0 3} 0 0 {0 1} 0} }
	{^ATE0$} { set-client-echo $c 0 }
	{^ATE1$} { set-client-echo $c 1 }
    

proc dchan-line {l} {
    global cclient
    switch -regexp $l {
	{\+CREG:}   { async-notif-creg             +CREG   $l }
	{\+CGREG:}  { async-notif-creg             +CGREG      $l }
	{\*ERINFO:} { async-notif-or-resp-fixed    *ERINFO $l }
	{\+CGEV:}   { async-notif                  +CGEREP   $l }

	{\+CIEV:}   { async-notif                  +CIEV   $l }
    }

    if {[info exists cclient

proc sendout-async
proc logquote


try-open-our-device