#!/bin/sh
# shellcheck shell=dash

# This script is shamelessly adapted from the rustup project (https://github.com/rust-lang/rustup/blob/master/rustup-init.sh).
# The full license file with all attributions can be found at https://github.com/memflow/sh.memflow.io/blob/main/LICENSE

# This is just a little script that can be downloaded from the internet to
# install memflowup. It just does platform detection, downloads the installer
# and runs it.

# It runs on Unix shells like {a,ba,da,k,z}sh. It uses the common `local`
# extension. Note: Most shells limit `local` to 1 var per line, contra bash.

if [ "$KSH_VERSION" = 'Version JM 93t+ 2010-03-05' ]; then
    # The version of ksh93 that ships with many illumos systems does not
    # support the "local" extension.  Print a message rather than fail in
    # subtle ways later on:
    echo 'memflowup does not work with this ksh93 version; please try bash!' >&2
    exit 1
fi


set -u

main() {
    # check existence of basic utilities
    need_cmd sh
    need_cmd whoami
    need_cmd sudo
    need_cmd cp
    need_cmd chmod

    # The installer is going to want to ask for confirmation by
    # reading stdin.  This script was piped into `sh` though and
    # doesn't have stdin to pass to its children. Instead we're going
    # to explicitly connect /dev/tty to the installer's stdin.
    if [ ! -t 1 ]; then
        err "Unable to run interactively. Run with -y to accept defaults, --help for additional options"
    fi

    # check if user ran the script as root
    if [ "$(id -u)" -eq 0 ]; then
        warn "The installation script has been started as the root user ($(whoami)) or via sudo. By default rustup installs cargo in your home directory."
        warn "memflowup installation will only succeed if you also installed rust/cargo as $(whoami)."
        warn "memflowup will also only be available when logged in to $(whoami)."
        ask "Do you really want to continue the memflowup installation as root?"
    fi

    # just ensure to source cargo env
    . "$HOME/.cargo/env" > /dev/null 2>&1

    # check if cargo is properly setup
    if ! echo "$PATH" | grep '.cargo/bin'; then
        say "The .cargo/bin/ directory was not found in your path. Please make sure the \$PATH variable was updated properly after installing rust/cargo."
        err "If you did not install rust/cargo for the current user ($(whoami)) yet we recommend heading to https://rustup.rs/ and installing rust/cargo via rustup."
    fi

    # check compiler specific tools
    need_cmd rustc
    need_cmd cargo
    need_cmd cc
    need_cmd git

    if semver_lt "$(get_cargo_version)" "1.51.0"; then
        warn "The detected cargo version does not meet the minimum requirements to compile memflow."
        warn "memflow currently requires a minimum cargo of version of 1.51.0, however the detected version on your system is $(get_cargo_version)"
        ask "Do you really want to continue with a potentially incompatible rust version?"
    fi

    get_architecture || return 1
    local _arch="$RETVAL"
    assert_nz "$_arch" "arch"

    local _ext=""
    case "$_arch" in
        *windows*)
            _ext=".exe"
            ;;
    esac

    # Install memflowup via cargo
    cargo install memflowup --force

    # Display the memflowup help
    local _file="memflowup${_ext}"
    ignore "$_file" help "$@" < /dev/tty
}


check_proc() {
    # Check for /proc by looking for the /proc/self/exe link
    # This is only run on Linux
    if ! test -L /proc/self/exe ; then
        err "fatal: Unable to find /proc/self/exe.  Is /proc mounted?  Installation cannot proceed without /proc."
    fi
}

get_bitness() {
    need_cmd head
    # Architecture detection without dependencies beyond coreutils.
    # ELF files start out "\x7fELF", and the following byte is
    #   0x01 for 32-bit and
    #   0x02 for 64-bit.
    # The printf builtin on some shells like dash only supports octal
    # escape sequences, so we use those.
    local _current_exe_head
    _current_exe_head=$(head -c 5 /proc/self/exe )
    if [ "$_current_exe_head" = "$(printf '\177ELF\001')" ]; then
        echo 32
    elif [ "$_current_exe_head" = "$(printf '\177ELF\002')" ]; then
        echo 64
    else
        err "unknown platform bitness"
    fi
}

get_architecture() {
    local _ostype _cputype _bitness _arch _clibtype
    _ostype="$(uname -s)"
    _cputype="$(uname -m)"
    _clibtype="gnu"

    if [ "$_ostype" = Linux ]; then
        if [ "$(uname -o)" = Android ]; then
            _ostype=Android
        fi
        if ldd --version 2>&1 | grep -q 'musl'; then
            _clibtype="musl"
        fi
    fi

    if [ "$_ostype" = Darwin ] && [ "$_cputype" = i386 ]; then
        # Darwin `uname -m` lies
        if sysctl hw.optional.x86_64 | grep -q ': 1'; then
            _cputype=x86_64
        fi
    fi

    if [ "$_ostype" = SunOS ]; then
        # Both Solaris and illumos presently announce as "SunOS" in "uname -s"
        # so use "uname -o" to disambiguate.  We use the full path to the
        # system uname in case the user has coreutils uname first in PATH,
        # which has historically sometimes printed the wrong value here.
        if [ "$(/usr/bin/uname -o)" = illumos ]; then
            _ostype=illumos
        fi

        # illumos systems have multi-arch userlands, and "uname -m" reports the
        # machine hardware name; e.g., "i86pc" on both 32- and 64-bit x86
        # systems.  Check for the native (widest) instruction set on the
        # running kernel:
        if [ "$_cputype" = i86pc ]; then
            _cputype="$(isainfo -n)"
        fi
    fi

    case "$_ostype" in

        Android)
            _ostype=linux-android
            ;;

        Linux)
            check_proc
            _ostype=unknown-linux-$_clibtype
            _bitness=$(get_bitness)
            ;;

        FreeBSD)
            _ostype=unknown-freebsd
            ;;

        NetBSD)
            _ostype=unknown-netbsd
            ;;

        DragonFly)
            _ostype=unknown-dragonfly
            ;;

        Darwin)
            _ostype=apple-darwin
            ;;

        illumos)
            _ostype=unknown-illumos
            ;;

        MINGW* | MSYS* | CYGWIN*)
            _ostype=pc-windows-gnu
            ;;

        *)
            err "unrecognized OS type: $_ostype"
            ;;

    esac

    case "$_cputype" in

        i386 | i486 | i686 | i786 | x86)
            _cputype=i686
            ;;

        xscale | arm)
            _cputype=arm
            if [ "$_ostype" = "linux-android" ]; then
                _ostype=linux-androideabi
            fi
            ;;

        armv6l)
            _cputype=arm
            if [ "$_ostype" = "linux-android" ]; then
                _ostype=linux-androideabi
            else
                _ostype="${_ostype}eabihf"
            fi
            ;;

        armv7l | armv8l)
            _cputype=armv7
            if [ "$_ostype" = "linux-android" ]; then
                _ostype=linux-androideabi
            else
                _ostype="${_ostype}eabihf"
            fi
            ;;

        aarch64 | arm64)
            _cputype=aarch64
            ;;

        x86_64 | x86-64 | x64 | amd64)
            _cputype=x86_64
            ;;

        mips)
            _cputype=$(get_endianness mips '' el)
            ;;

        mips64)
            if [ "$_bitness" -eq 64 ]; then
                # only n64 ABI is supported for now
                _ostype="${_ostype}abi64"
                _cputype=$(get_endianness mips64 '' el)
            fi
            ;;

        ppc)
            _cputype=powerpc
            ;;

        ppc64)
            _cputype=powerpc64
            ;;

        ppc64le)
            _cputype=powerpc64le
            ;;

        s390x)
            _cputype=s390x
            ;;
        riscv64)
            _cputype=riscv64gc
            ;;
        *)
            err "unknown CPU type: $_cputype"

    esac

    # Detect 64-bit linux with 32-bit userland
    if [ "${_ostype}" = unknown-linux-gnu ] && [ "${_bitness}" -eq 32 ]; then
        case $_cputype in
            x86_64)
                if [ -n "${MEMFLOWUP_CPUTYPE:-}" ]; then
                    _cputype="$MEMFLOWUP_CPUTYPE"
                else {
                    # 32-bit executable for amd64 = x32
                    if is_host_amd64_elf; then {
                         echo "This host is running an x32 userland; as it stands, x32 support is poor," 1>&2
                         echo "and there isn't a native toolchain -- you will have to install" 1>&2
                         echo "multiarch compatibility with i686 and/or amd64, then select one" 1>&2
                         echo "by re-running this script with the MEMFLOWUP environment variable" 1>&2
                         echo "set to i686 or x86_64, respectively." 1>&2
                         echo 1>&2
                         echo "You will be able to add an x32 target after installation by running" 1>&2
                         echo "  memflowup target add x86_64-unknown-linux-gnux32" 1>&2
                         exit 1
                    }; else
                        _cputype=i686
                    fi
                }; fi
                ;;
            mips64)
                _cputype=$(get_endianness mips '' el)
                ;;
            powerpc64)
                _cputype=powerpc
                ;;
            aarch64)
                _cputype=armv7
                if [ "$_ostype" = "linux-android" ]; then
                    _ostype=linux-androideabi
                else
                    _ostype="${_ostype}eabihf"
                fi
                ;;
            riscv64gc)
                err "riscv64 with 32-bit userland unsupported"
                ;;
        esac
    fi

    # Detect armv7 but without the CPU features Rust needs in that build,
    # and fall back to arm.
    # See https://github.com/rust-lang/rustup.rs/issues/587.
    if [ "$_ostype" = "unknown-linux-gnueabihf" ] && [ "$_cputype" = armv7 ]; then
        if ensure grep '^Features' /proc/cpuinfo | grep -q -v neon; then
            # At least one processor does not have NEON.
            _cputype=arm
        fi
    fi

    _arch="${_cputype}-${_ostype}"

    RETVAL="$_arch"
}

say() {
    printf '%s\n' "$1"
}

err() {
    say "$1" >&2
    exit 1
}

warn() {
    say "$1" >&2
}

ask() {
    need_cmd read
    need_cmd grep
    need_cmd tr
    local _response
    read -r -p "$1 [y/N] " _response < /dev/tty
    _response=$(echo "$_response" | tr '[:upper:]' '[:lower:]')
    if ! echo "$_response" | grep -E "^(yes|y| )"; then
        err "user abort"
    fi
}

need_cmd() {
    if ! check_cmd "$1"; then
        err "need '$1' (command not found)"
    fi
}

check_cmd() {
    command -v "$1" > /dev/null 2>&1
}

assert_nz() {
    if [ -z "$1" ]; then err "assert_nz $2"; fi
}

# Run a command that should never fail. If the command fails execution
# will immediately terminate with an error showing the failing
# command.
ensure() {
    if ! "$@"; then err "command failed: $*"; fi
}

# This is just for indicating that commands' results are being
# intentionally ignored. Usually, because it's being executed
# as part of error handling.
ignore() {
    "$@"
}


# Returns the currently installed cargo version
get_cargo_version() {
    need_cmd cut
    cargo --version | cut -d' ' -f2
}

# The semantic versioning check has been vendored from Józef Sokołowski (https://github.com/qzb/sh-semver)
get_number() {
    echo "${1%%-*}"
}

# Gets prerelase part from normalized version
get_prerelease() {
    local pre_and_meta=${1%+*}
    local pre=${pre_and_meta#*-}
    if [ "$pre" = "$1" ]; then
        echo
    else
        echo "$pre"
    fi
}

semver_lt() {
    local number_a number_b prerelease_a prerelease_b
    number_a=$(get_number "$1")
    number_b=$(get_number "$2")
    prerelease_a=$(get_prerelease "$1")
    prerelease_b=$(get_prerelease "$2")

    local head_a=''
    local head_b=''
    local rest_a=$number_a.
    local rest_b=$number_b.
    while [ -n "$rest_a" ] || [ -n "$rest_b" ]; do
        head_a=${rest_a%%.*}
        head_b=${rest_b%%.*}
        rest_a=${rest_a#*.}
        rest_b=${rest_b#*.}

        if [ -z "$head_a" ] || [ -z "$head_b" ]; then
            return 1
        fi

        if [ "$head_a" -eq "$head_b" ]; then
            continue
        fi

        if [ "$head_a" -lt "$head_b" ]; then
            return 0
        else
            return 1
        fi
    done

    if [ -n "$prerelease_a" ] && [ -z "$prerelease_b" ]; then
        return 0
    elif [ -z "$prerelease_a" ] && [ -n "$prerelease_b" ]; then
        return 1
    fi

    local head_a=''
    local head_b=''
    local rest_a=$prerelease_a.
    local rest_b=$prerelease_b.
    while [ -n "$rest_a" ] || [ -n "$rest_b" ]; do
        head_a=${rest_a%%.*}
        head_b=${rest_b%%.*}
        rest_a=${rest_a#*.}
        rest_b=${rest_b#*.}

        if [ -z "$head_a" ] && [ -n "$head_b" ]; then
            return 0
        elif [ -n "$head_a" ] && [ -z "$head_b" ]; then
            return 1
        fi

        if [ "$head_a" = "$head_b" ]; then
            continue
        fi

        # If both are numbers then compare numerically
        if [ "$head_a" = "${head_a%[!0-9]*}" ] && [ "$head_b" = "${head_b%[!0-9]*}" ]; then
            [ "$head_a" -lt "$head_b" ] && return 0 || return 1
        # If only a is a number then return true (number has lower precedence than strings)
        elif [ "$head_a" = "${head_a%[!0-9]*}" ]; then
            return 0
        # If only b is a number then return false
        elif [ "$head_b" = "${head_b%[!0-9]*}" ]; then
            return 1
        # Finally if of identifiers is a number compare them lexically
        else
            test "$head_a" \< "$head_b" && return 0 || return 1
        fi
    done

    return 1
}


main "$@" || exit 1