#!/bin/bash

if [ -z "${1}" ]; then
    echo "usage: ${0} DOMAIN" >&2
    exit 1
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="${1}"
    local nodeinfo="https://${instance}/nodeinfo/2.0.json"
    local mastoinfo="https://${instance}/api/v1/instance"

    if curl -sIf "${nodeinfo}" | grep -q '200 OK'; then
        echo "Nodeinfo found."
        json="$(curl -s ${nodeinfo})"
        local implementation=""

        if grep -q pleroma <<<"${json}"; then
            implementation="Pleroma"
        fi
        [[ -n "${implementation}" ]] && echo "${implementation} detected."

        echo -n "Description: "
        grep -Eo '"nodeDescription":"[^"]+"' <<<"${json}" | cut -d: -f2

        echo "Admins: "
        pretty $(grep -Eo '"staffAccounts":\[[^]]+\]' <<<"${json}")

        echo -n "Number of users: "
        grep -Eo '"total":[0-9]+' <<<"${json}" | cut -d: -f2

        echo "Blocked instances: "
        pretty $(grep -Eo '"reject":\[[^]]+\]' <<<"${json}" | head -n1)

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

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

        echo -n "Description: "
        striphtml $(grep -Eo '"description":"[^,]+",' <<<"${json}") | cut -d: -f2,3,4,5,6,7,8,9

        local admin=$(grep -Eo '"acct":"[^"]+"' <<<"${json}" | cut -d: -f2 | sed 's/"//g')"@${instance}"
        [[ -n "${admin}" ]] && echo "Admin: @${admin}"

        local email=$(grep -Eo '"email":"[^"]+"' <<<"${json}" | cut -d: -f2)
        [[ -n "${email}" ]] && echo "E-Mail: ${email}"

        echo -n "Number of users: "
        grep -Eo '"user_count":[0-9]+' <<<"${json}" | cut -d: -f2

        if [[ "${implementation}" == "Mastodon" ]]; then
            echo "Further info, maybe: https://${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}"