#!/bin/sh
set -e # exit on failure
IFS=$(printf '\n\t') # smarter ifs

apprun() {
    export PATH="$APPDIR"/bin:"$PATH"
    export LD_LIBRARY_PATH="$APPDIR"/lib64:"$APPDIR"/lib:"$LD_LIBRARY_PATH"
    exec "$APPDIR/$(basename "$ARGV0")" "$@"
}

bundlehead() {
    MOUNTBIN=$(mktemp) # use provided offsets to supply dwarfs binary
    tail -n+"$OFF" "$0" | head -n"$LEN" | head -c-1 | zstd -cqd > "$MOUNTBIN"
    #shellcheck disable=SC2317
    dwarfs() { chmod +x "$MOUNTBIN"; "$MOUNTBIN" "$@"; rm "$MOUNTBIN"; }
}

header() {
    APPDIR=$(mktemp -d) APPIMAGE="$(realpath "$0")"
    export APPDIR APPIMAGE ARGV0="$0" OWD="$PWD"
    dwarfs -o offset=auto -o tidy_strategy=swap -o workers="$(nproc)" "$0" "$APPDIR"
    trap 'fusermount -quz $APPDIR; rmdir $APPDIR' 0 1 2 3 6 14 15 EXIT
    "$APPDIR/AppRun" "$@"
    exit $?
}

outfunc() {
    echo '#!/bin/sh'
    echo 'set -e' # running outfunc with no input just prints these two lines
    sed -n "/^$1() {$/,/^}$/s/^ *//p" "$0" | tail -n+2 | head -n-1
}

unappimage() {
    test "$(hexdump -n11 -e'"%x"' "$1")" = 464c457f1010224941 || return 1
    echo "AppImage found. Extracting..." # appimage magic matched
    o=$(($(readelf -h "$1" | sed -e 's/[^0-9]//g;13p;18,19p;d' | sed -e 1a+ -e 2a*)))
    unsquashfs -o "$o" "$@" # calculate offset via ELF header
}

zzexe() {
    [ "$1" = "-p" ] && p="$2" && shift # save prefix if present
    shift; out=$(mktemp) # make tmp file to avoid io operations
    { outfunc
        echo "OFF=$(($( (outfunc; outfunc zzexe_header) | wc -l)+2))"
        outfunc zzexe_header | sed -e "3s/)$/${1##*[./]})/" -e "8s/^/$p /"
        zstdmt -cq19 "$@"
    } > "$out"
    mv "$out" "$1"
    chmod +x "$1"
    exit
}

zzexe_header() {
    dir="$(dirname "$0")" out=$(mktemp -t .zzXXXX.)
    tail -n+"$OFF" "$0" | zstd -cd > "$out"
    chmod +x "$out"
    [ ! -f "$dir/$(basename "$out")" ] && ln -s "$out" "$dir"
    trap 'rm -f "$out" "$dir/$(basename "$out")"'  0 1 2 3 6 14 15 EXIT
    "$dir/$(basename "$out")" "$@"
    exit $?
}

case "$1" in
    -a )
        outfunc apprun > "$2"
        chmod +x "$2"
        exit ;;
    -b )
        outfunc apprun | sed '5s#/#/bin/#' > "$2"
        chmod +x "$2"
        exit ;;
    --bundle ) # allow bundling dwarfs binary
        BUNDLE=$(realpath "$2")
        shift 2;;
    -d | --decompress )
        d=dwarfs-root # just to keep line shorter, extract if file is dwarfs
        dwarfsck -d0 -i"$2" && mkdir $d && dwarfsextract -o $d -i "$2" && exit
        tmp=$(mktemp) # make tmp file to avoid io operations
        unappimage "$2" && exit # also extract appimages cuz we can
        tail -n+"$(sed -n '3s/^OFF=//p' "$2")" "$2" | zstd -cd > "$tmp"
        mv "$tmp" "$2"
        chmod +x "$2"
        exit ;;
    --fetch )
        FETCH=1
        shift ;;
    -p | -z | --prefix | --zzexe )
        zzexe "$@" ;;
    --version | -v )
        tput setaf 2; echo appdwarf 2023.02.04
        tput setaf 6; echo Built by July 🏳️‍🌈; exit ;;
    -* | '' )
        echo "Usage: appdwarf [option] [APP/FILE/FOLDER/URL] [compression options]"
        echo "  -a [FILE]                   write example AppRun file"
        echo "  -b [FILE]                   write bin subdir AppRun file"
        echo "  -d [--decompress] [FILE]    decompress a compressed program"
        echo
        echo "  --bundle [FILE]             bundle dwarfs with the appdwarf image"
        echo "  --fetch                     only fetch a remote AppImage"
        echo
        echo "  -p [--prefix] [PREFIX]      zzexe a file with prefix"
        echo "  -z [--zzexe]                zzexe a file"
        echo
        echo "  -h, --help                  Print this help text"
        echo "  -v, --version               Print the appdwarf version"; exit ;;
esac

if [ ! -d "$1" ]; then # directory doesn't exist, see if this is an appimage
    if [ ! -f "$1" ]; then # file doesn't exist, see if this is a url
        if ! echo "$1" | grep -q / ; then # AppImageHub
            echo "Checking AppImageHub for this program..."
            app=https://github.com/AppImage/appimage.github.io/raw/master/apps/$1.md
            shift
            set -- "$(curl -L "$app" | grep -o https.\*releases | sed 's|/releases$||')" "$@"
        elif ! echo "$1" | grep https ; then # GitHub in Author/Repo format
            app=$1
            shift
            set -- "https://github.com/$app" "$@"
        fi

        if echo "$1" | grep -q 'https://github.com/[^/]*/[^/]*/*$'; then # GitHub url
            echo "Assuming this is a GitHub repo..."
            app="$(echo "${1%/}"/releases | sed 's|github.com|api.github.com/repos|')"
            api="$(curl "$app" | jq -r .[].assets[].browser_download_url | grep 'AppImage$')"
            link="$(echo "$api" | grep "$(uname -m)" || echo "$api" | grep -vEe '-(aarch|arm)(64|hf)\.AppImage')"
            shift
            set -- "$(echo "$link" | head -n1)" "$@"
        fi

        app=$(basename "$1") # actually try to get the appimage
        if aria2c -x16 -s16 "$1" -o "$app" || wget "$1" -O "$app"; then
            shift
            set -- "$app" "$@"
            test "$FETCH" && chmod +x "$1" && exit
        else
            tput setaf 1; echo "No valid remote or local input found. Exiting..." >&2
            rm -f "$app"; exit 1
        fi
    fi

    # this is a file, but it might be an existing dwarfs image
    if dwarfsck -d0 -i"$1"; then
        set -- "$@" --recompress=none
    elif unappimage "$1"; then
        app="$(basename "$1" .AppImage)"
        rm -rf "$1" "$app"
        mv squashfs-root "$app"
        shift
        set -- "$app" "$@"
    else
        tput setaf 4; echo "$1 is not an AppImage, it will be zzexe'd"
        zzexe -z "$@"
    fi
fi

head="$(mktemp)"
if [ "$BUNDLE" ]; then { # behavior for bundling a dwarfs executable
    ZDATA="$(mktemp)"
    zstd -cq "$BUNDLE" > "$ZDATA"
    outfunc
    echo "OFF=$(($( (outfunc; outfunc bundlehead; outfunc header) | wc -l)+3))" 
    echo "LEN=$(($(wc -l < "$ZDATA")+1))"
    outfunc bundlehead
} > "$head"
fi
outfunc header >> "$head"
test "$BUNDLE" && cat "$ZDATA" >> "$head"
echo >> "$head"

mkdwarfs -o "$(realpath "$1").sh" -B5 --header "$head" -i "$@"
rm -rf "$head" "$1"
chmod +x "$(realpath "$1").sh"