# ------------------------------------------------------------------------------
# Install check_mk agent using xinetd superserver
# This file is part of the init.sh project
# Copyright (c) 2019-2023 Geoffray Levasseur <fatalerrors@geoffray-levasseur.org>
# ------------------------------------------------------------------------------
# This file is distributed under 3-clause BSD license.
# The complete license agreement can be obtained at:
# https://opensource.org/licenses/BSD-3-Clause
# ------------------------------------------------------------------------------
# Variable:
#  * MK_SERVER: Server IP address
#  * MK_SITE: The check_mk site (or instance) to use
#  * MK_URL: The URL to use to download the agent
#  * MK_SECRET: The secret to use to register the agent
#  * MK_USER: The user to use to register
# ------------------------------------------------------------------------------

export VER_install_mkagent="0.1.0"
export DEP_install_mkagent=""


# ------------------------------------------------------------------------------
# Extract CheckMK version from the server
get_checkmk_version_from_server()
{
    local ip="$1"
    local site="${2:-$MK_SITE}"
    local proto out v header
    local re_version='[0-9]+\.[0-9]+(\.[0-9]+)?p?[0-9]+'

    [[ -n "$MK_VERSION" ]] && { printf '%s' "$MK_VERSION"; return 0; }

    for proto in http https; do
        # 1) Tentative via version.py (souvent non protégée)
        if out=$(curl -fsS --max-time 3 "$proto://$ip/$site/check_mk/version.py" 2>/dev/null); then
            v=$(grep -oE "$re_version" <<<"$out" | head -n1)
            [[ -n "$v" ]] && { printf '%s' "$v"; return 0; }
        fi

        # 2) Tentative via login.py (page de connexion)
        if out=$(curl -fsS --max-time 3 "$proto://$ip/$site/check_mk/login.py" 2>/dev/null); then
            v=$(grep -oE "$re_version" <<<"$out" | grep -vE '2\.[0-9]{1,3}\.[0-9]{2,3}' | head -n1)
            [[ -n "$v" ]] && { printf '%s' "$v"; return 0; }
        fi

        # 3) En-têtes HTTP éventuels
        header=$(curl -fsSI --max-time 3 "$proto://$ip/$site/" 2>/dev/null || true)
        if [[ -n "$header" ]]; then
            v=$(grep -oiE "$re_version" <<<"$header" | head -n1)
            [[ -n "$v" ]] && { printf '%s' "$v"; return 0; }
        fi

        # 4) Fallback : page d'accueil, mais filtrer les faux positifs du JS
        out=$(curl -fsS --max-time 5 "$proto://$ip/$site/" 2>/dev/null || true)
        if [[ -n "$out" ]]; then
            # Filtre plus strict : commence par 1.x ou 2.x et max 2 chiffres après le point
            v=$(grep -oE "$re_version" <<<"$out" \
                | grep -E '^2\.[0-9]+(\.[0-9]+)?p?[0-9]*$' \
                | grep -vE '\.[0-9]{3,}' \
                | head -n1)
            [[ -n "$v" ]] && { printf '%s-1' "$v"; return 0; }
        fi
    done

    return 1
}

install_mkagent()
{
    local debfile="/tmp/check-mk-agent_latest_all.deb"
    prnt I "Downloading CheckMK agent from: $MK_URL"

    # try primary URL
    if ! wget -q "$MK_URL" -O "$debfile"; then
        prnt W "Primary download failed. Attempting to detect server version and fallback..."
        local mkver
        mkver=$(get_checkmk_version_from_server "$MK_SERVER_IP" 2>/dev/null || true)

        if [[ -n "$mkver" ]]; then
            prnt I "Detected Check_MK version: $mkver — building fallback URL"
            # replace the literal 'latest' token in MK_URL with the detected version
            local fallback_url
            fallback_url="${MK_URL/latest/$mkver}"
            prnt I "Trying fallback URL: $fallback_url"
            if ! wget -q "$fallback_url" -O "$debfile"; then
                prnt E "Fallback download with version $mkver failed."
                die 163
            fi
        else
            prnt E "Unable to detect Check_MK version on $MK_SERVER_IP and primary download failed."
            die 163
        fi
    fi

    # On non-systemd systems, install xinetd before the .deb to avoid postinst failures
    if ! pidof systemd >/dev/null; then
        pkginst xinetd
    fi

    # Install agent package
    pkginst "$debfile"
    rm -f "$debfile"

    # Enable service depending on init system
    if pidof systemd >/dev/null; then
        systemctl enable --now check-mk-agent.socket
    else
        backup_dist /etc/xinetd.d/check-mk-agent
        install_file cmk/check_mk /etc/xinetd.d/check-mk-agent
        tag_file /etc/xinetd.d/check-mk-agent
        sed -i -e "s/@MK_SERVER_IP@/$MK_SERVER_IP/" /etc/xinetd.d/check-mk-agent
        svc_restart xinetd
    fi

    # Debian plugin
    if [[ $PKG_MAN == "apt-get" ]]; then
        mkdir -pv /usr/lib/check_mk_agent/plugins/3600
        install_file cmk/mk_apt /usr/lib/check_mk_agent/plugins/3600/mk_apt
    fi

    # Registration (if secret provided)
    if [[ -n $MK_SECRET ]]; then
        local secret
        prnt I "Fetching secret $MK_SECRET..."
        secret=$(fetch_secret "$MK_SECRET")
        if [[ -e /var/lib/cmk-agent/cmk-agent-ctl.gz ]]; then
            gunzip -v -f  /var/lib/cmk-agent/cmk-agent-ctl.gz
            chmod -v +x /var/lib/cmk-agent/cmk-agent-ctl
        fi
        if [[ -x /var/lib/cmk-agent/cmk-agent-ctl ]]; then
            /var/lib/cmk-agent/cmk-agent-ctl register \
                --hostname "$HOSTNAME" \
                --server "$MK_SERVER_IP" \
                --site "$MK_SITE" \
                --user "$MK_USER" \
                --password "$secret"
        else
            prnt W "Agent control tool not found; skipping registration."
        fi
        unset secret
    else
        prnt W "No secret configured, agent cannot be registered."
    fi
}

precheck_install_mkagent()
{
    if [[ -z $MK_SITE ]]; then
        prnt E "Undeclared check_mk site to use."
        die 162
    fi
    if [[ -z $MK_URL ]]; then
        prnt E "Undeclared check_mk download URL."
        die 162
    fi
    if [[ -z $MK_SERVER_IP ]]; then
        prnt E "Undeclared check_mk server."
        die 162
    fi
    if [[ $PKG_MAN == "apt-get" ]]; then
        file_must_exists cmk/check_mk cmk/mk_apt
    fi
    if [[ -z $MK_SECRET ]]; then
        prnt W "No secret set for CheckMK, registration won't be possible."
        if [[ -z $MK_USER ]]; then
            prnt E "A CheckMK user is required to register."
            die 162
        fi
    fi
}

export -f install_mkagent
export -f precheck_install_mkagent

# EOF