#!/usr/bin/env bash
#
# scripts/test-fault.sh — fault-diagnostics verification.
#
# Proves the fault-dump path: every CPU exception prints a white-on-red
# band to the framebuffer and a parseable serial line before halting.
#
# Usage: ./scripts/test-fault.sh
# Env:   OVMF, QEMU, SYSTEM_IMG
#
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
PROJECT_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
cd "$PROJECT_DIR"

OVMF="${OVMF:-/usr/share/edk2/x64/OVMF.4m.fd}"
QEMU="${QEMU:-qemu-system-x86_64}"
SYSTEM_IMG="${SYSTEM_IMG:-/tmp/system.img}"
QPID=/tmp/rsdos-fault-qpid
SOCK=/tmp/rsdos-fault-qmon.sock
LOG=/tmp/rsdos-fault-serial.log
QLOG=/tmp/rsdos-fault-qemu.log

trap 'kill "$(cat "$QPID" 2>/dev/null)" 2>/dev/null || true' EXIT

fail() {
	echo "FAIL: $1"
	[ -f "$LOG" ] && tail -40 "$LOG"
	exit 1
}

wait_log() {
	local i=0
	while [ "$i" -lt $((${3:-60} * 10)) ]; do
		grep -q "$2" "$1" 2>/dev/null && return 0
		sleep 0.1
		i=$((i + 1))
	done
	return 1
}

echo "==> 1/5 build kernel (debug)"
cargo build --release --package rsdos --target x86_64-unknown-uefi

echo "==> 2/5 stage system image"
"$SCRIPT_DIR/mksystem.sh" --force "$SYSTEM_IMG"

echo "==> 3/5 boot QEMU (headless, + dedicated CRASHLOG stick)"
kill "$(cat "$QPID" 2>/dev/null)" 2>/dev/null || true
sleep 1
rm -f "$SOCK" "$LOG"
CRASH_IMG=/tmp/rsdos-crash.img
mkfs.fat -C -F 32 -n CRASHLOG "$CRASH_IMG" >/dev/null
"$QEMU" -bios "$OVMF" \
	-drive file="$SYSTEM_IMG",format=raw,if=none,id=disk \
	-device ide-hd,drive=disk,bus=ide.0 \
	-drive file="$CRASH_IMG",format=raw,if=none,id=crash \
	-device ide-hd,drive=crash,bus=ide.1 \
	-serial file:"$LOG" \
	-monitor unix:"$SOCK",server,nowait \
	-m 256M -machine q35 -cpu qemu64 -no-reboot -display none \
	>"$QLOG" 2>&1 &
echo $! >"$QPID"

wait_log "$LOG" "boot: entering shell" 90 || fail "kernel never reached the shell"

echo "==> 4/5 boot diagnostics present"
grep -aq "gop: fb base=" "$LOG" || fail "fb geometry diagnostic missing"
grep -aq "gop: mode .* selected" "$LOG" || fail "mode-selection diagnostic missing"
grep -aq "CRASHLOG" "$LOG" || fail "CRASHLOG stick not mounted"

echo "==> 5/5 inject a page fault (fault command)"
python3 "$SCRIPT_DIR/sendkeys.py" --sock "$SOCK" \
	"clear" \
	"fault"
sleep 2

grep -aq "!!! page fault vec=14 .*rip=" "$LOG" || fail "page-fault dump line missing"
grep -aq "cr2=0x400000000000" "$LOG" || fail "CR2 not reported (faulting address)"
grep -aq "task=0 \"shell\"" "$LOG" || fail "faulting task not identified"
grep -aq "!!! halting" "$LOG" || fail "no halt message"

echo ""
echo "PASS — fault dump verified"