#!/usr/bin/env bash
set -euo pipefail

[[ $# -eq 1 ]] || {
  echo "usage: test-native-recovery-beacon-grub-qemu.sh <receipt-output>" >&2
  exit 64
}
[[ ${EUID} -eq 0 ]] || {
  echo "the GRUB/QEMU recovery gate requires root for a disposable loop disk" >&2
  exit 77
}

source_root=$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)
receipt=$(readlink -m "$1")
test_root=$(mktemp -d)
disk=${test_root}/grub-recovery.img
mount_root=${test_root}/mnt
loop_device=

cleanup() {
  if mountpoint -q "${mount_root}"; then
    umount "${mount_root}"
  fi
  if [[ -n ${loop_device} ]]; then
    losetup -d "${loop_device}"
  fi
  if [[ ${GHOS_KEEP_TEST_ROOT:-0} != 1 ]]; then
    rm -rf "${test_root}"
  else
    echo "GHOS_TEST_ROOT=${test_root}" >&2
  fi
}
trap cleanup EXIT

for command_name in grub-install losetup mkfs.ext4 mount mountpoint nasm \
  parted qemu-system-x86_64 timeout udevadm; do
  command -v "${command_name}" >/dev/null
done

"${source_root}/scripts/render-native-recovery-beacon.sh" "${test_root}/beacon"
truncate -s 128M "${disk}"
parted -s "${disk}" mklabel gpt
parted -s "${disk}" mkpart bios_grub 1MiB 2MiB
parted -s "${disk}" set 1 bios_grub on
parted -s "${disk}" mkpart root ext4 2MiB 100%

loop_device=$(losetup --find --show --partscan "${disk}")
root_partition=${loop_device}p2
udevadm settle --timeout=10
for _ in {1..50}; do
  [[ -b ${root_partition} ]] && break
  sleep 0.1
done
[[ -b ${root_partition} ]]
mkfs.ext4 -q -F "${root_partition}"
mkdir -p "${mount_root}"
mount "${root_partition}" "${mount_root}"
grub-install \
  --target=i386-pc \
  --boot-directory="${mount_root}/boot" \
  --no-floppy \
  --recheck \
  "${loop_device}" >/dev/null

install -m 0644 /dev/stdin "${mount_root}/boot/grub/grub.cfg" <<'EOF'
serial --unit=0 --speed=115200
terminal_input serial
terminal_output serial
set timeout=0
set timeout_style=hidden
set default="guanghu-native-once"
insmod loadenv
set guanghu_recovery=
if load_env --file '(hd0)68+2' guanghu_recovery; then
    if [ "${guanghu_recovery}" = "ubuntu" ]; then
        set default="ubuntu-recovery-test"
    fi
fi
menuentry 'Guanghu native default test' --id 'guanghu-native-once' {
    insmod chain
    chainloader (hd0)80+1
    boot
}
menuentry 'Ubuntu recovery test' --id 'ubuntu-recovery-test' {
    insmod chain
    chainloader (hd0)81+1
    boot
}
EOF

install -m 0644 /dev/stdin "${test_root}/exit-sector.asm" <<'EOF'
bits 16
org 0x7c00
mov dx, 0xf4
mov al, EXIT_VALUE
out dx, al
cli
hlt
times 510 - ($ - $$) db 0
dw 0xaa55
EOF
nasm -f bin -DEXIT_VALUE=0x10 "${test_root}/exit-sector.asm" \
  -o "${test_root}/native-exit.bin"
nasm -f bin -DEXIT_VALUE=0x11 "${test_root}/exit-sector.asm" \
  -o "${test_root}/ubuntu-exit.bin"
dd if="${test_root}/native-exit.bin" of="${loop_device}" \
  bs=512 seek=80 count=1 conv=notrunc status=none
dd if="${test_root}/ubuntu-exit.bin" of="${loop_device}" \
  bs=512 seek=81 count=1 conv=notrunc status=none

sync
umount "${mount_root}"
losetup -d "${loop_device}"
loop_device=

run_qemu() {
  local stage=$1
  local expected_status=$2
  set +e
  timeout 20 qemu-system-x86_64 \
    -machine pc,accel=tcg \
    -m 64M \
    -drive "format=raw,file=${disk}" \
    -display none \
    -monitor none \
    -serial null \
    -no-reboot \
    -device isa-debug-exit,iobase=0xf4,iosize=0x04
  local observed_status=$?
  set -e
  printf 'GHNRP_QEMU_STAGE=%s EXPECTED=%s OBSERVED=%s\n' \
    "${stage}" "${expected_status}" "${observed_status}"
  [[ ${observed_status} -eq ${expected_status} ]]
}

dd if="${test_root}/beacon/guanghu-recovery-clear.env" of="${disk}" \
  bs=512 seek=68 count=2 conv=notrunc,fsync status=none
run_qemu clear_selects_native 33

dd if="${test_root}/beacon/guanghu-recovery-active.env" of="${disk}" \
  bs=512 seek=68 count=2 conv=notrunc,fsync status=none
run_qemu active_selects_hosted_recovery 35

"${source_root}/scripts/clear-native-recovery-beacon.sh" \
  "${disk}" \
  "${test_root}/beacon/guanghu-recovery-clear.env" >/dev/null
dd if="${disk}" of="${test_root}/beacon.after-ubuntu.env" \
  bs=512 skip=68 count=2 status=none
if grep -aFq 'guanghu_recovery=ubuntu' \
  "${test_root}/beacon.after-ubuntu.env"; then
  echo "hosted recovery did not consume the Guanghu recovery beacon" >&2
  exit 1
fi
cmp \
  "${test_root}/beacon/guanghu-recovery-clear.env" \
  "${test_root}/beacon.after-ubuntu.env"
run_qemu consumed_selects_native_again 33

mkdir -p "$(dirname "${receipt}")"
observed_at=$(date --iso-8601=seconds)
active_sha=$(sha256sum \
  "${test_root}/beacon/guanghu-recovery-active.env" | awk '{print $1}')
consumed_sha=$(sha256sum \
  "${test_root}/beacon.after-ubuntu.env" | awk '{print $1}')
cat >"${receipt}" <<EOF
schema: guanghu.native-recovery-beacon-grub-qemu/v1
receipt_id: GH-OS-LAB-001-NATIVE-RECOVERY-BEACON-GRUB-QEMU-001
status: VERIFIED
observed_at: ${observed_at}
beacon:
  disk_lba_start: 68
  sector_count: 2
  active_sha256: ${active_sha}
grub:
  raw_blocklist: (hd0)68+2
  whitelisted_variable: guanghu_recovery
  cleared_boot_selects_native: true
  active_boot_selects_ubuntu: true
  active_marker_consumed_by_grub: false
hosted_recovery:
  active_marker_consumed_on_boot: true
  post_consumption_sha256: ${consumed_sha}
acceptance:
  independent_of_linux_filesystem_extent: true
  qemu_permanent_default_recovery_cycle: true
  physical_permanent_default_recovery_cycle: false
next_action: INSTALL_ON_BS_SH_005_AND_RUN_PHYSICAL_DEFAULT_RECOVERY_GATE
EOF
cat "${receipt}"