#!/bin/bash
# This script load zfs kernel module for any archiso.
# github.com/eoli3n
# Thanks to CalimeroTeknik on #archlinux-fr, FFY00 on #archlinux-projects, JohnDoe2 on #regex

### Functions

print () {
    echo -e "\n\033[1m> $1\033[0m\n"
}

search_package () {
# $1 is package name to search
# $2 is version to match

    # Set regex to match package
    regex='href="\K'"$1"'-[0-9].*?'"$2"'.*?(?!.+\.sig)x86_64[^\"]+'
    # href="               # match href="
    # \K                   # don't return anything matched prior to this point
    # '"$1"'-[0-9]         # find me package-# escaped by shell
    # .*?                  # match anything but newlines 0 or more times, as few times as possible (non-greedy)
    # '"$kernel_version"'  # match version escaped by shell
    # .*?                  # match anything but newlines 0 or more times, as few times as possible (non-greedy)
    # (?![^"\n]+\.sig)     # remove .sig matches
    # x86_64               # now match architecture
    # [^\n"]+              # continue matching anything but newlines and ", 1 or more times, until end 
    
    # Set archzfs URLs list
    urls="http://archzfs.com/archzfs/x86_64/ http://archzfs.com/archive_archzfs/"
    
    # Loop search
    for url in $urls
    do
    
        print "Searching on $url..."
    
        # Query url and try to match package
        package=$(curl -s "$url" | grep -Po "$regex" | tail -n 1)
    
        # If a package is found
        if [[ ! -z $package ]]
        then
    
            print "$package found"
    
            # Build package url
            package_url="$url$package"

            return $package_url
        fi
    done
}


download_package () {
# $1 is package url to download in tmp

    filename="${url##*/}"

    # Download package in tmp
    wget "$1" -P /tmp

    # Set out file
    output="/tmp/$filename"

    print "Downloading $output ..."

    return "$output"
}

print "Testing if archiso is running"

grep archiso /proc/cmdline > /dev/null

print "Increasing cowspace to half of RAM"

mount -o remount,size=50% /run/archiso/cowspace

# Get running kernel version
# https://github.com/archzfs/archzfs/issues/337#issuecomment-624312576
kernel_version=$(pacman -Qi linux | sed -n 's/^Version\s*: //p')
kernel_version_fixed=$(sed 's/-/\./' <<< $kernel_version)

print "Adding archzfs repo"

cat >> /etc/pacman.conf <<"EOF"
[archzfs]
Server = http://archzfs.com/archzfs/x86_64
Server = http://mirror.sum7.eu/archlinux/archzfs/archzfs/x86_64
Server = https://mirror.biocrafting.net/archlinux/archzfs/archzfs/x86_64
EOF

print "Fetching archzfs signing keys"

pacman-key --recv-keys F75D9D76
pacman-key --lsign-key F75D9D76

print "Current kernel version is $kernel_version"

# Search kernel package

zfs_utils_package_url=$(search_package "zfs-linux" "$kernel_version_fixed")

# If a package is found
if [[ ! -z $zfs_utils_package_url ]]
then

    # Download package
    zfs_linux_package=$(download_package "zfs-linux" "$kernel_version_fixed")

    print "Extracting $zfs_linux_package"

    tar xvf $zfs_linux_package -C /tmp/extract

    print "Searching zfs-utils version required"

    zfs_utils_version=$(cat /tmp/extract/.PKGINFO | grep 'depend = zfs-utils' | grep -o '[[:digit:]].*')
    rm -Rf /tmp/extract

    zfs_utils_url=$(search_package "zfs-utils" "$zfs_utils_version")

    print "Installing zfs-utils"

    pacman -U $zfs_utils_url --noconfirm
    pacman -U $zfs_linux_package --noconfirm

    print "Loading zfs kernel module"

    # Load kernel module
    modprobe zfs && print "ZFS module is working"

else
    print "No module found for current kernel version on Archzfs repos"
fi