#!/usr/bin/env bash
#-------------------------------------------------------------------------------------------------------------
# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License. See https://go.microsoft.com/fwlink/?linkid=2090316 for license information.
#-------------------------------------------------------------------------------------------------------------
#
# Docs: https://github.com/microsoft/vscode-dev-containers/blob/main/script-library/docs/github.md
# Maintainer: The VS Code and Codespaces Teams

CLI_VERSION=${VERSION:-"latest"}
INSTALL_DIRECTLY_FROM_GITHUB_RELEASE=${INSTALLDIRECTLYFROMGITHUBRELEASE:-"true"}

GITHUB_CLI_ARCHIVE_GPG_KEY=23F3D4EA75716059
GPG_KEY_SERVERS="keyserver hkp://keyserver.ubuntu.com
keyserver hkp://keyserver.ubuntu.com:80
keyserver hkps://keys.openpgp.org
keyserver hkp://keyserver.pgp.com"

set -e

# Clean up
rm -rf /var/lib/apt/lists/*

if [ "$(id -u)" -ne 0 ]; then
    echo -e 'Script must be run as root. Use sudo, su, or add "USER root" to your Dockerfile before running this script.'
    exit 1
fi


# Import the specified key in a variable name passed in as 
receive_gpg_keys() {
    local keys=${!1}
    local keyring_args=""
    if [ ! -z "$2" ]; then
        keyring_args="--no-default-keyring --keyring $2"
    fi

    # Use a temporary location for gpg keys to avoid polluting image
    export GNUPGHOME="/tmp/tmp-gnupg"
    mkdir -p ${GNUPGHOME}
    chmod 700 ${GNUPGHOME}
    echo -e "disable-ipv6\n${GPG_KEY_SERVERS}" > ${GNUPGHOME}/dirmngr.conf
    # GPG key download sometimes fails for some reason and retrying fixes it.
    local retry_count=0
    local gpg_ok="false"
    set +e
    until [ "${gpg_ok}" = "true" ] || [ "${retry_count}" -eq "5" ]; 
    do
        echo "(*) Downloading GPG key..."
        ( echo "${keys}" | xargs -n 1 gpg -q ${keyring_args} --recv-keys) 2>&1 && gpg_ok="true"
        if [ "${gpg_ok}" != "true" ]; then
            echo "(*) Failed getting key, retring in 10s..."
            (( retry_count++ ))
            sleep 10s
        fi
    done
    set -e
    if [ "${gpg_ok}" = "false" ]; then
        echo "(!) Failed to get gpg key."
        exit 1
    fi
}

apt_get_update()
{
    if [ "$(find /var/lib/apt/lists/* | wc -l)" = "0" ]; then
        echo "Running apt-get update..."
        apt-get update -y
    fi
}

# Checks if packages are installed and installs them if not
check_packages() {
    if ! dpkg -s "$@" > /dev/null 2>&1; then
        apt_get_update
        apt-get -y install --no-install-recommends "$@"
    fi
}

# Figure out correct version of a three part version number is not passed
find_version_from_git_tags() {
    local variable_name=$1
    local requested_version=${!variable_name}
    if [ "${requested_version}" = "none" ]; then return; fi
    local repository=$2
    local prefix=${3:-"tags/v"}
    local separator=${4:-"."}
    local last_part_optional=${5:-"false"}    
    if [ "$(echo "${requested_version}" | grep -o "." | wc -l)" != "2" ]; then
        local escaped_separator=${separator//./\\.}
        local last_part
        if [ "${last_part_optional}" = "true" ]; then
            last_part="(${escaped_separator}[0-9]+)?"
        else
            last_part="${escaped_separator}[0-9]+"
        fi
        local regex="${prefix}\\K[0-9]+${escaped_separator}[0-9]+${last_part}$"
        local version_list="$(git ls-remote --tags ${repository} | grep -oP "${regex}" | tr -d ' ' | tr "${separator}" "." | sort -rV)"
        if [ "${requested_version}" = "latest" ] || [ "${requested_version}" = "current" ] || [ "${requested_version}" = "lts" ]; then
            declare -g ${variable_name}="$(echo "${version_list}" | head -n 1)"
        else
            set +e
            declare -g ${variable_name}="$(echo "${version_list}" | grep -E -m 1 "^${requested_version//./\\.}([\\.\\s]|$)")"
            set -e
        fi
    fi
    if [ -z "${!variable_name}" ] || ! echo "${version_list}" | grep "^${!variable_name//./\\.}$" > /dev/null 2>&1; then
        echo -e "Invalid ${variable_name} value: ${requested_version}\nValid values:\n${version_list}" >&2
        exit 1
    fi
    echo "${variable_name}=${!variable_name}"
}

# Use semver logic to decrement a version number then look for the closest match
find_prev_version_from_git_tags() {
    local variable_name=$1
    local current_version=${!variable_name}
    local repository=$2
    # Normally a "v" is used before the version number, but support alternate cases
    local prefix=${3:-"tags/v"}
    # Some repositories use "_" instead of "." for version number part separation, support that
    local separator=${4:-"."}
    # Some tools release versions that omit the last digit (e.g. go)
    local last_part_optional=${5:-"false"}
    # Some repositories may have tags that include a suffix (e.g. actions/node-versions)
    local version_suffix_regex=$6
    # Try one break fix version number less if we get a failure. Use "set +e" since "set -e" can cause failures in valid scenarios.
    set +e
        major="$(echo "${current_version}" | grep -oE '^[0-9]+' || echo '')"
        minor="$(echo "${current_version}" | grep -oP '^[0-9]+\.\K[0-9]+' || echo '')"
        breakfix="$(echo "${current_version}" | grep -oP '^[0-9]+\.[0-9]+\.\K[0-9]+' 2>/dev/null || echo '')"

        if [ "${minor}" = "0" ] && [ "${breakfix}" = "0" ]; then
            ((major=major-1))
            declare -g ${variable_name}="${major}"
            # Look for latest version from previous major release
            find_version_from_git_tags "${variable_name}" "${repository}" "${prefix}" "${separator}" "${last_part_optional}"
        # Handle situations like Go's odd version pattern where "0" releases omit the last part
        elif [ "${breakfix}" = "" ] || [ "${breakfix}" = "0" ]; then
            ((minor=minor-1))
            declare -g ${variable_name}="${major}.${minor}"
            # Look for latest version from previous minor release
            find_version_from_git_tags "${variable_name}" "${repository}" "${prefix}" "${separator}" "${last_part_optional}"
        else
            ((breakfix=breakfix-1))
            if [ "${breakfix}" = "0" ] && [ "${last_part_optional}" = "true" ]; then
                declare -g ${variable_name}="${major}.${minor}"
            else 
                declare -g ${variable_name}="${major}.${minor}.${breakfix}"
            fi
        fi
    set -e
}

# Fall back on direct download if no apt package exists
# Fetches .deb file to be installed with dpkg
install_deb_using_github() {
    check_packages wget
    arch=$(dpkg --print-architecture)

    find_version_from_git_tags CLI_VERSION https://github.com/cli/cli
    cli_filename="gh_${CLI_VERSION}_linux_${arch}.deb"

    mkdir -p /tmp/ghcli
    pushd /tmp/ghcli
    wget https://github.com/cli/cli/releases/download/v${CLI_VERSION}/${cli_filename}
    exit_code=$?
    set -e
    if [ "$exit_code" != "0" ]; then
        # Handle situation where git tags are ahead of what was is available to actually download
        echo "(!) github-cli version ${CLI_VERSION} failed to download. Attempting to fall back one version to retry..."
        find_prev_version_from_git_tags CLI_VERSION https://github.com/cli/cli
        wget https://github.com/cli/cli/releases/download/v${CLI_VERSION}/${cli_filename}
    fi

    dpkg -i /tmp/ghcli/${cli_filename}
    popd
    rm -rf /tmp/ghcli
}

export DEBIAN_FRONTEND=noninteractive

# Install curl, apt-transport-https, curl, gpg, or dirmngr, git if missing
check_packages curl ca-certificates apt-transport-https dirmngr gnupg2
if ! type git > /dev/null 2>&1; then
    check_packages git
fi

# Soft version matching
if [ "${CLI_VERSION}" != "latest" ] && [ "${CLI_VERSION}" != "lts" ] && [ "${CLI_VERSION}" != "stable" ]; then
    find_version_from_git_tags CLI_VERSION "https://github.com/cli/cli"
    version_suffix="=${CLI_VERSION}"
else
    version_suffix=""
fi

# Install the GitHub CLI
echo "Downloading github CLI..."

if [ "${INSTALL_DIRECTLY_FROM_GITHUB_RELEASE}" = "true" ]; then
    install_deb_using_github
else
   # Import key safely (new method rather than deprecated apt-key approach) and install
    . /etc/os-release
    receive_gpg_keys GITHUB_CLI_ARCHIVE_GPG_KEY /usr/share/keyrings/githubcli-archive-keyring.gpg
    echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/githubcli-archive-keyring.gpg] https://cli.github.com/packages stable main" > /etc/apt/sources.list.d/github-cli.list
    apt-get update
    apt-get -y install "gh${version_suffix}"
    rm -rf "/tmp/gh/gnupg"
    echo "Done!"
fi

# Clean up
rm -rf /var/lib/apt/lists/*