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

IMG="$HOME/Documents/toes-image-builder/toes-ubuntu-base.img"
USBBOOT="$HOME/apps/forks/usbboot"

list_external_disks() {
  diskutil list external physical 2>/dev/null | awk '/^\/dev\/disk[0-9]+ / { sub("^/dev/", "", $1); print $1 }' | sort || true
}

disk_bytes() {
  diskutil info "/dev/$1" | awk -F'[()]' '/Disk Size:/ { sub(/ Bytes.*/, "", $2); print $2; exit }'
}

if [[ "${SKIP_BUILD:-0}" != 1 ]]; then
  ssh toes-image-builder 'cd toes-image-builder && ./build.sh && cp build/toes-ubuntu-base.img /mnt/utm/toes-image-builder/'
fi

[[ -f "$IMG" ]] || { echo "missing $IMG" >&2; exit 1; }

target="${DISK:-}"
if [[ -n "$target" ]]; then
  target="${target#/dev/}"
  target="${target#r}"
else
  before="$(mktemp)"
  after="$(mktemp)"
  trap 'rm -f "$before" "$after"' EXIT
  list_external_disks >"$before"
  sudo "$USBBOOT/rpiboot" -d "$USBBOOT/mass-storage-gadget64"

  for _ in {1..30}; do
    list_external_disks >"$after"
    new="$(comm -13 "$before" "$after")"
    [[ -n "$new" ]] && { sleep 2; list_external_disks >"$after"; new="$(comm -13 "$before" "$after")"; break; }
    sleep 1
  done
  [[ -n "${new:-}" ]] || { echo "no new disks" >&2; exit 1; }

  echo "New disks:"
  target_size=0
  for disk in $new; do
    bytes="$(disk_bytes "$disk")"
    echo "  /dev/$disk ${bytes:-?} bytes"
    [[ "$bytes" =~ ^[0-9]+$ ]] && (( bytes > target_size )) && { target="$disk"; target_size="$bytes"; }
  done
fi

[[ "${target:-}" =~ ^disk[0-9]+$ ]] || { echo "bad disk: ${target:-}" >&2; exit 1; }

target_size="$(disk_bytes "$target")"
image_size="$(stat -f %z "$IMG")"
[[ "$target_size" =~ ^[0-9]+$ ]] || { echo "could not size /dev/$target" >&2; exit 1; }
(( target_size >= image_size )) || { echo "/dev/$target is smaller than $IMG" >&2; exit 1; }

echo "Selected /dev/$target"
echo "Image: $IMG"
diskutil info "/dev/$target"
printf 'Type FLASH to erase /dev/%s: ' "$target"
read -r answer
[[ "$answer" == FLASH ]] || { echo "aborted"; exit 1; }

diskutil unmountDisk "/dev/$target"
sudo dd if="$IMG" of="/dev/r$target" bs=16m status=progress conv=fsync
sync
diskutil eject "/dev/$target"