#!/bin/sh
# vmix: automated macOS install. Runs inside macOS Recovery's Terminal, started
# by vm-driver.py which types "sh /Volumes/VMIX/run.sh" for us.
#
#  1. erase the target disk (found by size) as APFS "Macintosh HD"
#  2. rebuild "Install macOS <name>.app": app skeleton from installer-app.tar
#     (host-extracted Payload) + SharedSupport.dmg copied byte-exact by dd from a
#     raw disk that maps that byte range of the pkg (Recovery's xar truncates an
#     18 GB member, which makes startosinstall report "pkgdmg is missing a footer")
#  3. startosinstall unattended, with the vmix agent pkg as --installpackage
#  4. when the prepare phase is done (SIGUSR1) also drop the agent + .AppleSetupDone
#     onto the volume, then let the installer reboot
#
# On first boot of the installed system the agent runs /Volumes/VMIX/vmix-run.sh
# and powers off, which ends the QEMU session on the host.

# macOS Recovery invokes us as `sh` (bash in POSIX mode, no process substitution);
# re-exec once under bash so `>(tee ...)` and other bashisms work.
if [ -z "${VMIX_REEXEC:-}" ]; then VMIX_REEXEC=1 exec bash "$0" "$@"; fi

V="/Volumes/VMIX"
# tee to the Terminal (visible in host screenshots) and to a log on the volume
exec > >(tee "$V/install.log") 2>&1
set -x
. "$V/vmix.conf"

fail() {
  echo "vmix-install: FAIL: $*"
  cp /var/log/install.log "$V/system-install.log" 2>/dev/null || true
  echo 1 >"$V/install.status"
  sync
  sleep 2
  shutdown -h now 2>/dev/null || halt 2>/dev/null || true
  exit 1
}

# whole-disk identifier (diskN) whose size in bytes is exactly $1
disk_by_size() {
  for d in $(diskutil list | grep -oE '^/dev/disk[0-9]+'); do
    s=$(diskutil info "$d" | sed -n 's/.*Disk Size:.*(\([0-9][0-9]*\) Bytes).*/\1/p')
    [ "$s" = "$1" ] && { echo "${d#/dev/}"; return 0; }
  done
  return 1
}

echo "vmix-install: $(date) app=$APP_NAME volume=$VOLUME_NAME"
TARGET=$(disk_by_size "$TARGET_BYTES") || fail "target disk ($TARGET_BYTES bytes) not found"
SSDISK=$(disk_by_size "$SS_DISK_BYTES") || fail "SharedSupport disk ($SS_DISK_BYTES bytes) not found"
echo "vmix-install: target=$TARGET sharedsupport=$SSDISK"

# --- 1. erase the target disk as an APFS volume
diskutil eraseDisk APFS "$VOLUME_NAME" GPT "$TARGET" || fail "eraseDisk $TARGET"
VOL="/Volumes/$VOLUME_NAME"
[ -d "$VOL" ] || fail "$VOL not mounted"

# --- 2. rebuild the installer app on the target volume
tar -xf "$V/installer-app.tar" -C "$VOL" || fail "untar installer-app.tar"
APP="$VOL/$APP_NAME"
SOI="$APP/Contents/Resources/startosinstall"
[ -x "$SOI" ] || fail "startosinstall missing in $APP"
SS="$APP/Contents/SharedSupport/SharedSupport.dmg"
mkdir -p "$APP/Contents/SharedSupport"
FULL=$((SS_LEN / 1048576))
REM=$((SS_LEN % 1048576))
dd if="/dev/r$SSDISK" of="$SS" bs=1048576 count=$FULL || fail "dd SharedSupport.dmg"
if [ "$REM" -gt 0 ]; then
  dd if="/dev/r$SSDISK" bs=1048576 skip=$FULL count=1 2>/dev/null | dd bs=1 count=$REM >>"$SS" || fail "dd SharedSupport.dmg tail"
fi
[ "$(stat -f %z "$SS")" = "$SS_LEN" ] || fail "SharedSupport.dmg size mismatch: $(stat -f %z "$SS") != $SS_LEN"
tail -c 512 "$SS" | grep -qa koly || fail "SharedSupport.dmg has no UDIF koly footer"
chflags -h norestricted "$SS" 2>/dev/null || true
echo "vmix-install: app=$APP SharedSupport.dmg=$(stat -f %z "$SS") bytes"

# macOS certificate validation needs a sane clock; a fresh VM RTC can be wrong.
echo "vmix-install: guest clock is $(date) (UTC $(date -u))"
if [ -n "${BUILD_DATE:-}" ]; then
  date -u "$BUILD_DATE" && echo "vmix-install: set clock to $(date)"
fi

# --- 3. unattended install
PREPARED=0
trap 'PREPARED=1' USR1
run_install() {
  "$SOI" --volume "$VOL" --agreetolicense --nointeraction --pidtosignal $$ "$@" &
  INSTALL_PID=$!
  while :; do
    wait $INSTALL_PID
    rc=$?
    [ "$PREPARED" = 1 ] && return 0
    kill -0 $INSTALL_PID 2>/dev/null || return $rc
  done
}
run_install --rebootdelay 300 --installpackage "$V/vmix-agent.pkg" \
  || { echo "vmix-install: retry without --rebootdelay"; run_install --installpackage "$V/vmix-agent.pkg"; } \
  || { echo "vmix-install: retry without --installpackage"; run_install; } \
  || fail "startosinstall"

# --- 4. prepare phase done: also drop the agent onto the volume directly.
T="$VOL"
if [ -d "$T" ]; then
  mkdir -p "$T/Library/LaunchDaemons" "$T/Library/vmix" "$T/private/var/db"
  cp "$V/agent/agent.sh" "$T/Library/vmix/agent.sh"
  cp "$V/agent/ch.vmix.agent.plist" "$T/Library/LaunchDaemons/ch.vmix.agent.plist"
  chmod 755 "$T/Library/vmix/agent.sh"
  chmod 644 "$T/Library/LaunchDaemons/ch.vmix.agent.plist"
  chown -R root:wheel "$T/Library/vmix" "$T/Library/LaunchDaemons/ch.vmix.agent.plist"
  touch "$T/private/var/db/.AppleSetupDone"
  chown root:wheel "$T/private/var/db/.AppleSetupDone"
else
  echo "vmix-install: WARNING: $T not mounted after prepare, relying on --installpackage"
fi

echo 0 >"$V/install.status"
sync
kill -USR1 $INSTALL_PID
wait $INSTALL_PID
exit 0