#!/usr/bin/env bash
#
# selftest.sh - non-persistent self-test for the IEC listener kernel module.
#
# This is NOT a full install: nothing is copied into /lib/modules and no
# autoload is configured. It only loads the module, tests it, and unloads it.
#
# Entry point: the built iec_listener.ko is already on the Pi. This script:
#   1. checks the module is compatible with the running kernel (vermagic),
#   2. loads it (insmod) - non-persistent, no reboot needed,
#   3. runs the self-test ioctl on /dev/iec0,
#   4. unloads it again (rmmod) so the Pi is left exactly as before.
#
# The module is never left loaded by this script; it always unloads, even if
# the self-test fails or the script is interrupted.
#
# Usage:
#   sudo ./selftest.sh [path/to/iec_listener.ko] [--address N]
#
# Defaults: ./iec_listener.ko (or ~/iec_listener.ko), address=4 (printer).

set -euo pipefail

MODULE="iec_listener"
ADDRESS=4
KO=""
LOADED=0

# ---- pretty output (color only on a tty) --------------------------------
if [ -t 1 ]; then
	C_OK=$'\033[32m'; C_ERR=$'\033[31m'; C_INFO=$'\033[36m'; C_RST=$'\033[0m'
else
	C_OK=""; C_ERR=""; C_INFO=""; C_RST=""
fi
ok()   { printf '%s  OK %s %s\n' "$C_OK" "$C_RST" "$*"; }
info() { printf '%s ==>%s %s\n' "$C_INFO" "$C_RST" "$*"; }
die()  { printf '%sFAIL%s %s\n' "$C_ERR" "$C_RST" "$*" >&2; exit 1; }

# ---- always unload on the way out ---------------------------------------
cleanup() {
	if [ "$LOADED" = 1 ] && lsmod | grep -q "^${MODULE}\b"; then
		info "rmmod ${MODULE} (releases DATA, removes /dev/iec0)"
		rmmod "$MODULE" 2>/dev/null && ok "unloaded - Pi left as before" \
			|| info "rmmod failed; unload manually: sudo rmmod ${MODULE}"
	fi
}
trap cleanup EXIT

# ---- args ---------------------------------------------------------------
while [ $# -gt 0 ]; do
	case "$1" in
		--address) ADDRESS="${2:-}"; shift 2 ;;
		--address=*) ADDRESS="${1#*=}"; shift ;;
		-h|--help) grep '^#' "$0" | sed 's/^# \{0,1\}//'; exit 0 ;;
		-*) die "unknown option: $1" ;;
		*) KO="$1"; shift ;;
	esac
done

# ---- preconditions ------------------------------------------------------
[ "$(id -u)" -eq 0 ] || die "must run as root (use: sudo $0 ...)"
case "$ADDRESS" in ''|*[!0-9]*) die "address must be 0-30 (got '$ADDRESS')" ;; esac
{ [ "$ADDRESS" -ge 0 ] && [ "$ADDRESS" -le 30 ]; } || die "address out of range 0-30: $ADDRESS"

if [ -z "$KO" ]; then
	for cand in "./${MODULE}.ko" "$HOME/${MODULE}.ko" "$(dirname "$0")/${MODULE}.ko"; do
		[ -f "$cand" ] && { KO="$cand"; break; }
	done
fi
[ -n "$KO" ] && [ -f "$KO" ] || die "module not found; pass the path, e.g. sudo $0 ~/${MODULE}.ko"
command -v modinfo >/dev/null || die "modinfo not found (install kmod)"

info "module:  $KO"
info "address: $ADDRESS"

# ---- 1. compatibility check (vermagic vs running kernel) ----------------
RUNNING="$(uname -r)"
ARCH="$(uname -m)"
VERMAGIC="$(modinfo -F vermagic "$KO")" || die "cannot read vermagic from $KO"
MOD_KVER="${VERMAGIC%% *}"   # first token of vermagic = kernel version

info "running kernel: $RUNNING ($ARCH)"
info "module vermagic: $VERMAGIC"

[ "$MOD_KVER" = "$RUNNING" ] || die \
"kernel mismatch: module built for '$MOD_KVER' but running '$RUNNING'.
     Rebuild against the current headers (see docs/kernel-notes.md):
       pkg=\"linux-headers-\$(uname -r | sed 's/.*+rpt-//')\"
       echo \"HEADERS_PKG=\$pkg KERNEL_VERSION=\$(dpkg-query -W -f='\${Version}' \"\$pkg\")\""

case "$VERMAGIC" in
	*"$ARCH"*) ;;
	*) die "arch mismatch: module vermagic has no '$ARCH' (wrong flavour built?)" ;;
esac
ok "compatible with running kernel"

# ---- 2. load (reload if a stale copy is already in) ---------------------
if lsmod | grep -q "^${MODULE}\b"; then
	info "a copy is already loaded; removing it first"
	rmmod "$MODULE" || die "rmmod failed (is /dev/iec0 in use?)"
fi
info "insmod ${MODULE}.ko address=${ADDRESS}"
insmod "$KO" address="$ADDRESS" || die "insmod failed; check: dmesg | tail"
LOADED=1
[ -c /dev/iec0 ] || die "/dev/iec0 was not created"
ok "loaded; /dev/iec0 present"

# ---- 3. self-test ioctl -------------------------------------------------
info "running self-test (IEC_IOC_SELFTEST) - run with the C64 disconnected"
set +e
python3 - <<'PY'
import array, fcntl, sys
IEC_IOC_SELFTEST = 0x80044903  # _IOR('I', 3, __u32)
BITS = [
    ("DATA_ASSERT_OK", 0x01),   # DATA read low while driven low
    ("DATA_FLOAT_OK",  0x02),   # DATA read high after release (Hi-Z)
    ("ATN_RELEASED",   0x04),   # ATN high (idle)
    ("CLK_RELEASED",   0x08),   # CLK high (idle)
    ("RESET_RELEASED", 0x10),   # RESET high (idle)
]
buf = array.array("I", [0])
with open("/dev/iec0", "rb", buffering=0) as f:
    fcntl.ioctl(f, IEC_IOC_SELFTEST, buf, True)
r = buf[0]
print("     selftest = 0x%02x (%s)" % (r, "PASS" if r == 0x1F else "FAIL"))
for name, bit in BITS:
    print("       %-15s %s" % (name, "ok" if r & bit else "MISSING"))
sys.exit(0 if r == 0x1F else 1)
PY
ST=$?
set -e

# ---- 4. report (rmmod happens in the EXIT trap) -------------------------
echo
if [ "$ST" -eq 0 ]; then
	ok "self-test PASSED (0x1F) - all four lines wired correctly"
else
	info "self-test did not fully pass."
	info "On a BARE board 0x15 is expected and fine: only DATA_ASSERT_OK is"
	info "meaningful; ATN/RESET pass via the SoC's fixed GPIO2/3 pull-ups."
	info "Re-run once the level shifter is wired + powered; you want 0x1F."
fi
exit "$ST"