#!/usr/bin/env bash

set -euo pipefail

WORKDIR="$(pwd)/work"
ROOTFS="$WORKDIR/rootfs"
ISO="$WORKDIR/iso"

rm -rf "$WORKDIR"

mkdir -p "$ROOTFS"
mkdir -p "$ISO/live"
cleanup() {
    umount -R "$ROOTFS" 2>/dev/null || true

    umount -lf "$ROOTFS/dev/pts" 2>/dev/null || true
    umount -lf "$ROOTFS/dev/shm" 2>/dev/null || true
    umount -lf "$ROOTFS/dev" 2>/dev/null || true
    umount -lf "$ROOTFS/proc" 2>/dev/null || true
    umount -lf "$ROOTFS/sys" 2>/dev/null || true
}

trap cleanup EXIT
echo "=== Extracting RootFS ==="

tar --zstd -xf espos-openrc-rootfs.tar.zst -C "$ROOTFS"

echo "=== Mounting pseudo filesystems ==="

mount --bind /dev "$ROOTFS/dev"
mount --bind /proc "$ROOTFS/proc"
mount --bind /sys "$ROOTFS/sys"

cleanup() {
    umount -lf "$ROOTFS/dev" 2>/dev/null || true
    umount -lf "$ROOTFS/proc" 2>/dev/null || true
    umount -lf "$ROOTFS/sys" 2>/dev/null || true
}

trap cleanup EXIT

echo "=== Configuring Live User ==="

chroot "$ROOTFS" bash <<'EOF'

set -e

apt update

DEBIAN_FRONTEND=noninteractive apt install -y \
    sudo \
    live-boot \
    live-config

if ! id liveuser >/dev/null 2>&1; then
    useradd -m -s /bin/bash liveuser
fi

passwd -d liveuser

echo "liveuser ALL=(ALL) NOPASSWD:ALL" \
    > /etc/sudoers.d/liveuser

chmod 440 /etc/sudoers.d/liveuser

mkdir -p /etc/conf.d

cat >/etc/conf.d/agetty.tty1 <<CFG
agetty_options="--autologin liveuser --noclear"
CFG

EOF

echo "=== Copying Kernel ==="

KERNEL="$(ls "$ROOTFS"/boot/vmlinuz-* | head -n1)"
INITRD="$(ls "$ROOTFS"/boot/initrd.img-* | head -n1)"

cp "$KERNEL" "$ISO/live/vmlinuz"
cp "$INITRD" "$ISO/live/initrd"
echo "=== Unmounting file systems ==="
umount -R "$ROOTFS" 2>/dev/null || true

umount -lf "$ROOTFS/dev/pts" 2>/dev/null || true
umount -lf "$ROOTFS/dev/shm" 2>/dev/null || true
umount -lf "$ROOTFS/dev" 2>/dev/null || true
umount -lf "$ROOTFS/proc" 2>/dev/null || true
umount -lf "$ROOTFS/sys" 2>/dev/null || true

echo "=== Building SquashFS ==="

mksquashfs \
    "$ROOTFS" \
    "$ISO/live/filesystem.squashfs" \
    -comp zstd \
    -e boot

echo "=== Creating GRUB Layout ==="

mkdir -p "$ISO/boot/grub"

cat > "$ISO/boot/grub/grub.cfg" <<EOF
set timeout=5

menuentry "EspOS OpenRC Live" {
    linux /live/vmlinuz boot=live quiet
    initrd /live/initrd
}
EOF

echo "=== Creating ISO ==="

grub-mkrescue \
    -o EspOS-OpenRC-Live.iso \
    "$ISO"

echo "=== Done ==="

ls -lh EspOS-OpenRC-Live.iso