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

[[ $# -eq 5 ]] || {
  echo "usage: prepare-jd-native-resident-once.sh <world-root> <resident-image> <recovery-root> <expected-image-sha256> <probe-recovery-root>" >&2
  exit 64
}
[[ ${EUID} -eq 0 ]] || exit 77

world_root=$(readlink -f "$1")
candidate=$(readlink -f "$2")
recovery_root=$(readlink -m "$3")
expected_candidate_sha=$4
probe_recovery_root=$(readlink -f "$5")
script_root=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)
render_root=$(mktemp -d)
trap 'rm -rf "${render_root}"' EXIT

grep -q '^node_id: JD-FD-PRIMARY$' "${world_root}/CURRENT.hldp"
grep -q '^status: PASS_100$' "${probe_recovery_root}/RETURN-RECEIPT.hldp"
/guanghu/bin/ghctl authorize "${world_root}" \
  write_bootloader_and_system_partitions >/dev/null
[[ ${expected_candidate_sha} =~ ^[0-9a-f]{64}$ ]]
[[ $(stat -c %s "${candidate}") -eq 14848 ]]
[[ $(sha256sum "${candidate}" | awk '{print $1}') == \
  "${expected_candidate_sha}" ]]
[[ ! -e ${recovery_root} ]]

partition_dump=$(sfdisk -d /dev/vda)
grep -q '^label: dos$' <<<"${partition_dump}"
grep -q '^label-id: 0xf4bb72a5$' <<<"${partition_dump}"
grep -Eq '^/dev/vda1 : start= *2048, size= *209713119, type=83$' \
  <<<"${partition_dump}"
[[ $(dd if=/dev/vda bs=512 count=105 status=none | sha256sum |
  awk '{print $1}') == \
  32291877e37647ee5b778f968676cc69b59fb5b07604366a21cbfd8e4a4b87a8 ]]
[[ $(dd if=/dev/vda bs=512 skip=105 count=38 status=none | sha256sum |
  awk '{print $1}') == \
  c597b1b463b7cec49548fac00d7588c9652bb67cc2b1b0c88676bf8f1558571e ]]

mkdir -m 0700 "${recovery_root}"
printf '%s\n' "${partition_dump}" >"${recovery_root}/sfdisk-before.txt"
dd if=/dev/vda of="${recovery_root}/first-2MiB.before.bin" \
  bs=1M count=2 status=none
disk_sectors=$(blockdev --getsz /dev/vda)
dd if=/dev/vda of="${recovery_root}/last-2MiB.before.bin" \
  bs=512 skip=$((disk_sectors - 4096)) count=4096 status=none
cp /boot/grub/grub.cfg "${recovery_root}/grub.cfg.before"
cp /boot/grub/grubenv "${recovery_root}/grubenv.before"
cp /etc/default/grub "${recovery_root}/default-grub.before"
cp /etc/grub.d/40_custom "${recovery_root}/40_custom.before"
cp "${candidate}" "${recovery_root}/jd-native-resident.img"
cat /proc/sys/kernel/random/boot_id >"${recovery_root}/linux-boot-id.before"

"${script_root}/render-native-recovery-beacon.sh" "${render_root}" \
  139 gnulinux-simple-9e4550a0-452b-4f28-b5a5-d5364aa450f6
install -m 0755 "${render_root}/08_guanghu_native_recovery" \
  /etc/grub.d/08_guanghu_native_recovery
install -m 0755 /dev/stdin /etc/grub.d/41_guanghu_jd_native_once <<'EOF'
#!/bin/sh
exec tail -n +3 $0
menuentry 'Guanghu OS JD native one-time resident' --id 'guanghu-jd-native-once' {
    insmod chain
    chainloader (hd0)105+1
}
EOF
install -D -m 0644 "${render_root}/guanghu-recovery-clear.env" \
  /usr/lib/guanghu-os/jd-recovery-clear.env
install -D -m 0755 "${script_root}/clear-native-recovery-beacon.sh" \
  /usr/local/sbin/guanghu-clear-native-recovery-beacon
install -m 0644 /dev/stdin \
  /etc/systemd/system/guanghu-jd-native-recovery-clear.service <<'EOF'
[Unit]
Description=Verify and clear the JD Guanghu native recovery beacon
After=local-fs.target
Before=multi-user.target

[Service]
Type=oneshot
ExecStart=/usr/local/sbin/guanghu-clear-native-recovery-beacon /dev/vda /usr/lib/guanghu-os/jd-recovery-clear.env 139

[Install]
WantedBy=multi-user.target
EOF
systemctl enable guanghu-jd-native-recovery-clear.service >/dev/null
dd if="${render_root}/guanghu-recovery-clear.env" of=/dev/vda \
  bs=512 seek=139 count=2 conv=notrunc,fsync status=none
dd if="${candidate}" of=/dev/vda bs=512 seek=105 count=29 \
  conv=notrunc,fsync status=none
update-grub >/dev/null
grub-script-check /boot/grub/grub.cfg
grep -q "load_env --file '(hd0)139+2' guanghu_recovery" \
  /boot/grub/grub.cfg
grep -q "menuentry 'Guanghu OS JD native one-time resident'.*'guanghu-jd-native-once'" \
  /boot/grub/grub.cfg
[[ $(dd if=/dev/vda bs=512 skip=105 count=29 status=none | sha256sum |
  awk '{print $1}') == "${expected_candidate_sha}" ]]
[[ $(dd if=/dev/vda bs=512 skip=139 count=2 status=none | sha256sum |
  awk '{print $1}') == \
  $(sha256sum "${render_root}/guanghu-recovery-clear.env" | awk '{print $1}') ]]

observed_at=$(date --iso-8601=seconds)
cat >"${recovery_root}/PREPARE-RECEIPT.hldp" <<EOF
schema: guanghu.jd-native-resident-prepare/v1
receipt_id: GH-OS-JD-FD-PRIMARY-001-RESIDENT-PREPARE
status: VERIFIED_NOT_ARMED
observed_at: ${observed_at}
node_id: JD-FD-PRIMARY
candidate:
  lba_start: 105
  sector_count: 29
  sha256: ${expected_candidate_sha}
proof_lba: 134
world_store_lba: 135
code_channel_lba: 136
code_object_lba: 137
branch_receipt_lba: 138
recovery_beacon_lba_start: 139
gestational_index_lba_start: 141
rollback:
  recovery_root: ${recovery_root}
  first_and_last_2mib_backed_up: true
  grub_backed_up: true
  one_time_entry_installed_not_armed: true
next_action: ARM_ONE_TIME_RESIDENT_AND_RUN_EXTERNAL_HLDP_PEER
EOF
chmod 0400 "${recovery_root}"/*
sync
cat "${recovery_root}/PREPARE-RECEIPT.hldp"