#!/bin/bash -e
# -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
# ex: ts=8 sw=4 sts=4 et filetype=sh

source /usr/share/makepkg/util/message.sh

# grabbed from mkinitcpio
kver() {
    # this is intentionally very loose. only ensure that we're
    # dealing with some sort of string that starts with something
    # resembling dotted decimal notation. remember that there's no
    # requirement for CONFIG_LOCALVERSION to be set.
    local kver re='^[[:digit:]]+(\.[[:digit:]]+)+'

    # scrape the version out of the kernel image. locate the offset
    # to the version string by reading 2 bytes out of image at at
    # address 0x20E. this leads us to a string of, at most, 128 bytes.
    # read the first word from this string as the kernel version.
    local offset=$(hexdump -s 526 -n 2 -e '"%0d"' "$1")
    [[ $offset = +([0-9]) ]] || return 1

    read kver _ < \
        <(dd if="$1" bs=1 count=127 skip=$(( offset + 0x200 )) 2>/dev/null)

    [[ $kver =~ $re ]] || return 1

    printf '%s' "$kver"
}

function do_uak() {
    msg "uak $*"
    /usr/bin/uak "$@" || return $?
}

ACTION="$1"

if [[ $ACTION == "install-preset" ]]; then
    kernel="$2"
    pkgbase="$3"
    kernel_version="$4"
    
    source "/etc/mkinitcpio.d/${pkgbase}.preset"
        
    for preset in "${PRESETS[@]}"; do
        preset_kernel_version=${kernel_version}-${preset}
        if [[ "$preset" == "default" ]]; then
            preset_kernel_version=${kernel_version}
        fi
        
        preset_initrd=${preset}_image
        
        if ! [[ -f ${!preset_initrd} ]]; then
            warning "No image file specified for preset $preset"
            continue
        fi

        do_uak install "$preset_kernel_version" "$kernel" $(echo /boot/*-ucode.img) "${!preset_initrd}" 
    done

    exit 0
elif [[ $ACTION == "remove-preset" ]]; then
    pkgbase="$2"
    kernel_version="$3"
    
    source "/etc/mkinitcpio.d/${pkgbase}.preset"
        
    for preset in "${PRESETS[@]}"; do
        preset_kernel_version=${kernel_version}-${preset}
        if [[ "$preset" == "default" ]]; then
            preset_kernel_version=${kernel_version}
        fi

        do_uak remove "$preset_kernel_version" || exit 1
    done

    exit 0
fi

ALL=0
KERNELS=()

if [[ $ACTION == "install-all" ]]; then
    ALL=1
    ACTION="install"
elif [[ $ACTION == "remove-all" ]]; then
    ALL=1
    ACTION="remove"
elif [[ $ACTION != "install" ]] && [[ $ACTION != "remove" ]]; then
    error "Unknown action: $ACTION"
    exit 1
else
    while read -r line; do
        kernel="/$line"

        if [[ $kernel != */vmlinuz ]]; then
            # triggers when it's a change to usr/lib/initcpio/*, usr/lib/systemd/boot/efi/linuxx64.efi.stub or boot/*-ucode.img
            if [[ $ACTION == "install" ]]; then
                ALL=1
            fi
            continue
        fi

        if ! read -r pkgbase > /dev/null 2>&1 < "${kernel%/vmlinuz}/pkgbase"; then
            # if the kernel has no pkgbase, we skip it
            continue
        fi

        KERNELS+=("$kernel")
    done
fi

if (( ALL )); then
    KERNELS=()

    for kernel in /usr/lib/modules/*/vmlinuz; do
        if ! read -r pkgbase > /dev/null 2>&1 < "${kernel%/vmlinuz}/pkgbase"; then
            # if the kernel has no pkgbase, we skip it
            continue
        fi
        KERNELS+=("$kernel")
    done
fi

for kernel in "${KERNELS[@]}"; do
    read -r pkgbase < "${kernel%/vmlinuz}/pkgbase";
        
    if ! [[ -f "/etc/mkinitcpio.d/${pkgbase}.preset" ]]; then
        error "Not found mkinitcpio preset for kernel $pkgbase (with image $kernel"
        exit 1
    fi
    
    kernel_version=$(kver "$kernel")
    
    if [[ $ACTION == "install" ]]; then
        "$0" install-preset "$kernel" "$pkgbase" "$kernel_version"
    else
        "$0" remove-preset "$pkgbase" "$kernel_version"
    fi
done