#!/usr/bin/env bash

DIRNAME=$(dirname "$0")
BINDIR="${DIRNAME}/bin"

download_binary() {
    echo "downloading launcher..."
    package="${BINDIR}/launcher.tar.gz"
    package_md5="${BINDIR}/launcher.tar.gz.md5"

    arch=none
    case $(uname -m) in
        aarch64 | arm64)
            arch=arm64
            ;;
        x86_64)
            arch=amd64
            ;;
        *)
            echo "ERROR: unsupported arch detected."
            exit 1
            ;;
    esac

    os=none
    case $(uname -o) in
        Darwin)
            os=darwin
            ;;
        GNU/Linux)
            os=linux
            ;;
        *)
            echo "ERROR: unsupported os detected."
            exit 1
            ;;
    esac

    curl -s -o ${package} -L https://get.discourse.org/launcher/latest/launcher-${os}-${arch}.tar.gz
    curl -s -o ${package_md5} -L https://get.discourse.org/launcher/latest/launcher-${os}-${arch}.tar.gz.md5

    tar -zxf ${package} -C ${BINDIR}
    rm ${package} ${package_md5}
}

# From https://stackoverflow.com/a/44660519/702738
compare_version() {
    if [[ $1 == $2 ]]; then
        return 1
    fi
    local IFS=.
    local i a=(${1%%[^0-9.]*}) b=(${2%%[^0-9.]*})
    local arem=${1#${1%%[^0-9.]*}} brem=${2#${2%%[^0-9.]*}}
    for ((i=0; i<${#a[@]} || i<${#b[@]}; i++)); do
        if ((10#${a[i]:-0} < 10#${b[i]:-0})); then
            return 1
        elif ((10#${a[i]:-0} > 10#${b[i]:-0})); then
            return 0
        fi
    done
    if [ "$arem" '<' "$brem" ]; then
        return 1
    elif [ "$arem" '>' "$brem" ]; then
        return 0
    fi
    return 1
}

check_prereqs() {

    docker_path=`which docker.io 2> /dev/null || which docker`
    git_path=`which git`
    docker_min_version='20.10.0'
    docker_rec_version='24.0.7'
    git_min_version='1.8.0'
    git_rec_version='1.8.0'
    kernel_min_version='4.4.0'

    if [ -z $docker_path ]; then
        echo "Docker is not installed, you will need to install Docker in order to run Launcher"
        echo "See https://docs.docker.com/installation/"
        exit 1
    fi

    # 1. docker daemon running?
    # we send stderr to /dev/null cause we don't care about warnings,
    # it usually complains about swap which does not matter
    test=`$docker_path info 2> /dev/null`
    if [[ $? -ne 0 ]] ; then
        echo "Cannot connect to the docker daemon - verify it is running and you have access"
        exit 1
    fi

    # 2. running an approved storage driver?
    if ! $docker_path info 2> /dev/null | grep -E -q 'Storage Driver: (btrfs|aufs|zfs|overlay2|overlayfs)$'; then
        echo "Your Docker installation is not using a supported storage driver.  If we were to proceed you may have a broken install."
        echo "overlay2 is the recommended storage driver, although zfs and aufs may work as well."
        echo "Other storage drivers are known to be problematic."
        echo "You can tell what filesystem you are using by running \"docker info\" and looking at the 'Storage Driver' line."
        echo
        echo "If you wish to continue anyway using your existing unsupported storage driver,"
        echo "read the source code of launcher and figure out how to bypass this check."
        exit 1
    fi

    # 3. running recommended docker version
    test=($($docker_path --version))  # Get docker version string
    test=${test[2]//,/}  # Get version alone and strip comma if exists

    # At least minimum docker version
    if compare_version "${docker_min_version}" "${test}"; then
        echo "ERROR: Docker version ${test} not supported, please upgrade to at least ${docker_min_version}, or recommended ${docker_rec_version}"
        exit 1
    fi

    # Recommend newer docker version
    if compare_version "${docker_rec_version}" "${test}"; then
        echo "WARNING: Docker version ${test} deprecated, recommend upgrade to ${docker_rec_version} or newer."
    fi

    case $(uname -m) in
        armv7l)
            echo "ERROR: 32bit arm is not supported. Check if your hardware support arm64, which is supported in experimental capacity."
            exit 1
            ;;
        aarch64 | arm64)
            echo "WARNING: Support for aarch64 is experimental at the moment. Please report any problems at https://meta.discourse.org/tag/arm"
            ;;
        x86_64)
            echo "x86_64 arch detected."
            ;;
        *)
            echo "ERROR: unknown arch detected."
            exit 1
            ;;
    esac


    # 4. discourse docker image is downloaded
    test=`$docker_path images | awk '{print $1 ":" $2 }' | grep "$image"`

    # 5. running recommended git version
    test=($($git_path --version))  # Get git version string
    test=${test[2]//,/}  # Get version alone and strip comma if exists

    # At least minimum version
    if compare_version "${git_min_version}" "${test}"; then
        echo "ERROR: Git version ${test} not supported, please upgrade to at least ${git_min_version}, or recommended ${git_rec_version}"
        exit 1
    fi

    # Recommend best version
    if compare_version "${git_rec_version}" "${test}"; then
        echo "WARNING: Git version ${test} deprecated, recommend upgrade to ${git_rec_version} or newer."
    fi

    # Check minimum kernel version due to https://bugs.ruby-lang.org/issues/13885
    test=($(uname -r))

    # At least minimum version
    if compare_version "${kernel_min_version}" "${test}"; then
        echo "ERROR: Kernel version ${test} not supported, please upgrade to at least ${kernel_min_version}"
        exit 1
    fi

    # 6. able to attach stderr / out / tty
    test=`$docker_path run -i --rm -a stdout -a stderr hello-world`
    if [[ "$test" =~ "Hello from Docker" ]] ; then : ; else
        echo "Your Docker installation is not working correctly"
        echo
        echo "See: https://meta.discourse.org/t/docker-error-on-bootstrap/13657/18?u=sam"
        exit 1
    fi

    # 7. enough space for the bootstrap on docker folder
    folder=`$docker_path info --format '{{.DockerRootDir}}'`
    safe_folder=${folder:-/var/lib/docker}
    if [[ -d $safe_folder && $(stat -f --format="%a*%S" $safe_folder)/1024**3 -lt 5 ]] ; then
        echo "You have less than 5GB of free space on the disk where $safe_folder is located. You will need more space to continue"
        df -h $safe_folder
        echo
        if tty >/dev/null; then
            read -p "Would you like to attempt to recover space by cleaning docker images and containers in the system? (y/N)" -n 1 -r
            echo
            if [[ $REPLY =~ ^[Yy]$ ]]
            then
                $docker_path container prune --force --filter until=24h >/dev/null
                $docker_path image prune --all --force --filter until=24h >/dev/null
                echo "If the cleanup was successful, you may try again now"
            fi
        fi
        exit 1
    fi
}

autocompletion=false
if [[ $1 == "sh" ]] || [[ $1 == "install-completions" ]]; then
    autocompletion=true
fi
if [[ autocompletion == false ]]; then
    echo "run './launcher update' to update launcher"
fi
if [[ $1 == "update" ]]; then
    rm ${BINDIR}/launcher
    download_binary
    echo "Launcher updated"
    exit 0
fi
if [ ! -f "${BINDIR}/launcher" ]; then
    download_binary
    if [[ autocompletion == false ]]; then
        echo "Launcher downloaded"
    fi
fi
exec "${BINDIR}/launcher" "$@"