#!/bin/bash

set -eu

# Use this script to download the latest Prysm release binary.
# Usage: ./prysm.sh PROCESS [--download-only] FLAGS
#   PROCESS can be one of beacon-chain or validator.
#   FLAGS are the flags or arguments passed to the PROCESS.
#   If --download-only flag is passed, binaries are checked for updates,
#   downloaded if necessary, no process is started.
# Downloaded binaries are saved to ./dist.
# Use USE_PRYSM_VERSION to specify a specific release version.
#   Example: USE_PRYSM_VERSION=v0.3.3 ./prysm.sh beacon-chain
# Use USE_PRYSM_MODERN to specify a non-portable version of BLST
#   Example: USE_PRYSM_MODERN=true ./prysm.sh beacon-chain

readonly PRYLABS_SIGNING_KEY=0AE0051D647BA3C1A917AF4072E33E4DF1A5036E

function color() {
    # Usage: color "31;5" "string"
    # Some valid values for color:
    # - 5 blink, 1 strong, 4 underlined
    # - fg: 31 red,  32 green, 33 yellow, 34 blue, 35 purple, 36 cyan, 37 white
    # - bg: 40 black, 41 red, 44 blue, 45 purple
    printf '\033[%sm%s\033[0m\n' "$@"
}

# `readlink -f` that works on OSX too.
function get_realpath() {
    if [ "$(uname -s)" == "Darwin" ]; then
        local queue="$1"
        if [[ "${queue}" != /* ]]; then
            # Make sure we start with an absolute path.
            queue="${PWD}/${queue}"
        fi
        local current=""
        while [ -n "${queue}" ]; do
            # Removing a trailing /.
            queue="${queue#/}"
            # Pull the first path segment off of queue.
            local segment="${queue%%/*}"
            # If this is the last segment.
            if [[ "${queue}" != */* ]]; then
                segment="${queue}"
                queue=""
            else
                # Remove that first segment.
                queue="${queue#*/}"
            fi
            local link="${current}/${segment}"
            if [ -h "${link}" ]; then
                link="$(readlink "${link}")"
                queue="${link}/${queue}"
                if [[ "${link}" == /* ]]; then
                    current=""
                fi
            else
                current="${link}"
            fi
        done

        echo "${current}"
    else
        readlink -f "$1"
    fi
}

# Complain if no arguments were provided.
if [ "$#" -lt 1 ]; then
    color "31" "Usage: ./prysm.sh PROCESS FLAGS."
    color "31" "       ./prysm.sh PROCESS --download-only."
    color "31" "PROCESS can be beacon-chain, validator, or client-stats."
    exit 1
fi

readonly wrapper_dir="$(dirname "$(get_realpath "${BASH_SOURCE[0]}")")/dist"


arch=$(uname -m)
arch=${arch/x86_64/amd64}
arch=${arch/aarch64/arm64}

readonly os_arch_suffix="$(uname -s | tr '[:upper:]' '[:lower:]')-$arch"

system=""
case "$OSTYPE" in
darwin*) system="darwin" ;;
linux*) system="linux" ;;
msys*) system="windows" ;;
cygwin*) system="windows" ;;
*) exit 1 ;;
esac
readonly system

if [ "$system" == "windows" ]; then
    arch="amd64.exe"
elif [[ "$os_arch_suffix" == *"arm64"* ]]; then
    arch="arm64"
fi

if [[ "$arch" == "armv7l" ]]; then
    color "31" "32-bit ARM is not supported. Please install a 64-bit operating system."
    exit 1
fi

mkdir -p "$wrapper_dir"

function get_prysm_version() {
    if [[ -n ${USE_PRYSM_VERSION:-} ]]; then
        readonly reason="specified in \$USE_PRYSM_VERSION"
        readonly prysm_version="${USE_PRYSM_VERSION}"
    else
        # Find the latest Prysm version available for download.
        readonly reason="automatically selected latest available version"
        prysm_version=$(curl -f -s https://prysmaticlabs.com/releases/latest) || (color "31" "Starting prysm requires an internet connection. If you are being blocked by your antivirus, you can download the beacon chain and validator executables from our releases page on Github here https://github.com/prysmaticlabs/prysm/releases/" && exit 1)
        readonly prysm_version
    fi
}

function verify() {
    file=$1

    skip=${PRYSM_ALLOW_UNVERIFIED_BINARIES-0}
    if [[ $skip == 1 ]]; then
        return 0
    fi
    checkSum="shasum -a 256"
    hash shasum 2>/dev/null || {
        checkSum="sha256sum"
        hash sha256sum 2>/dev/null || {
            echo >&2 "SHA checksum utility not available. Either install one (shasum or sha256sum) or run with PRYSM_ALLOW_UNVERIFIED_BINARIES=1."
            exit 1
        }
    }
    hash gpg 2>/dev/null || {
        echo >&2 "gpg is not available. Either install it or run with PRYSM_ALLOW_UNVERIFIED_BINARIES=1."
        exit 1
    }

    color "37" "Verifying binary integrity."

    gpg --list-keys "$PRYLABS_SIGNING_KEY" >/dev/null 2>&1 || curl --silent https://prysmaticlabs.com/releases/pgp_keys.asc | gpg --import
    (
        cd "$wrapper_dir"
        $checkSum -c "${file}.sha256" || failed_verification
    )
    (
        cd "$wrapper_dir"
        gpg -u "$PRYLABS_SIGNING_KEY" --verify "${file}.sig" "$file" || failed_verification
    )

    color "32;1" "Verified ${file} has been signed by Prysmatic Labs."
}

function failed_verification() {
    MSG=$(
        cat <<-END
Failed to verify Prysm binary. Please erase downloads in the
dist directory and run this script again. Alternatively, you can use a
A prior version by specifying environment variable USE_PRYSM_VERSION
with the specific version, as desired. Example: USE_PRYSM_VERSION=v1.0.0-alpha.5
If you must wish to continue running an unverified binary, specific the
environment variable PRYSM_ALLOW_UNVERIFIED_BINARIES=1
END
    )
    color "31" "$MSG"
    exit 1
}

get_prysm_version

color "37" "Latest Prysm version is $prysm_version."

if [ "${USE_PRYSM_MODERN:=false}" = "true" ]; then
    BEACON_CHAIN_REAL="${wrapper_dir}/beacon-chain-${prysm_version}-modern-${system}-${arch}"
else
    BEACON_CHAIN_REAL="${wrapper_dir}/beacon-chain-${prysm_version}-${system}-${arch}"
fi
VALIDATOR_REAL="${wrapper_dir}/validator-${prysm_version}-${system}-${arch}"
CLIENT_STATS_REAL="${wrapper_dir}/client-stats-${prysm_version}-${system}-${arch}"

if [[ $1 == beacon-chain ]]; then
    if [[ ! -x $BEACON_CHAIN_REAL ]]; then
        color "34" "Downloading beacon chain@${prysm_version} to ${BEACON_CHAIN_REAL} (${reason})"
        if [ "${USE_PRYSM_MODERN}" = "true" ]; then
            file=beacon-chain-${prysm_version}-modern-${system}-${arch}
        else
            file=beacon-chain-${prysm_version}-${system}-${arch}
        fi
        res=$(curl -w '%{http_code}\n' -f -L "https://prysmaticlabs.com/releases/${file}"  -o "$BEACON_CHAIN_REAL" | ( grep 404 || true ) )
        if [[ $res == 404 ]];then
            echo "No prysm beacon chain found for ${prysm_version},(${file}) exit"
            exit 1
        fi
        curl --silent -L "https://prysmaticlabs.com/releases/${file}.sha256" -o "${wrapper_dir}/${file}.sha256"
        curl --silent -L "https://prysmaticlabs.com/releases/${file}.sig" -o "${wrapper_dir}/${file}.sig"
        chmod +x "$BEACON_CHAIN_REAL"
    else
        color "37" "Beacon chain is up to date."
    fi
fi

if [[ $1 == validator ]]; then
    if [[ ! -x $VALIDATOR_REAL ]]; then
        color "34" "Downloading validator@${prysm_version} to ${VALIDATOR_REAL} (${reason})"

        file=validator-${prysm_version}-${system}-${arch}
        res=$(curl -w '%{http_code}\n' -f -L "https://prysmaticlabs.com/releases/${file}" -o "$VALIDATOR_REAL" | ( grep 404 || true ) )
        if [[ $res == 404 ]];then
            echo "No prysm validator found for ${prysm_version}, (${file}) exit"
            exit 1
        fi
        curl --silent -L "https://prysmaticlabs.com/releases/${file}.sha256" -o "${wrapper_dir}/${file}.sha256"
        curl --silent -L "https://prysmaticlabs.com/releases/${file}.sig" -o "${wrapper_dir}/${file}.sig"
        chmod +x "$VALIDATOR_REAL"
    else
        color "37" "Validator is up to date."
    fi
fi

if [[ $1 == client-stats ]]; then
    if [[ ! -x $CLIENT_STATS_REAL ]]; then
        color "34" "Downloading client-stats@${prysm_version} to ${CLIENT_STATS_REAL} (${reason})"

        file=client-stats-${prysm_version}-${system}-${arch}
        res=$(curl -w '%{http_code}\n' -f -L "https://prysmaticlabs.com/releases/${file}" -o "$CLIENT_STATS_REAL" | ( grep 404 || true ) )
        if [[ $res == 404 ]];then
            echo "No prysm client stats found for ${prysm_version},(${file}) exit"
            exit 1
        fi
        curl --silent -L "https://prysmaticlabs.com/releases/${file}.sha256" -o "${wrapper_dir}/${file}.sha256"
        curl --silent -L "https://prysmaticlabs.com/releases/${file}.sig" -o "${wrapper_dir}/${file}.sig"
        chmod +x "$CLIENT_STATS_REAL"
    else
        color "37" "Client-stats is up to date."
    fi
fi

if [[ $1 == slasher ]]; then
    color "41" "The slasher binary is no longer available. Please use the --slasher flag with your beacon node. See: https://docs.prylabs.network/docs/prysm-usage/slasher/"
    exit 1
fi

case $1 in
beacon-chain)
    readonly process=$BEACON_CHAIN_REAL
    ;;

validator)
    readonly process=$VALIDATOR_REAL
    ;;

client-stats)
    readonly process=$CLIENT_STATS_REAL
    ;;

*)
    color "31" "Process '$1' is not found!"
    color "31" "Usage: ./prysm.sh PROCESS FLAGS."
    color "31" "       ./prysm.sh PROCESS --download-only."
    color "31" "PROCESS can be beacon-chain, validator, or client-stats."
    exit 1
    ;;
esac

verify "$process"

if [[ "$#" -gt 1 ]] && [[ $2 == --download-only ]]; then
    color "37" "Only download operation is requested, done."
    exit 0
fi

color "36" "Starting Prysm $1 ${*:2}"
exec -a "$0" "${process}" "${@:2}"