#!/bin/bash

run_latehook() {
    echo

    touch /new_root/.custom_pkg_list

    # Remove /new_root/mnt/iso-update/.successful-update if exists
    rm -f /new_root/mnt/iso-update/.successful-update

    # Detect if update downloaded.
    if [[ -f /new_root/mnt/iso-update/.ready-for-update ]]; then
        # Available, rename old /usr and move new /usr to /.
        mv /new_root/usr /new_root/.old.usr
        mv /new_root/mnt/iso-update/squashfs-root/usr /new_root/usr

        # Copy package list
        mv /new_root/mnt/iso-update/squashfs-root/.custom_pkg_list /new_root

        # Update /usr/lib/modules for current kernel version.
        for kversion in /new_root/.old.usr/lib/modules/*; do
            if [[ ! -d /new_root/usr/lib/modules/"$(basename "$kversion")" ]]; then
                mv "$kversion" /new_root/usr/lib/modules/"$(basename "$kversion")"
            fi
        done
        
        # Same for /var/lib/pacman.
        mv /new_root/var/lib/pacman /new_root/.old.var.lib.pacman
        mv /new_root/mnt/iso-update/squashfs-root/var/lib/pacman /new_root/var/lib

        # Move to /etc stage.
        rm -f /new_root/mnt/iso-update/.ready-for-update
        touch /new_root/mnt/iso-update/.etc-stage
    fi
    
    # Detect if /etc stage is active.
    if [[ -f /new_root/mnt/iso-update/.etc-stage ]]; then
        # Rename existing /etc.
        mv /new_root/etc /new_root/.old.etc &>/dev/null || :
        
        # Create new /etc.
        cp -a /new_root/.old.etc /new_root/etc
        
        # Only copy non-existent files.
        cp -a -n /new_root/mnt/iso-update/squashfs-root/etc/* /new_root/etc
        
        # Update pacman config, and other system files that aren't
        # supposed to be edited.
        cp /new_root/mnt/iso-update/squashfs-root/etc/pacman.conf /new_root/etc
        rm -rf /new_root/etc/pacman.d
        cp -r /new_root/mnt/iso-update/squashfs-root/etc/pacman.d /new_root/etc
        cp /new_root/mnt/iso-update/squashfs-root/etc/blend_release /new_root/etc
        cp /new_root/mnt/iso-update/squashfs-root/etc/os-release /new_root/etc
        cp /new_root/mnt/iso-update/squashfs-root/etc/lsb-release /new_root/etc

        # Replace kernel and microcode images.
        mv /new_root/mnt/iso-update/iso/boot/initramfs-linux-zen.img /new_root/boot/initramfs-linux-zen.img

        if [[ -f /boot/amd-ucode.img ]]; then
            mv /new_root/mnt/iso-update/iso/boot/amd-ucode.img /new_root/boot/amd-ucode.img
        fi
        
        if [[ -f /boot/intel-ucode.img ]]; then
            mv /new_root/mnt/iso-update/iso/boot/intel-ucode.img /new_root/boot/intel-ucode.img
        fi

        for i in usr varlibpacman; do
            rm -f /new_root/.blend-overlays/future-$i/.okay
        done

        # Successful update.
        rm -f /new_root/mnt/iso-update/.etc-stage
        touch /new_root/mnt/iso-update/.successful-update
    fi
    
    # Handle overlays.

    if [[ ! -f /new_root/mnt/iso-update/.successful-update ]]; then
        if [[ -f '/new_root/.blend-overlays/future-usr/.okay' ]] && [[ -f '/new_root/.blend-overlays/future-varlibpacman/.okay' ]]; then
            for i in usr varlibpacman; do
                rm -rf /new_root/.blend-overlays/$i
                mv /new_root/.blend-overlays/future-$i /new_root/.blend-overlays/$i
            done
        else
            rm -rf /new_root/.blend-overlays/usr.workdir /new_root/.blend-overlays/varlibpacman.workdir
        fi
    else
        rm -rf /new_root/.blend-overlays
    fi

    for i in usr varlibpacman; do
        mkdir -p /new_root/.blend-overlays/$i
        mkdir -p /new_root/.blend-overlays/$i.workdir
    done
    
    mount -t overlay overlay -o index=off -o metacopy=off -o ro,lowerdir=/new_root/usr,upperdir=/new_root/.blend-overlays/usr,workdir=/new_root/.blend-overlays/usr.workdir /new_root/usr
    mount -t overlay overlay -o index=off -o metacopy=off -o ro,lowerdir=/new_root/var/lib/pacman,upperdir=/new_root/.blend-overlays/varlibpacman,workdir=/new_root/.blend-overlays/varlibpacman.workdir /new_root/var/lib/pacman
}