#!/bin/bash
# Convert a Linux-dd multi-session UDF cal ISO into a Windows-readable
# single-session ISO+UDF hybrid. Mounts the dd file via UDF loop, copies
# files into a temp tree, repacks via mkisofs with ISO9660+UDF.
#
# Use this when a Mitutoyo cal disc was ripped with `dd if=/dev/sr0`
# (default Linux rip). For multi-session UDF discs `dd` captures session
# 1 only and truncates trailing UDF Anchor Volume Descriptor Pointers;
# the file mounts on Linux (loop-udf) but Windows Mount-DiskImage reports
# IsReady=False. mkisofs rebuilds clean metadata Windows reads. Linux
# still reads the result.
#
# Single-session discs (older 218-458A Mitutoyo pattern) are already
# ISO9660 from dd - no conversion needed. Run `file CAL-*.iso`:
# ISO 9660 = fine; "data" = convert.
#
# Usage: convert-cal-iso.sh <input.iso>
# Replaces input in place. Saves <input>.dd-backup on first run.
#
# Requires: sudo (loop-udf mount), mkisofs (genisoimage / cdrtools).

set -euo pipefail

ISO="$1"
test -f "$ISO" || { echo "Missing: $ISO"; exit 1; }

# Extract label from filename, e.g. CAL-WJF00052_... -> 12AAE675-ish.
# Use the asset tag as the volume label so it stays unique + greppable.
ASSET=$(basename "$ISO" | sed -n 's/^CAL-\([A-Za-z0-9]*\)_.*/\1/p')
test -n "$ASSET" || { echo "Could not parse asset from $ISO"; exit 1; }
LABEL="CAL-$ASSET"

# Length cap: ISO9660 vol id <= 32 chars
LABEL="${LABEL:0:32}"

STAGE=$(mktemp -d -p /tmp calconv.XXXX)
MNT="$STAGE/mnt"
TREE="$STAGE/tree"
mkdir -p "$MNT" "$TREE"

cleanup() {
    if mountpoint -q "$MNT"; then sudo umount "$MNT" 2>/dev/null || true; fi
    rm -rf "$STAGE"
}
trap cleanup EXIT

echo "[$ASSET] mount $ISO"
sudo mount -t udf -o loop,ro "$ISO" "$MNT"

echo "[$ASSET] copy"
cp -a "$MNT/." "$TREE/"

sudo umount "$MNT"
rmdir "$MNT" 2>/dev/null || true

# Verify expected files present (case-insensitive: older WJRP discs use Setup.exe)
test -d "$TREE/data" -o -d "$TREE/Data" -o -d "$TREE/DATA" || { echo "[$ASSET] missing data/ dir in tree"; exit 1; }
find "$TREE" -maxdepth 1 -iname 'setup.exe' -type f -print -quit | grep -q . || { echo "[$ASSET] missing setup.exe in tree"; exit 1; }

NEW="$STAGE/new.iso"
echo "[$ASSET] mkisofs -> $NEW"
mkisofs -V "$LABEL" \
        -udf \
        -iso-level 3 \
        -J -joliet-long \
        -r \
        -o "$NEW" \
        "$TREE" 2>&1 | tail -3

NEW_SIZE=$(stat -c %s "$NEW")
echo "[$ASSET] new size: $NEW_SIZE"

# Replace original (backup the dd version once)
BACKUP="${ISO}.dd-backup"
if [ ! -f "$BACKUP" ]; then
    mv "$ISO" "$BACKUP"
    echo "[$ASSET] backed up dd version -> $BACKUP"
else
    rm "$ISO"
fi

mv "$NEW" "$ISO"
echo "[$ASSET] replaced. md5: $(md5sum $ISO | cut -d' ' -f1)"