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

# Version: 2019-06-24_4

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 pretty()
{
    local extract="${*}"
    if command -v json_pp > /dev/null; then
        echo "{${extract}}" | json_pp
    else
        echo "${extract}"
    fi
}

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

function main()
{
    local instance="${1}"
    # shellcheck disable=SC2155
    local nodeinfo=$(curl -s "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 -sIf -X POST "${misskeyinfo}" | grep -iq 'Content-Type: application/json'; then
        echo "Misskey API found."
        json=$(curl -s -X POST "${misskeyinfo}")

        # 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}"

        # NOTE: I'm not sure what the returned data means exactly and I couldn't find the API-documentation. So I commented it out for now.
        # # shellcheck disable=SC2155
        # local federation=$(curl -s -X POST "https://${instance}/api/federation/instances" | grep -Eo '"host":"[^"]+",' | sed 's/"host"://g')
        # # shellcheck disable=SC2046
        # [[ -n ${federation} ]] && echo -n "Federates with: " && pretty '"":['"${federation}"'""]'

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

        if [[ $(jq -r ".software.name" <<<"${json}") == "pleroma" ]]; then
            implementation="Pleroma"
        fi
        [[ -n "${implementation}" ]] && echo "${implementation} detected."

        echo -n "Description: "
        jq -r ".metadata.nodeDescription" <<<"${json}"

        echo "Admins: "
        # shellcheck disable=SC2046
        jq -r ".metadata.staffAccounts" <<<"${json}"

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

        echo "Federation restrictions: "
        # shellcheck disable=SC2046
        jq -r ".metadata.federation.mrf_simple" <<<"${json}"

        if [[ "${implementation}" == "Pleroma" ]]; then
            echo "Further info, maybe: https://${instance}/static/terms-of-service.html"
        fi
    elif curl -sIf "${mastoinfo}" | grep -iq 'Content-Type: application/json'; then
        echo "Mastodon API found."
        json=$(curl -s "${mastoinfo}")
        local implementation=""

        if grep -Eq '"is_(pro|verified)"' <<<"${json}"; then
            implementation="Gab"
        elif grep -Eq '"version":"[0-9]+\.[0-9]+\.[0-9]+"' <<<"${json}"; then
            implementation="Mastodon"
        fi
        [[ -n "${implementation}" ]] && echo "${implementation} detected."

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

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

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

main "${1}"