#!/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"
}

get_running_kernel_version () {
# Returns running kernel version

    # Get running kernel version
    local kernel_version=$(LANG=C pacman -Qi linux | sed -n 's/^Version\s*: //p')
    
    print "Current kernel version is $kernel_version"

    echo "$kernel_version"
}

get_iso_build_date () {
# Returns running kernel build date formated as 'YYYY/MM/DD'

    # Get running kernel build date
    local kernel_date=$(date +%Y/%m/%d -d "$(LANG=C pacman -Qi linux |sed -n 's/^Install Date\s*: //p')")

    echo "$kernel_date"
}

init_archzfs () {

    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 2>/dev/null
    pacman-key --lsign-key F75D9D76 2>/dev/null
}

init_archlinux_archive () {
# $1 is date formated as 'YYYY/MM/DD'
# Returns False if repo does not exists

    # Set repo
    repo="Server=https://archive.archlinux.org/repos/$1/\$repo/os/\$arch"

    # If repo exists, set it, if not, return False
    curl -s "$repo" && echo "$repo" > /etc/pacman.d/mirrorlist || return 1

    return 0

}

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

    # Set regex to match package
    local 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)
    # '"$2"'               # 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
    local 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
        local 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"
        fi
    done
}

download_package () {
# $1 is package url to download in tmp
# It returns downloaded file path

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

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

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

    print "Downloading $output ..."
}

### Main

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

# Init archzfs repository
init_archzfs

# Search kernel package
# https://github.com/archzfs/archzfs/issues/337#issuecomment-624312576
kernel_version=$(get_running_kernel_version)
kernel_version_fixed="${kernel_version//-/\.}"

# Search zfs-linux package matching running kernel version
search_package "zfs-linux" "$kernel_version_fixed"

# If a package is found
if [[ -n $package_url ]]
then

    # Download package
    download_package $package_url

    print "Extracting $zfs_linux_package"

    # Extract package
    tar xvf "$package_file" -C /tmp/extract

    print "Searching zfs-utils version required"

    # Get zfs-utils dependency version
    zfs_utils_version=$(grep 'depend = zfs-utils' /tmp/extract/.PKGINFO | grep -o '[[:digit:]].*')

    # Clean extracted dir
    rm -Rf /tmp/extract

    # Search zfs-utils package matching zfs-linux package dependency
    search_package "zfs-utils" "$zfs_utils_version"

    if [[ -n $package_url ]]
    then

        print "Installing zfs-utils"

        # Install packages
        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