#!/bin/bash
#
# This can be called from a crontab entry to send notifications
# when Epicyon events occur. You will need to have
# sendxmpp+prosody or Synapse (matrix) installed.
#
# Something like:
#
# */1 * * * * root /usr/local/bin/epicyon-notification
#
# License
# =======
#
# Copyright (C) 2020-2021 Bob Mottram <bob@freedombone.net>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

PROJECT_NAME=epicyon
epicyonInstallDir=/opt/${PROJECT_NAME}

MY_EMAIL_ADDRESS="username@domain"

local_domain=$HOSTNAME
if [ -f /var/lib/tor/hidden_service_epicyon/hostname ]; then
    local_domain=$(cat /var/lib/tor/hidden_service_epicyon/hostname)
fi


function notification_translate_text {
    text="$1"
    if ! grep -q '"language":' "${epicyonInstallDir}/config.json"; then
        echo "$text"
        return
    fi
    language=$(cat "${epicyonInstallDir}/config.json" | awk -F '"language":' '{print $2}' | awk -F '"' '{print $2}')
    translationsFilename="${epicyonInstallDir}/translations/${language}.json"
    if [ ! -f "$translationsFilename" ]; then
        echo "$text"
        return
    fi
    if ! grep -q "\"$text\":" "$translationsFilename"; then
        echo "$text"
        return
    fi
    grep "\"$text\":" "$translationsFilename" | awk -F '"' '{print $4}'
}

function kill_sendxmpp_process {
    # Sometimes the process can get stuck, so ensure that
    # it gets killed if necessary
    # shellcheck disable=SC2009
    sendxmpp_pid=$(ps ax | grep /usr/bin/sendxmpp | grep -v grep | awk -F ' ' '{print $1}')
    if [ "$sendxmpp_pid" ]; then
        kill -9 "$sendxmpp_pid"
    fi
}

function matrix_server_message {
    admin_username="$1"
    notifications_username="$2"
    message="$3"

    MATRIX_DATA_DIR='/var/lib/matrix'
    homeserver_config="${MATRIX_DATA_DIR}/homeserver.yaml"

    # shellcheck disable=SC2002
    MATRIX_DOMAIN_NAME=$(cat "$homeserver_config" | grep "server_name:" | head -n 1 | awk -F '"' '{print $2}')
    if [ ! "$MATRIX_DOMAIN_NAME" ]; then
        return
    fi

    # get the curl command and domain to send to
    curl_command='curl'
    homebase="https://$MATRIX_DOMAIN_NAME"
    if [ -f /var/lib/tor/hidden_service_matrix/hostname ]; then
        curl_command='torsocks curl'
        homebase="http://$(cat /var/lib/tor/hidden_service_matrix/hostname)"
    fi

    # get the token for the matrix admin user
    MATRIXADMIN="@${admin_username}:$MATRIX_DOMAIN_NAME"
    MATRIXUSER="@${notifications_username}:$MATRIX_DOMAIN_NAME"
    cd "$MATRIX_DATA_DIR" || return
    TOKEN=$(sqlite3 homeserver.db "select token from access_tokens where user_id like '$MATRIXADMIN' order by id desc limit 1;")
    if [ ! "$TOKEN" ]; then
        admin_username="${notifications_username}"
        TOKEN=$(sqlite3 homeserver.db "select token from access_tokens where user_id like '$MATRIXUSER' order by id desc limit 1;")
        if [ ! "$TOKEN" ]; then
            echo "No matrix token for $MATRIXADMIN"
            return
        fi
    fi
    # send server notice
    MATRIXPOST="${homebase}/_synapse/admin/v1/send_server_notice?access_token=${TOKEN}"
    MATRIXMESSAGE="{\"user_id\": \"${MATRIXUSER}\",\"content\": { \"msgtype\": \"m.text\",\"body\": \"${message}\" }}"
    # shellcheck disable=SC2086
    ${curl_command} --request POST --silent --header "Content-Type: application/json" --data "${MATRIXMESSAGE}" ${MATRIXPOST} > /dev/null
}

function sendNotification {
    USERNAME="$1"
    SUBJECT="$2"
    MESSAGE="$3"

    hasSent=

    if [ -d /etc/prosody ]; then
        if [ -f /usr/bin/sendxmpp ]; then
            # generate a random password for a temporary user account
            notification_user_password=$(openssl rand -base64 32 | tr -dc A-Za-z0-9 | head -c 30 ; echo -n '')
            # register a temporary xmpp user account to send the message
            if prosodyctl register "notification" "$local_domain" "$notification_user_password"; then
                if [[ "$SUBJECT" == *' Tor '* ]]; then
                    MESSAGE="$SUBJECT"
                fi

                if [ -f /usr/bin/sendxmpp ]; then
                    # kill any existing message which hasn't sent
                    kill_sendxmpp_process
                    # send the xmpp notification using the temporary account
                    echo "${MESSAGE}" | /usr/bin/sendxmpp -u notification -p "${notification_user_password}" -j localhost -o ${local_domain} --message-type=headline -n -t -s ${PROJECT_NAME} ${USERNAME}@${local_domain}
                    hasSent=1
                fi
            fi
            # remove the temporary xmpp account
            prosodyctl deluser "notification@$local_domain"
        fi
    fi

    if [ -d /etc/matrix ]; then
        matrix_server_message "${USERNAME}" "${USERNAME}" "$MESSAGE"
        hasSent=1
    fi

    if [ ! "$hasSent" ]; then
        if [[ "$MY_EMAIL_ADDRESS" != "username@domain" ]]; then
            # send to a fixed email address for a single user instance
            echo "$MESSAGE" | /usr/bin/mail -s "$SUBJECT" "$MY_EMAIL_ADDRESS"
        fi
    fi
}

function notifications {
    # checks if DMs or replies have arrived and sends notifications to users
    if [ ! -f "$epicyonInstallDir/config.json" ]; then
        return
    fi

    if [ ! -f "${epicyonInstallDir}/config.json" ]; then
        return
    fi

    # shellcheck disable=SC2002
    EPICYON_DOMAIN_NAME=$(cat "${epicyonInstallDir}/config.json" | awk -F '"domain":' '{print $2}' | awk -F '"' '{print $2}')
    for d in ${epicyonInstallDir}/accounts/*/ ; do
        if [[ "$d" != *'@'* ]]; then
            continue
        fi
        epicyonDir="${d::-1}"
        USERNAME=$(echo "$epicyonDir" | awk -F '/' '{print $5}' | awk -F '@' '{print $1}')

        # send notifications for calendar events to XMPP/email users
        epicyonCalendarfile="$epicyonDir/.newCalendar"
        if [ -f "$epicyonCalendarfile" ]; then
            if ! grep -q "##sent##" "$epicyonCalendarfile"; then
                epicyonCalendarmessage=$(notification_translate_text 'Calendar')
                epicyonCalendarfileContent=$(echo "$epicyonCalendarmessage")" "$(cat "$epicyonCalendarfile")
                if [[ "$epicyonCalendarfileContent" == '/calendar'* ]]; then
                    epicyonCalendarmessage="Epicyon: ${EPICYON_DOMAIN_NAME}/users/${USERNAME}${epicyonCalendarfileContent}"
                fi
                sendNotification "$USERNAME" "Epicyon" "$epicyonCalendarmessage"
                echo "##sent##" >> "$epicyonCalendarfile"
                chown ${PROJECT_NAME}:${PROJECT_NAME} "$epicyonCalendarfile"
            fi
        fi

        # send notifications for DMs to XMPP/email users
        epicyonDMfile="$epicyonDir/.newDM"
        if [ -f "$epicyonDMfile" ]; then
            if ! grep -q "##sent##" "$epicyonDMfile"; then
                epicyonDMmessage=$(notification_translate_text 'DM')
                epicyonDMfileContent=$(echo "$epicyonDMmessage")" "$(cat "$epicyonDMfile")
                if [[ "$epicyonDMfileContent" == *':'* ]]; then
                    epicyonDMmessage="Epicyon: $epicyonDMfileContent"
                fi
                sendNotification "$USERNAME" "Epicyon" "$epicyonDMmessage"
                echo "##sent##" > "$epicyonDMfile"
                chown ${PROJECT_NAME}:${PROJECT_NAME} "$epicyonDMfile"
            fi
        fi

        # send notifications for likes to XMPP/email users
        epicyonLikeFile="$epicyonDir/.newLike"
        if [ -f "$epicyonLikeFile" ]; then
            if ! grep -q "##sent##" "$epicyonLikeFile"; then
                epicyonLikeMessage=$(notification_translate_text 'Liked by')
                epicyonLikeFileContent=$(cat "$epicyonLikeFile" | awk -F ' ' '{print $1}')" "$(echo "$epicyonLikeMessage")" "$(cat "$epicyonLikeFile" | awk -F ' ' '{print $2}')
                if [[ "$epicyonLikeFileContent" == *':'* ]]; then
                    epicyonLikeMessage="Epicyon: $epicyonLikeFileContent"
                fi
                "${PROJECT_NAME}-notification" -u "$USERNAME" -s "Epicyon" -m "$epicyonLikeMessage" --sensitive yes
                echo "##sent##" > "$epicyonLikeFile"
                chown ${PROJECT_NAME}:${PROJECT_NAME} "$epicyonLkeFile"
            fi
        fi

        # send notifications for replies to XMPP/email users
        epicyonReplyFile="$epicyonDir/.newReply"
        if [ -f "$epicyonReplyFile" ]; then
            if ! grep -q "##sent##" "$epicyonReplyFile"; then
                epicyonReplyMessage=$(notification_translate_text 'Replies')
                epicyonReplyFileContent=$(echo "$epicyonReplyMessage")" "$(cat "$epicyonReplyFile")
                if [[ "$epicyonReplyFileContent" == *':'* ]]; then
                    epicyonReplyMessage="Epicyon: $epicyonReplyFileContent"
                fi
                sendNotification "$USERNAME" "Epicyon" "$epicyonReplyMessage"
                echo "##sent##" > "$epicyonReplyFile"
                chown ${PROJECT_NAME}:${PROJECT_NAME} "$epicyonReplyFile"
            fi
        fi

        # send notifications for git patches to XMPP/email users
        epicyonPatchFile="$epicyonDir/.newPatch"
        if [ -f "$epicyonPatchFile" ]; then
            if [ -f "${epicyonPatchFile}Content" ]; then
                if ! grep -q "##sent##" "$epicyonPatchFile"; then
                    epicyonPatchMessage=$(cat "$epicyonPatchFile")
                    if [ "$epicyonPatchMessage" ]; then
                        # notify the member
                        sendNotification "$USERNAME" "Epicyon" "$epicyonPatchMessage"
                        echo "##sent##" > "$epicyonPatchFile"
                        chown ${PROJECT_NAME}:${PROJECT_NAME} "$epicyonPatchFile"
                        # send the patch to them by email
                        cat "${epicyonPatchFile}Content" | mail -s "[Epicyon] $epicyonPatchMessage" "${USERNAME}@${HOSTNAME}"
                        rm "${epicyonPatchFile}Content"
                    fi
                fi
            fi
        fi

        # send notifications for new shared items to XMPP/email users
        epicyonShareFile="$epicyonDir/.newShare"
        if [ -f "$epicyonShareFile" ]; then
            if ! grep -q "##sent##" "$epicyonShareFile"; then
                epicyonShareMessage=$(notification_translate_text 'Shares')
                epicyonShareFileContent=$(echo "$epicyonShareMessage")" "$(cat "$epicyonShareFile")
                if [[ "$epicyonShareFileContent" == *':'* ]]; then
                    epicyonShareMessage="Epicyon: $epicyonShareFileContent"
                fi
                sendNotification "$USERNAME" "Epicyon" "$epicyonShareMessage"
                echo "##sent##" > "$epicyonShareFile"
                chown ${PROJECT_NAME}:${PROJECT_NAME} "$epicyonShareFile"
            fi
        fi

        # send notifications for follow requests to XMPP/email users
        epicyonFollowFile="$epicyonDir/followrequests.txt"
        epicyonFollowNotificationsFile="$epicyonDir/follownotifications.txt"
        if [ -f "$epicyonFollowFile" ]; then
            if [ -s "$epicyonFollowFile" ]; then
                epicyonNotify=
                if [ -f "$epicyonFollowNotificationsFile" ]; then
                    hash1=$(sha256sum "$epicyonFollowFile" | awk -F ' ' '{print $1}')
                    hash2=$(sha256sum "$epicyonFollowNotificationsFile" | awk -F ' ' '{print $1}')
                    if [[ "$hash1" != "$hash2" ]]; then
                        epicyonNotify=1
                    fi
                else
                    epicyonNotify=1
                fi
                if [ $epicyonNotify ]; then
                    cp "$epicyonFollowFile" "$epicyonFollowNotificationsFile"
                    chown ${PROJECT_NAME}:${PROJECT_NAME} "$epicyonFollowNotificationsFile"

                    epicyonFollowMessage=$(notification_translate_text 'Approve follower requests')" ${EPICYON_DOMAIN_NAME}/users/${USERNAME}/followers"
                    sendNotification "$USERNAME" "Epicyon" "$epicyonFollowMessage"
                fi
            fi
        fi
    done
}

notifications