#!/bin/bash
# Print some basic info about fediverse instances.

# Version: 2019-07-16_2

if [[ -z "${1}" ]]; then
    echo "usage: ${0} DOMAIN" >&2
    exit 1
fi

if ! command -v jq > /dev/null; then
    echo "You need to install jq (https://stedolan.github.com/jq/)" >&2
    exit 2
fi

function striphtml()
{
    local extract="${*}"
    echo "${extract}" | sed 's/\\u003c/</g' | sed 's/\\u003e/>/g' | sed -E 's/<[^>]+>//g' | sed 's/\\r\\n/ /g' | sed -E 's/(^"|"$)//g'
}

function main()
{
    local instance="${1}"
    # shellcheck disable=SC2155
    local nodeinfo=$(curl -sL "https://${instance}/.well-known/nodeinfo" | jq -r '.links[-1].href' 2> /dev/null)
    local mastoinfo="https://${instance}/api/v1/instance"
    local misskeyinfo="https://${instance}/api/meta"

    if curl -sILf -X POST "${misskeyinfo}" | grep -iq 'Content-Type: application/json'; then
        echo "Misskey API found."
        json=$(curl -s -X POST "${misskeyinfo}")

        # shellcheck disable=SC2155
        local version=$(jq -r ".version" <<<"${json}")
        echo "Misskey ${version} detected."

        # shellcheck disable=SC2155
        local email=$(jq -r ".maintainerEmail" <<<"${json}")
        [[ -n "${email}" ]] && echo "E-Mail: ${email}"

        # shellcheck disable=SC2155
        local users=$(curl -s -X POST "https://${instance}/api/stats" | jq -r ".usersCount")
        [[ -n ${users} ]] && echo "Number of users: ${users}"

        echo -n "Open registrations: "
        jq -r ".features.registration" <<<"${json}"

        # shellcheck disable=SC2155
        local tos=$(jq -r ".ToSUrl" <<<"${json}")
        [[ -n "${tos}" ]] && echo "ToS: ${tos}"
    elif curl -sILf "${nodeinfo}" | grep -iq 'Content-Type: application/json'; then
        echo "Nodeinfo found."
        json=$(curl -s "${nodeinfo}")

        # shellcheck disable=SC2155
        local implementation=$(jq -r ".software.name" <<<"${json}")
        # shellcheck disable=SC2155
        local version=$(jq -r ".software.version" <<<"${json}")
        echo "${implementation} ${version} detected."

        # shellcheck disable=SC2155
        local description=$(jq -r ".metadata.nodeDescription" <<<"${json}")
        if [[ "${description}" == "null" ]]; then
            description=$(jq -r ".metadata.shortDescription" <<<"${json}")
        fi
        if [[ "${description}" == "null" ]]; then
            description=$(jq -r ".metadata.nodeName" <<<"${json}")
        fi
        [[ "${description}" != "null" ]] && echo "Description: ${description}"

        # shellcheck disable=SC2155
        local admins=$(jq -r ".metadata.staffAccounts" <<<"${json}")
        if [[ "${admins}" == "null" ]]; then
            admins=$(jq -r ".metadata.adminAccount" <<<"${json}")
        fi
        [[ "${admins}" != "null" ]] && echo "Admins: ${admins}"

        echo -n "Number of users: "
        jq -r ".usage.users.total" <<<"${json}"

        # shellcheck disable=SC2155
        local active=$(jq -r ".usage.users.activeMonth" <<<"${json}")
        [[ "${active}" != "null" ]] && echo "Active user (month): ${active}"

        echo -n "Open registrations: "
        jq -r ".openRegistrations" <<<"${json}"

        # shellcheck disable=SC2155
        local restrictions=$(jq -r ".metadata.federation.mrf_simple" <<<"${json}")
        [[ "${restrictions}" != "null" ]] && echo "Federation restrictions: ${restrictions}"

        if [[ "${implementation}" == "pleroma" ]]; then
            echo "Further info, maybe: https://${instance}/about"
        elif [[ "${implementation}" == "funkwhale" ]]; then
            echo -n "Artists / tracks: "
            jq -rj ".metadata.library.artists.total" <<<"${json}"
            echo -n " / "
            jq -r ".metadata.library.tracks.total" <<<"${json}"
        elif [[ "${implementation}" == "mastodon" ]]; then
            echo "Further info, maybe: https://${instance}/about/more"
        elif [[ "${implementation}" == "pixelfed" ]]; then
            echo "Further info, maybe: https://${instance}/site/terms"
        elif [[ "${implementation}" == "peertube" ]]; then
            echo "Further info, maybe: https://${instance}/about/instance"
        fi
    elif curl -sILf "${mastoinfo}" | grep -iq 'Content-Type: application/json'; then
        echo "Mastodon API found."
        json=$(curl -s "${mastoinfo}")
        local implementation=""

        if grep -Eq '"is_(pro|verified)"' <<<"${json}"; then
            implementation="Gab"
        elif grep -Eq '"version":"[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+\."' <<<"${json}"; then
            implementation="Florence"
        elif grep -Eq '"version":"[0-9]+\.[0-9]+\.[0-9]+"' <<<"${json}"; then
            implementation="Mastodon"
        elif grep -Eq '"version":"[0-9]+\.[0-9]+\.[0-9][\._\-]?[a-zA-Z]+"' <<<"${json}"; then
            implementation="Mastodon fork"
        fi
        if [[ -n "${implementation}" ]]; then
            # shellcheck disable=SC2155
            local version=$(jq -r ".version" <<<"${json}")
            echo "${implementation} ${version} detected."
        fi

        echo -n "Description: "
        # shellcheck disable=SC2046
        striphtml $(jq ".description" <<<"${json}")

        # shellcheck disable=SC2155
        local admin=$(jq -r ".contact_account.acct" <<<"${json}")
        [[ -n "${admin}" ]] && echo "Admin: https://${instance}/users/${admin}"

        # shellcheck disable=SC2155
        local email=$(jq -r ".email" <<<"${json}")
        [[ -n "${email}" ]] && echo "E-Mail: ${email}"

        echo -n "Number of users: "
        jq -r ".stats.user_count" <<<"${json}"

        echo -n "Open registrations: "
        jq -r ".registrations" <<<"${json}"

        if [[ "${implementation}" == "Mastodon"
                || "${implementation}" == "Mastodon fork"
                || "${implementation}" == "Florence" ]]; then
            echo "Further info, maybe: https://${instance}/about/more"
        elif [[ "${implementation}" == "Gab" ]]; then
            echo "Further info, maybe: https://${instance}/about"
        fi
    else
        echo "Could not detect type of server."
        curl -I "https://${instance}/"
    fi

    if curl -sILf "${instance}" | grep -q 'Server: cloudflare'; then
        echo "Uses CloudFlare."
    fi

    echo "See also: https://fediverse.network/${instance}"
}

main "${1}"