#!/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-dvx-serial.sh - both-directions RS-232 gate for the DVX port.
#
# Runs SERTEST (examples/sertest: banner, then echo) as the desktop of a
# scratch DVX in DOSBox Staging, with COM1 a nullmodem connecting to the
# host peer (scripts/lib/serialLoopPeer.py), which waits for the banner,
# sends a probe and expects it echoed. That exercises the chain: JoeyLib's
# serial layer -> the DVX port (src/dvx/serial.c) -> DVX's rs232 library and
# its interrupt -> DOSBox's UART -> host.
#
# Then the DTR check (--dtr-check): 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
# (DTR dropped, port closed). jlSerialSetDtr must reach the line, and
# jlSerialClose must leave DTR as it is, up or down: DVX's serial library
# used to reset the modem lines when it closed a port.
#
# Usage:   scripts/verify-dvx-serial.sh
# Env:     DVX_SERIAL_PORT   TCP port the peer listens on (default 6803)
# Requires: DOSBox Staging, Xvfb, python3, the dvx component; the sertest
#           program (make dvx).
set -uo pipefail

repo=$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)
source "$repo/scripts/lib/joeyEnv.sh"
source "$repo/scripts/lib/dvxGate.sh"
joeyNeed DOSBOX dosbox
joeyNeed DVX_ROOT dvx

program=sertest
port="${DVX_SERIAL_PORT:-6803}"
peerWall=95          # DVX boot, the banner and the echo, then the DTR check
runSeconds=110       # SERTEST idles forever after the check: DOSBox ends by timeout

dvxNeedBuild "$program"

work=$(mktemp -d -t joeylib-dvx-serial.XXXXXX)
peerPid=""
guard=""
dosbox=""
xvfb=""
# 2>/dev/null: bash reports the SIGKILLed timeout wrapper as "Killed".
cleanup() {
    joeyStop "$dosbox" "$guard" "$peerPid" "$xvfb" 2> /dev/null
    rm -rf "$work"
}
trap cleanup EXIT

dvxStage "$work/c" "$(dvxAppDir "$program")"
dvxDosboxConf "$work/dosbox.conf" "$work/c"
printf '\n[serial]\nserial1 = nullmodem server:127.0.0.1 port:%s transparent:0\n' "$port" >> "$work/dosbox.conf"
mkdir -p "$work/xdg"

python3 "$repo/scripts/lib/serialLoopPeer.py" tcp-server "$port" "$peerWall" --dtr-check > "$work/peer.log" 2>&1 &
peerPid=$!
sleep 1

display=":$((RANDOM % 400 + 3300))"
Xvfb "$display" -screen 0 1024x768x24 -nolisten tcp > /dev/null 2>&1 &
xvfb=$!
sleep 1

XDG_CONFIG_HOME="$work/xdg" DISPLAY="$display" SDL_AUDIODRIVER=dummy \
    timeout -s KILL "$runSeconds" "$DOSBOX" "${JOEY_DOSBOX_ISOLATE[@]}" \
    --conf "$work/dosbox.conf" > "$work/dosbox.log" 2>&1 &
guard=$!
dosbox=$(joeyChild "$guard")

wait "$peerPid"
rc=$?
peerPid=""
joeyStop "$dosbox" "$guard" 2> /dev/null
dosbox=""
guard=""
cat "$work/peer.log"
if [ "$rc" -eq 0 ]; then
    echo "verify-dvx-serial: PASS (banner out, probe echoed through COM1 and DVX's serial library; DTR follows jlSerialSetDtr and survives jlSerialClose)"
else
    echo "verify-dvx-serial: FAIL (DVX.LOG follows)" >&2
    dvxDvxLog "$work/c" >&2
fi
exit "$rc"