#!/bin/sh
# GNU Guix --- Functional package management for GNU
# Copyright © 2017 sharlatan <sharlatanus@gmail.com>
# Copyright © 2018 Ricardo Wurmus <rekado@elephly.net>
# Copyright © 2018 Efraim Flashner <efraim@flashner.co.il>
# Copyright © 2019, 2020 Tobias Geerinckx-Rice <me@tobias.gr>
# Copyright © 2020 David A. Redick <david.a.redick@gmail.com>
#
# This file is part of GNU Guix.
#
# GNU Guix is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or (at
# your option) any later version.
#
# GNU Guix is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

# We require Bash but for portability we'd rather not use /bin/bash or
# /usr/bin/env in the shebang, hence this hack.
if [ "x$BASH_VERSION" = "x" ]
then
    exec bash "$0" "$@"
fi

set -e

[ "$UID" -eq 0 ] || { echo "This script must be run as root."; exit 1; }

REQUIRE=(
    "dirname"
    "readlink"
    "wget"
    "gpg"
    "grep"
    "which"
    "sed"
    "sort"
    "getent"
    "mktemp"
    "rm"
    "chmod"
    "uname"
    "groupadd"
    "groupdel"
    "tail"
    "tr"
    "xz"
)

PAS=$'[ \033[32;1mPASS\033[0m ] '
ERR=$'[ \033[31;1mFAIL\033[0m ] '
WARN=$'[ \033[33;1mWARN\033[0m ] '
INF="[ INFO ] "

DEBUG=0
GNU_URL="https://ftp.gnu.org/gnu/guix/"
OPENPGP_SIGNING_KEY_ID="3CE464558A84FDC69DB40CFB090B11993D9AEBB5"

# This script needs to know where root's home directory is.  However, we
# cannot simply use the HOME environment variable, since there is no guarantee
# that it points to root's home directory.
ROOT_HOME="$(echo ~root)"

# ------------------------------------------------------------------------------
#+UTILITIES

_err()
{ # All errors go to stderr.
    printf "[%s]: %s\n" "$(date +%s.%3N)" "$1"
}

_msg()
{ # Default message to stdout.
    printf "[%s]: %s\n" "$(date +%s.%3N)" "$1"
}

_debug()
{
    if [ "${DEBUG}" = '1' ]; then
        printf "[%s]: %s\n" "$(date +%s.%3N)" "$1"
    fi
}


chk_require()
{ # Check that every required command is available.
    declare -a warn
    local c

    _debug "--- [ $FUNCNAME ] ---"

    for c in "$@"; do
        command -v "$c" &>/dev/null || warn+=("$c")
    done

    [ "${#warn}" -ne 0 ] &&
        { _err "${ERR}Missing commands: ${warn[*]}.";
          return 1; }
    
    _msg "${PAS}verification of required commands completed"
}

chk_gpg_keyring()
{ # Check whether the Guix release signing public key is present.
    _debug "--- [ $FUNCNAME ] ---"

    # Without --dry-run this command will create a ~/.gnupg owned by root on
    # systems where gpg has never been used, causing errors and confusion.
    gpg --dry-run --list-keys ${OPENPGP_SIGNING_KEY_ID} >/dev/null 2>&1 || (
        _err "${ERR}Missing OpenPGP public key.  Fetch it with this command:"
        echo "  wget https://sv.gnu.org/people/viewgpg.php?user_id=15145 -qO - | gpg --import -"
        exit 1
    )
}

chk_term()
{ # Check for ANSI terminal for color printing.
    local ansi_term

    if [ -t 2 ]; then
        if [ "${TERM+set}" = 'set' ]; then
            case "$TERM" in
                xterm*|rxvt*|urxvt*|linux*|vt*|eterm*|screen*)
                    ansi_term=true
                    ;;
                *)
                    ansi_term=false
                    ERR="[ FAIL ] "
                    PAS="[ PASS ] "
                    WAR="[ WARN ] "
                    ;;
            esac
        fi
    fi
}

chk_init_sys()
{ # Return init system type name.
    if [[ $(/sbin/init --version 2>/dev/null) =~ upstart ]]; then
        _msg "${INF}init system is: upstart"
        INIT_SYS="upstart"
        return 0
    elif [[ $(systemctl 2>/dev/null) =~ -\.mount ]]; then
        _msg "${INF}init system is: systemd"
        INIT_SYS="systemd"
        return 0
    elif [[ -f /etc/init.d/cron && ! -h /etc/init.d/cron ]]; then
        _msg "${INF}init system is: sysv-init"
        INIT_SYS="sysv-init"
        return 0
    else
        INIT_SYS="NA"
        _err "${ERR}Init system could not be detected."
    fi
}

chk_sys_arch()
{ # Check for operating system and architecture type.
    local os
    local arch

    os="$(uname -s)"
    arch="$(uname -m)"

    case "$arch" in
        i386 | i486 | i686 | i786 | x86)
            local arch=i686
            ;;
        x86_64 | x86-64 | x64 | amd64)
            local arch=x86_64
            ;;
        aarch64)
            local arch=aarch64
            ;;
	armv7l)
	    local arch=armhf
	    ;;
        *)
            _err "${ERR}Unsupported CPU type: ${arch}"
            exit 1
    esac

    case "$os" in
        Linux | linux)
            local os=linux
            ;;
        *)
            _err "${ERR}Your operation system (${os}) is not supported."
            exit 1
    esac

    ARCH_OS="${arch}-${os}"
}

# ------------------------------------------------------------------------------
#+MAIN

guix_get_bin_list()
{ # Scan GNU archive and save list of binaries
    local gnu_url="$1"
    local -a bin_ver_ls
    local latest_ver
    local default_ver

    _debug "--- [ $FUNCNAME ] ---"

    # Filter only version and architecture
    bin_ver_ls=("$(wget -qO- "$gnu_url" \
        | sed -n -e 's/.*guix-binary-\([0-9.]*\)\..*.tar.xz.*/\1/p' \
        | sort -Vu)")

    latest_ver="$(echo "$bin_ver_ls" \
                       | grep -oP "([0-9]{1,2}\.){2}[0-9]{1,2}" \
                       | tail -n1)"

    default_ver="guix-binary-${latest_ver}.${ARCH_OS}"

    if [[ "${#bin_ver_ls}" -ne "0" ]]; then
        _msg "${PAS}Release for your system: ${default_ver}"
    else
        _err "${ERR}Could not obtain list of Guix releases."
        exit 1
    fi

    # Use default to download according to the list and local ARCH_OS.
    BIN_VER="$default_ver"
}

guix_get_bin()
{ # Download and verify binary package.
    local url="$1"
    local bin_ver="$2"
    local dl_path="$3"

    _debug "--- [ $FUNCNAME ] ---"

    _msg "${INF}Downloading Guix release archive"

    wget --help | grep -q '\--show-progress' && \
        _PROGRESS_OPT="-q --show-progress" || _PROGRESS_OPT=""
    wget $_PROGRESS_OPT -P "$dl_path" "${url}/${bin_ver}.tar.xz" "${url}/${bin_ver}.tar.xz.sig"

    if [[ "$?" -eq 0 ]]; then
       _msg "${PAS}download completed."
    else
        _err "${ERR}could not download ${url}/${bin_ver}.tar.xz."
        exit 1
    fi

    pushd $dl_path >/dev/null
    gpg --verify "${bin_ver}.tar.xz.sig" >/dev/null 2>&1
    if [[ "$?" -eq 0 ]]; then
        _msg "${PAS}Signature is valid."
        popd >/dev/null
    else
        _err "${ERR}could not verify the signature."
        exit 1
    fi
}

sys_create_store()
{ # Unpack and install /gnu/store and /var/guix
    local pkg="$1"
    local tmp_path="$2"

    _debug "--- [ $FUNCNAME ] ---"

    cd "$tmp_path"
    tar --warning=no-timestamp \
        --extract \
        --file "$pkg" &&
    _msg "${PAS}unpacked archive"

    if [[ -e "/var/guix" || -e "/gnu" ]]; then
        _err "${ERR}A previous Guix installation was found.  Refusing to overwrite."
        exit 1
    else
        _msg "${INF}Installing /var/guix and /gnu..."
        mv "${tmp_path}/var/guix" /var/
        mv "${tmp_path}/gnu" /
    fi

    _msg "${INF}Linking the root user's profile"
    mkdir -p "${ROOT_HOME}/.config/guix"
    ln -sf /var/guix/profiles/per-user/root/current-guix \
       "${ROOT_HOME}/.config/guix/current"

    GUIX_PROFILE="${ROOT_HOME}/.config/guix/current"
    source "${GUIX_PROFILE}/etc/profile"
    _msg "${PAS}activated root profile at ${ROOT_HOME}/.config/guix/current"
}

sys_delete_store() {
    _msg "${INF}removing /var/guix"
    rm -rf /var/guix

    _msg "${INF}removing /gnu"
    rm -rf /gnu

    _msg "${INF}removing ${ROOT_HOME}/.config/guix"
    rm -rf ${ROOT_HOME}/.config/guix
}

sys_create_build_user()
{ # Create the group and user accounts for build users.

    _debug "--- [ $FUNCNAME ] ---"

    if [ $(getent group guixbuild) ]; then
        _msg "${INF}group guixbuild exists"
    else
        groupadd --system guixbuild
        _msg "${PAS}group <guixbuild> created"
    fi

    for i in $(seq -w 1 10); do
        if id "guixbuilder${i}" &>/dev/null; then
            _msg "${INF}user is already in the system, reset"
            usermod -g guixbuild -G guixbuild           \
                    -d /var/empty -s "$(which nologin)" \
                    -c "Guix build user $i"             \
                    "guixbuilder${i}";
        else
            useradd -g guixbuild -G guixbuild           \
                    -d /var/empty -s "$(which nologin)" \
                    -c "Guix build user $i" --system    \
                    "guixbuilder${i}";
            _msg "${PAS}user added <guixbuilder${i}>"
        fi
    done
}

sys_delete_build_user() {
    for i in $(seq -w 1 10); do
        userdel -f guixbuilder${i}
    done

    _msg "${INF}delete group guixbuild"
    groupdel -f guixbuild
}

sys_enable_guix_daemon()
{ # Run the daemon, and set it to automatically start on boot.

    local info_path
    local local_bin
    local var_guix

    _debug "--- [ $FUNCNAME ] ---"

    info_path="/usr/local/share/info"
    local_bin="/usr/local/bin"
    var_guix="/var/guix/profiles/per-user/root/current-guix"

    case "$INIT_SYS" in
        upstart)
            { initctl reload-configuration;
              cp "${ROOT_HOME}/.config/guix/current/lib/upstart/system/guix-daemon.conf" \
                 /etc/init/ &&
                  start guix-daemon; } &&
                _msg "${PAS}enabled Guix daemon via upstart"
            ;;
        systemd)
            { # systemd .mount units must be named after the target directory.
              # Here we assume a hard-coded name of /gnu/store.
              # XXX Work around <https://issues.guix.gnu.org/41356> until next release.
              if [ -f "${ROOT_HOME}/.config/guix/current/lib/systemd/system/gnu-store.mount" ]; then
                  cp "${ROOT_HOME}/.config/guix/current/lib/systemd/system/gnu-store.mount" \
                     /etc/systemd/system/;
                  chmod 664 /etc/systemd/system/gnu-store.mount;
                  systemctl daemon-reload &&
                      systemctl enable gnu-store.mount;
              fi

              cp "${ROOT_HOME}/.config/guix/current/lib/systemd/system/guix-daemon.service" \
                 /etc/systemd/system/;
              chmod 664 /etc/systemd/system/guix-daemon.service;

	      # Work around <https://bugs.gnu.org/36074>, present in 1.0.1.
	      sed -i /etc/systemd/system/guix-daemon.service \
	          -e "s/GUIX_LOCPATH='/'GUIX_LOCPATH=/";

	      # Work around <https://bugs.gnu.org/35671>, present in 1.0.1.
	      if ! grep en_US /etc/systemd/system/guix-daemon.service >/dev/null;
	      then sed -i /etc/systemd/system/guix-daemon.service \
		       -e 's/^Environment=\(.*\)$/Environment=\1 LC_ALL=en_US.UTF-8';
	      fi;

              systemctl daemon-reload &&
                  systemctl enable guix-daemon &&
                  systemctl start  guix-daemon; } &&
                _msg "${PAS}enabled Guix daemon via systemd"
            ;;
        sysv-init)
            { mkdir -p /etc/init.d;
              cp "${ROOT_HOME}/.config/guix/current/etc/init.d/guix-daemon" \
                 /etc/init.d/guix-daemon;
              chmod 775 /etc/init.d/guix-daemon;

              update-rc.d guix-daemon defaults &&
                  update-rc.d guix-daemon enable &&
                  service guix-daemon start; } &&
                _msg "${PAS}enabled Guix daemon via sysv"
            ;;
        NA|*)
            _msg "${ERR}unsupported init system; run the daemon manually:"
            echo "  ${ROOT_HOME}/.config/guix/current/bin/guix-daemon --build-users-group=guixbuild"
            ;;
    esac

    _msg "${INF}making the guix command available to other users"

    [ -e "$local_bin" ] || mkdir -p "$local_bin"
    ln -sf "${var_guix}/bin/guix"  "$local_bin"

    [ -e "$info_path" ] || mkdir -p "$info_path"
    for i in ${var_guix}/share/info/*; do
        ln -sf "$i" "$info_path"
    done
}

sys_delete_guix_daemon()
{ # Disabled, stop and remove the various guix daemons.

    local info_path
    local local_bin
    local var_guix

    _debug "--- [ $FUNCNAME ] ---"

    info_path="/usr/local/share/info"
    local_bin="/usr/local/bin"


    case "$INIT_SYS" in
        upstart)
            _msg "${INF}stopping guix-daemon"
            stop guix-daemon
            _msg "${INF}removing guix-daemon"
            rm /etc/init/guix-daemon.conf
            ;;

        systemd)
            _msg "${INF}disabling guix-daemon"
            systemctl disable guix-daemon
            _msg "${INF}stopping guix-daemon"
            systemctl stop guix-daemon
            _msg "${INF}removing guix-daemon"
            rm -f /etc/systemd/system/guix-daemon.service

            if [ -x /etc/systemd/system/gnu-store.mount ]; then
                _msg "${INF}disabling gnu-store.mount"
                systemctl disable gnu-store.mount
                _msg "${INF}stopping gnu-store.mount"
                systemctl stop gnu-store.mount
                _msg "${INF}removing gnu-store.mount"
                rm -f /etc/systemd/system/gnu-store.mount
            fi
            systemctl daemon-reload
            ;;

        sysv-init)
            update-rc.d guix-daemon disable
            service guix-daemon stop
            rm -rf /etc/init.d/guix-daemon
            ;;
        NA|*)
            _msg "${ERR}unsupported init system; disable, stop and remove the daemon manually:"
            echo "  ${ROOT_HOME}/.config/guix/current/bin/guix-daemon --build-users-group=guixbuild"
            ;;
    esac


    _msg "${INF}removing $local_bin/guix"
    rm -f "$local_bin"/guix

    _msg "${INF}removing $info_path/guix*"
    rm -f "$info_path"/guix*
}

sys_authorize_build_farms()
{ # authorize the public key of the build farm
    while true; do
        read -p "Permit downloading pre-built package binaries from the project's build farm? (yes/no) " yn
        case $yn in
            [Yy]*) guix archive --authorize < "${ROOT_HOME}/.config/guix/current/share/guix/ci.guix.gnu.org.pub" &&
                       _msg "${PAS}Authorized public key for ci.guix.gnu.org";
                   break;;
            [Nn]*) _msg "${INF}Skipped authorizing build farm public keys"
                   break;;
            *) _msg "Please answer yes or no.";
        esac
    done
}

sys_create_init_profile()
{ # Create /etc/profile.d/guix.sh for better desktop integration
    [ -d "/etc/profile.d" ] || mkdir /etc/profile.d # Just in case
    cat <<"EOF" > /etc/profile.d/guix.sh
# _GUIX_PROFILE: `guix pull` profile
_GUIX_PROFILE="$HOME/.config/guix/current"
if [ -L $_GUIX_PROFILE ]; then
  export PATH="$_GUIX_PROFILE/bin${PATH:+:}$PATH"
  # Export INFOPATH so that the updated info pages can be found
  # and read by both /usr/bin/info and/or $GUIX_PROFILE/bin/info
  # When INFOPATH is unset, add a trailing colon so that Emacs
  # searches 'Info-default-directory-list'.
  export INFOPATH="$_GUIX_PROFILE/share/info:$INFOPATH"
fi

# GUIX_PROFILE: User's default profile
GUIX_PROFILE="$HOME/.guix-profile"
[ -L $GUIX_PROFILE ] || return
GUIX_LOCPATH="$GUIX_PROFILE/lib/locale"
export GUIX_PROFILE GUIX_LOCPATH

[ -f "$GUIX_PROFILE/etc/profile" ] && . "$GUIX_PROFILE/etc/profile"

# set XDG_DATA_DIRS to include Guix installations
export XDG_DATA_DIRS="$GUIX_PROFILE/share:${XDG_DATA_DIRS:-/usr/local/share/:/usr/share/}"
EOF
}

sys_delete_init_profile() {
    _msg "${INF}removing /etc/profile.d/guix.sh"
    rm -f /etc/profile.d/guix.sh
}

sys_delete_user_profiles() {
    _msg "${INF}removing ${ROOT_HOME}/.guix-profile"
    rm -f ${ROOT_HOME}/.guix-profile
    rm -rf ${ROOT_HOME}/.cache/guix

    _msg "${INF}removing .guix-profile, .cache/guix and .config/guix of all /home users"
    for user in `ls -1 /home`; do
        rm -f /home/$user/.guix-profile
        rm -rf /home/$user/.cache/guix
        rm -rf /home/$user/.config/guix
    done
}

welcome()
{
    local uninstall_flag=$1
    cat<<"EOF"
    ░░░                                     ░░░
    ░░▒▒░░░░░░░░░               ░░░░░░░░░▒▒░░
     ░░▒▒▒▒▒░░░░░░░           ░░░░░░░▒▒▒▒▒░
         ░▒▒▒░░▒▒▒▒▒         ░░░░░░░▒▒░
               ░▒▒▒▒░       ░░░░░░
                ▒▒▒▒▒      ░░░░░░
                 ▒▒▒▒▒     ░░░░░
                 ░▒▒▒▒▒   ░░░░░
                  ▒▒▒▒▒   ░░░░░
                   ▒▒▒▒▒ ░░░░░
                   ░▒▒▒▒▒░░░░░
                    ▒▒▒▒▒▒░░░
                     ▒▒▒▒▒▒░
     _____ _   _ _    _    _____       _
    / ____| \ | | |  | |  / ____|     (_)
   | |  __|  \| | |  | | | |  __ _   _ ___  __
   | | |_ | . ' | |  | | | | |_ | | | | \ \/ /
   | |__| | |\  | |__| | | |__| | |_| | |>  <
    \_____|_| \_|\____/   \_____|\__,_|_/_/\_\

https://www.gnu.org/software/guix/
EOF

    if [ '--uninstall' == $uninstall_flag ]; then
        echo "${WARN}This script will uninstall GNU Guix from your system"
        echo "To install, run this script with no parameters."
    else
        echo "This script installs GNU Guix on your system"
        echo "To uninstall, pass in the '--uninstall' parameter."
    fi

    echo -n "Press return to continue..."
    read -r  ANSWER
}

main_install() {
    local tmp_path
    welcome

    _msg "Starting installation ($(date))"

    chk_term
    chk_require "${REQUIRE[@]}"
    chk_gpg_keyring
    chk_init_sys
    chk_sys_arch

    _msg "${INF}system is ${ARCH_OS}"

    umask 0022
    tmp_path="$(mktemp -t -d guix.XXX)"

    guix_get_bin_list "${GNU_URL}"
    guix_get_bin "${GNU_URL}" "${BIN_VER}" "$tmp_path"

    sys_create_store "${BIN_VER}.tar.xz" "${tmp_path}"
    sys_create_build_user
    sys_enable_guix_daemon
    sys_authorize_build_farms
    sys_create_init_profile

    _msg "${INF}cleaning up ${tmp_path}"
    rm -r "${tmp_path}"

    _msg "${PAS}Guix has successfully been installed!"
    _msg "${INF}Run 'info guix' to read the manual."
}

main_uninstall() {
    welcome --uninstall
    _msg "Starting uninstall process ($(date))"

    chk_term
    chk_require "${REQUIRE[@]}"
    # it's ok to leave the gpg key
    chk_init_sys
    chk_sys_arch

    _msg "${INF}system is ${ARCH_OS}"

    # stop the build, package system.
    sys_delete_guix_daemon
    # stop people from accessing their profiles.
    sys_delete_user_profiles
    # kill guix off all the guts of guix
    sys_delete_store
    # clean up the system
    sys_delete_init_profile
    sys_delete_build_user

    # these directories are created on the fly during usage.
    _msg "${INF}removing /etc/guix"
    rm -rf /etc/guix
    _msg "${INF}removing /var/log/guix"
    rm -rf /var/log/guix

    _msg "${PAS}Guix has successfully been uninstalled!"
}

main()
{
    # expect no parameters
    # or '--uninstall'
    if [ 0 -eq $# ]; then
        main_install
    else
        local uninstall_flag="$1"
        if [ '--uninstall' = "${uninstall_flag}" ]; then
            main_uninstall
        else
            echo "unsupported parameters $@"
            exit 1
        fi
    fi
}

main "$@"
