#!/usr/bin/env bash
# Part of JoeyLib, Copyright (c) 2026 Scott Duensing, under the MIT License.
# See LICENSE.md for license information.
# SPDX-License-Identifier: MIT
#
# verify-win16-serial.sh - both-directions RS-232 gate for the Win16 port.
#
# Runs SERTEST.EXE (examples/sertest: banner, then echo) on Windows 3.11
# under DOSBox (scripts/lib/win16Gate.sh) with COM1 as a nullmodem
# connecting to the host peer (tests/gate/serialLoopPeer.c), which waits
# for the banner, sends a probe and expects it echoed. That exercises the
# chain: JoeyLib's Win16 serial HAL -> OpenComm/WriteComm/ReadComm ->
# KPCOMM.DRV (the communications driver JoeyLib's Windows runs with in place
# of COMM.DRV) and Windows' virtual COM device -> DOSBox's UART -> host.
#
# Then the DTR check (--dtr-check), as verify-dvx-serial.sh does it: the
# nullmodem runs non-transparent, so DOSBox reports the guest's modem lines to
# the peer in the byte stream, and SERTEST drops and raises DTR, closes and
# reopens the port, then hangs up. jlSerialSetDtr must reach the line, and
# jlSerialClose must leave DTR as it is, up or down: KPCOMM.DRV keeps it at
# CloseComm when the HAL asks (KPESC_KEEP_DTR_ON_CLOSE).
#
# Usage:   scripts/verify-win16-serial.sh
# Env:     WIN16_SERIAL_PORT  TCP port the peer listens on (default 6804)
# Requires: Windows on DOSBox (install.sh install emulator:win16);
#           build/win16/bin/SERTEST.EXE (make win16).

set -uo pipefail

repo=$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)
source "$repo/scripts/lib/joeyEnv.sh"
source "$repo/scripts/lib/win16Gate.sh"

label=verify-win16-serial
win16Need
program=$(joeyExampleProgram sertest win16)
[ -f "$program" ] || { echo "$label: build SERTEST.EXE first (make win16)" >&2; exit 2; }
port="${WIN16_SERIAL_PORT:-6804}"
# The peer's budget: Windows' boot, the banner and the echo, then the DTR check.
wall=95

work=$(mktemp -d -t joeylib-win16-serial.XXXXXX)
peerPid=""
cleanup() {
    joeyStop "$peerPid"
    win16Stop
    rm -rf "$work"
}
trap cleanup EXIT

peer=$(joeyTool serialLoopPeer) || exit 1
"$peer" tcp-server "$port" "$wall" --dtr-check > "$work/peer.log" 2>&1 &
peerPid=$!
sleep 1
mkdir -p "$work/program"
cp "$program" "$work/program/SERTEST.EXE"
win16Stage "$work" "$work/program" SERTEST.EXE
# transparent:0 -- DOSBox sends the guest's modem lines in-band, which the
# peer's --dtr-check reads.
WIN16_DOSBOX_ARGS=(--set "serial1=nullmodem server:127.0.0.1 port:$port transparent:0")
win16Start "$work"
wait "$peerPid"
rc=$?
peerPid=""
cat "$work/peer.log"
if [ "$rc" -eq 0 ]; then
    echo "$label: PASS (banner out, probe echoed through COM1; DTR follows jlSerialSetDtr and survives jlSerialClose)"
else
    echo "$label: FAIL" >&2
fi
exit "$rc"