#!/bin/bash
# create-iso.sh — Create a bootable ISO from kernel + initramfs
# Uses isolinux (syslinux) for Phase 1 simplicity (GRUB in Phase 3)
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
ROOTFS_DIR="${ROOTFS_DIR:-$PROJECT_ROOT/build/rootfs-work}"
OUTPUT_DIR="${OUTPUT_DIR:-$PROJECT_ROOT/output}"
VERSION="$(cat "$PROJECT_ROOT/VERSION")"
OS_NAME="kubesolo-os"

ISO_STAGING="$ROOTFS_DIR/iso-staging"
ISO_OUTPUT="$OUTPUT_DIR/${OS_NAME}-${VERSION}.iso"

VMLINUZ="$ROOTFS_DIR/vmlinuz"
INITRAMFS="$ROOTFS_DIR/kubesolo-os.gz"

# Validate inputs
for f in "$VMLINUZ" "$INITRAMFS"; do
    if [ ! -f "$f" ]; then
        echo "ERROR: Missing required file: $f"
        echo "Run 'make initramfs' first."
        exit 1
    fi
done

# Check for required tools
for cmd in mkisofs xorriso genisoimage; do
    if command -v "$cmd" >/dev/null 2>&1; then
        MKISO_CMD="$cmd"
        break
    fi
done

if [ -z "${MKISO_CMD:-}" ]; then
    echo "ERROR: Need mkisofs, genisoimage, or xorriso to create ISO"
    exit 1
fi

# --- Stage ISO contents ---
rm -rf "$ISO_STAGING"
mkdir -p "$ISO_STAGING/boot/isolinux"

cp "$VMLINUZ" "$ISO_STAGING/boot/vmlinuz"
cp "$INITRAMFS" "$ISO_STAGING/boot/kubesolo-os.gz"

# Find isolinux.bin
ISOLINUX_BIN=""
for path in /usr/lib/ISOLINUX/isolinux.bin /usr/lib/syslinux/isolinux.bin \
            /usr/share/syslinux/isolinux.bin /usr/lib/syslinux/bios/isolinux.bin; do
    [ -f "$path" ] && ISOLINUX_BIN="$path" && break
done

if [ -z "$ISOLINUX_BIN" ]; then
    echo "ERROR: Cannot find isolinux.bin. Install syslinux/isolinux package."
    exit 1
fi

cp "$ISOLINUX_BIN" "$ISO_STAGING/boot/isolinux/"

# Copy ldlinux.c32 if it exists (needed by syslinux 6+)
LDLINUX_DIR="$(dirname "$ISOLINUX_BIN")"
for mod in ldlinux.c32 libcom32.c32 libutil.c32 mboot.c32; do
    [ -f "$LDLINUX_DIR/$mod" ] && cp "$LDLINUX_DIR/$mod" "$ISO_STAGING/boot/isolinux/"
done

# Isolinux config
cat > "$ISO_STAGING/boot/isolinux/isolinux.cfg" << 'EOF'
DEFAULT kubesolo
TIMEOUT 30
PROMPT 0

LABEL kubesolo
    MENU LABEL KubeSolo OS
    KERNEL /boot/vmlinuz
    INITRD /boot/kubesolo-os.gz
    APPEND quiet kubesolo.data=LABEL=KSOLODATA

LABEL kubesolo-debug
    MENU LABEL KubeSolo OS (debug)
    KERNEL /boot/vmlinuz
    INITRD /boot/kubesolo-os.gz
    APPEND kubesolo.data=LABEL=KSOLODATA kubesolo.debug console=ttyS0,115200n8

LABEL kubesolo-shell
    MENU LABEL KubeSolo OS (emergency shell)
    KERNEL /boot/vmlinuz
    INITRD /boot/kubesolo-os.gz
    APPEND kubesolo.shell console=ttyS0,115200n8

LABEL kubesolo-nopersist
    MENU LABEL KubeSolo OS (RAM only, no persistence)
    KERNEL /boot/vmlinuz
    INITRD /boot/kubesolo-os.gz
    APPEND kubesolo.nopersist
EOF

# --- Create ISO ---
mkdir -p "$OUTPUT_DIR"

case "$MKISO_CMD" in
    xorriso)
        xorriso -as mkisofs \
            -o "$ISO_OUTPUT" \
            -isohybrid-mbr /usr/lib/ISOLINUX/isohdpfx.bin 2>/dev/null || true \
            -c boot/isolinux/boot.cat \
            -b boot/isolinux/isolinux.bin \
            -no-emul-boot \
            -boot-load-size 4 \
            -boot-info-table \
            "$ISO_STAGING"
        ;;
    *)
        "$MKISO_CMD" \
            -o "$ISO_OUTPUT" \
            -b boot/isolinux/isolinux.bin \
            -c boot/isolinux/boot.cat \
            -no-emul-boot \
            -boot-load-size 4 \
            -boot-info-table \
            -J -R -V "KUBESOLOOS" \
            "$ISO_STAGING"
        ;;
esac

# Make ISO hybrid-bootable (USB stick)
if command -v isohybrid >/dev/null 2>&1; then
    isohybrid "$ISO_OUTPUT" 2>/dev/null || true
fi

# Clean staging
rm -rf "$ISO_STAGING"

echo ""
echo "==> ISO created: $ISO_OUTPUT"
echo "    Size: $(du -h "$ISO_OUTPUT" | cut -f1)"
echo ""
echo "    Boot in QEMU:  make dev-vm"
echo "    Write to USB:   dd if=$ISO_OUTPUT of=/dev/sdX bs=4M status=progress"