#!/usr/bin/env bash
#
# scripts/test-disk.sh — full automated data-disk round trip.
#
# Builds the kernel, ensures the FAT32 image exists (with --fresh it is
# re-formatted and re-seeded), boots QEMU headless, drives the shell via
# the monitor, then verifies the results with mtools and fsck.
#
# Usage:
#   ./scripts/test-disk.sh            # reuse existing image
#   ./scripts/test-disk.sh --fresh    # re-format the image first
#
# Environment:
#   DISK_IMG  data disk path (default: /tmp/disk.img)
#   OVMF      firmware (default: /usr/share/edk2/x64/OVMF.4m.fd)
#   QEMU      qemu binary (default: qemu-system-x86_64)
#
set -euo pipefail

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

FRESH=0
[ "${1:-}" = "--fresh" ] && FRESH=1

OVMF="${OVMF:-/usr/share/edk2/x64/OVMF.4m.fd}"
QEMU="${QEMU:-qemu-system-x86_64}"
IMG="${SYSTEM_IMG:-/tmp/system.img}"
QPID=/tmp/rsdos-test-qpid
SOCK=/tmp/rsdos-test-qmon.sock
LOG=/tmp/rsdos-test-serial.log
QLOG=/tmp/rsdos-test-qemu.log
STAMP="$(date +%s)"

# Never leave a QEMU behind (an orphan holding our stdout would hang any
# caller that pipes our output).
trap 'kill "$(cat "$QPID" 2>/dev/null)" 2>/dev/null || true' EXIT

fail() {
	echo "FAIL: $1"
	[ -f "$LOG" ] && tail -20 "$LOG"
	exit 1
}

# wait_log FILE PATTERN TIMEOUT-SECONDS — poll a file for a regex.
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
}

# wait_qemu_exit TIMEOUT-SECONDS — poll until the pid is gone.
wait_qemu_exit() {
	local i=0
	while [ "$i" -lt $((${1:-30} * 10)) ]; do
		kill -0 "$(cat "$QPID" 2>/dev/null)" 2>/dev/null || return 0
		sleep 0.1
		i=$((i + 1))
	done
	return 1
}

echo "==> 1/6 build kernel (debug)"
cargo build --release --package rsdos --target x86_64-unknown-uefi

echo "==> 2/6 ensure system image"
if [ "$FRESH" -eq 1 ]; then
	"$SCRIPT_DIR/mksystem.sh" --force "$IMG"
else
	"$SCRIPT_DIR/mksystem.sh" "$IMG"
fi

echo "==> 3/6 boot QEMU (headless)"
kill "$(cat "$QPID" 2>/dev/null)" 2>/dev/null || true
sleep 1
rm -f "$SOCK" "$LOG"
# Throwaway OVMF varstore: a stale/poisoned NvVars (e.g. left by the old
# vvfat setup) makes the firmware skip the \EFI\BOOT fallback entirely.
NV="/tmp/rsdos-test-ovmf-vars.fd"
rm -f "$NV"
cp /usr/share/edk2/x64/OVMF.4m.fd "$NV"
"$QEMU" -bios "$NV" \
	-drive file="$IMG",format=raw,if=none,id=disk \
	-device ide-hd,drive=disk,bus=ide.0 \
	-serial file:"$LOG" \
	-monitor unix:"$SOCK",server,nowait \
	-m 256M -machine q35 -cpu qemu64 -no-reboot -display none \
	>"$QLOG" 2>&1 &

wait_log "$LOG" "boot: entering shell" 90 || fail "kernel never reached the shell"
sleep 1

# Volumes mount under /disk/<UID>/ where UID = "LABEL-SERIAL" (e.g.
# RSDOS-5BD1E55F).  Discover it from the boot log so the test works on
# any image without knowing the serial in advance.
VOL_UID="$(grep -a 'fat: mounted' "$LOG" | sed -n 's/.*at \/disk\/\([^ )]*\).*/\1/p' | head -1)"
[ -n "$VOL_UID" ] || fail "no FAT32 volume was mounted (look for 'fat: mounted' in the log)"
echo "  mounted volume UID: $VOL_UID"

echo "==> 4/6 drive the shell (ls / mkdir / echo WRITING / cat / poweroff)"
# The filename is deliberately >13 chars so the FAT LFN path gets
# multi-entry entries (they're stored last-first on disk).
TESTFILE="disk-test-$STAMP.txt"
python3 "$SCRIPT_DIR/sendkeys.py" --sock "$SOCK" \
	"ls /disk" \
	"mkdir /disk/$VOL_UID/sub" \
	"echo disk-test-$STAMP WRITING /disk/$VOL_UID/sub/$TESTFILE" \
	"cat /disk/$VOL_UID/sub/$TESTFILE" \
	"poweroff"

echo "==> 5/6 wait for shutdown"
wait_qemu_exit 30 || fail "QEMU did not exit after poweroff"

echo "==> 6/6 verify"
grep -a "disk-test-$STAMP" "$LOG" >/dev/null || fail "cat output missing from serial log"
if ! fsck.fat -n "$IMG" >/tmp/rsdos-fsck.out 2>&1; then
	fail "fsck.fat reports problems: $(cat /tmp/rsdos-fsck.out | tail -3)"
fi
MT="$(mtype -i "$IMG" "::/sub/$TESTFILE" 2>/dev/null || true)"
[ "$MT" = "disk-test-$STAMP" ] || fail "mtype mismatch: got '$MT'"

echo ""
echo "PASS — disk round trip OK (fsck clean, file survived poweroff)"
echo "  image:      $IMG"
echo "  volume:     /disk/$VOL_UID"
echo "  written:    /disk/$VOL_UID/sub/$TESTFILE = \"disk-test-$STAMP\""