#!/usr/bin/expect -f
# Auto-detect TNC2C host line on a serial device.
# Usage: ./tnc2c-expect.exp /dev/ttyS4

set timeout 6
if {[llength $argv] < 1} {
    puts "Usage: $argv0 <device>"
    exit 1
}
set dev [lindex $argv 0]

proc try_line {dev baud parity} {
    global timeout
    if {$parity eq "7E1"} {
        spawn stty -F $dev $baud cs7 parenb -cstopb raw -echo min 0 time 10
        expect eof
    } else {
        spawn stty -F $dev $baud cs8 -parenb -cstopb raw -echo min 0 time 10
        expect eof
    }

    spawn cu -l $dev -s $baud
    if {[catch {expect {
        -re "." { }
        timeout { }
    }}]} {
        catch {close}
        return 0
    }

    set score 0
    set sample ""

    send "\r\r"
    sleep 1
    send "INFO\r"
    sleep 3

    if {[catch {set sample $expect_out(buffer)}]} {
        set sample ""
    }

    if {[string match -nocase *cmd:* $sample]} { incr score 300 }
    if {[string match -nocase *MYCALL* $sample]} { incr score 150 }
    if {[string match -nocase *TXDELAY* $sample]} { incr score 100 }
    if {[string match -nocase *INFO* $sample]} { incr score 20 }
    incr score [string length $sample]

    puts "  $baud $parity score=$score"
    if {$sample ne ""} {
        set short [string range $sample 0 180]
        regsub -all {\r} $short {\\r} short
        regsub -all {\n} $short {\\n} short
        puts "    $short"
    }

    send "~.\r"
    catch {close}
    return $score
}

puts "TNC2C expect scan on $dev"
set best 0
set bestcfg ""

foreach baud {9600 2400 4800 1200 19200 600 300} {
    foreach parity {7E1 8N1} {
        set s [try_line $dev $baud $parity]
        if {$s > $best} {
            set best $s
            set bestcfg "$baud $parity"
        }
    }
}

puts "\nBest: $bestcfg (score=$best)"
if {$best >= 200} {
    exit 0
}
exit 2