[ircbot] / bot.tcl

# Actual IRC bot code

set helpfile helpinfos

source irccore.tcl
source parsecmd.tcl
source stdhelp.tcl

proc privmsg_unlogged {prefix ischan params} {
    if {!$ischan ||
        [regexp {^![a-z][-a-z]*[a-z]( .*)?$} [lindex $params 1]]} {
        return 0
    }
    # on-channel message, ignore
    set chan [lindex $params 0]
    upvar #0 chan_lastactivity([irctolower $chan]) la
    set la [clock seconds]
    catch { recordlastseen_p $prefix "talking on $chan" 1 }
    return 1
}

proc showintervalsecs {howlong abbrev} {
    return [showintervalsecs/[opt timeformat] $howlong $abbrev]
}

proc showintervalsecs/beat {howlong abbrev} {
    return [format "%g B" [expr {$howlong/86.4}]]
}

proc showintervalsecs/ks {howlong abbrev} {
    if {$howlong < 1000} {
        return "${howlong}s"
    } else {
        if {$howlong < 1000000} {
            set pfx k
            set scale 1000
        } else {
            set pfx M
            set scale 1000000
        }
        set value [expr "$howlong.0 / $scale"]
        foreach {min format} {100 %.0f 10 %.1f 1 %.2f} {
            if {$value < $min} continue
            return [format "$format${pfx}s" $value]
        }
    }
}

proc format_qty {qty unit abbrev} {
    set o $qty
    if {$abbrev} {
        append o [string range $unit 0 0]
    } else {
        append o " "
        append o $unit
        if {$qty != 1} { append o s }
    }
    return $o
}

proc showintervalsecs/hms {qty abbrev} {
    set ul {second 60 minute 60 hour 24 day 7 week}
    set remainv 0
    while {[llength $ul] > 1 && $qty >= [set uv [lindex $ul 1]]} {
        set remainu [lindex $ul 0]
        set remainv [expr {$qty % $uv}]
        set qty [expr {($qty-$remainv)/$uv}]
        set ul [lreplace $ul 0 1]
    }
    set o [format_qty $qty [lindex $ul 0] $abbrev]
    if {$remainv} {
        if {!$abbrev} { append o " " }
        append o [format_qty $remainv $remainu $abbrev]
    }
    return $o
}

proc showinterval {howlong} {
    if {$howlong <= 0} {
        return {just now}
    } else {
        return "[showintervalsecs $howlong 0] ago"
    }
}

proc showtime {when} {
    return [showinterval [expr {[clock seconds] - $when}]]
}

proc def_msgproc {name argl body} {
    proc msg_$name "varbase $argl" "\
    upvar #0 msg/\$varbase/dest d\n\
    upvar #0 msg/\$varbase/str s\n\
    upvar #0 msg/\$varbase/accum a\n\
$body"
}

def_msgproc begin {dest str} {
    set d $dest
    set s $str
    set a {}
}

def_msgproc append {str} {
    set ns "$s$str"
    if {[string length $s] && [string length $ns] > 65} {
        msg__sendout $varbase
        set s " [string trimleft $str]"
    } else {
        set s $ns
    }
}

def_msgproc finish {} {
    msg__sendout $varbase
    unset s
    unset d
    return $a
}

def_msgproc _sendout {} {
    lappend a [string trimright $s]
    set s {}
}

proc looking_whenwhere {when where} {
    set str [showtime [expr {$when-1}]]
    if {[string length $where]} { append str " on $where" }
    return $str
}

proc recordlastseen_n {n how here} {
    global lastseen lookedfor
    set lastseen([irctolower $n]) [list $n [clock seconds] $how]
    if {!$here} return
    upvar #0 lookedfor([irctolower $n]) lf
    if {[info exists lf]} {
        switch -exact [llength $lf] {
            0 {
                set ml {}
            }
            1 {
                manyset [lindex $lf 0] when who where
                set ml [list \
 "FYI, $who was looking for you [looking_whenwhere $when $where]."]
            }
            default {
                msg_begin tosend $n "FYI, people have been looking for you:"
                set i 0
                set fin ""
                foreach e $lf {
                    incr i
                    if {$i == 1} {
                        msg_append tosend " "
                    } elseif {$i == [llength $lf]} {
                        msg_append tosend " and "
                        set fin .
                    } else {
                        msg_append tosend ", "
                    }
                    manyset $e when who where
                    msg_append tosend \
                            "$who ([looking_whenwhere $when $where])$fin"
                }
                set ml [msg_finish tosend]
            }
        }
        unset lf
        msendprivmsg_delayed 1000 $n $ml
    }
}

proc note_topic {showoff whoby topic} {
    set msg "FYI, $whoby has changed the topic on $showoff"
    if {[string length $topic] < 160} {
        append msg " to $topic"
    } else {
        append msg " but it is too long to reproduce here !"
    }
    set showoff [irctolower $showoff]
    set tell [chandb_get $showoff topictell]
    if {[lsearch -exact $tell *] >= 0} {
        set tryspies [chandb_list]
    } else {
        set tryspies $tell
    }
    foreach spy $tryspies {
        set see [chandb_get $spy topicsee]
        if {[lsearch -exact $see $showoff] >= 0 || \
                ([lsearch -exact $see *] >= 0 && \
                [lsearch -exact $tell $spy] >= 0)} {
            sendprivmsg $spy $msg
        }
    }
}

proc recordlastseen_p {p how here} {
    prefix_nick
    recordlastseen_n $n $how $here
}

proc chanmode_arg {} {
    upvar 2 args cm_args
    set rv [lindex $cm_args 0]
    set cm_args [lreplace cm_args 0 0]
    return $rv
}

proc chanmode_o1 {m g p chan} {
    global nick chan_initialop
    prefix_nick
    set who [chanmode_arg]
    recordlastseen_n $n "being nice to $who" 1
    if {"[irctolower $who]" == "[irctolower $nick]"} {
        set nlower [irctolower $n]
        upvar #0 nick_unique($nlower) u
        if {[chandb_exists $chan]} {
            sendprivmsg $n Thanks.
        } elseif {![info exists u]} {
            sendprivmsg $n {Op me while not on the channel, why don't you ?}
        } else {
            set chan_initialop([irctolower $chan]) $u
            sendprivmsg $n \
 "Thanks. You can use `channel manager ...' to register this channel."
            if {![nickdb_exists $n] || ![string length [nickdb_get $n username]]} {
                sendprivmsg $n \
 "(But to do that you must register your nick securely first.)"
            }
        }
    }
}

proc chanmode_o0 {m g p chan} {
    global nick chandeop
    prefix_nick
    set who [chanmode_arg]
    recordlastseen_p $p "being mean to $who" 1
    if {"[irctolower $who]" == "[irctolower $nick]"} {
        set chandeop($chan) [list [clock seconds] $p]
    }
}

proc msg_MODE {p c dest modelist args} {
    if {![ischan $dest]} return
    if {[regexp {^\-(.+)$} $modelist dummy modelist]} {
        set give 0
    } elseif {[regexp {^\+(.+)$} $modelist dummy modelist]} {
        set give 1
    } else {
        error "invalid modelist"
    }
    foreach m [split $modelist] {
        set procname chanmode_$m$give
        if {[catch { info body $procname }]} {
            recordlastseen_p $p "fiddling with $dest" 1
        } else {
            $procname $m $give  $p $dest
        }
    }
}

proc leaving {lchan} {
    foreach luser [array names nick_onchans] {
        upvar #0 nick_onchans($luser) oc
        set oc [grep tc {"$tc" != "$lchan"} $oc]
    }
    upvar #0 chan_nicks($lchan) nlist
    unset nlist
    upvar #0 chan_lastactivity($lchan) la
    catch { unset la }
}

proc doleave {lchan} {
    sendout PART $lchan
    leaving $lchan
}

proc dojoin {lchan} {
    global chan_nicks
    sendout JOIN $lchan
    set chan_nicks($lchan) {}
}

proc check_justme {lchan} {
    global nick
    upvar #0 chan_nicks($lchan) nlist
    if {[llength $nlist] != 1} return
    if {"[lindex $nlist 0]" != "[irctolower $nick]"} return
    if {[chandb_exists $lchan]} {
        set mode [chandb_get $lchan mode]
        if {"$mode" != "*"} {
            sendout MODE $lchan $mode
        }
        set topic [chandb_get $lchan topicset]
        if {[string length $topic]} {
            sendout TOPIC $lchan $topic
        }
    } else {
        doleave $lchan
    }
}

proc process_kickpart {chan user} {
    global nick
    check_nick $user
    set luser [irctolower $user]
    set lchan [irctolower $chan]
    if {![ischan $chan]} { error "not a channel" }
    if {"$luser" == "[irctolower $nick]"} {
        leaving $lchan
    } else {
        upvar #0 nick_onchans($luser) oc
        upvar #0 chan_nicks($lchan) nlist
        set oc [grep tc {"$tc" != "$lchan"} $oc]
        set nlist [grep tn {"$tn" != "$luser"} $nlist]
        nick_case $user
        if {![llength $oc]} {
            nick_forget $luser
        } else {
            check_justme $lchan
        }
    }
}

proc msg_TOPIC {p c dest topic} {
    prefix_nick
    if {![ischan $dest]} return
    recordlastseen_n $n "changing the topic on $dest" 1
    note_topic [irctolower $dest] $n $topic
}

proc msg_KICK {p c chans users comment} {
    set chans [split $chans ,]
    set users [split $users ,]
    if {[llength $chans] > 1} {
        foreach chan $chans user $users { process_kickpart $chan $user }
    } else {
        foreach user $users { process_kickpart [lindex $chans 0] $user }
    }
}

proc msg_KILL {p c user why} {
    nick_forget $user
}

set nick_counter 0
set nick_arys {onchans username unique}
# nick_onchans($luser) -> [list ... $lchan ...]
# nick_username($luser) -> <securely known local username>
# nick_unique($luser) -> <counter>
# nick_case($luser) -> $user  (valid even if no longer visible)
# nick_markid($luser) -> <after id for marktime>

# chan_nicks($lchan) -> [list ... $luser ...]
# chan_lastactivity($lchan) -> [clock seconds]

proc lnick_forget {luser} {
    global nick_arys chan_nicks
    lnick_marktime_cancel $luser
    foreach ary $nick_arys {
        upvar #0 nick_${ary}($luser) av
        catch { unset av }
    }
    foreach lch [array names chan_nicks] {
        upvar #0 chan_nicks($lch) nlist
        set nlist [grep tn {"$tn" != "$luser"} $nlist]
        check_justme $lch
    }
}

proc nick_forget {user} {
    global nick_arys chan_nicks
    lnick_forget [irctolower $user]
    nick_case $user
}

proc nick_case {user} {
    global nick_case
    set nick_case([irctolower $user]) $user
}

proc msg_NICK {p c newnick} {
    global nick_arys nick_case calling_nick
    prefix_nick
    recordlastseen_n $n "changing nicks to $newnick" 0
    set calling_nick $newnick
    recordlastseen_n $newnick "changing nicks from $n" 1
    set luser [irctolower $n]
    lnick_marktime_cancel $luser
    set lusernew [irctolower $newnick]
    foreach ary $nick_arys {
        upvar #0 nick_${ary}($luser) old
        upvar #0 nick_${ary}($lusernew) new
        if {[info exists new]} { error "nick collision ?! $ary $n $newnick" }
        if {[info exists old]} { set new $old; unset old }
    }
    upvar #0 nick_onchans($lusernew) oc
    foreach ch $oc {
        upvar #0 chan_nicks($ch) nlist
        set nlist [grep tn {"$tn" != "$luser"} $nlist]
        lappend nlist $lusernew
    }
    lnick_marktime_start $lusernew "Hi." 500
    nick_case $newnick
}

proc nick_ishere {n} {
    global nick_counter
    upvar #0 nick_unique([irctolower $n]) u
    if {![info exists u]} { set u [incr nick_counter].$n.[clock seconds] }
    nick_case $n
}

proc msg_JOIN {p c chan} {
    prefix_nick
    recordlastseen_n $n "joining $chan" 1
    set nl [irctolower $n]
    set lchan [irctolower $chan]
    upvar #0 nick_onchans($nl) oc
    upvar #0 chan_nicks($lchan) nlist
    if {![info exists oc]} {
        global marktime_join_startdelay
        lnick_marktime_start $nl "Welcome." $marktime_join_startdelay
    }
    lappend oc $lchan
    lappend nlist $nl
    nick_ishere $n
}
proc msg_PART {p c chan args} {
    prefix_nick
    set msg "leaving $chan"
    if {[llength $args]} {
        set why [lindex $args 0]
        if {"[irctolower $why]" != "[irctolower $n]"} { append msg " ($why)" }
    }
    recordlastseen_n $n $msg 1
    process_kickpart $chan $n
}
proc msg_QUIT {p c why} {
    prefix_nick
    recordlastseen_n $n "leaving ($why)" 0
    nick_forget $n
}

proc msg_PRIVMSG {p c dest text} {
    global errorCode
    
    prefix_nick
    if {[ischan $dest]} {
        recordlastseen_n $n "invoking me in $dest" 1
        set output $dest
    } else {
        recordlastseen_n $n "talking to me" 1
        set output $n
    }
    nick_case $n

    execute_usercommand $p $c $n $output $dest $text
}

proc msg_INVITE {p c n chan} {
    after 1000 [list dojoin [irctolower $chan]]
}

proc grep {var predicate list} {
    set o {}
    upvar 1 $var v
    foreach v $list {
        if {[uplevel 1 [list expr $predicate]]} { lappend o $v }
    }
    return $o
}

proc msg_353 {p c dest type chan nicklist} {
    global names_chans nick_onchans
    set lchan [irctolower $chan]
    upvar #0 chan_nicks($lchan) nlist
    lappend names_chans $lchan
    if {![info exists nlist]} {
        # We don't think we're on this channel, so ignore it !
        # Unfortunately, because we don't get a reply to PART,
        # we have to remember ourselves whether we're on a channel,
        # and ignore stuff if we're not, to avoid races.  Feh.
        return
    }
    set nlist_new {}
    foreach user [split $nicklist { }] {
        regsub {^[@+]} $user {} user
        if {![string length $user]} continue
        check_nick $user
        set luser [irctolower $user]
        upvar #0 nick_onchans($luser) oc
        lappend oc $lchan
        lappend nlist_new $luser
        nick_ishere $user
    }
    set nlist $nlist_new
}

proc msg_366 {p c args} {
    global names_chans nick_onchans
    set lchan [irctolower $c]
    foreach luser [array names nick_onchans] {
        upvar #0 nick_onchans($luser) oc
        if {[llength names_chans] > 1} {
            set oc [grep tc {[lsearch -exact $tc $names_chans] >= 0} $oc]
        }
        if {![llength $oc]} { lnick_forget $n }
    }
    unset names_chans
}

proc check_username {target} {
    if {
        [string length $target] > 8 ||
        [regexp {[^-0-9a-z]} $target] ||
        ![regexp {^[a-z]} $target]
    } { error "invalid username" }
}

proc somedb__head {} {
    uplevel 1 {
        set idl [irctolower $id]
        upvar #0 ${nickchan}db($idl) ndbe
        binary scan $idl H* idh
        set idfn $fprefix$idh
        if {![info exists iddbe] && [file exists $idfn]} {
            set f [open $idfn r]
            try_except_finally { set newval [read $f] } {} { close $f }
            if {[llength $newval] % 2} { error "invalid length" }
            set iddbe $newval
        }
    }
}

proc def_somedb {name arglist body} {
    foreach {nickchan fprefix} {nick users/n chan chans/c} {
        proc ${nickchan}db_$name $arglist \
            "set nickchan $nickchan; set fprefix $fprefix; $body"
    }
}

def_somedb list {} {
    set list {}
    foreach path [glob -nocomplain -path $fprefix *] {
        binary scan $path "A[string length $fprefix]A*" afprefix thinghex
        if {"$afprefix" != "$fprefix"} { error "wrong prefix $path $afprefix" }
        lappend list [binary format H* $thinghex]
    }
    return $list
}

proc def_somedb_id {name arglist body} {
    def_somedb $name [concat id $arglist] "somedb__head; $body"
}

def_somedb_id exists {} {
    return [info exists iddbe]
}

def_somedb_id delete {} {
    catch { unset iddbe }
    file delete $idfn
}

set default_settings_nick {timeformat ks  marktime off}
set default_settings_chan {
    autojoin 1
    mode *
    userinvite pub
    topicset {}
    topicsee {}
    topictell {}
}

def_somedb_id set {args} {
    upvar #0 default_settings_$nickchan def
    if {![info exists iddbe]} { set iddbe $def }
    foreach {key value} [concat $iddbe $args] { set a($key) $value }
    set newval {}
    foreach {key value} [array get a] { lappend newval $key $value }
    set f [open $idfn.new w]
    try_except_finally {
        puts $f $newval
        close $f
        file rename -force $idfn.new $idfn
    } {
    } {
        catch { close $f }
    }
    set iddbe $newval
}

def_somedb_id get {key} {
    upvar #0 default_settings_$nickchan def
    if {[info exists iddbe]} {
        set l [concat $iddbe $def]
    } else {
        set l $def
    }
    foreach {tkey value} $l {
        if {"$tkey" == "$key"} { return $value }
    }
    error "unset setting $key"
}

proc opt {key} {
    global calling_nick
    if {[info exists calling_nick]} { set n $calling_nick } { set n {} }
    return [nickdb_get $n $key]
}

proc check_notonchan {} {
    upvar 1 dest dest
    if {[ischan $dest]} { usererror "That command must be sent privately." }
}

proc nick_securitycheck {strict} {
    upvar 1 n n
    if {![nickdb_exists $n]} {
        usererror "You are unknown to me, use `register'."
    }
    set wantu [nickdb_get $n username]
    if {![string length $wantu]} {
        if {$strict} {
            usererror "That feature is only available to secure users, sorry."
        } else {
            return
        }
    }
    set luser [irctolower $n]
    upvar #0 nick_username($luser) nu
    if {![info exists nu]} {
        usererror "Nick $n is secure, you must identify yourself first."
    }
    if {"$wantu" != "$nu"} {
        usererror "You are the wrong user -\
                the nick $n belongs to $wantu, not $nu."
    }
}

proc channel_ismanager {channel n} {
    set mgrs [chandb_get $channel managers]
    return [expr {[lsearch -exact [irctolower $mgrs] [irctolower $n]] >= 0}]
}

proc channel_securitycheck {channel} {
    upvar n n
    if {![channel_ismanager $channel $n]} {
        usererror "You are not a manager of $channel."
    }
    nick_securitycheck 1
}

proc def_chancmd {name body} {
    proc channel/$name {} \
            "    upvar 1 target chan; upvar 1 n n; upvar 1 text text; $body"
}

proc ta_listop {findnow procvalue} {
    # findnow and procvalue are code fragments which will be executed
    # in the caller's level.  findnow should set ta_listop_ev to
    # the current list, and procvalue should treat ta_listop_ev as
    # a proposed value in the list and check and possibly modify
    # (canonicalise?) it.  After ta_listop, ta_listop_ev will
    # be the new value of the list.
    upvar 1 ta_listop_ev exchg
    upvar 1 text text
    set opcode [ta_word]
    switch -exact _$opcode {
        _= { }
        _+ - _- {
            uplevel 1 $findnow
            foreach item $exchg { set array($item) 1 }
        }
        default {
            error "list change opcode must be one of + - ="
        }
    }
    foreach exchg [split $text " "] {
        if {![string length $exchg]} continue
        uplevel 1 $procvalue
        if {"$opcode" != "-"} {
            set array($exchg) 1
        } else {
            catch { unset array($exchg) }
        }
    }
    set exchg [lsort [array names array]]
}

def_chancmd manager {
    ta_listop {
        if {[chandb_exists $chan]} {
            set ta_listop_ev [chandb_get $chan managers]
        } else {
            set ta_listop_ev [list [irctolower $n]]
        }
    } {
        check_nick $ta_listop_ev
        set ta_listop_ev [irctolower $ta_listop_ev]
    }
    if {[llength $ta_listop_ev]} {
        chandb_set $chan managers $ta_listop_ev
        ucmdr "Managers of $chan: $ta_listop_ev" {}
    } else {
        chandb_delete $chan
        ucmdr {} {} "forgets about managing $chan." {}
    }
}

def_chancmd autojoin {
    set yesno [ta_word]
    switch -exact [string tolower $yesno] {
        no { set nv 0 }
        yes { set nv 1 }
        default { error "channel autojoin must be `yes' or `no' }
    }
    chandb_set $chan autojoin $nv
    ucmdr [expr {$nv ? "I will join $chan when I'm restarted " : \
            "I won't join $chan when I'm restarted "}] {}
}

def_chancmd userinvite {
    set nv [string tolower [ta_word]]
    switch -exact $nv {
        pub { set txt "!invite will work for $chan, but it won't work by /msg" }
        here { set txt "!invite and /msg invite will work, but only for users who are already on $chan." }
        all { set txt "Any user will be able to invite themselves or anyone else to $chan." }
        none { set txt "I will not invite anyone to $chan." }
        default {
            error "channel userinvite must be `pub', `here', `all' or `none'
        }
    }
    chandb_set $chan userinvite $nv
    ucmdr $txt {}
}

def_chancmd topic {
    set what [ta_word]
    switch -exact $what {
        leave {
            ta_nomore
            chandb_set $chan topicset {}
            ucmdr "I won't ever change the topic of $chan." {}
        }
        set {
            set t [string trim $text]
            if {![string length $t]} {
                error "you must specific the topic to set"
            }
            chandb_set $chan topicset $t
            ucmdr "Whenever I'm alone on $chan, I'll set the topic to $t." {}
        }
        see - tell {
            ta_listop {
                set ta_listop_ev [chandb_get $chan topic$what]
            } {
                if {"$ta_listop_ev" != "*"} {
                    if {![ischan $ta_listop_ev]} {
                        error "bad channel \`$ta_listop_ev' in topic $what"
                    }
                    set ta_listop_ev [irctolower $ta_listop_ev]
                }
            }
            chandb_set $chan topic$what $ta_listop_ev
            ucmdr "Topic $what list for $chan: $ta_listop_ev" {}
        }
        default {
            usererror "Unknown channel topic subcommand - see help channel."
        }
    }
}

def_chancmd mode {
    set mode [ta_word]
    if {"$mode" != "*" && ![regexp {^(([-+][imnpst]+)+)$} $mode mode]} {
        error {channel mode must be * or match ([-+][imnpst]+)+}
    }
    chandb_set $chan mode $mode
    if {"$mode" == "*"} {
        ucmdr "I won't ever change the mode of $chan." {}
    } else {
        ucmdr "Whenever I'm alone on $chan, I'll set the mode to $mode." {}
    }
}

def_chancmd show {
    if {[chandb_exists $chan]} {
        set l "Settings for $chan: autojoin "
        append l [lindex {no yes} [chandb_get $chan autojoin]]
        append l ", mode " [chandb_get $chan mode]
        append l ", userinvite " [chandb_get $chan userinvite] "."
        append l "\nManagers: "
        append l [join [chandb_get $chan managers] " "]
        foreach {ts sep} {see "\n" tell "  "} {
            set t [chandb_get $chan topic$ts]
            append l $sep
            if {[llength $t]} {
                append l "Topic $ts list: $t."
            } else {
                append l "Topic $ts list is empty."
            }
        }
        append l "\n"
        set t [chandb_get $chan topicset]
        if {[string length $t]} {
            append l "Topic to set: $t"
        } else {
            append l "I will not change the topic."
        }
        ucmdr {} $l
    } else {
        ucmdr {} "The channel $chan is not managed."
    }
}

proc channelmgr_monoop {} {
    upvar 1 dest dest
    upvar 1 text text
    upvar 1 n n
    upvar 1 p p
    upvar 1 target target
    global chan_nicks

    prefix_nick

    if {[ischan $dest]} { set target $dest }
    if {[ta_anymore]} { set target [ta_word] }
    ta_nomore
    if {![info exists target]} {
        usererror "You must specify, or invoke me on, the relevant channel."
    }
    if {![info exists chan_nicks([irctolower $target])]} {
        usererror "I am not on $target."
    }
    if {![ischan $target]} { error "not a valid channel" }

    if {![chandb_exists $target]} {
        usererror "$target is not a managed channel."
    }
    channel_securitycheck $target
}

def_ucmd op {
    channelmgr_monoop
    sendout MODE $target +o $n
}

def_ucmd leave {
    channelmgr_monoop
    doleave $target
}

def_ucmd invite {
    global chan_nicks errorCode errorInfo
    prefix_nick
    
    if {[ischan $dest]} {
        set target $dest
        set onchan 1
    } else {
        set target [ta_word]
        set onchan 0
    }
    set ltarget [irctolower $target]
    if {![ischan $target]} { error "$target is not a channel" }
    if {![info exists chan_nicks($ltarget)]} {
        usererror "I am not on $target."
    }
    set ui [chandb_get $ltarget userinvite]
    if {[catch {
        if {"$ui" == "pub" && !$onchan} {
            usererror "Invitations to $target must be made there with !invite."
        }
        if {"$ui" != "all"} {
            if {[lsearch -exact $chan_nicks($ltarget) [irctolower $n]] < 0} {
                usererror "Invitations to $target may only be made\
                        by a user on the channel."
            }
        }
        if {"$ui" == "none"} {
            usererror "Sorry, I've not been authorised\
                    to invite people to $target."
        }
    } emsg]} {
        if {"$errorCode" == "BLIGHT USER" && [channel_ismanager $target $n]} {
            if {[catch {
                nick_securitycheck 1
            } emsg2]} {
                if {"$errorCode" == "BLIGHT USER"} {
                    usererror "$emsg2  Therefore you can't use your\
                            channel manager privilege.  $emsg"
                } else {
                    error $error $errorInfo $errorCode
                }
            }
        } else {
            error $emsg $errorInfo $errorCode
        }
    }
    if {![ta_anymore]} {
        usererror "You have to say who to invite."
    }
    set invitees {}
    while {[ta_anymore]} {
        set invitee [ta_word]
        check_nick $invitee
        lappend invitees $invitee
    }
    foreach invitee $invitees {
        sendout INVITE $invitee $ltarget
    }
    set who [lindex $invitees 0]
    switch -exact llength $invitees {
        0 { error "zero invitees" }
        1 { }
        2 { append who " and [lindex $invitees 1]" }
        * {
            set who [join [lreplace $invitees end end] ", "]
            append who " and [lindex $invitees [llength $invitees]]"
        }
    }
    ucmdr {} {} {} "invites $who to $target."
}

def_ucmd channel {
    if {[ischan $dest]} { set target $dest }
    if {![ta_anymore]} {
        set subcmd show
    } else {
        set subcmd [ta_word]
    }
    if {[ischan $subcmd]} {
        set target $subcmd
        if {![ta_anymore]} {
            set subcmd show
        } else {
            set subcmd [ta_word]
        }
    }
    if {![info exists target]} { error "privately, you must specify a channel" }
    set procname channel/$subcmd
    if {"$subcmd" != "show"} {
        if {[catch { info body $procname }]} {
            usererror "unknown channel setting $subcmd."
        }
        prefix_nick
        if {[chandb_exists $target]} {
            channel_securitycheck $target
        } else {
            nick_securitycheck 1
            upvar #0 chan_initialop([irctolower $target]) io
            upvar #0 nick_unique([irctolower $n]) u
            if {![info exists io]} {
                usererror "$target is not a managed channel."
            }
            if {"$io" != "$u"} {
                usererror "You are not the interim manager of $target."
            }
            if {"$subcmd" != "manager"} {
                usererror "Please use `channel manager' first."
            }
        }
    }
    channel/$subcmd
}

def_ucmd who {
    if {[ta_anymore]} {
        set target [ta_word]; ta_nomore
        set myself 1
    } else {
        prefix_nick
        set target $n
        set myself [expr {"$target" != "$n"}]
    }
    set ltarget [irctolower $target]
    upvar #0 nick_case($ltarget) ctarget
    set nshow $target
    if {[info exists ctarget]} {
        upvar #0 nick_onchans($ltarget) oc
        upvar #0 nick_username($ltarget) nu
        if {[info exists oc]} { set nshow $ctarget }
    }
    if {![nickdb_exists $ltarget]} {
        set ol "$nshow is not a registered nick."
    } elseif {[string length [set username [nickdb_get $target username]]]} {
        set ol "The nick $nshow belongs to the user $username."
    } else {
        set ol "The nick $nshow is registered (but not to a username)."
    }
    if {![info exists ctarget] || ![info exists oc]} {
        if {$myself} {
            append ol "\nI can't see $nshow on anywhere."
        } else {
            append ol "\nYou aren't on any channels with me."
        }
    } elseif {![info exists nu]} {
        append ol "\n$nshow has not identified themselves."
    } elseif {![info exists username]} {
        append ol "\n$nshow has identified themselves as the user $nu."
    } elseif {"$nu" != "$username"} {
        append ol "\nHowever, $nshow is being used by the user $nu."
    } else {
        append ol "\n$nshow has identified themselves to me."
    }
    ucmdr {} $ol
}

def_ucmd register {
    prefix_nick
    check_notonchan
    set old [nickdb_exists $n]
    if {$old} { nick_securitycheck 0 }
    set luser [irctolower $n]
    switch -exact [string tolower [string trim $text]] {
        {} {
            upvar #0 nick_username($luser) nu
            if {![info exists nu]} {
                ucmdr {} \
 "You must identify yourself before using `register'.  See `help identify', or use `register insecure'."
            }
            nickdb_set $n username $nu
            ucmdr {} {} "makes a note of your username." {}
        }
        delete {
            nickdb_delete $n
            ucmdr {} {} "forgets your nickname." {}
        }
        insecure {
            nickdb_set $n username {}
            if {$old} {
                ucmdr {} "Security is now disabled for your nickname !"
            } else {
                ucmdr {} "This is fine, but bear in mind that people will be able to mess with your settings.  Channel management features need a secure registration." "makes an insecure registration for your nick."
            }
        }
        default {
            error "you mean register / register delete / register insecure"
        }
    }
}

proc timeformat_desc {tf} {
    switch -exact $tf {
        ks { return "Times will be displayed in seconds or kiloseconds." }
        hms { return "Times will be displayed in hours, minutes, etc." }
        beat { return "Times will be displayed in beats (1000B = 1d)." }
        default { error "invalid timeformat: $v" }
    }
}

proc def_setting {opt show_body set_body} {
    proc set_show/$opt {} "
        upvar 1 n n
        set opt $opt
        $show_body"
    if {![string length $set_body]} return
    proc set_set/$opt {} "
        upvar 1 n n
        upvar 1 text text
        set opt $opt
        $set_body"
}

def_setting timeformat {
    set tf [nickdb_get $n timeformat]
    return "$tf: [timeformat_desc $tf]"
} {
    set tf [string tolower [ta_word]]
    ta_nomore
    set desc [timeformat_desc $tf]
    nickdb_set $n timeformat $tf
    ucmdr {} $desc
}

proc marktime_desc {mt} {
    if {"$mt" == "off"} {
        return "I will not send you periodic messages."
    } elseif {"$mt" == "once"} {
        return "I will send you one informational message when I see you."
    } else {
        return "I'll send you a message every [showintervalsecs $mt 0]."
    }
}

def_setting marktime {
    set mt [nickdb_get $n marktime]
    set p $mt
    if {[string match {[0-9]*} $mt]} { append p s }
    append p ": "
    append p [marktime_desc $mt]
    return $p
} {
    global marktime_min
    set mt [string tolower [ta_word]]
    ta_nomore

    if {"$mt" == "off" || "$mt" == "once"} {
    } elseif {[regexp {^([0-9]+)([a-z]+)$} $mt dummy value unit]} {
        switch -exact $unit {
            s { set u 1 }
            ks { set u 1000 }
            m { set u 60 }
            mb { set u 0.0864 }
            b { set u 86.4 }
            kb { set u 86400 }
            default { error "unknown unit of time $unit" }
        }
        if {$value > 86400*21/$u} { error "marktime interval too large" }
        set mt [expr {round($value*$u)}]
        if {$mt < $marktime_min} { error "marktime interval too small" }
    } else {
        error "invalid syntax for marktime"
    }
    nickdb_set $n marktime $mt
    lnick_marktime_start [irctolower $n] "So:" 500
    ucmdr {} [marktime_desc $mt]
}

def_setting security {
    set s [nickdb_get $n username]
    if {[string length $s]} {
        return "Your nick, $n, is controlled by the user $s."
    } else {
        return "Your nick, $n, is not secure."
    }
} {}

def_ucmd set {
    prefix_nick
    check_notonchan
    if {![nickdb_exists $n]} {
        ucmdr {} "You are unknown to me and so have no settings.  (Use `register'.)"
    }
    if {![ta_anymore]} {
        set ol {}
        foreach proc [lsort [info procs]] {
            if {![regexp {^set_show/(.*)$} $proc dummy opt]} continue
            lappend ol [format "%-10s %s" $opt [set_show/$opt]]
        }
        ucmdr {} [join $ol "\n"]
    } else {
        set opt [ta_word]
        if {[catch { info body set_show/$opt }]} {
            error "no setting $opt"
        }
        if {![ta_anymore]} {
            ucmdr {} "$opt [set_show/$opt]"
        } else {
            nick_securitycheck 0
            if {[catch { info body set_set/$opt }]} {
                error "setting $opt cannot be set with `set'"
            }
            set_set/$opt
        }
    }
}

def_ucmd identpass {
    set username [ta_word]
    set passmd5 [md5sum "[ta_word]\n"]
    ta_nomore
    prefix_nick
    check_notonchan
    set luser [irctolower $n]
    upvar #0 nick_onchans($luser) onchans
    if {![info exists onchans] || ![llength $onchans]} {
        ucmdr "You must be on a channel with me to identify yourself." {}
    }
    check_username $username
    exec userv --timeout 3 $username << "$passmd5\n" > /dev/null \
            irc-identpass $n
    upvar #0 nick_username($luser) rec_username
    set rec_username $username
    ucmdr "Pleased to see you, $username." {}
}

def_ucmd summon {
    set target [ta_word]
    ta_nomore
    check_username $target
    prefix_nick

    upvar #0 lastsummon($target) ls
    set now [clock seconds]
    if {[info exists ls]} {
        set interval [expr {$now - $ls}]
        if {$interval < 30} {
            ucmdr {} \
 "Please be patient; $target was summoned only [showinterval $interval]."
        }
    }
    regsub {^[^!]*!} $p {} path
    if {[catch {
        exec userv --timeout 3 $target irc-summon $n $path \
                [expr {[ischan $dest] ? "$dest" : ""}] \
                < /dev/null
    } rv]} {
        regsub -all "\n" $rv { / } rv
        error $rv
    }
    if {[regexp {^problem (.*)} $rv dummy problem]} {
        ucmdr {} "The user `$target' $problem."
    } elseif {[regexp {^ok ([^ ]+) ([0-9]+)$} $rv dummy tty idlesince]} {
        set idletime [expr {$now - $idlesince}]
        set ls $now
        ucmdr {} {} {} "invites $target ($tty[expr {
            $idletime > 10 ? ", idle for [showintervalsecs $idletime 0]" : ""
        }]) to [expr {
            [ischan $dest] ? "join us here" : "talk to you"
        }]."
    } else {
        error "unexpected response from userv service: $rv"
    }
}

proc md5sum {value} { exec md5sum << $value }

def_ucmd seen {
    global lastseen nick
    prefix_nick
    set ncase [ta_nick]
    set nlower [irctolower $ncase]
    ta_nomore
    set now [clock seconds]
    if {"$nlower" == "[irctolower $nick]"} {
        usererror "I am not self-aware."
    } elseif {![info exists lastseen($nlower)]} {
        set rstr "I've never seen $ncase."
    } else {
        manyset $lastseen($nlower) realnick time what
        set howlong [expr {$now - $time}]
        set string [showinterval $howlong]
        set rstr "I last saw $realnick $string, $what."
    }
    if {[ischan $dest]} {
        set where $dest
    } else {
        set where {}
    }
    upvar #0 lookedfor($nlower) lf
    if {[info exists lf]} { set oldvalue $lf } else { set oldvalue {} }
    set lf [list [list $now $n $where]]
    foreach v $oldvalue {
        if {"[irctolower [lindex $v 1]]" == "[irctolower $n]"} continue
        lappend lf $v
    }
    ucmdr {} $rstr
}

proc lnick_marktime_cancel {luser} {
    upvar #0 nick_markid($luser) mi
    if {![info exists mi]} return
    catch { after cancel $mi }
    catch { unset mi }
}

proc lnick_marktime_doafter {luser why ms} {
    lnick_marktime_cancel $luser
    upvar #0 nick_markid($luser) mi
    set mi [after $ms [list lnick_marktime_now $luser $why]]
}

proc lnick_marktime_reset {luser} {
    set mt [nickdb_get $luser marktime]
    if {"$mt" == "off" || "$mt" == "once"} return
    lnick_marktime_doafter $luser "Time passes." [expr {$mt*1000}]
}

proc lnick_marktime_start {luser why ms} {
    set mt [nickdb_get $luser marktime]
    if {"$mt" == "off"} {
        lnick_marktime_cancel $luser
    } else {
        lnick_marktime_doafter $luser $why $ms
    }
}

proc lnick_marktime_now {luser why} {
    upvar #0 nick_onchans($luser) oc
    global calling_nick
    set calling_nick $luser
    sendprivmsg $luser [lnick_pingstring $why $oc ""]
    lnick_marktime_reset $luser
}    

proc lnick_pingstring {why oc apstring} {
    global nick_onchans
    catch { exec uptime } uptime
    set nnicks [llength [array names nick_onchans]]
    if {[regexp \
 {^ *([0-9:apm]+) +up.*, +(\d+) users?, +load average: +([0-9., ]+) *$} \
            $uptime dummy time users load]} {
        regsub -all , $load {} load
        set uptime "$time  $nnicks/$users  $load"
    } else {
        append uptime ", $nnicks nicks"
    }
    if {[llength $oc]} {
        set best_la 0
        set activity quiet
        foreach ch $oc {
            upvar #0 chan_lastactivity($ch) la
            if {![info exists la]} continue
            if {$la <= $best_la} continue
            set since [showintervalsecs [expr {[clock seconds]-$la}] 1]
            set activity "$ch $since"
            set best_la $la
        }
    } else {
        set activity unseen
    }
    set str $why
    append str "  " $uptime "  " $activity
    if {[string length $apstring]} { append str "  " $apstring }
    return $str
}

def_ucmd ping {
    if {[ischan $dest]} {
        set oc [irctolower $dest]
    } else {
        global nick_onchans
        prefix_nick
        set ln [irctolower $n]
        if {[info exists nick_onchans($ln)]} {
            set oc $nick_onchans($ln)
        } else {
            set oc {}
        }
        if {[llength $oc]} { lnick_marktime_reset $ln }
    }
    ucmdr {} [lnick_pingstring "Pong!" $oc $text]
}

proc ensure_globalsecret {} {
    global globalsecret
    
    if {[info exists globalsecret]} return
    set gsfile [open /dev/urandom r]
    fconfigure $gsfile -translation binary
    set globalsecret [read $gsfile 32]
    binary scan $globalsecret H* globalsecret
    close $gsfile
    unset gsfile
}

proc connected {} {
    foreach chan [chandb_list] {
        if {[chandb_get $chan autojoin]} { dojoin $chan }
    }
}

ensure_globalsecret
loadhelp
ensure_connecting