#!/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 [[ -n $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=$(pacman -Qi linux | sed -n 's/^Version\s*: //p')
kernel_version_fixed="${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 [[ -n $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=$(grep 'depend = zfs-utils' /tmp/extract/.PKGINFO | grep -o '[[:digit:]].*')

    rm -Rf /tmp/extract

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

    if [[ -n $zfs_utils_url ]]
    then

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