#!/bin/bash
set -euo pipefail

# Pi-Kit flashing helper (small wrapper around xzcat | dd).
# Usage: sudo ./flash_sd.sh /path/to/image.img.xz /dev/sdX
# Example: sudo ./flash_sd.sh images/output/DietPi_RPi5-ARMv8-Trixie-base.img.xz /dev/sdb
# Safety guardrails:
#   - Requires root (sudo).
#   - WILL wipe the target block device; prompt asks for YES before writing.
#   - If a .sha256 sits next to the image, consider verifying it first.

img="${1:-}"
dev="${2:-}"

if [[ -z "$img" || -z "$dev" ]]; then
  echo "Usage: sudo $0 image.img.xz /dev/sdX"
  exit 1
fi

if [[ $EUID -ne 0 ]]; then
  echo "Please run as root (sudo)."
  exit 1
fi

if [[ ! -b "$dev" ]]; then
  echo "Device $dev not found or not a block device."
  exit 1
fi

echo "About to wipe and flash $dev with $img"
read -rp "Type YES to continue: " yn
[[ "$yn" == "YES" ]] || { echo "Aborted."; exit 1; }

echo "Decompressing and writing... this may take several minutes."
xzcat "$img" | pv | dd of="$dev" bs=4M conv=fsync status=none

echo "Syncing..."
sync

echo "Flashed $img to $dev successfully."

echo "Ejecting $dev..."
sudo eject "$dev" || true