#!/bin/bash
#
# hyperbola-bootstrap: Bootstrap a base Hyperbola GNU+Linux-libre system using any GNU distribution.
#
# Dependencies: bash >= 4, coreutils, wget, sed, gawk, tar, gzip, chroot, xz, zstd.
# Project: https://git.sr.ht/~heckyel/hyperbola-bootstrap
#
# Usage:
#
#   # ./hyper-bootstrap.sh destination
#   # ./hyper-bootstrap.sh -a x86_64 -r https://repo.hyperbola.info:50011/gnu-plus-linux-libre/testing destination-64
#
# Example:
#
#   # ./hyper-bootstrap.sh -a x86_64 -r "https://mirror.fsf.org/hyperbola/gnu-plus-linux-libre/testing" myhyper
#   # ./hyper-bootstrap.sh myhyper
#
# And then you can chroot to the destination directory (user: root, password: root):
#
#   # chroot destination
#
# Note that some packages require some system directories to be mounted. Some of the commands you can try:
#
#   # mount --bind /proc myhyper/proc
#   # mount --bind /sys myhyper/sys
#   # mount --bind /dev myhyper/dev
#   # mount --bind /dev/pts myhyper/dev/pts
#

set -e -u -o pipefail

# Packages needed by pacman (see get-pacman-dependencies.sh)
PACMAN_PACKAGES=(
    bash acl hyperbola-keyring attr bzip2 curl expat glibc gpgme libarchive lzip grep sed coreutils
    libassuan libgpg-error libnghttp2 libssh2 lzo libressl pacman pacman-mirrorlist xz zlib libffi
    krb5 e2fsprogs keyutils libidn2 gcc-libs lz4 libpsl icu zstd readline libunistring findutils
    ncurses pinentry-curses lsb-release ca-certificates ca-certificates-utils p11-kit libtasn1
    libcap shadow pcre gzip gettext-tiny
)
BASIC_PACKAGES=(${PACMAN_PACKAGES[*]} filesystem)
EXTRA_PACKAGES=(gawk file tar hyperrc)
DEFAULT_REPO_URL="https://mirror.fsf.org/hyperbola/gnu-plus-linux-libre/testing"

stderr() {
    echo "$@" >&2
}

debug() {
    echo -e "\e[1;32m==>\e[0m\033[1m $* \e[m"
}

extract_href() {
    sed -n '/<a / s/^.*<a [^>]*href="\([^\"]*\)".*$/\1/p'
}

fetch() {
    curl -L -s "$@"
}

fetch_file() {
    local FILEPATH=$1
    shift
    if [[ -e "$FILEPATH" ]]; then
        curl -L -z "$FILEPATH" -o "$FILEPATH" "$@"
    else
        curl -L -o "$FILEPATH" "$@"
    fi
}

uncompress() {
    local FILEPATH=$1 DEST=$2

    case "$FILEPATH" in
        *.gz)
            tar xzf "$FILEPATH" -C "$DEST";;
        *.xz)
            xz -dc "$FILEPATH" | tar x -C "$DEST";;
        *.lz)
            tar xf "$FILEPATH" -C "$DEST";;
        *.zst)
            zstd -dc "$FILEPATH" | tar x -C "$DEST";;
        *)
            debug "Error: unknown package format: $FILEPATH"
            return 1;;
    esac
}

###

get_default_repo() {
    local ARCH=$1
    if [[ "$ARCH" == x86* || "$ARCH" == i686 ]]; then
        echo $DEFAULT_REPO_URL
    fi
}

get_core_repo_url() {
    local REPO_URL=$1 ARCH=$2
    if [[ "$ARCH" == x86* || "$ARCH" == i686 ]]; then
        echo "${REPO_URL%/}/core/os/$ARCH"
    fi
}

get_template_repo_url() {
    local REPO_URL=$1 ARCH=$2
    if [[ "$ARCH" == x86* || "$ARCH" == i686 ]]; then
        echo "${REPO_URL%/}/\$repo/os/$ARCH"
    fi
}

configure_pacman() {
    local DEST=$1 ARCH=$2
    debug "Configuring SERVER"
    SERVER=$(get_template_repo_url "$REPO_URL" "$ARCH")
    echo "Server = $SERVER" > "$DEST/etc/pacman.d/mirrorlist"
    debug "Configuring CERT"
    cp -fv certs/1.pem "$DEST/etc/ca-certificates/extracted/tls-ca-bundle.pem"
}

clean_chroot() {
    local DEST=$1
    debug "Clean Chroot"
    rm -rf "$DEST/.BUILDINFO" "$DEST/.INSTALL" "$DEST/.MTREE" "$DEST/.PKGINFO" || true
    for i in $DEST/usr/share/{doc,man,info}; do
        rm -rf "$i" && install -d "$i"
    done
    truncate -s 0 "$DEST/var/log/pacman.log"
}

configure_minimal_system() {
    local DEST=$1

    mkdir -p "$DEST/dev"
    sed -ie 's|^root:.*$|root:$1$GT9AUpJe$oXANVIjIzcnmOpY07iaGi/:14657::::::|' "$DEST/etc/shadow"
    touch "$DEST/etc/group"
    echo "nameserver 9.9.9.9" > "$DEST/etc/resolv.conf"
    echo "bootstrap" > "$DEST/etc/hostname"

    rm -f "$DEST/etc/mtab"
    echo "rootfs / rootfs rw 0 0" > "$DEST/etc/mtab"
    test -e "$DEST/dev/null" || mknod "$DEST/dev/null" c 1 3
    test -e "$DEST/dev/random" || mknod -m 0644 "$DEST/dev/random" c 1 8
    test -e "$DEST/dev/urandom" || mknod -m 0644 "$DEST/dev/urandom" c 1 9

    sed -i "s|^[[:space:]]*\(CheckSpace\)|# \1|" "$DEST/etc/pacman.conf"
    sed -i "s|^[[:space:]]*SigLevel[[:space:]]*=.*$|SigLevel = Never|" "$DEST/etc/pacman.conf"
}

configure_locale() {
    local DEST=$1
    sed -e 's/^#en_US.UTF-8 UTF-8/en_US.UTF-8 UTF-8/g' -i "$DEST/etc/locale.gen"
    echo LANG=en_US.UTF-8 > "$DEST/etc/locale.conf"
    LC_ALL=C chroot "$DEST" \
          locale-gen
}

fetch_packages_list() {
    local REPO=$1

    debug "Fetch packages list: $REPO/"
    fetch "$REPO/" | extract_href | awk -F"/" '{print $NF}' | sort -rn ||
        { debug "Error: cannot fetch packages list: $REPO"; return 1; }
}

install_pacman_packages() {
    local BASIC_PACKAGES=$1 DEST=$2 LIST=$3 DOWNLOAD_DIR=$4
    debug "pacman package and dependencies: $BASIC_PACKAGES"

    for PACKAGE in $BASIC_PACKAGES; do
        local FILE=$(echo "$LIST" | grep -m1 "^$PACKAGE-[[:digit:]].*\(\.gz\|\.xz\|\.lz\|\.zst\)$")
        test "$FILE" || { debug "Error: cannot find package: $PACKAGE"; return 1; }
        local FILEPATH="$DOWNLOAD_DIR/$FILE"

        debug "Download package: $REPO/$FILE"
        fetch_file "$FILEPATH" "$REPO/$FILE"
        debug "Uncompress package: $FILEPATH"
        uncompress "$FILEPATH" "$DEST"
    done
}

configure_static_qemu() {
    local ARCH=$1 DEST=$2
    [[ "$ARCH" == arm* ]] && ARCH=arm
    QEMU_STATIC_BIN=$(command -v qemu-$ARCH-static || echo )
    [[ -e "$QEMU_STATIC_BIN" ]] ||\
        { debug "No static qemu for $ARCH, ignoring"; return 0; }
    cp "$QEMU_STATIC_BIN" "$DEST/usr/bin"
}

install_packages() {
    local ARCH=$1 DEST=$2 PACKAGES=$3
    debug "Install packages: $PACKAGES"
    LC_ALL=C chroot "$DEST" \
          /usr/bin/pacman --noconfirm --noprogressbar --quiet --arch $ARCH -Syy --force $PACKAGES \
          && /usr/bin/pacman --noconfirm --noprogressbar --quiet -Scc
}

configure_keyring() {
    local DEST=$1
    sed -i 's|SigLevel = Never|SigLevel = Required DatabaseOptional|' "$DEST/etc/pacman.conf"
    LC_ALL=C chroot "$DEST" \
          /usr/bin/pacman-key --init && /usr/bin/pacman-key --populate hyperbola \
        && /usr/bin/pacman-key --keyserver pgp.rediris.es --refresh-keys
}

show_usage() {
    stderr "Usage: $(basename "$0") [-q] [-a i686|x86_64|arm] [-r REPO_URL] [-d DOWNLOAD_DIR] DESTDIR"
}

main() {
    # Process arguments and options
    test $# -eq 0 && set -- "-h"
    local ARCH=
    local REPO_URL=
    local USE_QEMU=
    local DOWNLOAD_DIR=
    local PRESERVE_DOWNLOAD_DIR=

    while getopts "qa:r:d:h" ARG; do
        case "$ARG" in
            a) ARCH=$OPTARG;;
            r) REPO_URL=$OPTARG;;
            q) USE_QEMU=true;;
            d) DOWNLOAD_DIR=$OPTARG
               PRESERVE_DOWNLOAD_DIR=true;;
            *) show_usage; return 1;;
        esac
    done
    shift $(($OPTIND-1))
    test $# -eq 1 || { show_usage; return 1; }

    [[ -z "$ARCH" ]] && ARCH=$(uname -m)
    [[ -z "$REPO_URL" ]] && REPO_URL=$(get_default_repo "$ARCH")

    local DEST=$1
    local REPO=$(get_core_repo_url "$REPO_URL" "$ARCH")
    [[ -z "$DOWNLOAD_DIR" ]] && DOWNLOAD_DIR=$(mktemp -d)
    mkdir -p "$DOWNLOAD_DIR"
    [[ -z "$PRESERVE_DOWNLOAD_DIR" ]] && trap "rm -rf '$DOWNLOAD_DIR'" TERM EXIT
    debug "Destination directory: $DEST"
    debug "Core repository: $REPO"
    debug "Temporary directory: $DOWNLOAD_DIR"

    # Fetch packages, install system and do a minimal configuration
    mkdir -p "$DEST"
    local LIST=$(fetch_packages_list $REPO)
    install_pacman_packages "${BASIC_PACKAGES[*]}" "$DEST" "$LIST" "$DOWNLOAD_DIR"
    configure_pacman "$DEST" "$ARCH"
    configure_minimal_system "$DEST"
    [[ -n "$USE_QEMU" ]] && configure_static_qemu "$ARCH" "$DEST"
    install_packages "$ARCH" "$DEST" "${BASIC_PACKAGES[*]} ${EXTRA_PACKAGES[*]}"
    configure_keyring "$DEST"
    configure_locale  "$DEST"
    clean_chroot "$DEST" # clean
    [[ -z "$PRESERVE_DOWNLOAD_DIR" ]] && rm -rf "$DOWNLOAD_DIR"

    debug "Done!"
    debug
    debug "You may now chroot or arch-chroot from package arch-install-scripts:"
    debug "$ doas arch-chroot $DEST"
}

main "$@"