#!/usr/bin/env bash
# ─────────────────────────────────────────────────────────────
# Nexus One AI — Custom ISO Builder
# Runs directly on Ubuntu 22.04 (run on the server)
#
# Usage:
#   cd ~/aipackage
#   bash autoinstall/build-iso.sh
#
# Output: ~/aipackage/autoinstall/cezen-ai-ubuntu2204.iso
# Then copy the ISO to a USB stick or burn it.
# ─────────────────────────────────────────────────────────────
set -e

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PACKAGE_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
WORK_DIR="/tmp/cezen-iso-work"
ORIGINAL_ISO="/tmp/ubuntu-22.04.5-live-server-amd64.iso"
OUTPUT_ISO="$SCRIPT_DIR/cezen-ai-ubuntu2204.iso"
UBUNTU_URL="https://releases.ubuntu.com/22.04.5/ubuntu-22.04.5-live-server-amd64.iso"

echo "╔══════════════════════════════════════════╗"
echo "║   Nexus One AI — ISO Builder                 ║"
echo "╚══════════════════════════════════════════╝"
echo ""

# ── Install build tools ────────────────────────
echo "→ Installing build tools..."
apt-get update -qq
apt-get install -y -qq xorriso wget isolinux rsync
echo "✓ Tools ready"

# ── Download Ubuntu ISO ────────────────────────
if [ -f "$ORIGINAL_ISO" ]; then
  echo "✓ Ubuntu ISO already downloaded"
else
  echo "→ Downloading Ubuntu 22.04.5 Server ISO (~1.8 GB)..."
  wget --show-progress -O "$ORIGINAL_ISO" "$UBUNTU_URL"
  echo "✓ Downloaded"
fi

# ── Extract ISO ────────────────────────────────
echo "→ Extracting ISO..."
rm -rf "$WORK_DIR"
mkdir -p "$WORK_DIR"
xorriso -osirrox on \
  -indev "$ORIGINAL_ISO" \
  -extract / "$WORK_DIR" 2>/dev/null
chmod -R u+w "$WORK_DIR"
echo "✓ Extracted"

# ── Inject autoinstall files ───────────────────
echo "→ Injecting autoinstall config..."
mkdir -p "$WORK_DIR/nocloud"
cp "$SCRIPT_DIR/user-data" "$WORK_DIR/nocloud/user-data"
cp "$SCRIPT_DIR/meta-data" "$WORK_DIR/nocloud/meta-data"
echo "✓ user-data and meta-data injected"

# Keep this as an online installer ISO. The installed system pulls the current
# Nexus One AI package from cgit during first boot, which keeps the ISO small and
# avoids shipping stale backend/portal code inside the image.
echo "✓ Online installer mode: package will be pulled from cgit on first boot"

# ── Patch GRUB ────────────────────────────────
echo "→ Patching GRUB config..."
GRUB_CFG="$WORK_DIR/boot/grub/grub.cfg"
cp "$GRUB_CFG" "$GRUB_CFG.orig"

# Set 5 second countdown then auto-install
sed -i "s/set timeout=.*/set timeout=5/" "$GRUB_CFG"
sed -i "s/set timeout_style=.*/set timeout_style=countdown/" "$GRUB_CFG"

# Add autoinstall params BEFORE the '---' separator on the kernel line.
# Anything after '---' in a GRUB linux line goes to init, not the kernel.
# So 'autoinstall' and 'ds=' must be inserted BEFORE '---'.
# Semicolon is backslash-escaped so GRUB doesn't treat it as a command separator.
sed -i '/^\s*linux.*vmlinuz/s|---|autoinstall ds=nocloud\\;s=/cdrom/nocloud/ ---|' "$GRUB_CFG"
echo "✓ GRUB patched"

# ── Extract MBR and EFI partition from original ISO ────
echo "→ Extracting boot data from original ISO..."
MBR_TEMPLATE=$(mktemp)
EFI_IMG=$(mktemp)
dd if="$ORIGINAL_ISO" bs=1 count=432 of="$MBR_TEMPLATE" 2>/dev/null

# Find EFI partition (partition 2) start and size in 512-byte sectors
EFI_LINE=$(fdisk -l "$ORIGINAL_ISO" 2>/dev/null | grep "EFI")
echo "  EFI partition info: $EFI_LINE"
EFI_START=$(echo "$EFI_LINE" | awk '{print $2}')
EFI_SIZE=$(echo  "$EFI_LINE" | awk '{print $4}')

if [ -z "$EFI_START" ] || [ -z "$EFI_SIZE" ]; then
  echo "ERROR: Could not detect EFI partition in ISO."
  echo "Run: fdisk -l $ORIGINAL_ISO"
  exit 1
fi

dd if="$ORIGINAL_ISO" bs=512 skip="$EFI_START" count="$EFI_SIZE" \
   of="$EFI_IMG" 2>/dev/null
echo "✓ EFI partition extracted (start=$EFI_START, size=$EFI_SIZE)"

# ── Repack ISO ─────────────────────────────────
echo "→ Repacking ISO (pass 1)..."
xorriso -as mkisofs \
  -r \
  -V "Cezen_AI_Ubuntu2204" \
  -o "$OUTPUT_ISO" \
  --grub2-mbr "$MBR_TEMPLATE" \
  -partition_offset 16 \
  --mbr-force-bootable \
  -append_partition 2 28732ac11ff8d211ba4b00a0c93ec93b "$EFI_IMG" \
  -appended_part_as_gpt \
  -iso_mbr_part_type a2a0d0ebe5b9334487c068b6b72699c7 \
  -c "/boot.catalog" \
  -b "/boot/grub/i386-pc/eltorito.img" \
  -no-emul-boot \
  -boot-load-size 4 \
  -boot-info-table \
  --grub2-boot-info \
  -eltorito-alt-boot \
  -e "--interval:appended_partition_2:::" \
  -no-emul-boot \
  "$WORK_DIR"

echo "→ Refreshing md5sum.txt from pass-1 ISO contents..."
FINAL_DIR=$(mktemp -d)
VERIFY_DIR=$(mktemp -d)
trap 'rm -rf "$WORK_DIR" "$MBR_TEMPLATE" "$EFI_IMG" "$FINAL_DIR" "$VERIFY_DIR"' EXIT
xorriso -osirrox on \
  -indev "$OUTPUT_ISO" \
  -extract / "$FINAL_DIR" >/dev/null 2>&1
chmod -R u+w "$FINAL_DIR"
(
  cd "$FINAL_DIR"
  rm -f md5sum.txt
  find . -type f \
    ! -path './md5sum.txt' \
    ! -path './boot.catalog' \
    -print0 \
    | sort -z \
    | xargs -0 md5sum > md5sum.txt
)
echo "✓ md5sum.txt refreshed"

echo "→ Repacking ISO (pass 2 with final manifest)..."
xorriso -as mkisofs \
  -r \
  -V "Cezen_AI_Ubuntu2204" \
  -o "$OUTPUT_ISO" \
  --grub2-mbr "$MBR_TEMPLATE" \
  -partition_offset 16 \
  --mbr-force-bootable \
  -append_partition 2 28732ac11ff8d211ba4b00a0c93ec93b "$EFI_IMG" \
  -appended_part_as_gpt \
  -iso_mbr_part_type a2a0d0ebe5b9334487c068b6b72699c7 \
  -c "/boot.catalog" \
  -b "/boot/grub/i386-pc/eltorito.img" \
  -no-emul-boot \
  -boot-load-size 4 \
  -boot-info-table \
  --grub2-boot-info \
  -eltorito-alt-boot \
  -e "--interval:appended_partition_2:::" \
  -no-emul-boot \
  "$FINAL_DIR"

# ── Verify output ISO integrity manifest ─────────────────
echo "→ Verifying rebuilt ISO manifest..."
xorriso -osirrox on \
  -indev "$OUTPUT_ISO" \
  -extract / "$VERIFY_DIR" >/dev/null 2>&1
chmod -R u+w "$VERIFY_DIR"
(
  cd "$VERIFY_DIR"
  md5sum -c md5sum.txt >/tmp/cezen-iso-md5check.log 2>&1 || {
    echo "ERROR: Rebuilt ISO failed its own md5sum.txt verification."
    sed -n '1,40p' /tmp/cezen-iso-md5check.log
    exit 1
  }
)
echo "✓ Output ISO manifest verified"

echo ""
echo "╔══════════════════════════════════════════════════════╗"
echo "║   Done!                                              ║"
echo "╚══════════════════════════════════════════════════════╝"
echo ""
ls -lh "$OUTPUT_ISO"
echo ""
echo "→ Copy to your MacBook:"
echo "   scp user@172.16.10.180:~/aipackage/autoinstall/cezen-ai-ubuntu2204.iso ."
echo ""
echo "→ Flash to USB on MacBook:"
echo "   diskutil list                        # find USB e.g. /dev/disk4"
echo "   diskutil unmountDisk /dev/disk4"
echo "   sudo dd if=cezen-ai-ubuntu2204.iso of=/dev/disk4 bs=4m status=progress"