synth

#! /bin/sh


case "$1" in
    ( -h | --help )
        put "synth: Generate the ISO image described in the given file." \
            "" \
            "Usage:" \
            "  synth opts  Where opts is any option." \
            "  synth args  Where args are the arguments." \
            "" \
            "Options:" \
            "  -h,--help   Show this help." \
            "" \
            "Arguments:" \
            "  file img    Given file as input, generate the ISO image img." \
            "              img is optional. If not passed, it will be named after file."
        exit;;
esac


#   Functions.

put () { printf "%b\n" "$@"; }
err () { put "synth: \e[31mError:\e[0m $*" >&2; exit 1; }

get_k () { put "$desc" | grep "$1" | cut -d " " -f 2-; }


setup_base () {
    sys_base=$(get_k BASE)

    case "$sys_base" in
        ( @URL:* )      tmp=$(mktemp)
                        wget -qO $tmp "${sys_base#@URL:}"
                        tar xf "$tmp" -C "$tmp_root";;

        ( @LOCAL:* )    tar xf "${sys_base#@LOCAL:}" -C "$tmp_root";;

        ( * )           pull "$tmp_root" "$sys_base";;
    esac

    test -x "${input%/*}/preinst" ||
        return

    cp "${input%/*}/preinst" "$tmp_root"
    runch "$tmp_root" "/preinst"
    rm -rf "$tmp_root/preinst"
}


install_pkgs () {
    pm=$(get_k PACKAGE_MANAGER)
    pkgs=$(get_k PACKAGES)

    case "$pm" in
        ( pacman )
            pm_u="$pm --noconfirm -Syu"
            pm_i="$pm --noconfirm -S";;

        ( apt )
            pm_u="$pm -y upgrade"
            pm_i="$pm -y install";;

        ( apk )
            pm_u="$pm update"
            pm_i="$pm add";;

        ( "" )
            put " :: Warning: No package manager specified."
            return;;

        ( * )  err "Unsupported package manager '$pm'. Aborting.";;
    esac

    runch $tmp_root $pm_u

    test "$pkgs" || {
        put " :: Warning: No additional packages were specified."
        return
    }

    runch "$tmp_root" $pm_i $pkgs

    test -x "${input%/*}/postinst" ||
        return

    runch \
        -m "${input%/*}/postinst:/postinst"  \
        -r "/postinst" \
        "$tmp_root" "/postinst"
}


setup_bootloader () {
    get_k BOOT_FILES | while read item; do
        src="$tmp_root/${item%=>*}"
        dst="$iso_dir/${item#*=>}"
        src_path="${src%/*}"
        dst_path="${dst%/*}"

        test -e "$src" ||
            err "'$src' does not exist."

        mkdir -p "$dst_path"
        cp -r "$src" "$dst"
    done
}


#   Start the build.

root_sfs=rootfs.sfs
tmp_root=$(mktemp -d $(pwd)/.tmp.XXXX)
iso_dir=$(mktemp -d $(pwd)/.tmp.XXXX)

input="${1:-synthfile}"
output="${2:-img.iso}"

test -f "$input" ||
    err "'$input' is not a file."


#   Remove waste after the build.

trap "rm -rf '$tmp_root' '$iso_dir'" EXIT HUP INT TERM


#   TODO FIXME
#   Stop doing parsing, use bcf instead.

desc=$(
    sed -E \
        -e ":x N" \
        -e "/,$/ b x" \
        -e "/[A-Z_][ \t]*$/ b x" \
        -e "s/,\n[ \t]*/ /g" \
        -e "s/([A-Z_]+)\n*[ \t]*/\1 /g" \
        -e "s/[ \t]*->[ \t]*/->/g" \
    "$input"
)

setup_base
install_pkgs
setup_bootloader


#   All done. Generate the artifacts.

mksquashfs "$tmp_root" \
           "$iso_dir/$root_sfs" \
           -b 1M \
           -comp xz \
           -no-progress


mkiso -u "$(get_k UPDATE_URL)" \
      -s "$(get_k HASH_URL)" \
      -r "$(get_k RELEASE)" \
      $(test $(get_k BIOS_BOOT) = on && put "-b") \
      $(test $(get_k UEFI_BOOT) = on && put "-e") \
      "$iso_dir" \
      "$output"


zsyncmake "$output" \
          -u "$(get_k UPDATE_URL)" \
          -o "$output.zsync"


sha256sum "$output" > "$output.sha256sum"

put "$output"*